Citation
Cost Impacts of Acoustic Changes at Different Phases of an Office Buildings Service Life

Material Information

Title:
Cost Impacts of Acoustic Changes at Different Phases of an Office Buildings Service Life
Creator:
Garcia, Claudia
Place of Publication:
[Gainesville, Fla.]
Publisher:
University of Florida
Publication Date:
Language:
english
Physical Description:
1 online resource (120 p.)

Thesis/Dissertation Information

Degree:
Master's ( M.S.B.C.)
Degree Grantor:
University of Florida
Degree Disciplines:
Building Construction
Committee Chair:
Sullivan, James
Committee Co-Chair:
Kibert, Charles J
Committee Members:
Chini, Abdol R
Graduation Date:
8/11/2012

Subjects

Subjects / Keywords:
Acoustic noise ( jstor )
Buildings ( jstor )
Ceilings ( jstor )
Construction costs ( jstor )
Gypsum ( jstor )
Insulation ( jstor )
Offices ( jstor )
Sealants ( jstor )
Sound ( jstor )
Sound transmission ( jstor )
Building Construction -- Dissertations, Academic -- UF
acoustics -- building -- construction -- cost -- feasibility -- finishes -- noise -- sound -- sustainability
City of Gainesville ( local )
Genre:
Electronic Thesis or Dissertation
bibliography ( marcgt )
theses ( marcgt )
government publication (state, provincial, terriorial, dependent) ( marcgt )
Building Construction thesis, M.S.B.C.

Notes

Abstract:
Poor building acoustics have a marked effect on occupants’ productivity and workers’ health and safety. According to published research, over 70% of workers agree that productivity would increase if acoustic problems in their workplaces decreased. Unfortunately, acoustic comfort is an element of indoor environmental quality that often falls far down the list of priorities of owners and designers alike who wait until occupant discomfort is manifest to take action. Surprisingly, research to date has also found that buildings described as “sustainable” or “green” often perform even worse than their conventional counterparts when it comes to acoustic comfort. According to acoustical consultants, one of the biggest hurdles to overcome when trying to implement acoustics during the design phase of a building is the first costs associated with proper acoustical design. Because acoustics is somewhat difficult to explain and its impact in health and productivity is hard to measure, designers and consultants have a difficult time trying to “sell” acoustics. Additionally, most owners also have preconceived ideas about the cost of improving building acoustics which may be out of touch with reality. For this reason it was thought important to find out whether there is truth behind the common perception of acoustic conditioning being overly pricey, and whether making the decision after occupancy has any significant impact on costs. The overall aim of the research was to determine the economic feasibility of improved acoustical performance in office buildings. A case study of a LEED Gold building was selected and four costing scenarios were set up for comparison. The first three assessed the costs associated with the achievement of different levels of acoustic performance before construction, while the latter quantified the costs related to improving acoustic performance after occupancy. The results indicated an increase in total building cost of 0.78% to achieve high-level acoustics at the office areas (8,832 sf) before construction, and 1.27% after occupancy. The additional cost per square foot resulting from targeting high-level acoustics in office spaces was found to be $8.20 before construction, and $13.40 after occupancy. Several comparisons between the scenarios are discussed in the analysis. ( en )
General Note:
In the series University of Florida Digital Collections.
General Note:
Includes vita.
Bibliography:
Includes bibliographical references.
Source of Description:
Description based on online resource; title from PDF title page.
Source of Description:
This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Thesis:
Thesis (M.S.B.C.)--University of Florida, 2012.
Local:
Adviser: Sullivan, James.
Local:
Co-adviser: Kibert, Charles J.
Statement of Responsibility:
by Claudia Garcia.

Record Information

Source Institution:
UFRGP
Rights Management:
Copyright Garcia, Claudia. Permission granted to the University of Florida to digitize, archive and distribute this item for non-profit research and educational purposes. Any reuse of this item in excess of fair use or other copyright exemptions requires permission of the copyright holder.
Resource Identifier:
857767613 ( OCLC )
Classification:
LD1780 2012 ( lcc )

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1 COST IMPACTS OF ACOUSTIC CHANGES AT DIFFERENT PHASES OF AN OFFICE SERVICE LIFE By CLAUDIA GARCIA A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN BUILDING CONSTRUCTION UNIVERSITY OF FLORIDA 2012

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2 2012 Claudia Garcia

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3 To my mom and dad who are m y biggest source of inspiration

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4 ACKNOWLEDGMENTS First and foremost, I would like to give special thanks to Dr. Jim Sullivan : t hank you for your patience and for guiding me, believing in me and motivating me every step of the way. Thank you for all you have taught me during my time at the Rinker s chool, and for always being willing to o ff er me a helping hand. Also, my most sincere thanks go to Dr. Abdol Chini, who believed in me since the first day and who on that day gave me an opportunity that changed my life. Thank you for your help with this research and for your continuing support dur ing the last two years. I would like to thank Dr. Charles Kibert for his help during the research and for his valuable contributions to my formation as a sustainable construction professional : I look forward to implementing all of your teachings to make a real difference in the world. I would also like to thank Fran, Lyle and Bob Brambier for always giving me unconditional support an encouragement, for inspiring me to explore the world of acous tics, and for teaching me about the importance of details. I would like to thank my parents who have always pushed me in the direction of my dreams and who have set the most perfect example of what love and perseverance can achieve : you inspire me every s ingle day to be all that I can be. Thanks also to my roommate and dear friend Angie Trujillo for being my reality check in moments of high stress and for keeping me sane through grad uate school. Lastly, I want to give special thanks to the rest of Rinker f amily classmates, faculty and staff for making the last two years truly memorable for me.

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5 TABLE OF CONTENTS page ACKNOWLEDGMENTS ................................ ................................ ................................ .. 4 LIST OF TABLES ................................ ................................ ................................ ............ 8 LIST OF FIGURES ................................ ................................ ................................ .......... 9 LIST OF ABBREV IATIONS ................................ ................................ ........................... 10 ABSTRACT ................................ ................................ ................................ ................... 11 CHAPTER 1 INTRODUCTION ................................ ................................ ................................ .... 13 Backgr ound of Problem ................................ ................................ .......................... 13 Problem Statement ................................ ................................ ................................ 14 Research Aim and Objectives ................................ ................................ ................. 16 Aim ................................ ................................ ................................ ................... 16 Objectives ................................ ................................ ................................ ......... 16 Significance of the Study ................................ ................................ ........................ 16 Scope ................................ ................................ ................................ ...................... 17 2 LITERATURE REVIEW ................................ ................................ .......................... 19 Basic De finitions and Concepts ................................ ................................ .............. 19 Critical Issues in Building Acoustics ................................ ................................ ........ 22 Speech Intelligibility and Speech Privacy ................................ ......................... 23 Sound Absorption ................................ ................................ ............................. 24 Sound Transm ission ................................ ................................ ......................... 25 HVAC Noise ................................ ................................ ................................ ..... 26 Zoning ................................ ................................ ................................ .............. 26 Common Sources of Noise ................................ ................................ ..................... 27 Exterior Sources ................................ ................................ ............................... 27 Interior Sources ................................ ................................ ................................ 28 Strategies to Improve Acoustical Performance in Buildings ................................ .... 28 Sound Reduction ................................ ................................ .............................. 29 Sound Absorption ................................ ................................ ............................. 30 Sound Blocking ................................ ................................ ................................ 30 Sound Masking ................................ ................................ ................................ 31 Proper Space Planning ................................ ................................ .................... 32 Vibration Control ................................ ................................ ............................... 33 Reasons fo r the Common Disregard of Acoustics ................................ .................. 34 Rating Systems Criteria and Building Code Requirements ................................ ..... 36 Voluntary and References Standards ................................ ............................... 36

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6 Leadership in Energy and Environmental Design (LEED) ................................ 36 Green Globes ................................ ................................ ................................ ... 37 ANSI ................................ ................................ ................................ ................. 37 ASHRAE ................................ ................................ ................................ ........... 38 Mandatory Regulations and Building Codes ................................ ..................... 38 Building code ................................ ................................ ............................. 38 HIPAA and FGI ................................ ................................ .......................... 39 Dissatisfaction with Building Acoustics ................................ ................................ ... 40 Building Acoustics in Green Buildings ................................ ................................ .... 40 Effects of Poor Acoustics ................................ ................................ ........................ 42 Importance of the Implementation of Acoustics in Early Design Stages ................. 43 Acoustics and Integrated Design ................................ ................................ ............ 44 Modeling Tools for Aco ustics ................................ ................................ .................. 45 Current Research Addressing Acoustics in Offices ................................ ................ 47 3 METHODOLOGY ................................ ................................ ................................ ... 52 Strategies for Acoustical Improvement ................................ ................................ ... 53 Basic Scenario ................................ ................................ ................................ 54 Baseline Scenario ................................ ................................ ............................ 55 Improved Scenario ................................ ................................ ........................... 56 Additional layer of gypsum board ................................ ............................... 56 Additional sound insulation at walls ................................ ........................... 57 Full height walls ................................ ................................ ......................... 57 Sound attenuation batt throughout ceilings ................................ ................ 57 High performance acoustical ceiling tile ................................ ..................... 58 Absorptive panels ................................ ................................ ...................... 58 Absorptive duct lining ................................ ................................ ................. 59 Retrofit Scenario ................................ ................................ ............................... 60 Quantity Takeoff ................................ ................................ ................................ ..... 61 Costs and Co mparisons ................................ ................................ .......................... 61 Basic Scenario ................................ ................................ ................................ 62 Baseline Scenario ................................ ................................ ............................ 62 Improved Scenario ................................ ................................ ........................... 63 Retrofit Scenario ................................ ................................ ............................... 63 4 RESULTS AND ANALYSIS ................................ ................................ .................... 70 5 CONCLUSIONS AND RECOMMENDATIONS ................................ ....................... 83 Conclusions ................................ ................................ ................................ ............ 83 Recommendations for Further Study ................................ ................................ ...... 84 APPENDIX A PARTITION LIST AND DETAILS FOR BASELINE SCENARIO ............................. 86 B APPROXIMATE SQUARE FOOTAGE OF EACH AREA ................................ ........ 88

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7 C BREAKDOWN OF COSTS FOR EACH SCENARIO, OFFICE AREAS ONLY ....... 89 D BREAKDOWN OF COSTS FOR EACH SCENARIO, ALL AREAS ........................ 92 E QUANTITY TAKEOFF FOR ALL SCENARIOS ................................ ...................... 95 F RECOMMENDED STC RATINGS BY ANSI S12.60 2002 ................................ ... 115 G RECOMMENDED STC RATINGS FOR COMPLIANCE WITH HIPAA ................. 116 LIST OF REFERENCES ................................ ................................ ............................. 117 BIOGRAPH ICAL SKETCH ................................ ................................ .......................... 120

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8 LIST OF TABLES Table page 2 1 Effects of the Sound Tr ansmission Class (STC) rating on sound transmission through a building element. ................................ ................................ ................ 49 3 1 Acoustical strategies implemented for each cost scenario ................................ 65 4 1 Total costs for each scenario ................................ ................................ .............. 78 4 2 Additional costs per square foot for each scenario ................................ ............. 78 4 3 Additional costs for each scenario: private offices ................................ .............. 78 4 4 Additional costs for each scenario: shared offices ................................ .............. 78 4 5 Additional costs for each scenario: conf erence rooms ................................ ....... 78 4 6 design ................................ ................................ ................................ ................. 79 4 7 Additional investment required for strategy implementation ............................... 79

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9 LIST OF FIGURES Figure page 2 1 Common flanking paths used by sound to travel through office spaces ............. 50 2 2 Conventional design team organization ................................ .............................. 50 2 3 Integrated design team organization ................................ ................................ .. 51 3 1 Flow chart depicting the steps followed in the methodology. .............................. 66 3 2 Location of full ceiling, baseline scenario. ................................ ................................ .................. 67 3 3 Location of walls with sound attenuation batt included in the cavity as compared to those that do not have any sound insulation, baseline scen ario. ... 67 3 4 Location of sound insulation at ceilings, baseline scenario. ............................... 68 3 5 Location of walls with one additional layer of gypsum board added to one side, improved and retrofit scenarios. ................................ ................................ 68 3 6 Location of absorptive panels in the main corridor, improved and retrofit scenarios. ................................ ................................ ................................ ........... 69 4 1 Additional costs for improved acoustics at private offices ................................ ... 80 4 2 Additional costs for improved acoustics at shared offices ................................ .. 80 4 3 Additional costs for improved acoustics at conference rooms ............................ 81 4 4 Distribution of additional costs per strategy, for each scenario ........................... 81 4 5 Total costs for ea ch scenario, for offices and all areas. ................................ ...... 82

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10 LIST OF ABBREVIATION S AC Articulation Class AI Articulation Index ANSI American National Standards Institute ASA Acoustical Society of America ASHRAE American Society of Heating, Refrigerating and Air c onditioning Engineers CAC Ceiling Attenuation Class dB Decibels dBA A weighted decibels FGI Facility Guidelines Institute GBI Green Building Initiative HIPAA Health In surance Portability and Accountability Act HVAC Heating Ventilation and Air Conditioning IAQ Indoor Air Quality IEQ Indoor Environmental Quality IIC Impact Insulation Class LEED Leadership in Energy and Environmental Design NRC Noise Reduction Coefficient OITC Outdooor Indoor Transmission Class RC Room Criteria RT Reverberation Time SII Speech Intelligibility Index STC Sound Transmission Class USGBC United States Green Building Council

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11 Abstract of Thesis Presented to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Master of Science in Building Construction COST IMPACTS OF ACOUSTIC CHANGES AT DIFFERENT PHASES OF AN OFFICE BUILDING SERVICE LIFE By Claudia Garcia August 2012 Chair: James Sullivan C o chair: Charles Kibert Major: Building Construction P oor building acoustics have a marked productivity and According to published research, over 70% of workers agree that productivity wo uld increase if acoustic problems in their workplaces decreased. Unfortunately, a coustic comfort is a n element of indoor environmental quality that often falls far down the list of priorities of owners and designers alike who wait until occupant discomfort is manifest to take action. Surprisingly, research to date has also found that often perform even worse than their conventional counterparts when it comes to acoustic comfort According to acoustical consultants, one of t he biggest hurdle s to overcome when trying to implement acoustic s during the design phase of a building is the first costs associated with proper acoustical design. B ecause acoustics is somewhat difficult to exp lain and its impact in health and productivity is hard to measure, designers and have preconceived ideas about the cost of improving building acoustics which may b e out of touch with reality. For this reason it was thought important to find out whether

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12 there is truth behind the common perception of acoustic conditioning being overly pricey and whether making the dec ision after occupan cy has any significant impact o n costs The overall aim of the research was to determine the economic feasibility of improved acoustical performance in office buildings. A case study of a LEED G old building was selected and f our costing scenar ios were set up for comparison. The first three assessed the costs associated with the achievement of different levels of acoustic performance before construction, while the latter quantified the costs related to improving acoustic performance after occupancy. The results indicated a n increase in total building cost of 0.78% to achieve high level acoustics at the office areas (8,832 sf) before construction and 1.27% after occupancy. The additional cost per square foot resulting from targeting high level acoustics in office spaces was found to be $ 8.20 before construction and $ 13.40 after occupancy. Several comparisons between the scenarios are discussed in the analysis.

