Air-borne contamination resulting from transferable contamination on surfaces


Material Information

Air-borne contamination resulting from transferable contamination on surfaces
Physical Description:
12 p. : ill. ; 26 cm.
Bailey, J. C
Rohr, R. C
U.S. Atomic Energy Commission
Carbide and Carbon Chemicals Company (K-25 Plant)
Place of Publication:
Oak Ridge, TN
Publication Date:


Subjects / Keywords:
Air -- Pollution   ( lcsh )
Biology   ( lcsh )
federal government publication   ( marcgt )
bibliography   ( marcgt )
technical report   ( marcgt )
non-fiction   ( marcgt )


Includes bibliographical references.
Statement of Responsibility:
by J. C. Bailey, R. C. Rohr
General Note:
General Note:
"November 24, 1953."
General Note:
Title from cover.
General Note:
"Subject category: Biology."
General Note:
"Work performed under Contract No. W-7405-Eng-26"--P.5.

Record Information

Source Institution:
University of Florida
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
aleph - 005012237
oclc - 69647494
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Subject Category: BIOLOGY



By ~
J. C. Bailey
R. C. Rohr ~p

F B 283 57

November 24, 1953

K-25 Plant
Carbide and Carbon Chemicals Company
Oak Ridge, Tennessee

Technical information Service, 0ak Ridge, Tennessee



The Atomnic Energy Commission makes no representation or warranty
as to the accumcy or usefulness of the information or statements contained
in this report, or that the use of any Itnfomrmaton, appartus, method or
process disclorsd in this report may not Infringe privately-owned rights.
The Commission assumes no liability with respect to the use of, or for
damages resulting frm the user of, any information, appatras, method or
proessr disclosed In this report.

Changed frotm Official Utse Only Seprtermber 6, 1955.

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Since nonechnical ;and nonesse~Ential prefatory mnateirial
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Printed in USA, Price 15 cents. Available from the
Office of Technical Services, D~epartnt of Commerce, Wash-
ington 25, D. C.

SPo 367290


J. C. Bailey and R. C. Rohr

Supervised by: H. F. Benry

Safety and Protection Division.
W. L. Richardson, Superintendent


A comparison of air-borne activity with transferable surface activity in tva
contaminated plant locations during normal operation indicates that the ratio
of air activity to surface activity~ is in the range of about 0.25 to 1.9
(dis./min. /m. 3 air)/(dis./min./cm. surface). This latter figure. is considered
to be the maximum value of this ratio which might exist for long continued oper-
ations at K-25. However, a test designed to indicate the maximum activity which
might result from plant operations included the combined action of air circulating
fans and equipment vibrations and2gave a corresponding ratio of about 20
(dis./min.ImS air)/(dis./min./cm. surface) for short periods.

Workr performed under Contract No. W-74O$-Eng-26

K-25 Plant
Oak Ridge, Tennessee


Int roduction

Since the inhalation of uranium probably presents a much greater hazard than does
any of the other types of urmanirn exposure, it is felt that the principal hazard
due to tranferable uranium contamination over wide areas is that resulting from
the possibility that it may become air-borne and thus be inhaled. In order to
estimate the relationship between transferable surface contamination and the degree
of air-borne activity which man be produced by air currents blowing over these
surfaces, some tests were performed in the higaily contaminated, abandoned K-1405
Engineering Development Building. In addition, the relationship between air-borne
activity and transferable surface activity as experienced during normal operations
was determined fran survey results obtained in this building and in the K-1131
Feed Manufacture Building where contamination is comparable.


When the air circulating fans in the K-1405 Building were placed in operation as
normally used, the average ratio between air-borne contamination and transferable
sur face activity was found to be 13 (dis ./min./n.3)/(dis ./min./cm.2) t wit h minor
vibrations added to the action of the fans to simulate equipment vibrations, the
average ratio increased to approximately 20 (dis./nin./m.3 )/(dis./min./cmn.2)
With continuing operation of the fans, however, the airborne activity was found
to decrease, presumably as a result of the settling out in areas of small air
disturbance, of material which was origijnally in regions where air currents would
cause it to become air-borne.

