Armored 
Medical Research Laboratory 
Fort Knox, Keikjtuc^v 
First iartial Report 
On 
PROJECT NO. T-5 - TEST OF FLAMEIROOFED CLOTHING 
SUBJECT; FHYSI0L0GIC EFFECTS OF ABASING FLAME- 
clothing in hot environments 
Project No, T-5 
17 July 1945 ARMORED MEDICAL RESEARCH LABORATORY 
Fort Knox, Kentucky 
Project No, T-5 
File SPMEA 727-2 
17 July 1945 
1, PROJECT; HO, T-5 - Test of Flameproofed Clothing, First Partial Reporto 
Subject: Physiologic Effects of Wearing Flameproofed Clothing in Hot Environments, 
a* Authority: Letter, 6th Indorsement, SPMDO 421, ASF, SCO, Washington, 
25, D, C., 7 December 1944. 
b. Purpose; To determine the physiologic effects from wearing flame- 
proofed garments in hot environments, with particular reference to the heat load 
imposed. 
2. DISCUSSION; 
Protection of personnel against fire has always been a problem in armored 
vehicleso A high proportion of the tanks knocked out in combat bum, and the 
incidence of burns to total casualties is disproportionately higher in tank crews 
than in other combat arms. The increasing use of flame as an offensive weapon by 
ground troops emphasizes the necessity of adequate protection of personnel against 
fire. As one of the means of protection, flameproofed clothing has been developed. 
However, the impregnation of clothing with flame resisting substances raises new 
problems apart from the actual flame resistance of the garments. 
It was the purpose of this investigation to study some of these new 
problems, principally those dealing with (l) the heat load imposed by the clothing, 
(2) the general acceptability of the clothing from the standpoint of its flexibility, 
porosity and comfort, and (3) possible toxic effects from the impregnite, both 
locally in the form of skin rashes and systemically in whatever manner they might 
be manifested. Of these, the question of the heat load of the clothing is particu- 
larly important to the Armored Command because in hot climates closed armored 
vehicles may develop internal environments which are more severe than any naturally 
occurring climate. Such conditions impose severe stresses on the crew, making 
additional thermal loads undesirable. 
The garments were prepared by the Technical Division of Chemical Warfare 
Service, The impregnating formula of the flameproofed clothing here studied was 
chlorinated paraffin/CC-2/zinc oxide/aluminura stearate/acetylene tetrachloride in 
the following amounts by weight 139/139/139/17/1623, These garments were labelled 
"D", “Hie initial pick-up was 47# of the original garment weight. As this was 
considered to be excessive, it was reduced to 3B# by one laundering prior to ship- 
ment for test. The impregnite was designed to protect against both fire and chemical 
warfare agents. Garments impregnated with compounds to protect against flame alone 
were not available. For comparison, the men worked nude or in herringbone twill. It has been assumed that adequate fire resisting qualities had been 
imparted to the test clothing and that these qualities were retained throughout 
this study. Representative garments have been submitted to proper agencies for 
flame resistance testsc* 
In the design of these experiments, three categories of hot environments 
were chosen: 
a. Naturally occurring climates 
(1) Hot temperate - D.B. 100°F, W.B. 90°F. 
(2) Hot humid (tropical) - D.B. 90°F, W.B* 88°F. 
b0 Severe conditions which may occur within tanks 
D.B. 120°F, W.B. 80°F to 90°F. 
c. The upper environmental limits at which men can work: 
(1) Saturated conditions D.B. 95°F, W.B. 94°F. 
(2) Hot dry conditions D.B. 120°F, W.B. 92°P. 
The test period consisted of four (4) hours of continuous work requiring the expendi- 
ture of approximately 250 Cals/hour, equal to the energy expenditure of a tank driver 
during rough cross country driving. 
3. CONCLUSIONS: 
a. In hot environments simulating severe naturally occurring hot temperate 
(D.B. 100°F, W.B. 80°F, relative humidity 43$) and hot humid (tropical, D.B. 90°F, 
W.B. 88°F, relative humidity climates; 
(l) Well acclimatized men are capable of working effectively, without 
disability and with equal efficiency whether they wear regulation 
herringbone twill or flameproofed MDM garments. 
(2) In comparison with the nude state, this clothing imposes only a 
slight heat load and two layers of clothing, with or without hood 
end gloves, are tolerated easily and almost as well as one layer 
of clothing. 
b. In hot environments simulating those found within tanks (D.B, 120°F, 
W.B. 88° to 90°F, relative humidity operating in hot climates; 
(1) Clothing imposes definite and considerable heat loads. In the 
performance of a given amount of work, clothed men exhibit greater 
physiologic changes than nude men. 