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13 CHAPTER 1 INTRODUCTION Background of Problem Space comfort is considered one of the most important factors determining human productivity. It covers elements such as thermal comfort, lighting quality, availability of daylight, and acoustic comfort. Of these the fir st three have gained ground as important design factors in recent years a direct result of the exponential increase in the constructio n of high performance buildings and the continued adoption of voluntary rating systems such as the United Stated Green Ener g y and Environmental Design ( LEED ) and Green Globes building certification s Unfortunately acoustic comfort still falls far down the list of priorities of owners and designers ali ke who often wait until occupant discomfort is manifest to take action. Moreover the disparity in weight given to acoustic comfort relative to the other elements of space comfort is also reflected in its reduced role in the current LEED rating system s : the only rating systems wh ich specify acoustic criteria and award points specifically for acoustical performance are LEED for Schools and LEED for Healthcare The premise is that, because of their use, these two kinds of facilities warrant a more detailed consideration of acoustics in one the main concern being the ability of children to learn, in the other the privacy of patients. While there certainly are additional concerns with schools and hospitals, acoustic problems affect occupants of all buildin gs, regardless of use O ffice s are a case in point: 70% of office workers believe that productivity would increase if distracting noise in their workspaces decreased (Carsia 2002) A number of studies have fi ndings, elaborating on different acoustic problems of office s specifically highlighting

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14 the issues posed by a widely used layout the open (Jensen, Arens & Zagreus 2005) ; (Lee 2010) ; (Lee & Guerin 2010) ; (Mahbub, Kua & Lee 2010) ; (Pop & Rindel 2005) ; (Carsia 2002) Most of the researchers agree that the main concern s in offices are speech privacy and disturbing noise from adjacent spaces both of which have a marked impact in productivity But poor building acoustics not only have a ty by causing environmental stress, which is in turn tied to problems such as high blood pressure, headaches, hypertension, ulcers, and digestive disorders. Lastly, it is also well known that noise can have ecological impacts beyond the human species playing a role in disrupting the life and activity patterns of wildlife species. Problem Statement Research su ggest s that building acoustics p lay a very important role in the productivity and health of occupants, particularly in commercial and office space s where people tend to spend long periods of time exposed to the same acoustic environment while performing tasks that require high levels of concentration and social interaction Even though acoustical performance may be difficult to assess by an untraine d ear, the constant exposure to poor acoustic conditions has made office employees the ideal subject s for of satisfaction with acoustic comfort (2) identify sources of problems, and (3) pinpoint impact s that perhaps ha d not been considered before. The result s of most studies reveal that even though a big percentage of office workers complain about workplace acoustics, most owners, designers, and even business executives are not concerned or even aware of the magnitude of the problem. Interestingly, research also shows that in high performance green office buildings where more emphasis is put on indoor environmental quality and

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15 individual user control the level of satisfaction with acoustics is often less than that at the conventional counterparts (Lee 2010) There are a number of reasons why acoustics are often neglected in offices and other commercial buildings: the code requirements are minimal and the associated LEED rati n g systems do not provide any acoustical criteria acoustics is a quality of space that is hard to grasp and measure, there is the perception that improved acoustics are only a concern in acoustically practice room and owners believe the cost will be prohibitive. According to most acoustical consultants (Lucky Tsaih, pers.comm.) one of t he biggest hurdle s seems to be the first cost s associated with proper acoustical design Owners want to justify the use of every dollar invested in a project, but because acoustics is somewhat difficult to explain and its impact on health and productivity is acoustics. Additionally, m ost owners also have preconceived ideas about the cost of improving building acoustics (assuming it to be very high), and therefore do not explicitly make it a part of their requirements for the design of the building Thus, it results imperative to find out w hether there is truth behind the common perception of acoustic conditioning being overly pricey. Acoustics should be regarded as having an integral role in the sustainable design of buildings, a concept that should be expanded to consider human efficiency (p roductivity), health and safety, occupant comfort, functionality, and the overall impact of noise pollution in all types of spaces (restaurants, lobbies, libraries, medical offices, schools and airports, to name a few).

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16 Research Aim and Objectives Aim The aim of the research was to determine the economic feasibility of improved acoustical performance in office buildings. In order to reach this aim, the researcher initially posed the following questions regarding product selection, acoustical contracting and cost: Which acoustical products or finishes are chosen most often? W hat are the real costs associated with improved acoustical performance ? H ow can these costs change when integrated design is used ? W hat percentage of the contract should be assigned to acoustics? These questions served to frame the issues to address as part of the literature review and they were also important points of discussion when speaking with the acoustical professional s consulted during the course of the research. Objectives In order to organize the steps to reach the aim specific research objectives were formulated. They can be described as follows: 1. To review the importance of acoustics as an integral part of indoor environmental quality in offices 2. To review acoustical per formance as addressed by the different sustainable rating systems. 3. To i dentify the different performance options available to designers and owners who implement acoustics before construction versus those who decide to improve acoustical performance as ret rofit after occupancy. 4. To i dentify the costs a ssociated with the selection of the different alternatives. Significance of the Study Most research related to acoustics in offices and commercial buildings has focused on finding the level of satisfaction of o ccupants with the acoustic conditions of

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17 their work environment, assessing the acoustic performance of high performance green buildings, and identifying the differences between the various rating systems and standards in terms of their inclusion or exclusi on of acoustic criteria. Furthermore, it is widely supported by researchers that good building acoustics increases productivity and decreases stress However, although most industry professionals claim that the additional cost of improved acoustics is argu ably the biggest reason behind its exclusion from the typical building design process particularly office buildings the actual percentage of the total budget that should be assigned for acoustics is often unknown or overestimated No research completed to date has attempted to provide a realistic idea of the cost of integrating good acoustics in to a commercial or office building. In order for owners and companies to make the right decision for the productivity and well being of thei r employees, a study dollar amount w ill undoubtedly be very helpful in making the best possible decision. Scope The scope and limits of the research are as follows: 1. The study focus e s on one building type ( office/commercial building ) 2. The third floor of Rinker Hall, a University of Florida building, was used as case study and established a s a base for determining design options and costs. 3. The study evaluate s the costs specifically associated with acoustics It d oes so by using four scenarios: no acoustic considerations, current level of acoustical performance, improved level of acoustical performance before construction and enhanced acoustics during retrofit. 4. The study is limited to the walls and ceilings. Floors and oth er finishes are not considered in the acoustical strategies. 5. Only interior sources of noise were addressed, specifically targeting the issues of speech privacy, sound transmission, and noise reduction. The study excludes any acoustic considerations for ext erior walls and exterior windows.

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18 6. Cubicle partitions were excluded from the study, as they were installed after occupancy. 7. There exists a wide variety of acoustical products available, but for reasons of simplicity, only a limited range was evaluated for t he case study. The alternatives provided through this research, as well as their cost were arrived at through extensive review of the literature and in collaboration with four acoustical experts 8. Redesign of the mechanical ductwork layout and substitution of mechanical equipment for acoustical reasons were not considered as alternatives, as th is would have significantly increased the complexity of the research

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19 CHAPTER 2 LITERATURE REVIEW Th e li terature review provides a brief overview of the extensive world of acoustics, focusing primarily on building acoustics specifically the elements which are critical to office and commercial buildings It attempts to give the reader an initial understandi ng of the complex issues involve d, explain the importance of good acoustics and its impact on people, and expand on the need for a whole building approach or integrated design in order to achieve proper acoustical performance Furthermore, it addresses th e reduced role of acoustics in building codes, regulations and voluntary standards, the common reasons associated with its neglect as a design criterion, and the general feelings of dissatisfaction with acoustics as assessed by several studies. T he literature review also discusses the common disparity between sustainable building projects and projects that integrate proper acoustical design. A brief section is dedicated to modeling tools available to acousticians as their increased use can have a positive impact in the improvement of acoustic performance in buildings. Basic Definitions and Concepts The easiest way to think about sound is as a kind of energy. This type of energy can be understood and expressed as pressure variations in air, which m eans that everything a person hear s is actually an arrangement of chang es in frequency (pitch) and intensity (volume) in a number of pressure waves (Yost 2001) Another way of understanding sound is as a vibration in an elastic medium such as air, water, most building materials, and the earth. Sound can be examined from two angles: a positive angle and a negative angle. The positive includes, for example, the study of music or acoustics in an auditorium

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20 where the attempt is to improve the quality and clarity of the sound. The negative angle is related to disturbing sounds which interfere with people live s cause annoyance, and reduce productivity. T he main purpose of studying sound from this angle is to find ways to reduce no ise. In general, controlling noise is achieved by proper space planning, impact noise and vibration control, and airborne noise control (Egan 2007) Noise, from the Latin word nausea disgust, annoyance, discomf ort and it is defined as unwanted sound coming from internal or external sources. In terms of its relationship with sound, it can be said that t he measurement of noise is largely a subjective measurement of sound related to auditory perception (Yost 2001) That measure is often expressed in decibels (dB) the unit commonly associated with the volume of a sound. Depending on the range of the frequency under study (since human ears are more sensitive to certain frequen associated with the decibels to denote the type of measurement. The most commonly used filter dBA weighted decibels, and it covers the range that includes human speech (Egan 2007) Other units which are commonly used to measure sound ( and thus the acoustic performance of materials and construction assemblies in building spaces ) are: The Sound Transmission Class (STC) rating used to measure airborne sound i nsulation performance I t relates to privacy between adjacent spaces and sound infiltration from the outside best expresses the transmission loss in decibels through a panel or material the higher the number, the more sound the panel blocks. An STC of 25 for a panel or partition (reducing sound transmission by 25 dB) would permit ordinary conversation to be understood through the barrier; an STC of 50 would stop all but (Yost 2001) STC is an importan t criterion for the selection of i nterior partitions, exterior walls and window assemblies, and its practicality is derived from the fact that it takes into account multiple parameters such as the frequ ency range (low, mid and high), tonality and others T able 2 1 at the end of this chapter

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21 shows the effects of different STC ratings in the perception of sound transmission through a building element (Kibert n.d.) The Noi se absorb sound or reflect it back into the surrounding space. This rating is particularly important for rooms and spaces in which speech intelligibility is important, such as classrooms, le cture halls, performance facilities, etc. The NRC rating for any given material goes from zero to one ; the higher the number, the more absorptive the material ( i.e. an NRC of zero describes a perfectly reflective material, while an NRC describes a perfectl y absorptive material ) An important aspect of NRC and STC is understanding that sound absorption is not always corr elated with sound transmission, that is, an absorptive material may have poor sound transmission qualities. The NRC is often used together w ith Ceiling Attenuation Class (CAC) and Articulation Class (AC) to compare among different ceiling and wall covering products (USG Corporation 2009) Reverberation Time is another important description of the acoustic environme nt of a space, and a factor which is closely related to speech intelligibility. It is a measure of the time in seconds it takes for a sound to decay 60 decibels (Kibert n.d.), and it depends mainly on the size of a space and the ratio of reflective to abso rptive surfaces. In enclosed spaces where most surfaces are hard, smooth and rigid, sound has the ability to bounce from one surface to another, and so each sound emitted tends to blend with the next. Conversely, spaces which contain rough, porous or perfo sound to be heard clearly, uninterruptedly. A long reverberation time may be to blend together for the creation of beautifu l symphonies, while short be highly intelligible (such as the university auditorium in the example described before). It is for this reason that both mandatory and voluntary bu ilding standards for schools specify maximum reverberation times for learning spaces (USGBC 2009). Articulation Index (AI) (also referred to as Speech Intelligibility Index or SII) is a measure of speech intelligibility in a room (Yost 2001) Similarly to STC, it takes into account several elements contributing to overall speech clarity (ceiling and wall assemblies, background noise, etc.) Room Criteria (RC) assesses background noise leve ls resulting from HVAC system components, general outside noise, and other sources. The relevance of this criterion is that, while too much background noise is disturbing and reduces productivity, there is a minimum optimal level which is necessary for gen eral speech privacy particularly in open plan offices where an RC rating of 35 to 45 would suffice for general speech privacy.