The ratios of air-borne to transferable surface contamination indicated by these
tests are approximately 50 to 75 times thie corresponding ratio of 0.25 (dis./min./
m.3 )/(dia./min./om.2) which has been experienced during normal operations within
the building. They may also be compared with the average ratio of 0.654 (dis./
min./n.3 )/(dis./min./cm.2) as shown by long-tern samples taken during normal
operations over an extended period of time at 2 fixed locations in the KI-1131 Feed
]Manufacture Building, and with the ratio of 1.9 (dis./min./m.3 )/(dis./nin./cm.2)
as shown by short-term samples taken uniformly throughout this building.

Other than the long-tern sampling in K-1131_ and K;-1405, the tests were not
extensive and were not extended over a period of tim; thus, the results should
not be considered as necessarily .representing accurate quantitative estimates of
the relation between air-borne activity and the extent of transferable surface
contamination. Similarly, the ratios of air-born to transferable surface
activity found for the operating periods apply only to the conditions considered;
however, in view of the rather extrane air disturbance and vibration conditions
in the~ K-1131 Feed Manufacture Building, it is felt that the ratio of 1.9 (dis./
nin./an.3 )/(dis./nin./an .2) shown by samples taken throughout this building,
represents nearly the maximumm which might result from transferable contamination.
This is particularly true since at least scame of the air-borne contamination
occurring under operating conditions probably results from new releases of
material rather than from transferable activity which becomes air-borne.

On the basis of this last ratio. the degree of transferable bulldin -wide surface
contamination which would corresp ~nd to the McA*C, of 111 dis,/mrin /m for air~-
boeuaim s5 i./a.a this isequlvalent to 1200 counts/min./100
em. as obtained by smear samples counted with a Samson alpha survey meter. On
the basis of the extreme alr contamination conditions produced by the fans and
vibration during the tests the transferabl5 activity corresponding to the M.AC.
for air-borne material Is 5.3 dis,/rin./cm.

Description of Tests

Test 1

Before anything was disturbed, a series of air sunples was taken at 4 loca-
tions in the laboratory and in the room below as shown In the attached sketch,
the samplers being directly on the floor or work bench. For clarity, the
figure shows a cutaway view of the laboratory. It should be noted however,
that the side of the room where the panel board Is located is open except for
the space occupied by the panel board Itself.

A survey of the transferable activity of dust which had settled out on the
surfaces of the laborato5ry was made by the normal method of rubbing a piece of
paper over an area of 100 an,2 and counting the activity picked up with a
Samson alpha survey meter. Following the survey, two 16.N heater fans and a
24" pedestal fan were turned to maximum velocity with all the building doors
an~d windows closed, The positions of the fans are shown In the sketch, A
few minutes after the fans were turned on, a second series of air samples was
taken at the same k locations- After all of these samples had been obtained,
another set of air samples wa~s taken at the same locations wxth the fans in
operation and with pipes mad equipment being struck wilth a meter stick to
simulate the effect of vibrations, A railroad locomotive passed the building
during this test, adding sligaitly to the vibration*

The average transferable activity on beams window sills,, pipes, etc., was
about 120 dis./min./cm.2, UF powder being visible on some of these surfaces,
the average transferable actuaity for all surfaces in the laboratory was about
20 dis./rmn./an.2 + The results of the air samples are given in table 1 fran
which it may be seen that the average ratio of anr-bonne activity produced by2
the fans to trans ferable surface activity was 13 (dis./min./ and)3/ Cdis/min/Cm~. )o
and that the vlbrations Increased this by an additional factor of 1.6 to 21
(dis./min./m.3)/(di s./min./cm. 2), As will be noted in the table, the average
air activity produced with both fans and vibrations was approximately 4 times
the plant acceptable limit of 1 c/mins/ft.Lawr

40 c/mn./10 an obtained by near samples counted with a Samson alpha
survey meter (205g geometry)-
** This value corresponds to 111 dis./rmn,/m*8 or 5 brc/an.3, the plant acceptable
limit for a.k0-hour work week.



