Effect of attic wood floor on temperatures and fuel-oil consumption in a frame dwelling

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Material Information

Title:
Effect of attic wood floor on temperatures and fuel-oil consumption in a frame dwelling
Series Title:
Report ;
Physical Description:
4, 4 leaves : ill. ; 26 cm.
Language:
English
Creator:
Mathewson, J. S
Forest Products Laboratory (U.S.)
University of Wisconsin
United States -- Forest Service
Publisher:
U.S. Dept. of Agriculture, Forest Service, Forest Products Laboratory
Place of Publication:
Madison, Wis
Publication Date:

Subjects

Subjects / Keywords:
Wooden-frame houses -- Heating and ventilation   ( lcsh )
Attics -- Heating and ventilation   ( lcsh )
Flooring, Wooden   ( lcsh )
Dwellings -- Energy consumption   ( lcsh )
Genre:
federal government publication   ( marcgt )
non-fiction   ( marcgt )

Notes

General Note:
Cover title.
General Note:
"Published in Domestic Engineering October 1936."
General Note:
"In cooperation with the University of Wisconsin."
Statement of Responsibility:
by J.S. Mathewson.

Record Information

Source Institution:
University of Florida
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
aleph - 029606491
oclc - 757823009
System ID:
AA00020723:00001

Full Text
,'/iJ: /
I. *. 1 -


U. S. Department of Agriculture, Forest Service

FOREST PRODUCTS LABORATORY

In cooperation with the University of Wisconsin

MADISON, WISCONSIN


P 1 11


EFFECT OF ATTIC WOOD FLOOR ON TEMPERATURES

AND FUEL-OIL CONSUMPTION IN A FRAME DWELLING

By J. S. MATHEWSON
Senior Engineer









J
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Published in
DOMESTIC ENGINEERING
October 1936














I








EFFECT OF ATTIC WOOD FLOOR ON TE .PAT'?E3 AMD


FUEL-OIL CC::3UT.TMPTION IN A FRAK' W.ELLIU1


By

J. S. .ATE-S70N,
Senior Engineer





The unfloored attic has long been condemned by domestic heating
engineers as a source of great loss of heat, yet little factual information
has been available as to the magnitude of such loss. Recently the Forest
Products Laboratory. ma'n-Gained at :.'kei.son, Wis., in cooperation with the
University of Wisconsin, in the course of its researches on the efficient
utilization of wood in modern buildings, made a thorough study of the loss
of heat through an attic floor. A small dwelling, representative of the
type of frame construction employed in regions of the United States where
the winters are severe, was used for the study. The effect of the attic
floor on fuel-oil consumption was also determined. The following paragraphs
describe the study and may be of interest not only to engineers, but to
architects, contractors, and home owners as well.

The study was made at Madison, Wisconsin, and covered a period of
4 years. During the first half of the study about 42 percent of the attic
area, namely, a strip through the center, was floored with spruce shiplap.


7wLLI:TG CCOISTR7CTION


During the last half, the entire arga was floored with white fir
shiplap making a double floor over the central part occupied by the old
floor and a single floor over the remainder. A 1-inch space -.was provided
between the old and new floors, which were nailed to joists. The second-
story ceiling was wood lath and plaster.

The %'alls of the dwelling consisted of wood shingles, building
paper, sheathing, 2 inch by 4 inch studs, wood lath and plaster. In addition,
the west wall and about 43 percent of the north wall had a 1/2 inch semi-
flexible fibre insulation between the studs. The two outside doors and
five of the second-story windows were weather stripped. With the exception
of three small windows, all the windows had storm sash. The roof sheathing
was laid with little or no space between the edges of the boards, and was
cov--r-ed with asphalt shingles. The foundation and basement floor were
concrete.


R1 130







APPARATUS AID EQUIPj.EIIT


An automatic instrument was used to record the tcrmperature at
three places: (1) on the attic floor, (2) directly below on the second floor
ceiling, and (3) outdoors above the middle window in the second story and
about 6 inches away from the wall. Mercurial thermometers were used to
check the recorder.

The dwelling had a common type of heating plant with a motor-
driven centrifugal atomizing oil burner equipped with a 3-inch atomizer.
The overall efficiency of the burner was calculated from the heat losses
obtained in the study to be 77 percent and the efficiency of combustion was
determined experimentally to be 80 percent, from which it follows that the
flame of the oil burner was regulated so as to supply heat at about the rate
heat was required by the heating system. The oil burner was rated as being
c-.pable of burning No. 4 fuel oil, but No. 2 fuel oil was used.