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22 These ratings and measures are the most commonly used, however, depending on the specific acoustic application there may be oth er units and forms of assessment (e.g. Ceiling Attenuation Class or CAC for acoustical ceilings) Critical Issues in Building Acoustics Many studies completed to date have focused on the assessment of space comfort and indoor environmental quality as perc eived by office building occupants. Of these, a rguably the most commonly referenced is the one published in 2005 as a collaboration between the Technical University of Denmark and the University of California Berkeley. In this study, Jensen, Arens and Zagr eus surveyed a total of 23,450 occupants of 142 commercial and office buildings in an attempt to gain an understanding of their relative satisfaction with some of the elements affecting space comfort (e.g. office layout, office furnishings, thermal comfort air quality, lighting, acoustics, cleanliness and maintenance, among others). The results of the study very clearly indicated that most respondents were dissatisfied with acoustics The main lack of speech privacy ; more than half felt that poor acoustics interfered with their ability to correctly perform on the phone, people overhearing private conversa tions, and the sound of people (Jensen, Arens & Zagreus 2005) Other studies have arrived at the same conclusion, citing noise as the greatest source of distraction for office workers, and speech privacy as the primary concern (Lee 2010) ; (Carsia 2002) In order to obtain an indoor environment that contributes to the health and productivity of the occupants, it is necessary t o pay a close look at acoustics and evaluate it from a holistic point of view. Nowhere does this hold truer than in office and

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23 commercial build ings, where many different elements such as the type of furniture, partition height and composition, space planning, ceiling height and material, wall treatment, shape and placement, the Heating Ventilation and Air Conditioning ( HVAC ) system and other mech anical systems need to work in concert to enable a company to save money while facilitating communication and encouraging work. Many aspects of acoustic comfort need to be accounted for if this kind of productive environment is desired, the most important ones will be described in the next section. Speech Intelligibility a nd Speech Privacy Since results of previous researchers have pointed to lack of speech privacy as the main disturbance to office building occupants, it seems logical to begin with this cr iterion as a main design concern. Acoustically speaking, there exist a wide variety of spaces which require an array of different acoustic treatments depending on their use. For example, speech intell igibility is the main concern for a large university aud itorium where dozens of students must have a clear auditory perception to understand what is being said, regardless of their distance and location in reference to the lecturer. In this case, the ability of sound to travel from the teaching area to the last seat at the back of the room is of main importance. Musical venues work in a similar way. In offices, however, keeping the sound from being transmitted far away from its source is much more of a concern than is speech intelligibility. This is given by the fact that people in offices are usually not speaking to large audiences, in fact, they are often engaging in one on one conversations which should remain private they may be discussing potential clients, business leads, company finances, and the like Thus, designing for speech privacy is, in many cases, the opposite of designing for speech intelligibility

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24 Determining the uses of spaces early on, and designing for the proper acoustics for each is paramount to occupant satisfaction Sound Absorption E very time sound travels through space and bounces off a surface, a certain portion of its acoustical energy is lost through absorption (a result of surface friction which causes sound energy to transform into heat energy). This energy loss happens in two ways: (1) during the passage of the sound through air, and (2) when the sound comes in contact with an obstruction or membrane As was mentioned previously rough, porous and, particularly, perforated surfaces have a higher capacity for sound absorption th an do smooth, dense ones This is because more heat energy is dissipated as sound energy tries to pass through a perforation, or gets in contact with a porous surface (Egan 2007) Sound absorption is an important consideration when planning for enclosed spaces where speech must be clearly would represent an annoyance, and also for semi enclosed spaces such as office cubicles where the goal is to retain some of the sound energy within the boundaries of the partitions for reasons of privacy and noise control. A large part of choosing acoustical treatments and designing for acoustics in office buildings has to do with fine tuning the amount of absorptive surfaces where speech privacy would be compromised (especially in the case of open plan offices), and too few could result in a noisy environment where it would be nearly impossible to work. to absorb sound is given by its sound absorptio n coefficient which is a measure of the percent of sound that can be absorbed by the material. This number is often provided by manufacturers of acoustical finishes.

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25 Aside from the composition of finishes and surfaces in a space, sound absorption varies with the specific frequency of sounds and thickness of the material (i.e. thicker materials provide more bass sound absorption, while panel absorbers are more efficient at absorbing low pitch sounds ) and the size of the space also influences the ability o f single surfaces to absorb sound. Sound Transmission When it comes to the built environment, acousticians are concern ed with sound transmission through air (sound emitted and reflected within a room or space) a s well as sound transmission through solid materials (sound travel between adjacent rooms, or from the outside to the inside of the building) Interestingly, b oth s ound and vibration have the ability to travel easier from one solid material to another than from a solid material into the air so air gaps can in fact act as sound insulators if they are introduced properly Speech privacy as a function of sound transmission from one side of a wall to the other is recognized as the main acoustic concern in private or semi private offices, hospitals, court rooms, and other spaces where confidential matters are discussed. The pr oblem extends beyond speech privacy to include the transmission of not only words and conversations, but noise created by other sources such outside traffic equipment in the building, and other s which have a marked effect on worker productivity (Carsia 2002) Sound transmission is one of the largest acoustic problems in buildings because of the many paths that sound can use to travel through spaces; just as is the case with water, sound also travels through the weakest points so any unsealed joint or penetration can have consequences. Figure 2 1 at the end of the chapter shows the many different paths that sound can use to travel from one office space into another.

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26 HVAC Noise An internal source of noise, H eating, V entilation, and Air Conditioning (HVAC) systems can either improve or hinder the acoustic properties of a space. This is speech privacy (particularly in open plan offices), too much noi se by the HVAC system can result in annoyance to building occupants, affecting their ability to concentrate and thus reducing their productivity. The level of HVAC noise depends on the location of the system (emitter) in relation to the person (receiver), the velocity of the air traveling through the ducts, the presence of insulation on the ducts or a sealed plenum space, among others (Paradis 2010) Additionally, a poor layout of the HVAC system can also cancel the sound transmission rating of the partitions As one author states, locating air supplies or sound to pass directly from one room to another, negatin g the acoustical value of the (Paradis 2010) Zoning Zoning refers to the adjacencies of program within a building. Because acoustics are affected by so many different things, a ll of the concepts discussed before sh ould be for the different spaces in a building. For example, when planning for proper acoustics in an be held need to be placed away from public areas, unless proper sound insulation is present. Similarly, workspace and service or mechanical rooms should, as much as possible, be kept apart in order to reduce noise infiltration, reduce distractions, and imp rove productivity. In

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27 terms of exterior noise, if the potential for noise infiltration is high, the service areas may be located along the perimeter while the acoustically sensitive areas cluster at the core, for example (Kibert n.d. ) Common Sources of Noise There are many different sources of noise that can cause disturbance to a s occupants, some of which are exterior to the building and some which come from within. Evidently, the variety of factors involved in acoustic performance, as well as the diversity of the sources make of acoustics a topic that must be addressed in an integrated fashion. structural, envelope and mechanical systems, it is critical to assess acoustic (Mahbub, Kua & Lee 2010) Exterior Sources A good portion of e xterior sources of noise are regulated by public poli cy, which provides acoustic amenity criteria for various development uses and building types These sources are varied, and may include noise from outdoor recreational activities, transportation (e.g. cars, motorcycles, trains, aircraft overflights, highwa y noise, etc.), or air handling units and other exterior mounted mechanical equipment from the building under study or from neighboring buildings (Yost 2001) This begins to shed light over the relationship between sustainable development and e xterior noise control an aspect that also needs close consideration. For example, the control of external mechanical equipment plant noise propagation to surrounding areas can be achieved by suitable selection of equipment or the provision of no ise control measures both of which could be done at the project planning stage, mutually inclusive with non acoustic site planning

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28 considerations (Field 2008) Similarly, issues of site selection (sites close to industrial areas, highways, etc.) and urban planning (future development in neighboring space) will also play a part in the effect and mitigation of exterior noise. Interior Sources Interior sources of noise are just as varied as exterior ones, but planning for their mitigation can result much more difficult, especially if acoustical conditioning is needed after the building is constructed and occupied (remediation). Interior sources of noise in office buildings include ringing telephones, printers, copiers and other equipment, other miscellane ous sounds from adjacent rooms d ue to sound transmission issues and noise from the mechanical system ( the effect of whi ch may vary with equipment selection, air speed and system layout ). As was discussed previously, internal sound or noise transmission between rooms affects office building occupants in terms of presenting a distraction, but also in terms of speech privacy Strategies to Improve Acoustical Performance in Buildings As stated by Yost (Yost 2001) in order to improve the acoustic conditions of a building or space, we must consider the four basic principles of sound: Airborne sound energy d issipates rapidly over distance ( thus, distance may be the best sound insulator and the worst sound transmitter). Sound energy striking a surface can be reflected, absorbed or transmitted. Any sound energy not reflected is either absorbed or transm itted. Sounds that are forms of communication (such as speech, music or signals) are special forms of noise with elevated levels of distraction for a given level of sound energy (which means they have higher potential to distract building occupants as comp ared to other sounds with equal decibels).

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29 Very few sounds consist of a wave of single amplitude and frequency, most sounds and noise are an array of waves with many different amplitudes and frequencies. In order to arrive at strategies which successfully address the acoustic concerns of the building at hand, it is necessary to understand these principles and apply them correctly and in an integrated manner with the rest of the building systems. Broadly de fined, the strategies that arise from this process are: sound reduction, sound absorption, sound blocking, sound masking, proper space planning, and vibration control Sound Reduction Whenever practical, sound reduction is the most effective strategy for n oise control. It is based on a simple premise: the fewer the noise sources or the quieter they are the lower the impact. Sound reduction is usually achieved through a combination of factors, such as selecting better performing equipment and increasing th e distance from the source to the potential receivers Common measures suggested by the literature to achieve sound reduction are: U se of low noise fan and controlled air speed (Mahbub, Kua & Lee 2010) Design of the mechanical system so that airflow velocities in low pressure ductwork do not exceed 900 f/m in main duct trunk lines 700 f/m in branch ducts 400 f/m in final run outs and 1200 f/m in main vertical ducts in shafts (Green Building Initiative Inc. 2010) Use of cast iron pipe to mitigate waste water piping noise (Green Building Initiative, Inc. 2010) Installation of low noise ballasts in quiet areas and conference rooms (Green Buildin g Initiative, Inc. 2010) Design of the mechanical system to achieve maximum background noise leve l from the equipment of 40 45 dBA in private spaces (USGBC 2009)

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30 Sound Absorption A variety of materials may act as sound absorbers to reduce the level of noise in a building or space by allowing sound to penetrate them, then trapping the sound energy within their structure. In this manner, sound becomes a series of short, disconnected vibrations (Yost 2001) Some of the measures suggested by the literature to achieve sound absorption are: Installation of sound absorbing surfaces on both sides of walls; (Paradis 2010) ; (Yost 2001) Installation of floor ceiling assemblies with a minimum Impact Insulation Class (IIC) rating of 50 (Green Building Initiative, Inc. 2010) Proper room geometry design and installation of enough ab sorptive finishes to achieve maximum reverberation time of 0.6 seconds for areas under 10,000 cubic feet in volume when speech intelligibility is important (Green Building Initiative, Inc. 2010) Installation of ceiling tiles w ith a minimum NRC of 0.75, preferably 0.9 or higher (Paradis 2010) ; (Yost 2001) LEED 2009 for Schools recommends an NRC of 0.7 for the total ceiling area, excluding lights, diffusers and grilles. I nstallation of suspended light fixtures which incorporate acoustic absorptive materials, or placement of acoustically absorptive finishes in light shelves (Field 2008) Installation of sound attenuators and/or silencers in the mechanical system (Green Building Initiative, Inc. 2010) Installation of absorptive lining inside the ducts (Moore 2010) acoustically line d vents, or trickle vent attenuators (Field 2008) ; (Gierzak 2003) ; (Mahbub, Kua & Lee 2010) ; (Yost 2001) Sound Blocking A strategy often applied to reduce exposure to exterior noise sound blocking consists of placing physical barriers between areas of different uses. A common example of sound blocking is the placement of sound barriers along inter state highway s, especially in the presence of residential areas on either side Sound blocking

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31 works mainly by reflecting the sound energy ( sound barriers also absorb it, albeit to a lesser degree) thus keeping it away from the desired quiet areas. Measures to achieve sound blocking include: Con struction of full height walls which extend to the underside of the next floor above or roof deck (Jackie Drake, pers.comm.) ; (Green Building Initiative, Inc. 2010) ; (Paradis 2010) ; (Lucky Tsaih, pers.comm.); (Yost 2001) Application of acoustical sealant in all joints and penetrations along walls separating quiet areas from other areas (Jackie Drake, pers.comm.) ; (Green Building Initiative, Inc. 2010) ; (Yost 2001) Integration of office furniture and partitions that consist of opaque barriers at lower elevations, while using transparent materials such as glass above (Field 2008) ; (Fullerton 2009) Installation of 60 inch high minimum partitions/furniture in offices (Green Building Initiative, Inc. 2010) ; (Yost 2001) Insulat ion of partition cavities as a way to increase STC rating (Paradis 2010) Design ing for an STC rating of 45 for wall assemblies separating acoustically separated areas and corridors, stairs, offices, or conference rooms, and an STC rating of 50 for wall assemblies separating two acoustically separated areas (Green Building Initiative, Inc. 2010) In contrast LEED 2009 for Schools requires a minimum STC of 35 for partitions ( USGBC 2009) Selection of doors to quiet areas with an STC rating of 50, and exterior windows with an STC rating of 35 (Green Building Initiative, Inc. 2010) Use of a ducted air return system instead of plenum to avoid pr ivacy issues (Paradis 2010) Placement of sound attenuation boxes behind return grilles to reduce sound transmission without affecting airflow (Yost 2001) paths exist (Green Building Initiative, Inc. 2010) Sound Masking Sound masking addresses instances in buildings when ambient noise is so low that it becomes detrimental by: (1) reducing speech privacy, and (2) increasing