Undisturbed Fans an Fans on and Vibrations
Post- Ratio Ratio Ratio
tion o/mindfrtS die./min./m.3 Af* o/min/t.3 dia./min./m.3 B~F abbdit.3 di./ain./m.3C

1 0.20 22 1.1 4. 06 450 22.5 6.25 694 34.7
2 0.25i 28 1.4 3.58 397 19.9 5.51 611 30.6
3 0.04 4.5 0.23 1.40 155 7.8 1.76 195 9.8
4 M21 1.1 OfA& M15 8.0

Avg. 0.17 19 1.0 2.36 262 131 3.70 415 20.8

w T = Transferable Activity = 20 dis./min./cm.2,

Test 2

On a second test, the heater blowers had been in constant operation for a number
of days and remained in operation throughout the test and the pedestal fan was
moved. With the exception of this and the fact that sanmples were taken a~pproxi-
mately 4 feet above the floor and were confined to the laboratory area, the
procedure was essentially the same as outlined above. The arrangement of the
samplers and the fan is shown in the figure and the results are tabulated in
table 2.


20 min. after Pan on and
Post. U~nd sturbed Ratiol Pan on IRatiol Fan on IRatioJ Vib -ation Ratio
tican o4t/mi ds/ A/P c/min / dis, minf 8*/min3/l dis in; C/F* c/m / / dis. min./' Dpe
ft. A) ft. m. (B ft. m. (C f. m(D

1 0.33 37 1.9 0.44 49 2.5 0.08 8.9 10.45 5.9 650 32.5
2 0.07 8 0.4 0.17 19 1.0 0.0851 9.4 (0.47 2.0 222 11.1
5 0.12 13 0.7 0.19 21 1.1 0.0891 9.9 10.5 J al 166 18.3

Avg. 0.17 19 1.0 0.27 30 1,5 0.0851 9.4 0.47 3.7 413 20.7

+ T = Transferable Contamination = 20 dis./min./cm.2






Transferable contamination in the affected area was approximately the same as
that on the first test, the average being about 20 dis./nin./cm. .Although
the original air-borne activity and the average activity produced by vibrations
were about the same as in the first test, the activity produced by air currents
was much lower, this being attributed to the fact that the heater fans had
been in constant operation for a long period of time. Such a decrease with
continued air circulation might be anticipated since, presumably, the contani-
nating material would tend to be removed fran regions of high air velocity and
to settle in areas of small disturbances. However, if contamination were being
continuously added to the surfaces or were being continuously disturbed, as
might be the case in some operations, such a marked decrease might not occur.

As will be noted from the data of the above table, 2 sets of samples were taken
after the pedestal fan was started and before vibration was added, the time
between the beginning of the first and second sets being 20 minutes. As in Test
1, the fan caused an increase in activity; however, after it had been in opera-
tion for about 20 minutes, it was found that air contamination had decreased to
about half that found on the samples taken before the fan was started, the
original contamination being partly attributed to air disturbances produced by
the samplers thanselves. This decrease with continued fan operation was
primarily attributed to the settling out of material in regions of low air
disturbance as described above.

Air-borne and Transferable Surface Contamination During Normal Operations

The monthly averages for air-borne activity as indicated by continuous air sampling
at a single fixed location in the K-1405 rdagineering Development Building and at
2 locations in the K-1131 Feed Muanufacture Building during 3-month periods of
normal operation are compared in tables 3 and 4 wzth the average transferable
contamination in those locations. The average ratio of air-borne to transferable
surface contaninat on during the above period when K-1605 was in operation was
0.25 (dis./nin./m. )/(dis ./mifn./an.2), whereas a recent corresponding value for
the K-1131 Building is 0.64.