* N.E.C. Project Q.M.C. No. 27, Preliminary Report Sub-project 27-A5-X-2, dated 
30 April 1945. (2) Fit, well acclimatized men are still capable of working effective- 
ly and without disability when clothed in single layer herringbone 
twill or single layer flamsproofed WDU garments. 
(3) For a given amount of work, greater physiologic changes are in- 
duced in men wearing single layer flameproofed “D" clothing than 
in men clothed in single layer herringbone twill garments. 
c. At the upper limits of hot environments in which men can work (D.B. 9$°F, 
W.B. 94°F, relative humidity 96/t; and D.B. 120°F, W.B. 92°F, relative humidity 2>5%)i 
(l) Clothing now imposes a critical heat load which decreases the 
ability of men to work. It lowers the limiting wot bulb tempera- 
ture of the upper environmental limits by from 2°F to 4°F. 
(2) In this regard, single layer flameproofed **Dn clothing has a 
greater and more deleterious effect than single layer herringbone 
twill. 
(3) The effect of clothing (single layer) on the limiting wet bulb 
temperature of the upper limits at which men can work for four (4) 
hours is summarized in the following table. 
Limiting Wot Bulb 
Saturated Environments 
Limiting Wet Bulb 
Environments with D.Bo 120°F. 
Difficult 
Impossible 
Difficult 
Impossible 
Nude 
94 
96* 
92 
94* 
Single Layer Herring- 
bone Twill 
92 
94 
90 
92 
Single Layer Flame- 
proofed "D" Twill 
92 
94 
B8 
90 
♦ Established in a previous study. 
d. The principal differences between the herringbone twill and flame 
proofed "D" garments are; 
(l) With wear, herringbone twill rapidly becomes pliable. The flame- 
proofed nDn clothing remains rather stiff, hard, coarse and is 
physically irritating to the skin. 
(2) Herringbone twill readily absorbs water while the flameproofed 
"D” garments appear to be relatively water repellent. 
(3) The physical gradient for evaporation (volume sweat evaporated 
per square meter of surface area per mm Hg difference in water 
vapor pressure at the temperature of the skin and the environment) 
through flameproofed "D" clothing in the erect subject was found 
to be roughly two-thirds of the gradient through herringbone twill. e. The flameproofed MDW clothing did not produce toxic changes of either 
a local or systemic nature. 
f. Healthy, fit, well acclimatized men can work effectively in hot 
surroundings when wearing flaraeproafed MD" clothing. At the extreme upper limits 
of heat, the wearing of impregnated clothing induces greater stresses than the 
wearing of ordinary herringbone twill fatigues0 
4. RECOMMENDATIONS; 
a. That the material of trds report be distributed to agencies concerned 
in the development of formulae and ultimate use of clothing designed to protect 
against fire and chemical warfare agents. 
b. That these agencies continue to consider, along the lines developed in 
this report, not only the protective qualities of such clothing but all of the new 
problems which arise in the ultimate wearer* 
Submitted by: 
Ludwig W. Eichna, Major, MC 
Steven M, Horvath, Major, SnC 
Walter B* Shelley, Captain, MC 
Assisted by: 
Howard Golden, Tec 3 
John S. Wagar, Tec 3 
Kenneth C. Davis, Tec 3 
Janies F, Stack, Tec 3 
William J« Robinson, Tec 5 
James W. Gregg, F-4 
APPROVED, 
WILLARD MACHIE 
Colonel, Medical Corps 
Commanding 
4 InclSo 
#1 - Appendix with Tables 1 and 2 
#2 - Tables 3 thru 17 
#3 - Charts 1 thru 12 
#4 - Photographs 1 and 2 APPENDIX 
A. SUBJECTS . EXPERIMENTAL CONDITIONS AND PROCEDURES 
This investigation was conducted in the same general manner as a previously 
reported study.* All observations were made in the laboratory hot room during 
January, February and March, 1945* 
1, Subjects 
Their ages ranged from 20 years to 24 years (average 21,3 years). Their 
weights varied from 140 pounds to 1?B pounds (average 1$6 pounds); their heights 
from 64 inches to 72 inches (average 69 inches); their surface areas from 1„7 
square meters to 2.0 square meters (average 1,89 square meters). They were all 
normal, healthy and physically fito 
2. Environments 
The studies were carried out in three (3) types of environments. 
a. Environments simulating severe naturally occurring climates both hot 
temperate and hot humid (tropical). 
b. Environments comparable to those within tanks operating in hot climatesc 
c. Environments at the upper limits tolerated by working men. The character- 
istics ,of the environments studied are detailed in Table 1. 