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32 interference from other office sounds. Most authors agree that sometimes there is not enough background noise to conceal most sounds, so the possibilities of distraction for any giv en sound (even those that normally are unnoticeable) become higher than normal (Field 2008) ; (Kibert n.d.) ; and (Paradis 2010) particularly in office environments. Sound masking improves acoustic conditions in these spaces by introducing a range of unobtrusive background sounds which are similar to blowing air (Tony Sola, pers.comm.) These are electronically generated and evenly distributed for any given area, and they c an even be adjusted depending on the needs for privacy (Paradis 2010) Yost expands on this, stating that w ithin a certain range, if the background level is raised with sound of particular quality intensity, frequency, and la ck of pattern the Masking systems are most often employed in office buildings to deal with the special (Yost 2001) Many authors agree that the target levels of Room Criteria to design for when implementing sound masking in open offices should be between 35 and 45 dba (Green Building Initiative, Inc. 2010) ; (Yost 2001) Proper Space Planning Program stacking, noise sensitivity, noise generation and privacy are some of the to achieve satisfacto ry acoustic results (Schuyler 2006) Proper space planning is a strategy that studies these issues to arrive at zoning and program adjacencies for the building. N ot only does proper planning reduce acoustic problems, it can als o decrease the excess materials being used in the building which is positive from an economic as

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33 well as an environmental standpoint. Chin space layouts can reduce wall and floor thickness, clearances for sound contr ol ceilings (Chin Quee n.d.) Good practices suggested by the literature to achieve s pace planning and avoid long term acoustical problems include: Location of acoustically separated areas awa y from noise producing areas or restrooms ( Lyle Brambier, pers.comm. ); (Green Building Initiative, Inc. 2010) Staggering of doors along rooms that are on the same corridor (Green Building Initiative, In c. 2010) ; (Paradis 2010) Location of mechanical rooms away from offices and conference rooms (Paradis 2010) Location of air supply or return registers far away from each other on opposite sides of a wall or partition in order to prevent sound transmission (Paradis 2010) Avoiding placement of pipe runs above quiet areas, except for t he sprinkler system (Green Building Initiative, Inc. 2010) Stagger ing of electrical outlets to avoid flanking paths in sound transmission (Yost 2001) Avoiding placement of lighting fixtures direct ly over partitions in open offices as they reflect sound to the adjacent cubicle (Paradis 2010) Location of copy machines and other noise producing equipment in separate rooms, away from offices (Paradi s 2010) Vibration Control Noise itself is not the only problem caused by poorly designed building acoustics. Impact noise (measured by the Impact Insulation Class or IIC) and vibration are also a large source of distraction for occupants of office bu ildings, and they are also related to the propagation of unwanted sound within a building. This includes impact noise and vibration from footfalls, chairs and other furniture scraping, rotating or reciprocating mechanical equipment which is not properly is olated from the building structure, and others. One way to apply this strategy is by using thick, res ilient finishes for hard floors

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34 and installing isolators between the structural floor and subfloor, however, because of possible floor level discontinuitie s, extra height and cost, this kind of work is rarely done in new buildings (Chin Quee n.d.) Other measures to address vibration control include: Installation of vibration isolators to avoid structure borne noise from fans and other powered HVAC equipment (Green Building Initiative, Inc. 2010) Installation of ducts which are supported on resilient mounts to isolate them from the structural system (Green Building Initiative, Inc. 2010) Reasons for the Common Disregard of Acoustics The existing literature provides hints about the reasons for the predominant neglect of the building design industry towards acoustics. First of all, a coustics is a quality of space th at is har d to grasp and measure T he causes and consequences of poor acoustics in a building are usually not understood well enough by owners and designers and, as a result, the acoustical issues normally do not get addressed or they get inadequatel y addressed (Jensen, Arens & Zagreus 2005) Second, because many of the benefits of improved acoustics (and, conversely, the consequences of poor acoustics) increased or decreased productivity and health, owners and designers tend to put their primary focus on overt functionality and economy (factors which can be easily measured, analyzed and compared) as opposed to integrating acoustics to project planning and design Unsurprisingly, research sho ws that for many different fields and industry types, elements affecting worker productivity often get undervalued and overlooked, lag ging behind in evolution, development and implementation when compared to those affecting cost, functionality or aesthetics (Jensen, Arens & Zagreus 2005) ; (Paradis 2010)

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35 Third particularly i n the case of offices and commercial buildings, t he code requirements and sustainable rating systems seem to also lag behind. Section 1207 of the Florida Building Code is the only part of the code addressing acoustics and it is very limited both in terms of the building sector (providing regulations only for residential buildings) as well as in terms of the acoustical i ssues being addressed by it only sound transmission and impact noise (Florida Building Code 2010) As for voluntary the associated LEED rating systems released to date for commercial and o ffice buildings do not provide any acoustical criteria for applicants to follow when designing the building Lastly, arguably the strongest reason for the disregard of building acoustics as an important design aspect is the o wners belie f that the cost of improved acoustics will be prohibitive. According to most researchers the biggest hurdle seems to be the first costs associated with proper acoustical design priority because it competes for limited project do llars with a number of other project goals, including: sustainable design/development, physical security, information (Paradis 2010) As a result, a general attitude has been established where improved acoustics are desirable and pursued only for spaces specifically designated by the owner as ; when a given percentage of the budget is assigned to acoustics, the type of space will determ ine the portion of the budget allocated. F or example, if a ceiling simply needs to close the plenum, without regard to acoustical performance, inexpensive grid and tile products are general ly (USG Corporation 2009)

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36 Rating Systems Criteria and Building Code Requirements As has been suggested throughout this paper, high performance green buildings which are designed with sustainable construction and operation goals in mind must account for acoustical considerations in order to properly address issues related to indoor environmental quality and occupant health. Evolving changes in standards, regulations, criteria and rating systems affec t indoor acoustics (Evans 2010) so it is important to k now the specific requirements or guidelines they cover. Voluntary and References Standards Voluntary and referenced standards that impact building acoustics include LEED, Green Globes, ANSI, and ASHRAE Leadership in Energy and Environmental Design (LEED) As of the latest release, there exist no specific acoustic requirements or criteria suggested under the LEED standards for most types of buildings, so acoustics and noise control points can only be earned throug h Innovation and Design credits T he only exc eption is the case of LEED for Schools and LEED for Healthcare (Evans 2010) ; (Evans & Himmel 2009) ; (Mahbub, Kua & Lee 2010) where acoustic criteria is included in the category of indoor environmental quality. Elements addressed by LEED for Schools at the prerequisite level consist of maximum background noise from HVAC systems, minimum reverberation time, and minimum NRC. For enhanced acoustical performance, the rating l ists additional criteria which require minimum STC ratings (USGBC 2009) In the case of hospitals, the concerns are different, and so is the focus of each of the credits. While there are no prerequisites for acoustical performance in LEED for Healthcare, o ne point can be earned for improved speech privacy (measured by the

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37 STC rating of the assemblies), and another for acoustical finishes and details and environmental noise (Evans 2010) ; (Evans & Himmel 2009) which addresses issues related to sound and vibration as well as average sound absorption for different functional spaces (e.g. atriums, patient rooms, and waiting areas). The acoustical criteria in LEED for H ealthcare are based on and run parallel to the Facility Guidelines Institute (FGI) interim guidelines on acoustics (Evans & Himmel 2009) Green Globes Another sustainable rating system for high performance green buildings whose influence is increasing is Green Globes. In contrast to LEED for New Construction and Major Renovations, Green Globes lists extensive parameters specific to acoustic comfort within their Indoor Environment category, going as far as to specify measures tha t focus specifically on zoning, transmission, vibration control, impact noise control, acoustic privacy, reverberation time and mechanical noise. A total of 22 points can be earned through implementation of improved acoustical design (Green Building Initiative, Inc. 2010) ANSI In 1998, the American National Standards Institute (ANSI) partnered with Acoustical Society of America (ASA) to develop a new standard that would help eliminate acoustical barriers t o learning in schools. The partnership resulted in the publishing and introduction in 2002 of the American National Standard S12.60 2002 (Evans & Him mel 2009) This standard is very important, as it establishes the baseline by which both LEED for Schools and Green Globes measure improved acoustical performance. The minimum STC ratings required by ANSI S12.60 2002 for assemblies

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38 that separate core learning space and ancillary spaces ( those where informal learning takes place) from other adjacent space s can be found in Appendix F. ASHRAE Published in 2009, t he American Society of Heating, Refrigerating and Air Conditioning Engineers ( ASHRAE ) 189.1 S tandard for the Design of High Performance Green Buildings Except Low Rise Residential is another standard published as a collaboration of differ ent institutes, including the United States Green Building Council (USGBC). It was designed to be adopted in bu ilding codes as mandatory in the future, and includes specific requirements for indoor environmental quality issues such as environmental tobacco smoke control, outdoor air delivery monitoring, thermal comfort, low emitting m aterials and acoustical control emitted by both interior and exterior sources. The acoustical criteria are based mainly on Outdoor Indoor Transmission Class (OITC) for all buildings types, and STC is, as in the case of other standards, limited to few building type uses that are consider ed acoustically sensitive (Evans 2010) Mandatory Regulations and Building Codes Similarly to voluntary standards, mandatory regulations that impact building acoustics are generally limited to residential and health care applications. A case in point is the 2010 Florida Building Code, the U.S. Health Insurance Portability and Accountability Act of 1995 (HIPAA) and the FGI. Building c ode The Interior Environment Section 1207 of the 2010 Florida Building Code applies floor/ceiling assemblies between adjacent dwelling units or between dwelling units and

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39 adjacent public areas such as halls, corridors, stairs, or service areas (Florida Building Code 2010) It provides requirements for airborne sound (measured as a function of the STC of wall, floor and ceiling assemblies), and structure borne sound (measur ed as function of the IIC of the assemblies). It is worth of notice that, s ince n o requirements are provided in the building code for any other building type, commercial and office buildings are not by law mandated to comply with any minimum acoustical per formance. HIPAA and FGI Standards and requirements for healthcare facilities are defined by the U.S. Health Insurance Portability and Accountability Act of 1995 ( HIPAA ) and the F acilities G uidelines I nstitute (FGI) The HIPAA was created from the premise t hat speech privacy in healthcare facilities must be protected, and adopts the related ANSI reference standard. The 2010 FGI Guidelines for Health Care Facilities is a document that provides comprehensive criteria for acoustics, speech privacy, sound system s and building vibration in all types of healthcare facilities (Evans & Himmel 2009) It has been adopted and enforced by regulation in building codes in 42 states, and it is also voluntarily used or referenced in other states, internationally, and as part of the sustainability rating systems such as LEED for Healthcare (Evans 2010) Since the HIPAA regulations are not quantitative, the American Institute of Architects (AIA) and the Academy of Architecture for Health (AAH) developed a quasi standard which is to be used as benchmark for sound transmission limitations in hospital design (Yantis 2006) The minimum STC ratings arrived at through this collaboration can be found in Appendix G.

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40 Dissatisfaction w ith Building Acoustics Numerous researchers have studied the acoustic performance of office buildings fr and most of them have found that acoustic comfort is the single most cited complaint re lated to indoor environmental quality (Jensen, Arens & Zagreus 2005) ; (Lee 2010) ; (Lee & Guerin 2010) ; (Mahbub, Kua & Lee 2010) ; (Paradis 2010) ; (Yost 2001) from a list of issues which include office layout, office furni shings, thermal comfort, air quality, lighting, acoustics and building cleanliness and maintenance Much of th e research was completed following the results obtained by Jensen, Arens and Zagreus (2005), study that used a very large sample size (23,450 respondents from more 142 buildings) to obtain values of high st atistical significance (p<0.01). The results from their study revealed that speech privacy and intermittent noise (such as telephones ringing) a re the mo st common reasons for dissatisfaction with acoustics in office buildings Other causes of dissatisfaction were irrelevant speech and equipment noise. Building Acoustics in Green Buildings Some sustainable design practices can introduce challenges to proper acoustic design while others may make acoustics work together to achieve more comprehensive sustainability goals (Fullerton 2009) ; (Paradis 2010) For example, sustainable strategies such as site s election based on development ratio of an area, extensive glazing for views and daylighting and operable windows for natural ventilation, or the use of radiant c eilings for space conditioning, may make the attainment of proper acoustics in a building more difficult (Field 2008) ; while the use of high light reflectance acoustical ceilings may in fact increase energy efficiency of a building (Bischel & Beakes 2008) The impact on acoustics usually depends on whether measurable

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41 aspects (e.g. energy efficiency ) are considered to have equal or higher importance when compared to soft human factors (e.g. productivity ), and whether the proper acoustic solutions are being considered from the beginning In the case of acoustics, comfortably acoustically, and therefore not fit for its purpose, is actually a sustainable (Fiel d 2008) After the study by Jensen, Arens and Zagreus (2005), s ubsequent researchers have begun look ing specifically at LEED certified buildings to assess whether the level of satisfaction with building acoustics varies from conventional to high perf ormance buildings the premise being that the latter should provide opportunities to design better workspaces, and hence an improvement in acoustics should be expected (c riteria used to assess acoustic quality included satisfaction with noise level, satisf action with speech ability to get a task done). It is important to note that t hese studies focused on office buildings which was very important because, among commerc ial projects seeking LEED certification, the largest segment is offices (Lee 2010) Surprisingly, it was found certified buildings were more satisfied with office furnishings, IAQ, and clea nliness and maintenance, but less satisfied with office layout, lighting and acoustic quality than the ones in non LEED (Lee 2010) ; (Paradis 2010) This stresses the fact that n ot only is there a big gap in proper acoustic design for office buildings, but high performance buildings ( which are supposed to excel in indoor environmental quality ) actually ha ve a worse acoustic performance when compared to their conventional counterparts.