The chart on the temperature recorder was cLhri-ed once a week.
Each of the three curves on each chart (see Fig. 1) was planinmetered in order
to calculate the average weekly temperature in the attic, at the second story
ceiling, and outdoors. In other words, the area within the chart was deter-
mined. The differences between the second story ceiling temperatures and
corresponding attic floor temperatures were determined and plotted against
the differences between 69 F. and outdoor temperatures during the heating
season as shown in Figure 2.

Fig-ure 3 shows the general trend of the temperatures in the
attic, on the second story ceiling, and outdoors throughout the year. Some
of the data obtained are not plotted in these curves because they involve
the effect of opening and closing the attic windows and trap door during
the summer. For example, in Figure 1, which is the record for the period
June 19 to 26, 1932, it may be noted that at 3 p. m. on Tuesday the attic
temperature was about 104 F. when the outdoor temperature was a.eut g4 F.
The difference of 20 degrees occurred when the attic windows and trap door
were closed. On the following day, Wednesday, the attic temperature was
about 99 F. when the outdoor temperature was 92 F. In this case the
difference was only 7 degrees when the attic windows and trap door were
open, and notwithstanding the fact that the sun shone 11.6 hours on Tuesday
and 13.0 hours on Wednesday.

The actual observed maximum temperature in the attic was 118 F.
and occurred on July 19, 1930.

As a rule the oil tank gauge reading was noted on the first day
of each month and in addition numerous readings were noted on intermediate
dates. These readings were converted into gallons on a 30-day basis and
correlated with Weather Bureau temperature records. The thermostat in the
living room was set to give a temperature of 7l1 F. during the daytime and
65 F. at night. The average was taken as 690, since for about one-third


R1130









of the time the lower temperature obtained. The number of gallons of oil
burned in 30 days and the differences between 69 F. and the outdoor t;m-r -r-
atures were plotted coordinately in Figure 4.

Calculations based on the graphs in Figure 2 show that when the
outdoor temperature was 350 F., the average outdoor temperature in .1atlison,
Wisconsin, during the period October to May, inclusive, the differences in
temperature between the second story ceiling and attic floor were respectively
130 and 16 before and after the new7 attic floor was laid.

A sumnnmary of heat loss calculations is given in Table 1.


Table l.--Summary of heat loss calculations

Items :Uninsulatcd : Insulated : Heat loss-
:---------- -----------------:----------- -- fe--t------ : -.----
:Square feet :Square feet : B.t.u.


- 85............... :
- 29............... :
- 57 ...... . ... :
- ...93 .*..... .:..
Total ......... :


227
383
39 001
11001


S 366
S 171


* 9.9.9.99...
~99~~~* 999k


... 5~**
* 5. :*
: 537"


1,001 x 0.27 x 34 ...............:
537 x 0.16 x 34...............

Attic floor
647 x 0.242 x 16.2.................

Glass
66 x 1.13 x 34............. ........
266 x 0.45 x 34 ...................

Volume
pT4.5 x 27) + (4 x 19)] 16.7 =
12,320 cubic feet.


12, 320 x 34
55


V"When outdoor temperature is 350 F.


R1130


Walls
West
North
North
East
South


16.7
16.7
16.7
16.7
16.7


. .. .. .. . 9* *9



* . .9 9 .
:
* *e~ O O ~ l l l le e O


9,190
2,920


2, 540


2,535
4, 070





7, 620

28, 875


@0@@O@00@0@


Total ......... : ............ : ............ :








The total heat loss given in Table 1 of 28,875 B13.t.u. per hour
includes a loss of 2, 540 B.t.u. through the second story ceiling after the
nr".', floor was laid. The loss through the second story ceiling before the
new attic floor was laid (647 x 0.48 x 13.0) equals 4,040 B.t.u. The total
heat loss -efore the new attic floor "'as laid equals (28,875 minus 2,540)
plus 4,040 or 30,375 3.t.u. The percentage of the total loss through the
second story ceiling before the attic floor was laid equals 4,040 divided
by 30,375 or 13.3 percent. The percenta.-e of the total loss through the
second story ceiling after the new attic floor was laid equals 2,540 divided
by 28,875 or -8.7 percent. The reduction in heat loss as a result of the
installation of the new attic floor equals (4,040 minus 2,540) divided by
30,375 or 4.9 percent.


FUEL-OIL CC17-:.!PTION


Calculations based on the graphs in Figure 4 show that when the
outdoor temperature is 35 F. the monthly fuel oil consumption was 203.2
gallons before the new attic floor was laid and 191.9 gallons after the
floor was laid. This difference corresponds to a reduction of 5.6 percent.