The above ratio value for K-1131, is of the same order of magnitude as the ratio of
1.9 (disi./nin./n.3)/(dis ./min./cn.2) indicated for this bu ilding by short-term
samples taken at points distributed uniformly throughout the building as compared
with the surface activity;; these results, which are shown in table 5, represent
the averages of about 85 samples per month with the sampling periods varied from
5 minutes to 8 hours, and with some of the samples being taken in locations where
respiratory protection is routinely worn. Because of the uniformity of distribu-
tion of the sample locations within the building, it is felt that these results
represent the best available estimate of the over-all air-borne activity, and
provide a more signi fic ant value for comparison wplth surface-contaminat ion values,
which also represe~nt over-all building averages, than do the continuous samples
taken at fixed locations.

The higher values for K-1131 as compared to K-1405 are probably due both to
larger releases to the air and to more favorable conditions for the production
of air-borne activity fran loose contamination, there being considerably more
equipment vibration in this location than was normally experienced in K-1405.

It should be noted that a large fraction of the air-borne activity detected during
the operating periods could have been due to material released from various
systems rather than to transferable activity which became air-borne. The average
alr-borne activities shown in this report are thus considered as upper limits to
those which may have resulted from transferable contamination under the particular
conditions considered.



Average Air Activity Average Transferable
Month c/min. ft.j dis./min,/m, c/min./100 cm. dls./mln. cm.2 Ratio
(A) (T) /

1 0.059 6.5 480 24 0.27
2 0.054 6.0 320 16 0.38
3 0.033 3.7 660 33 0.11

Avg. 0.25



Avere Air Activlt Average Transferable Surface Activity
Month cmnun/ft. dls./'rmbn.m. c/nin. 100 cm. dis, min. cm.d Ratio
(A) 1T) AT

1 0.21L 23.3 1200 60 0.39
2 0.52 57.8 1000 50 0.87
3 0.33 36 6 1100 55 0.67

Avg. 0.64



Average Air Activity Transferable Surface Contamina~tion
Month c/min./ft, dis./min,/m)j c/min./100~ em.* dis. ancm. Ratio o
(A) (T) AT

1 2.1 2j6 2800 140 1.69
2 3.2 353 3100 155 2.28
3 1.1 14Z 3 900 122&

Avg. 2. 8 311 32~70 163 1.91


From these tests, it appears that tanporary air-borne activity may be produced by
air currents as a result of the presence of transferable contamination on large
fractions of the surfaces in a location. However, the tests were only designed to
indicate if the presence of tranferable activity could result in a possible air-
borne hazard as a result of certain plant operating conditions, and the data should
not be considered as representing accurate quantitative estimates of the relation
between such air-borne activity and the exrtent of transferable surface contamina-

Although the comparisons of air-borne and transferable surface contamination during
operating periods apply only to the conditions considered it is believed that the
air-borne to surface activity ratio of 1.9 (dis./min./mn.3l/(dis./min./am.2) indi-
cated by the samples taken throughout thie IE-1131 Feed Manufacture Building represents
nearly the maximum which might result from transferable contamination in the K-25
Plant, since wind and vibration are considerably more pronounced in this building
than in other plant locations and since some of the noterial probably came from
releases occurring during sampling periods.

On the basis of this ratio, the degree of transferable building-wide surface con-
tamination which would correspond to the M.A.C. of 111 dis./min./m.3 for air-
borne uranian is 58 dia./nin./cm.2 this is equivalent to 1200 c/min./100 em.2 as
obtained by snear samls counted with a Samson alpha survey meter. On the basis
of the extrane air contamination conditions produced by the fans and vibration
during the shor6-tern tests, the transferable activity corresponding to the M.A.C.
for air-borne material is 5.3 dia./min./cm.2.



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