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42 Effects of Poor Acoustics Depending on the range, frequency, and decibel level, noise and vibration have the potential to have marked effects on people and animals, including damage to hearing, impaired growth and development of babies and children, overall s tress and sleep disturbance, poor performance in school s and disruption of wildlife habitats (Yost 2001). In office buildings the biggest concern s are reduced productivity by distractions from work tasks, as well as increased stress F or example, n oise from HVAC, light and other sources can cause discomfort, annoyance and result in headaches and fatigue (Prakash 2005) increasing stress and reducing productivity Findings by the University of California Berk eley support this, as their results showed that over 60 percent of occupants in cubicles believe that poor acoustics interfere with their ability to get their job done (Jensen, Arens & Zagreus 2005) Similarly, another study fo und that 57% of workers reported that noises at their workplace had major impacts in their ability to concentrate (Mahbub, Kua & Lee 2010) R esearch suggests that occupants ability to hear other people talking on telephones o r talking in surrounding offices ar e the largest cause of annoyance and dissatisfaction. Interestingly, irrelevant speak or intermittent noise such as telephones authors attribute this to the information content of the noise that causes the distraction explaining that (Jensen, Arens & Zagreus 2005) Briefly stated, a constant, non information rich sound causes less distraction than one which is irregular and unintelligible

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43 Prakash (2005) points to studies where environmental str essors such as noise were found to be a cause for loss of motivation a both of which negatively affect normal learning and performance. Mahbub, Kua & Lee (2010) agree, citing numerous studies where noise was found to contribute to absenteeism, illness and staff turnover ; and where loud back ground noise was cause for distraction and other productivity losses. Importance of the Implementation of Acoustics in Early Design Stages Of primary importance in the proper acoustical design of a space o r building is t he i mplementation of a holistic stra tegy in the early stages of the design process. There are two main benefits to obtain from the early integration of acoustical consultants : (1) it can reduce cost and (2) it can serve as a way to evaluate the feasibility of the proposed building systems (Schuyler 2006) Additionally, it also helps the team think in an integrated, holistic manner, thus reducing disputes, misunderstandings and change orders and increasing occupant satisfaction Most acoustical problems have fea sible, cost effective solutions if they are addressed early on, as opposed to cases in which only widespread dissatisfaction and negative impacts trigger the implementation of the correct acoustical strategies (Schuyler 2006) This is because, a s is the case with many other building systems, it is likely that when acoustics are carefully thought out and designed for, the costs arising from the need for acoustic al retrofit (including demolition, loss of productive work days, etc. ) are avoided, so owners pay for acoustical conditioning of a space only once. Simil arly, successful acoustic al design at the planning or schematic phase provides the opportunity to evaluate the function of the spaces and their individual acoustic needs, and analyze and resolve any issues before they arise in a finished or

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44 constructed space At minimum, acoustic analysis and considerations at the early phases of the construction project make the owner aware of the acoustic conditions of the building as the y relate to building program. Acoustics and Integrated Design The importance of integrating acoustics into the design process using a holistic, whole building performance approach cannot be overemphasized. Several authors agree that most of the acoustic pr oblems in existing buildings result from the use of conventional design and construction practices where performance is analyzed looking at the different systems in isolation, as opposed to considering the synergies one system may have with another (Busby Perkins + Will 2007) ; (Field 2008) ; (Mahbub, Kua & Lee 2010) ; and (Larsson 2009) Using an integrated design approach ensures that factors such as cost, schedule, labor, equipment, access, aesthetics, maintenance and functionality are weighted appropriately in the selection of a n acoustical system or finish When using conventional design approaches, acoustical consultants are usually brough t into the project after the main parties (architect, mechanical engineers, structural engineers, civil engineers, landscape architects and interior designers) have developed the larger part of the design. By contrast, when using an integrated design appro ach, acoustic consultants are brought in during the design development phase and post occupancy A n example of the difference between a conventional linear design team organization versus an integrated design team organization can be found in Figure 2 2 a nd Figure 2 3 at the end of the chapter. Integrated approaches should be used in new construction projects as well as in retrofit projects of buildings with poor acoustic performance. While many authors

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45 describe the integrated design process for new construction, Mahbub, Kua & Lee (2009) offer a very good example of a total building performance approach for addressing and improving acoustics in existing office buildings In their case study, they assess a variety of as pects, including physiological, sociological, and economic needs. There are many benefits to reap fr om the use of integrated design to achieve improved acoustics in office buildings particularly for sustainable buildings : All members are committed to achieving the same goal. The multi disciplinary team inherent of an integrated design process gives the opportunity to arrive at new, innovative solutions to problems. Teamwork and collaboration are fostered, reducing adversarial relationships. All components of the buildings are considered and designed as a totality, not as isolated parts, so their effects on other building components and systems are accounted for. It makes it easier to achieve a green design due to the ra pid identification of synergies between systems, thus improving performance and re ducing costs of green buildings. Modeling Tools for Acoustics Several tools exist for modeling acoustics, most of which have been developed or have evolved in the last decades to become highly accurate prediction models The inputs which are generally requ ired for the use of most acoustic modeling tools are: (1) approximate room dimensions, (2) surface areas of walls and ceilings, and (3) acoustical system being used (e.g. acoustical tile ceilings and gypsum board walls) (Rindel & Chr istensen n.d.) ; (Lucky Tsaih, pers.comm.). One of the most advanced forms of acoustic modeling is auralization. Auralization (Vorlander 2008) In other words, auralization consists in expressing

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46 the numerical or analytical output of acoustical simulation in terms of sounds, where aspects such as loudness, timbre, roughness, sharpness, character or quality can be easi ly assessed. The premise behind it is simply that sound energy can be interpreted easier if it is made audible than made into it a list of numerical parameters and acoustical measures and ratings. Although most forms of acoustic simulation, including aur alization, were originally used for the design of highly acoustically sensitive spaces such as music rooms and auditoriums, researchers have found out that offices and workrooms may have problems which are equally challenging, so similar modeling technique s and analysis can be applied (Rindel & Christensen n.d.) In terms of computer modeling, some of the challenges presented by comm ercial and office buildings are: (1) spaces can be irregular; (2) diffusion of sound and noise sources can be uneven; (3) sound absorption can be very unevenly distributed; and (4) many acoustic factors need to be taken into account (reverberation time, so und transmission, speech privacy, etc). However, advanced modeling techniques such as auralization have been successfully used in the study of speech privacy and other acoustic concerns in offices (Rindel & Christensen n.d.) So me acoustical consultants use ODEON (Rindel & Christensen n.d.) INSUL (Insul n.d.) and V A Select to design for acoustics to assess acoustics in a n already built space. ODEON is a software develo ped in Denmark which provides reliable estimates of reverberation time noise mapping, and spatial sound decay rate, and it may even rank the most important sources of noise and allows for auralization, so it is particularly successful at analyzing complic ated room geometries (Rindel & Christensen

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47 n.d.) I n contrast, INSUL is able to predict the sound insulation (STC values) of walls, floors, ceilings and windows with great accuracy (within 3dB for most constructions), as it mode ls individual materials and thicknesses using elastic plate theory (Insul n.d.) Lastly, V A Select is a free software developed by Vibro Acoustics which analyzes the acoustic implications of HVAC systems thus, acoustical consultants use it mainly to address noise control concerns. Current Research Addressing Acoustics in Offices Most of the research published to date which focuses on the acoustic problems of offices has attempted to identify the correlation s between office layout and occupant satisfaction with acoustic and spatial comfort. The types of layout cited by most studies (i.e. enclosed private offices, enclosed shared offices, high cubicles, low cubicles, and open are based on an extensive p ost occupancy evaluation database for commercial buildings created and maintained by the Center for the Built Environment at the University of California Berkeley perception of indoor environmental quality related issues. As of 20 05, the sample surveyed included 142 buildings and 23,450 occupants (Jensen, Arens & Zagreus 2005) Through the analysis and careful examination of this and other data, researchers have made important findings, namely: Acoustic quality receives the lowest average satisfaction among all categories of indoor environmental quality, and most occupants attribute the lack of speech privacy to their dissatisfaction (Jensen, Arens & Zagreus 2005) Most offic e workers believe that acoustics interfere with their ability to get the job done (Paradis 2010)

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48 At least in LEED certified buildings, having cubicles or partitions does not seem to contribute to better acoustic solutions, whe ther the partition is low or high. The possible re asons for this are discussed by Lee (2010) In order to improve worker satisfaction, the selection of a given office layout needs to account for the need for privacy, interaction, and acoustic quality none of which are directly addressed in the LEED I ndoor E nvironmental Q uality (IEQ) category. Issues such as organizational culture, purpose of the organization, nature of the work, and seniority at work must also be weigh ed (Lee 2010) Significant c orrelations exist between overall noise and factors such as office conversation, air conditioner noise, noise in adjacent workstation s and noise due to activity in other floors (Mahbub Kua & Lee 2010) Over 30% of building occupants surveyed by Mahbub, Kua & Lee (2010) also reported disturbance in concentration and annoyance by noises during work hours. Open offices, which tend to have higher rates of spatial sound decay may yiel d higher speech privacy (Pop & Rindel 2005) Noise, even at low levels, is a known cause of stress (Carsia 2002) and when sound carries information the degree of distraction is higher (Jensen, Arens & Zagreus 2005) As can be seen by the listed summary of findings, most research a bout office building acoustics has aimed to find the specific reasons for occupant dissatisfaction, as well as the optimal office layout that will reduce acoustic problems and diminish impacts in health and productivity. However, no research to date has addressed the economic concerns of owners who, once made aware of the widespread dissatisfaction and effects on productivity, are left pondering about the cost of addressing these problems before construction or after occupancy.

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49 Table 2 1. Effects of the Sound Transmission Class ( STC ) rating on sound transmission through a building element (Kibert n.d.) STC Rating S ound Level 25 Normal speech can be understood quite easily and distinctly through the wall. 30 Loud speech can be understood fairly well, normal speech heard but not understood. 35 Loud speech audible but not intelligible. 40 Onset of" privacy." 42 Loud speech audible as a murmur. 45 Loud speech not clearly audible; 90% of statistical population not annoyed. 50 Very loud sounds such as musical instruments or stereo can be faintly heard; 99% of population not annoyed. 60+ Superior soundproofing; most sounds inaudible.

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50 Figure 2 1. Common flanking paths used by sound to travel through office spaces Figure 2 2 Conventional design team organization ( adapted from Busby Perkins+Will) Client Architect Contractor Mechanical Engineer Electrical Engineer Structural Engineer Civil Engineer Landscape Architect Specialists Specialists (ie. geothermal simulation) Specialists (ie. controls or technology experts ) Specialists (ie. seismic ) Specialists (ie. stormwater management ) Specialists (ie. ecologists) Specialists (ie. acoustics, daylighting)

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51 Figure 2 3 Integrated design team organization ( adapted from Busby Perkins+Will)

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52 CHAPTER 3 METHODOLOGY The primary objective of this research is to demonstrate that investing in good acoustics s design is favorable not only in terms of the health and comfort of the employees and other building occupants, but also as a smart economic decision for the owner. Implementation of ac oustics as a design criterion before constr uction can improve productivity and reduce liabilities, as well as decrease the total costs that owners and tenants must pay to achieve good indoor environmental quality and a true sustainable building. In ord er t o support this theory, a case study was selected and detailed cost analyses were completed which show approximate dollar amounts for implementation (or lack thereof) of acoustical strategies before and after construction, at the same time comparing it to the current conditions. The chosen case study is an existing building at the University of Florida campus in Gainesville: Rinker Hall. Th e building is a three story, 47,254 square feet LEED Gold facility built in 2003 for approximately $8 million; it houses the M.E. Rinker, Sr. Sch ool of Building Construction. The first two levels of Rinker Hall consist of classrooms primarily while the third floor is comprised of three specialized research centers, a s well as office space for faculty, graduate assis tants, staff and administration The author bounded the case study analysis to the third floor of the building due to the fact that classrooms and other spaces existing on the two bottom levels have different acoustic considerations which fall outside of t he scope of this research. For educational purposes, the entire set of construction documents (including construction drawings, specifications, and pictures of construction in progress) is made so background information and

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53 documentation used in the study w ere comprehensive, and gathered fairly easily during the beginning stages of the research. Using the third floor plan, all areas were separated and organized in seven categories based on program a nd acoustic al needs, namely: private offices, shared offices, conference rooms, vertical circulation, service areas, storage, and corridors. In order to make an assessment of the costs associated with improved acoustical performance when implemented at dif ferent stages (i.e. before construction, or after occupancy) four schemes were set up for the analysis. In the f irst scheme ( the case study was assumed to be constructed with no acoustic cons iderations at all. The second scenario was the and costs for this scheme were based on the design of the building as it currently stands ( where some degree of acoustic performance was considered ) T he third scenario involve d the co st s related to implementation of strategies to improve acoustical performance at the design phase, while addressed the costs of remediation or retrofit to improve acoustical performance after occupancy. A graphical representa tion of the steps fol lowed can be seen in Figure 3 1 at the end of this chapter Strategies for Acoustical Improvement The acoustical addressed two acoustical problems, speech privacy and noise control, and they were arrived at through: Recommendations suggested by the literature, Acoustical criteria described by L eadership in E nergy and E nvironmental D esign (LEED) rating system for Schools

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54 and the Green Building Initiative as guidelines for the Green Globes rating system (which are largely based on ANSI S12.60 2002) and Suggestions provided by two acoustical consultants and two members of the industry who work for acoustical subcontractors. Once a ll strategies and recommendations had been gathered from these sources, the impractical alternatives were eliminated and the strategies that were feasible (as well as those that could be most successful) given the specific conditions of the case study were selected for adoption. The following section describes the acoustic performance of the different scenarios. Basic Scenario The basic scenario does not contain any acoustic considerations for wall or ceiling construction. Walls were assumed to be construc the gypsum board finished ceiling, and no acoustical sealant is used. As a base for comparison, the Sound Transmission Class (STC) rating of these types of wall assemblies is 38 although flanking paths of sound transmission and air gaps caused by the lack of acoustical sealant and walls not extending full h eight might reduce this number by several points. Ceilings for this scenario are assumed to be made of gypsum board and metal studs, without any sound insulation or absorptive materials added, and no acoustical sealant placed in the assembly. The NRC of t hese types of ceilings ranges between 0.05 and 0.1.