The corresponding figure based on heat losses as calculated in
the preceding paragraph was 4.9 percent. The heat losses before and after
the installation of the new attic floor were 13.3 end -8.7 percent, respect-
ively, of the total. Converted to fuel oil consumption (203.2 x 13.3) this
amounts to 27.0 gallons before the attic was completely floored and 16.7
gallons (191.9 x 8.7) afterwards. The difference (27.0 minus 16.7) equals
a calculated savings of 10.3 gallons as a result of completely flooring the
attic. This result compares reasonably well with 11.3 gallons, which is
based cn the consumption of fuel oil.

1. The addition of a second attic floor increased the temperature
differential between the second story ceiling and attic floor by about 3 F.
and decreased the fuel oil consumption by about 5 percent when the outdoor
temperature was 35 F.

2. During hot weather a reduction in attic temperatures was made
by opening attic windows and door.


R11l30


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7 7- C .....







SECOND STOY -
CElL/NC 7
./ : / . ,-


r.. I ,,
uc IL/IN G .. .- -ib.. ''-' 4f'/^''* y *


Figure l.-Each of the three curves on the temperature recorder chart was
planimetered to calculate the average temperature.













1 T T i T r T T r 1" i ,-,


u IC. 2, I/928 MI Y Z6, 1929
___ EXCLUSIVE OF FEB. ____




__ __ ___0_ ____ ______ __________



o0 O Y = 0.41X- 0.89
0 *
I' f


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FEPT. 29,1929 -JUNE!, 1930
o
0
0 l
*- 00


0 0 0

0 o Y 0.35x 1.07


0 0


_______ _______ _______ a a i i *.................,...................a & a.. ..........U .L.................J _______
I T 1 i 1 ~ I I if ~----r T ______


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, 30


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f I1 0*
SEPT 27, 1931-MA Y 8, 193Z



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00



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-_ I 1_


5 /0 /5 20 25 30 35 40 45 50 55 60 65 0 5 10 /5 20 25 30 35 40 45 50 55 60 65
690 MINVUS OUTDOOR TEMPERATURES)


M 28319 F




Figure 2.-Differences between the second floor ceiling temperatures and the
corresponding attic floor temperatures were determined and plotted
against differences between 69 degrees F. and outdoor temperatures.


.1U-


OCT. 13, /930 MAY 3/, /93/








___0 YO.54X- 1.26
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1930


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-, ,--'t- ---


--SECOND-STORY CELINC TEMPERATURE
--- ATTIC FLOOR TEMPERATURE
-.- OUTDOOR TEMPERATURfE


. ..* i


''/-* -I
,^.-- -T-*-^^'1

__I___
I
1 ''v


4L-- -1--- ---
.-.. .' . ..


;. A ,
J-CO ND-ST0,?vY CiELINC TMPERATUrE
--ATTIC FLOOR rfMPEA'ATU#F
IlTOOOR TEMPEA'4TAUfR


WAY JAW I JOLY 4fl.-. 1 SEPT OCT NOV iC,


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_' .' + -Ar c _f
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r ~-


STORY Cf i,"C TOEMPERA E
OOR TIMPERATc/PE
T EMPEK TORE


Figure 3.--The general trend of the temperatures in the attic, on the corresponding
second floor throughout the entire year, has been shown on these charts.


193/


M 29162 F


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NOV. 1930-MAY 1931 WO
Z40 20 'L_

2f
Z4k




',2s6o No?.




IO0

,oo
040
' /


d0
60 MAYI





0 10 zo 30 40
695 I. Nf1M. OUTDOOR TUMPERATURE (F)


OCT. 19Z8 -MAY 19Z9 JAN.
400 -


366
340
32O
o -FEB.

300-


Z66


OZ40
2200

/80

160/

140


/00
80------ -APR.
860

40-

20-
C0


0 10

Z, 39163 7


20 30 40 50O
69MINU,$ OVTROOR TEMPERATURE (E)


zoo
OCT 1931- MA4Y 193Z /
Z ----0-- --- -- -- /

140-- / _______
/Offs,
2ZO --- ---
ZOO---- --- ---*'---

1 60


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to /- -

0 10 SO 40 _
69sMwNuf" OUTDOfOR rfemptRArTUtie ()


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*""'~ ------- I --------- ] -- 7
DEC. 1929 MAY 1930 JA.
360-











/o .
300 ------ -_
DECOY
28/
260
240

ZOO



160
140 --
M/w/ Fee.




100




60-
140 ------ ----Y -- ---- --- ---



so--C-/ --- --- --- -----
Uo ---- JO- --- 50------


IO O O P40 5
69' MINUP OUTOOOR TtMPtR#ATURE (f)


Figure 4*.-The number of gallons of oil burned in 30 days and differences
between 69 degrees F. and outdoor temperatures have been plotted
in these charts.


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UNIVERSITY OF FLORIDA


3 1262 08927 9185