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55 Baseline Scenario In the baseline scenario, the only acoustical strategies considered were the ones which are in place in the current design of the building. These were considerations made by the designer s to address mainly the issue of speech privacy at the third floor of Rinker Hall and, while they are not comprehensive, significant improvements in acoustic performance exist when compared to the basic scenario. Walls were assumed to be, per the plans an the ones separating shared offices, as we ll as those between offices and common areas, extend full height to the roof deck above. Sound insulation is placed inside of the wall assemblies surrounding most offices, except those of graduate assistants. Most other walls are constructed similarly, but without any sound insulation in the cavity. The approximate STC rating of the wa lls with insulation in the cavity is 47, while that of walls w ithout insulation is 38. Figure 3 2, Figure 3 3 and Figure 3 4 located at the end of the chapter show the location in plan of full height walls, walls with sound insulation, and ceilings with sound insulatio n in the baseline scenario. A detailed description of all interior walls and partitions can be found in Appendix A. acoustical ceiling tile, which is a product manufactured by Armstrong World Industries with an NRC rating of 0.7. The main corridor and other shared office areas have gypsum board ceilings, whose NRC rating is negligible since it ranges between 0.05

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56 and 0.1. Sound attenuation batt is placed above the ceiling assem blies on either side of the walls which separate private offices, but it only covers the perimeter area, extending three feet beyond the center of the wall. Improved Scenario The improved scenario built on the conditions of the baseline scenario, but assu med a better performance was designed for and acoustical strategies were implemented before construction. Thus, the specifics of the wall and ceiling assemblies are the same as in the baseline scenario, except for instances where the following acoustic str ategies were implemented: Additional layer of gypsum board Following the criteria provided by the Green Globes sustainable rating system, all walls separating two acoustically separated areas (e.g. meeting rooms, conference rooms, or private offices) shoul d have a minimum STC rating of 50 for the assembly (Green Building Initiative, Inc. 2010) Since the walls between all private offices and between a private office and a conference room had an STC rating of 47 in the baseline s cenario, an additional layer of gypsum board was added to these on the improved model in order to meet the Green Globes guidelines and improve acoustical performance as potential alternatives to improve the STC of the assemblies but their contribution to increasing the STC rating was insufficient to reach the desired goal of STC 50, and the foot of wall ). For this reason, the was seen as the most practical alternative Th e raises the STC

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57 rating to 52. Figure 3 5 shows the location in plan of all walls where the additional layer of gypsum board was added. Additional sound insulation at walls Following the criteria provided by the Green Globes sustainable rating system, all walls between acousticall y separated areas and corridors or stairs should have a minimum STC rating of 45 for the assembly (Green Building Initiative, Inc. 2010) In the n batt along the perimeter walls that separate them from the corridors. For this reason, sound insulation was added to these walls on the improved model in order to meet the Green Globes guidelines and improve acoustical performance. Th e implementation of this strategy raises the STC rating of those walls from 38 to 47. Full height walls Much of the literature as well as the consulted professionals reiterated the importance of extending all walls to the bottom of the floor or roof deck above in order to cr eate a physical barrier that prevents sound from traveling through the plenum from one room into the other (Jackie Drake, pers.comm.) ; (Tony Sola, pers.comm.); (Lucky Tsaih, pers.comm.) For this reason, all walls in the improved scenario are assumed to ex tend full height to the bottom of the roof deck. Sound attenuation batt throughout ceilings When plenum spaces are created by the installation of suspended ceiling systems such as the acoustical tile ceiling used in the baseline scenario, the space created by default is an echo chamber where sounds bounce off the different surfaces and are essentially magnified by the absence of absorptive finishes, thus greatly increasing the possibility of sound transmission between rooms (Jackie Drake, pers.comm.) Extending

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58 the sound attenuation batt to cover the entire plenum area above the acoustical tile ceilings (as opposed to just the perimeter of the dividing wall) decreases the possibilities of sound transmission. For this reason, sound insulation was added above all acoustical tile ceilings in the improved scenario, as compared to the baseline scenario where only 3 feet on either side of certain walls was considered. High performance acoustical ceiling tile Yost (2001) and Paradis (2010) suggest the impleme ntation of ceiling finishes with minimum NRC ratings of 0.75, and 0.9 preferably. The acoustical ceiling tile used in the rating of 0.7. Thus, in order to improve the aco ustical performance at the improved substituted by performance ceiling tile with an NRC of 0.9 resulting in a 20% improvement in sound absorption Absorptive panels Professionals consulted during the course of the research agreed that the current design of the main corridor was very poor in terms of acoustics (Lyle Brambier, pers. comm.); (Tony Sola, pers.comm.). This can be attributed to the peculiar shape of the hard ceilings in this space, where fun nel like shapes originating at the bottom of fourteen skylights create a perfect vehicle for the amplification of any sound albeit some frequencies a re more problematic than others This may be the cause behind longer reverberation times, increased noise levels at the corridor, and further noise intrusion into the adjacent office spaces at Rinker Hall. Aside from drastic measures such as completely changing the design of the ceiling and space, for noise control purposes the literature and industry professi onals advise an increase in absorptive surfaces. For this reason, all ceiling surfaces including the angled ceilings and the

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59 smaller walls at the base of the skylights were assumed to be covered with fixed, fabric wrapped acoustical panels which can signif icantly increase the NRC rating from 0.05 to 0.8 improving performance by 75% An illustration depicting the location of the panels is showed in Figure 3 6. Absorptive duct lining made sound t (Moore 2010) and th us, they can cause major problems with sound transmission across long distances and emphasiz e selected frequencies. As a solution, ducts can be lined along their inside faces in order to a ddress concerns related to noise from the mechanical system, and crosstalk issues w hen ducts run from one office to another. Most offices in the case study are arranged in sequence around the perimeter, and most ductwork runs longitudinally across the offi ces, thus causing problems with crosstalk. While a redesign of the HVAC system (including ductwork layout and HVAC equipment) could be ideal as a strategy before construction, for reasons of simplicity acoustic lining was chosen as a strategy. Thus, non f ibrous acoustic lining, resistant to moisture, bacterial and fungal growth was implemented as an acoustical strategy in the improved scenario by adding 6 feet of lining at every point of intersection of ductwork with a wall The application of this strateg y would reduce 1 decibel of sound transmitted per foot of lined duct (Tony Sola, pers.comm.). It is important to note that, while it was implemented theoretically in this case study this strategy actually may not have been feasible for application at Rink er Hal l This is because the University of Florida Construction Standards may not allow it in the design of (UF Facilities Planning and

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60 Construction 2011 ) Usually, the concern with having lining inside of the ductwork is that due to the hi gh velocity air running through there may be the potential that fibers may b ecome dislodged and airborne, thus compromising ind oor air quality (Moore 2010) Also, since the air in the ducts may also contain a variety of airborne microbes, there are also concerns about fungal growth, mold, etc. However, the s e only apply to fibrous forms of acoustical li ning, reason why non fibrou s lining, bacteria and moisture resistant liner was selected for implementation of this strategy. Retrofit Scenario The main objective behind the selection of strategies to adopt at the retrofit level was to achieve the same acou stic performance as in the improved scenario. While most of the measures adopted in both the improved and retrofit scenarios were the same, the duct lining strategy was not considered practical or feasible as a retrofit option, thus, a different alternativ e was added to compensate. The final selection for the retrofit scenario included: One additional layer of gypsum board for walls between two acoustically separated areas, similarly to the improved scenario. Additional sound insulation at the graduate improved scenario. Sound attenuation batt throughout the entire area above suspended ceiling systems, similarly to the improved scenario. larly to the improved scenario. Absorptive panels at the main corridor, similarly to the improved scenario. Sound masking system. Due to the variety of acoustic concerns in office buildings (e.g. speech privacy, reverberation time sound transmission, nois e control, etc.) it is suggested by the literature as well as by acoustical professionals that a sound masking system be installed in offices where multiple degrees of privacy and tolerance to noise are present (Tony Sola, pers.comm.) Thus, a sound maskin g

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61 system was implemented as a strategy for all private offices, shared offices, and conference rooms a way to mitigate distractions related to acoustics. Most of the strategies implemented for cost analysis addressed issues related to the office space cate gories (i.e. private offices, shared offices, and conference rooms), although all other spaces were also considered in an attempt to follow an integrated approach. Table 3 1 located at the end of the chapter summarizes the approaches taken for improving ac oustical performance for each cost scenario (i.e. basic, baseline, improved, and retrofit). Quantity Takeoff Once the strategies to adopt in each of the scenarios were sufficiently defined, they were carefully implemented using the construction documents i n both digital and printed format to ensure accuracy. Detailed quantity takeoffs were completed and organized using the seven program categories previously defined, and total amounts of material needed were calculated for the basic, baseline, improved and retrofit schemes. The complete takeoff can be found in Appendix E. Lastly, all costs per type of area as well as total costs for each scenario were calculated using RS Means Building Construction Cost Data 2012 and consulting with industry professionals. Costs and Comparisons The calculation, discussion and comparison of the costs incurred under each different scenario were approached in a detailed manner in order to be able to make accurate comparisons. The following section describes the elements include d in the cost calculation of each of the scenarios, as well as the way in which each was compared to the others.

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62 Basic Scenario The basic scenario included solely the minimal costs associated with materials, labor and equipment necessary to create the boun daries of the spaces (in the case of the walls), and to cover the mechanical equipment and plenum for aesthetic purposes (in the case of ceilings). This included gypsum board and metal studs for both the wall and hard ceiling assemblies. Scaffolding costs were considered negligible since it was assumed that, during the construction of a building, the scaffolding rental cost is normally carried by a larger trade, or divided among several smaller trades. The basic scenario itself was not compared to any other instead, it was simply used as reference for other scenarios. The premise behind this was that there is always a minimum cost for walls and ceilings which is independent of how much or if any consideration is given to acoustics. Thus, in order to make a fair assessment of the costs associated with enhanced acoustic al performance, other costs which are unrelated to the specific acoustical improvements (i.e. costs that would have to be incurred in any case) must be deducted. Given that the basic scenario did not include any acoustic considerations, it provided a way to establish a benchmark for the baseline, which in turn allowed for a fair comparison and determination of the amount invested strictly for acoustic purposes in the current design of the building. Baseline Scenario The baseline scenario included the costs for material, labor and equipment necessary to build the space as per the current design. This included the cost of gypsum board and metal studs for wall and ceiling assemblies, sound insulation,

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63 acoustical sealant, and suspended ceilings where applicable. As was the case in the basic scenario, scaffolding costs were considered negligible. The costs incurred by following the baseline scenario were compared to the basic scenario in order to obtain the dollar amount in vested specifically for acoustic considerations. Improved Scenario The improved scenario included the costs for material, labor and equipment necessary to achieve high acoustical performance and working spaces that promote health, privacy, comfort, and are free of distractions. The estimates included costs of gypsum board and metal studs for wall and ceiling assemblies, sound insulation for walls and ceilings, acoustical sealant, absorptive duct lining, absorptive wall and ceiling panels, and suspended ceil ings where applicable. Once again, scaffolding costs were considered negligible. The improved scenario was compared to the basic scenario to obtain the dollar amount that should have been invested in acoustics if proper acoustical performance is desired. I t was also compared to the baseline scenario to obtain an idea of the scale of the additional investment needed related to what is in place. Retrofit Scenario The retrofit scenario differed from the previous three in the fact that not only construction co sts were accounted for, but also other incidental costs resulting from demolition, replacement and others Total costs included material, labor and equipment needed to install additional layers of gypsum board and replace others where applicable, sound ins ulation for wall cavities as well as above suspended ceilings, acoustical sealant, absorptive wall and ceiling panels, suspended ceilings where

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64 applicable, and a sound masking system most of which were included in the costs for the improved scenario as we ll Additional costs included all selective demolition and removal, and allowances for after hours work, mobilization and storage, and scaffolding. An attempt to arrive at the approximate number of days that remediation activities would disturb regular ope from RS Means Building Construction Cost Data (RS Means 2012) but the economic impact of these lost days was n ot calculated as it fell outside the scope of this research Since the retrofit scenario addressed the costs of improved acoustical performance when changes are implemented after construction, it was compared to the improved scenario. Even though the strategies adopted varied for both, the acoustic conditi ons expected after all strategies were implemented for each are similar, providing for a fair comparison of costs based on performance.

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65 Table 3 1 Acoustical strategies implemented for each cost scenario Acoustical Strategies Basic Baseline Improved Retr ofit Wall Assemblies Doubl e layer of gypsum board on one side and single layer on the other (office areas) X X All walls are full height, extending to roof deck X Sound insulation in all walls surrounding acoustically sensitive areas X X Acoustic sealant at all joints and penetrations X X X Acoustical panels at walls in the main corridor X X Ceiling Assemblies Good performance acoustical tile ("Ultima") X Best performance acoustical tile ("Optima") X X Sound insulation above ACT ceilings only at wall perimeter X Sound insulation above entire area above ACT ceilings X X Acoustic sealant at wall ceiling joints X X X Acoustical panels at ceiling in the main corridor X X Mechanical System Absorptive lining installed in ducts traversing two acoustically sensitive areas X Sound Masking Sound masking system in acoustically sensitive areas X

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66 Figure 3 1 Flow chart depicting the steps followed in the methodology.

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67 Figure 3 2. Location of full ceiling, baseline scenario. Figure 3 3 Location of walls with sound attenuation batt included in the cavity as compared to those that do not have any sound insulation, baseline scenario.

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68 Figure 3 4 Location of sound insulation at ceilings, baseline scenario. Figure 3 5 Location of walls with one additional layer of gypsum board added to one side, improved and retrofit scenarios.

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69 Figure 3 6 Location of absorptive panels in the main corridor improved and retrofit scenarios A) L ooking up at the skylights B) L ooking longwise at the corridor.

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70 CHAPTER 4 RESULTS AND ANALYSIS This research aimed to measure and compare the economic impacts of improving acoustical performance in an office building before construction and after occupancy. F our costing scenarios were set up for comparison, namely: basic, baseline, improved and retrofit. The first three assessed the costs associated with the achievement of different levels of acoustic performance before construction, while the latter quantifie d the costs related to improving acoustic performance after occupancy. For each scenario, the quantities and costs were broken down according to area use, and placed within one of seven established categories: private offices, shared offices, conference ro oms, vertical circulation, service areas, storage, and corridors. The summary sheets grouping office areas can be found in Appendix C, while the summary sheet with all areas included can be found in Appendix D Table 4 1 shows the costs for each scenario w hen all areas are included as well as costs specifically related to the improvement of office areas ( which includes the costs associated with the categories of private offices, shared offices and conference rooms) Several things should be noted First, it can be inferred from the cost of the basic scenario that the minimum amount that could have been spent to build the walls and ceilings t hat create the boundaries for the different spaces is $60,557.92 for the offices, and $115,275.02 for the entire floo r regardless of the importance or budget allocated for acoustics While these amounts are included in all scenarios, they cannot be attributed to the conditioning of a space for a coustic reasons because they are only nested in the price as part of more complex assemblies. Thus, while the total price for each scenario represents what the owner or tenant would ultimate ly pay, only a portion

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71 of it is directly related to acoustic al performance Table 4 1 breaks down the costs for each scenario as a portion o f a basic cost (non acoustics related) plus a portion related to acoustical improvements. The amounts invested specifically on the improvement of acoustics at the different scenarios vary from $27,904 to $118,371 for the offices, and from $49,865 to $213,7 51 for the entire floor. This wide range is given by two factors: (1) the level of acoustical performance targeted, and (2) the time of implementation of the strategies. The level of acoustical performance targeted was increased from the basic scenario to the baseline, and from the baseline to the improved, thus, a similar upward trend in cost was expected. In the case of the retrofit scenario, a level of performance similar to that of the improved scenario was targeted, however, four additional factors rai sed the costs significantly: demolition costs derived from the need to remove some of the materials in place, increased labor costs resulting from working after hours to avoid noise and major disruption to the other working spaces, special scaffolding ne cessary to work in areas which were more accessible during initial construction, and first costs carried over from the initial installation of wall and ceiling assemblies being replaced (in other words, paying twice for the same material). It is also very useful to think of the relationships between the different scenarios in terms of costs per square foot albeit the use of square foot prices obtained from one analysis of one building may not apply to another Table 4 2 shows the additional costs per squar e foot incurred in each scenario analyzed on the case study when only offices are included (8,832 square feet) as well as for the entire floor (16,165 sf) In order to further dissect the results for analysis, the costs associated with improved acoustics in offices were broken down for each category of office space, namely: private offices,

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72 shared offices, and conference rooms. Table 4 3, Table 4 4, and Table 4 5 provide the additional costs per square foot over the basic sce nario for each category as well as the total additional costs In all cases, the square footage cost was based on the total area occupied by the spaces in each category listed (office space, private offices, shared offices and conference rooms) i n other words, the square footag e costs are specific to each type of office space. The average sizes of the private offices, shared offices and conference rooms were 159, 430 and 458 sq uare feet, respectively (t he complete list of the areas used in the case study and their square footage can be found in Appendix B ) The total additional costs listed in T able 4 3, Table 4 4, and Table 4 5 are also shown graphically in F igure 4 1, Figure 4 2 and Figure 4 3 for each category and scenario Similarly, i t was seen as important to analyze the results in relation to the cost of construction for the entire building in order to have an idea of just how much of the budget would need to be allocated to acoustics if improved performance was desired. The results are summarized on Table 4 6. Assuming a total building price of $ 9,315,000, the total building cost would increase an approximate 0.78% if only acoustical improvements at the office areas were done before occupancy or 2.3% if all areas were targeted. Albeit indirectly, Table 4 6 also accounts for the portion of the tot al budget that was spent by the University of Florida to arrive at the current acoustical performance, thus, the baseline scenario shows no increase or decrease (since the total building price assumes the materials which are in place in the current design), and the basic scenario shows a percentage decrease (the percentage that would have been

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73 It is important to note that these percentage increases are limited to the portion of the building analyzed in the case st udy (the third floor of Rinker Hall), and they should not be extrapolated to find a total percentage increase for improving acoustics in the entire building because the floor under study is not typical. However, given that the third floor of the Rinker Ha ll is the one which contains most of the office space, the findings are useful in the fact that they can begin to shed light over the additional budget needed for a significant improvement in acoustics in office spaces Another interesting finding was that e ven though the third floor of Rinker Hall consists mostly of office space, the costs (and hence the percentage increases) resulting from acoustical improvements in office areas were roughly half of the ones for the entire floor at each scenario. The rea son for this is that, although speech privacy and sound transmission at the offices were the main focus of the strategies implemented, the noise problems encountered in the main corridor were seen by the consulted acoustics professionals as too serious to leave unaddressed. As a result, recommendations were made by them to either change the design of the ceilings under the skylights, or cover most surfaces with acoustically absorptive panels. Unfortunately, in terms of price per square foot, the absorptive panels have by far the highest cost of all other assemblies and finishes included approximately $12 to $15 per square foot of surface covered. Table 4 7 shows a breakdown of the costs organized per strategy implemented and was developed to further identi fy the strategies which had the highest po tential for high costs those which would require a larger economic investment Figure 4 4 shows the distribution of additional costs for each strategy implemented above the basic

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74 baseline and improved scenarios. This information can be very valuable to an owner or tenant seeking to identify the feasible strategies to adopt for a given budget; several combinations of strategies could be adopted depending on the areas perceived as more important to target (before c onstruction), or those where the most acoustical problems exist (for remediation after occupancy). Both T able 4 7 and Figure 4 4 confirm that a very large portion of economic investment in the improved and retrofit scenarios is related to the absorptive pa nels except when the retrofit is compared to the improved scenario ( since both implement the same amount, and thus incur in the same costs, the increase in cost for the acoustical panel strategy is zero ). The costs for the absorptive panels were divided i n three areas: the angled ceiling walls, the rectangular walls at the base of the skylights, and the wall area next to the staircase. The professionals consulted indicated that the surfaces most important to cover in the main corridor if a noticeable impro vement in acoustics is desired were the angled ceiling walls, followed by the vertical walls along the stairs, and lastly, the rectangular walls at the base of the skylights. Needless to say, a complete acoustical evaluation both before construction and af ter occupancy could potentially reduce the impact of problematic areas and result in increased savings while significantly improving acoustic conditions in th e space. As an example, if only the angled ceilings were covered, $25,289 could be saved on the improved and retrofit scenarios. At the retrofit level, the single most expensive improvement was the replacement T his was th e result of having to

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75 when the y are replaced with the option In the same manner Table 4 7 can also help identify the less costly strategies wh ich The negative value of $927.50 obtained by comparing the extra cost of adding a sheet of gypsum board at the retrofit level with the improved scenario was surprising at first, however, a logica l explanation was found shortly after initial analysis of the results. Because the improved scenario is assumed to address acoustics before construction, full height walls were able to be implemented together with the additional layer of gypsum board neede d for some areas. However, at the retrofit level it would be impossible to extend the existing walls to reach full height without demolishing the whole wall assemblies and reconstructing them from scratch (which would raise the costs exponentially ) so the retrofit scenario assumes that walls extend to different heights above finished ceilings, as per the current design. For this reason the additional square footage of gypsum board required for the extended walls at the improved level results in a smaller cost for the additional layer at the retrofit level. It is important to reiterate, though, that regardless of the walls having sound insulation installed in the cavity or additional layers of gypsum board added to them to increase the STC rating, if they d o not extend full height, any strategy might be ineffective, as sound will have ample opportunity to travel from one room to the next through the plenum space. strategy is that of installing absorptive duct lining. This was an important finding because many of the acoustic problems expressed by people who are currently working

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76 in these areas have to do with crosstalk. Installing absorptive lining during initial construction as per the strategy implemented would significantly help this problem with a small additional investment of $9,168.97 Furthermore, while this strategy c ould be very effective, for reasons of practicality it can only be implemented at the point of initial installation of the mechanical system ducts which is when the lining can be applied as the duct lines are being created. Since installation of duct lining is no longer practical o nce the building is occupied, owners and tenants are forced to resort to rem ediation measures such as the installation of a sound masking system to fade out the crosstalk The cost to install this at kind of system for the case study is $13,247.75, which is $4,078.78 more expensive than installation of duct lining, and may not be as s uccessful Another cost effective strategy to prevent crosstalk before construction is the design of longer duct runs with u shapes and bends, which also helps dissipating room to room transmission. All of these strategies echo the importance of implem enting acoustical strategies at the design phase if cost effective solutions want to be a ttained. Sound attenuation batt is another strategy which was relatively inexpensive to implement at the retrofit level (only $ 2,905.72 above the improved ) I ts low cost in this study can be attributable to the lack of any demolition work needed (since the acoustical ceiling tiles were assumed to be removed and replaced for the implementation a nother strategy) and the fact that some sound attenuation batt was already present in the improved s cenario as well as the baseline. Acoustic professionals consulted confirmed that adding sound attenuation batt over the entire are above suspended ceilings was one of the first measures done as a retrofit, however, most agr eed that this only acted for cases where the walls do not extend the full height, since there is no

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77 real isola tion quality to batt insulation just absorption which means that sound could still travel through the plenum, but there is more buffer working against it. Another strategy suggested to decrease sound transmissi on and control noise intrusion was the staggering of doors along rooms that are on the same corridor. This is the case with rooms 314, 320, 327, and 331 which are faculty off ices and graduate studios whose doors face each other on Corridor 399C There would not be any additional costs associated with the relocation of these doors at the design phase, however, this would not be a practical alternative at the retrofit level. Las tly, i t is important to note that while the baseline design is far from perfect, it did includ e several measures to address one of the major concerns of office buildings ( speech privacy ) and used for them a relatively small added investment of $27,904 This is likely to have been considered a reasonable investment (less than 1% increase of t he total construction budget) Construction Division to achieve minimum desirable levels of speech privacy In c ontrast, the investment needed to achieve high level acoustic performance is $72,382 at the offices, and $149, 631 for all areas when implemented during initial construction. Figure 4 improved acoustical performance in each scenario for both offices, as well as the entire floor.

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78 Table 4 1. Total costs for each scenario Total Costs for Office Areas Only (8,832 sf) Total Costs for All Areas (16,165 sf) Basic Scenario $ 60,557.92 $ 115,275.02 Baseline Scenario $ 60,557.92 + $ 27,904.37 $ 115,275.02 + $ 49,864.85 Improved Scenario $ 60,557.92 + $ 72,382.35 $ 115,275.02 + $ 149,631.43 Retrofit Scenario $ 60,557.92 + $ 118,371.09 $ 115,275.02 + $ 213,751.04 Table 4 2. Additional costs per square foot for each scenario A dditional Cost per Square Foot, offices only ( 8,832 sf) Additional Cost Per Square Foot all areas included ( 16,165 sf) Basic Scenario Baseline Scenario $ 3.16 $ 3.09 Improved Scenario $ 8.20 $ 9.26 Retrofit Scenario $ 13.40 $ 13.22 Table 4 3. Additional costs for each scenario: private offices Additional Cost per Square Foot (3,181 sf) Total Additional Cost Basic Scenario Baseline Scenario $ 3.16 $ 10,054.78 Improved Scenario $ 10.95 $ 34,837.00 Retrofit Scenario $ 12.86 $ 40,908.15 Table 4 4. Additional costs for each scenario: shared offices Additional Cost per Square Foot (4,735 sf) Total Additional Cost Basic Scenario Baseline Scenario $ 3.22 $ 15,261.24 Improved Scenario $ 6.83 $ 32,315.61 Retrofit Scenario $ 14.37 $ 68,016.09 Table 4 5. Additional costs for each scenario: conference rooms Additional Cost per Square Foot (916 sf) Total Additional Cost Basic Scenario Baseline Scenario $ 2.83 $ 2,588.35 Improved Scenario $ 5.71 $ 5,229.75 Retrofit Scenario $ 10.31 $ 9,446.86

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79 Table 4 6. design ($9,315,000) Office Areas Only (8,832 sf) All Areas (16,165 sf) Basic Scenario 0.3 0 % 0.53% Baseline Scenario Improved Scenario + 0.78% + 1.61% Retrofit Scenario + 1.27% + 2.3 0 % Table 4 7. Additional investment required for strategy implementation Acoustical Strategy Additional Investment Required in Dollars Improved vs. Basic Improved vs. Baseline Retrofit vs. Basic Retrofit vs. Improved Additional layer of gypsum board $ 15,745.28 $ 9,545.25 $ 14,817.78 $ (927.50) Additional sound insulation at walls $ 15,418.27 $ 2,411.35 $ 19,334.42 $ 12,288.52 Full height walls $ 35,619.18 $ 18,062.70 Sound attenuation batt throughout ceilings $ 15,287.90 $ 11,250.36 $ 15,460.51 $ 2,905.72 High performance acoustical tile $ 30,879.54 $ 5,062.22 $ 77,553.21 $ 46,673.67 Absorptive panels $ 53,810.57 $ 53,810.57 $ 53,810.57 $ 0.00 Absorptive duct lining $ 9,168.97 $ 9,168.97 Sound masking system $ 13,247.75 $ 13,247.75

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80 Figure 4 1 Additional costs for improved acoustics at private offices Figure 4 2 Additional costs for improved acoustics at shared offices

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81 Figure 4 3 Additional costs for improved acoustics at conference rooms Figure 4 4 Distribution of additional cost s per strategy, for each scenario

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82 Figure 4 5. Total costs for each scenario, for offices and all areas.

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83 CHAPTER 5 CONCLUSIONS AND RECO MMENDATIONS Conclusions The cost analysis developed for the case study has demonstrated that the integration of strategies for improved acoustic al performance at the design stage s of an office building is a wise decision for developers and owners not only to improve productivity and promote health starting at the point of occupancy, but also to avoid the extensive costs associated with acoustic remediation. In the case study, w hen enhanced acoustical conditions in offices were targeted at the retrofit level, a 35% increase in costs is incurred as compared to the implementation of measures to achieve the same level o f performance before construction When all areas of the case study are considered (i.e. office and non office space), a 24% increase in costs was sustained. The increase in costs is attributable to increased labor cost for working after hours, scaffolding equipment needed for access to some areas, demolition costs for removing work in place, and first costs carried over from the initial installation. When only a reduced level of acoustic performance is targeted, as is the case with the baseline scenario, a 43% to 46% increase in the costs of wall and ceiling assemblies can be expected. I n terms of cost per square foot, the case study yielded an additional $4.48 for acoustical improvements implemented at the improved level, compared to $7.32 when they are ex ecuted at the retrofit level ( after occupancy ) These figures could potentially start to dissipate the perceptions that the costs of designing for acoustics are prohibitive. While they are not perfect measures, costs per square foot can also begin to provide rules of thumb for owners, developers and tenants who want to have an idea of the price to pay for improved acoustical performance in their buildings.

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84 There is currently limited concern for acoustics manifested in sustainable rating systems for buildings, as well as in the construction industry in general. The acoustical products and finishes chosen most often are selected based on the importance given to acoustics as a design criteria which in office buildings tends to be very low, thus leading to the selection of poor assemblies and finishes such as hollow gypsum board partitions with other non ab sorptive finishes Adding to the challenge when acoustic considerations do play a role in the design, their implementation is sometimes done in the later stages of design when the problems are less managea ble and more difficult to address resulting in ei ther higher costs or poorly designed buildings In order to continue progressing towards a sustainab le built environment the interpretation of what it means to be sustainab le, as well as what it means to build and work in a sustainable building needs to be analyzed from a holistic perspective A n office building that is not comfortable acoustically and therefore not fit for its purpose does not provide its occupants with a truly sustainable work environment T his needs to be better addressed by developers, owners tenants, and designers when planning for the construction of office buildings As an owner, the University of Florida is widely recognized for its efforts and achievements in sustainability ; and its support for an all encompassing, holi stic interpretation of their sustainability mission could only reinforce this image. Recommendations for Further Study For the retrofit scenario, this study assessed only hard costs directly related to acoustical improvements after occupancy. However, the costs related to lost productivity from employees who work in the spaces where remediation would need to

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85 take place are likely to increase the losses exponentially, and should be considered for future study. Furthermore, alternative strategies for improve ment ( e.g. longer duct runs, building on top of the existing walls to improve STC, or cutting into the gypsum board to spray insulating foam) in each scenario should be added to future studies in order to build a database that can inform owner and tenant d ecision s regarding the feasibility of each. This could include aspects excluded by this research, such as exterior walls, floors furniture, and other finishes which may have a significant impact in the acoustics of a space. with the acoustical problems of sound transmission and noise emission should also be studied more carefully. The integration of mechanical engineers in the critical issue of de signing for go od acoustics and noise control is extremely important for office buildings. While these professionals are already working closely with the design team to achieve high energy savings in green buildings, the role of mechanical engineers and the ir inclusion of noise and sound transmission as design criteria for mechanical systems should be more clearly defined.

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86 APPENDIX A PARTITION LIST AND D ETAILS FOR BASELINE SCENARIO RINKER HALL, THIRD FLOOR WALL AND PARTITION TYPE Interior partitions separ ating office areas from other areas P010 Partition Type (Most walls separating one office space from another office space) Wall: Total partition width = W006 Wall Type (Most walls separating an office from a corridor) Wall: Wall extends to bottom of deck W012 Wall Type (Shared spaces: walls separating Grad Studios, Kitchen and Storage from corridors) Wall: No sound attenuation batt Total partition width = Wall extends to bottom of deck Interior partitions separating service areas from common areas W101 Rated Wall Type (Unconditioned spaces: walls around elevator shaft and stairs) Wall: 1 No sound attenuation batt Wall extends to bottom of deck W103 Rated Wall Type (Walls around 308A (Telephone Rm.) and 336B (Elec. Closet)) Wall: 5/8 Wall extends to bottom of deck

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87 Fire sealant at the top W009 Rated Wall Type Wall: No sou nd attenuation batt other Wall extends to bottom of deck Interior partitions at chase walls and wet walls P001 Partition Type (Chase walls at at mechanical shafts) Wall: No sound attenuation batt W008 W all Type (Wet wall separating Men and Women Restrooms) Wall: No sound attenuation batt Wall extends to bottom of deck W005 W all Type Wall: Wall extend s to bottom of deck

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88 APPENDIX B APPROXIMATE SQUARE F OOTAGE OF EACH AREA

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89 APPENDIX C BREAKDOWN OF COSTS F OR EACH SCENARIO, OF FICE AREAS ONLY

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92 APPENDIX D BREAKDOWN OF COSTS F OR EACH SCENARIO, AL L AREAS

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95 APPENDIX E QUANTITY TAKEOFF FOR ALL SCENARIOS BASIC SCENARIO: NO ACOUSTIC CONSIDERATIONS

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98 BASELINE SCENARIO: CURRENT LEVEL OF ACOUSTICS QUANTITY TAKEOFF OF GYPSUM BOARD AND METAL STUDS

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101 QUANTITY TAKEOFF OF WALL AND CEILING SOUND INSULATION

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104 IMPROVED AND RETROFIT SCENARIO S : BASELINE DESIGN PLUS ACOUSTICAL STRATEGIES ADDITIONAL LAYER OF GYPSUM BOARD AND CEILING INSULATION TAKEOFF

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105

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106 QUANTITY TAKEOFF FOR ADDITIONAL GYPSUM BOARD AND METAL STUDS FOR EXTENDING WALLS TO ROOF DECK

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109 QUANTITY TAKEOFF FOR ACOUSTIC LINING FOR MECHANICAL DUCTWORK

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114 Q UANTITY TAKEOFF FOR ABSORPTIVE PANELS AT THE MAIN CORRIDOR

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115 APPENDIX F RECOMMENDED STC RATI NGS BY ANSI S12.60 2002

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116 APPENDIX G RECOMMENDED STC RATI NGS FOR COMPLIANCE WITH HIPAA

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117 LIST OF REFERENCES American National Standards Institute 2010, ANSI S12.60 2010. Acoustical Performance Criteria, Design Requirements, and Guidelines for Schools Me lville: ANSI. Bischel, MS & Beakes, WE 2008, 'Using High Light Reflectance Acoustical Ceilings to Increase the Energy Efficiency of Buildings', Acoustics 2008 Armstrong Building Products, Paris. Busby Perkins + Will 2007, 'Roadmap for the Integrated Design Process'. Carsia, T 2002, 'Designing Workspaces for Higher Productivity', Occupational Health and Safety vol 71, no. 9. Chin Quee, D, Technotes viewed 21 November 2011, < http://www.rwdi.com/cms/publications/20/t06.pdf >. Egan, MD 2007, Architectural Acoustics McGraw Hill, New York. Evans, JB 2010, 'Evolving Acoustical Standards and Criteria for Green and High Performing Buildings in North America', Proceedings o f 10th Congress on Acoustics Socit Franaise d'Acoustique (SFA), Lyon. Evans, JB & Himmel, CN 2009, 'Acoustical and Noise Control Criteria and Guidelines for Building Design and Operations', 9th International Conference for Enhanced Building Operations JEAcoustics, Austin. Field, C 2008, 'Acoustic Design in Green Buildings', ASHRAE Journal pp. 60 69. Florida Building Code 2010, Florida Department of Business and Professional Regulation. Fullerton, J 2009, Listen Up: Consider How Acoustics Can Compl ement Green Designs viewed 21 November 2011, < http://www.facilitiesnet.com/green/article/Listen Up Consider How Acoustics Can C omplement Green Designs -10976# >. Gierzak, J 2003, 'Duct Liner Materials and Acoustics', ASHRAE Journal pp. 46 49. Green Building Initiative, Inc. 2010, 'Green Globes Designs for New Buildings and Retrofits', Toronto. Insul, Insul About viewed 8 August 2011, < http://www.insul.co.nz/about.html >. Jensen, K, Arens, E & Zagreus, L 2005, 'Acoustical Quality in Office Workstations, as Assessed by Occupant Surveys', Proceedings of Indoor Air 2005 Indoo r Air Institute.

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118 Kibert, CJ, Sustainable Construction: Green Building Design and Delivery Third edn (Awaiting Publication), Wiley, New Jersey. Larsson, N 2009, Integrated Design Process: Theory, History, Demonstrations viewed 8 August 2011, < http://www.hkifm.org.hk/public_html/idp/paper/ppt_NilsLarsson 1.pdf >. Lee, Y 2010, 'Office Layout Affecting Privacy, Interaction, and Acoustic Quality in LEED certified Buildings', Building and Environment vol 45, pp. 1594 1600. Lee, Y & Guerin, D 2010, 'Indoor Environmental Quality Differences Between Office Types in LEED certified Buildings in the US', Building and Environment vol 45, pp. 1104 1112. Mahbub, A, Kua, H W & Lee, S E 2010, 'A Total Building Performance Approach to Evaluating Building Acoustics Performance', Architectural Science Review vol 53, pp. 213 223. Moore, D 2010, 'Sound Advice: Duct Liners for Acoustic Control and Indoor Air Quality', The Construction Spec ifier January 2010, pp. 56 62. Paradis, R 2010, Acoustic Comfort. Whole Building Design Guide viewed 21 November 2011, < http://www.wbdg.org/resources/acoustic.php >. Pop, C & Rindel, J 2005, 'Perceived Speech Privacy in Computer Simulated Open plan Offices', Environmental Noise Control Rio de Janeiro. Prakash, P 2005, 'Effect of Indoor Environmental Quality on Occupants' Perception of Performance: A Comparative Study', Maste r's Thesis, University of Florida, Gainesville. Rindel, HH & Christensen, CL, ODEON, a Design Tool for Noise Control in Indoor Environments viewed 10 August 2011, < http://www.odeon.dk/pdf/152_rindel. pdf >. RS Means 2012, RSMeans Building Construction Cost Data Robert S Means Co. Schuyler, G 2006, 'Acoustics: Plan Ahead for Proper Design', Tech Notes 2006, pp. 1 4. University of Florida Facilities Planning and Construction 2011. UF Design and Construction Standards Gainesville, UF. USG Corporation 2009, Acoustical Ceiling Design and Application viewed 21 October 2011, < www.usg.com/documents/construction handbook/chapter 9.pdf >.

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119 USGBC 2009, USGBC: LEED for Schools viewed 20 August 2011, < http://www.usgbc.org/ShowFile.aspx?DocumentID=8872 >. Vorlander, M 2008, Auralization: Fundamentals of Acoustics, Model ing, Simulation, Algorithms, and Acoustic Virtual Reality 1st edn, Springer, Aachen. Yantis, M 2006, 'The Quiet Hospital', Medical Construction & Design January February 2006, pp. 34 37. Yost, P 2001, 'Building Green Quietly: Noise Pollution and What t o Do About It', Environmental Building News 1 January 2001.

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120 BIOGRAPHICAL SKETCH Claudia Garcia was born and raised in Caracas, Venezuela. She moved to the United States when she was 17 years old and after polishing up her English she began attending Miami Dade College. In 2007 she transferred to the upper division of the architecture program at Florida International University, where two years later she graduated with high honors and obtained her Ba chelor in Arts in Architecture. Her love fo r details and an always inquisitive mind pushed her to gain increased experience and a better understanding of buildings which she looked to obtain by venturing into the technical side of the construction industry. After graduating from Florida Internati onal University she began working for company that specialize s in the installation of high end interior acoustical finishes. The company turned out to be a perfect fit for her, as she had the opportunity to learn about the i nner workings of the building construction industry while apply ing her design In 2010, Claudia moved to Gainesville to start the graduate program at the M.E. Rinker Sr. School of Building C onstruction While at the program, she was an active member of the Sigma Lambda Chi International Construction Honor Society and a member of the executive board of the National Association of Women in Construction student chapter. After graduating with her Master in Science in Building Construction with a Sustainable Construction concentration she will begin working for a general contractor