TABLE 1 
ENVIRONMENTS IN WHICH HEAT LOAD OF CLOTHING WAS STUDIED 
TYPE OF 
ENVIRONMENT 
Dry Bulb 
Temp. 
Op 
Wet Bulb 
Temp, 
oF 
ielativ© 
humidity 
% 
Severe, naturally 
Hot temperate 
100 
80 
41 
A. occurring 
Very hot temperate 
100 
86 
57 
climates 
Hot humid (tropical) 
90 
88 
92 
Conditions within 
B.' tanks in hot 
120 
88 
28 
environments 
Upper Environmental 
Hot, relatively dry 
120 
90 
31 
limits 
120 
92 
35 
Hot Humid 
93 
92 
95 
Almost saturated 
95 
94 
96 
Project 2, Sub-project 2-11, 2-13, 2-17, SubJ., The Upper Limits of Environmental 
Heat and Humidity Tolerated by Acclimatized, Normal, Young Men Working in Hot 
Environments, dated 2 October 1944* Throughout the teste, the dry and wet bulb temperatures, measured with a 
motor driven psychrometer, carried around the track 3 times, at a level of four (4) 
feet usually did not vary from the desired temperatures by more than 1°F. These 
were recorded every fifteen (15) minutes, The walls and floor were brought into 
equilibrium with the air temperature, by initiating the desired conditions in the 
hot room 12 to 15 hours before the men began to work* Wall and floor temperatures 
were not measured and are assumed to be the same as those previously determined 
under similar conditions; i.e., walls 2°F to 5°F cooler than the air and the floor 
10°F cooler at dry bulb temperatures under 100°F but 20°F cooler at dry bulb tempera- 
tures of 120°F. Additional radiant heat was not supplied. Dry bulb air temperatures 
showed a gradient of 4 to 5° from floor level to the six foot level. 
A mildly turbulent air movement in all parts of the room resulted from the 
combination of hot air inflow from four anemostats in the ceiling and four (4) sixteen 
(16") inch fans placed on the floor at the four comers of a wind tunnel in the middle 
of the room. The fans were directed toward the floor. Wind velocity was not measured 
but was essentially that produced by the movement of the men marching at 3 mph. 
3. MavUy 
The standard work consisted of walking, in single file, at 3 miles per hour 
around a 77 foot track in the hot room. The men carried 20 pound packs, were started 
at 4 minute intervals and walked simultaneously. This work rate was previously de- 
termined to be approximately 250 Calories per hour. Four (4) hours of such continuous 
marching without rest and without leaving the hot environment constituted the standard 
daily work requirement. At hourly intervals during work, each man halted and stood 
erect for 2 to 3 minutes while the hourly check data (heart rate and rectal temperature) 
were obtained. Observations were also made during an hour of quiet sitting in the 
afternoon. 
A standard day consisted of 8 to 9 hours spent in the hot environment: 0745 
hours to 1230 hours, walking period; 1300 hours to 1400 hours, lunch; 1400 hours to 
1600 hours, sitting period. When only one or two hours of walking were accomplished 
in the morning, walking, was substituted for the afternoon sitting period. After 
1600 hours, the men returned to their own quarters on the post and reported at the 
Laboratory the next morning. 
For one week, the men performed the standard work requirement under normal 
cool indoor conditions. Ibis toughened the feet, accustomed the men to the work and 
experimental procedures and tended to produce a more uniform state of physical fitness 
in all men. Then followed an acclimatization period of 10 days during which the men 
worked in an environment of D.B, 120°F*, W.B, 88°F*, H.H. After those two pre- 
liminary training periods, the definitive study of the heat loads of the clothing was 
begun. 
Thereafter each time that the environmental conditions were changed, the men 
were acclimatized to the new environment over a period of three or four days before 
the test runs were undertaken. However, in the environment D.B. 120°F, W.B. 90°P, 
* Henceforth D.B. will designate dry bulb temperature, W.B. wet bulb temperature 
and R.H, relative humidity. 
2 it was necessary to shorten this period to one day. Previous studies have shown 
the need for acclimatization to each new environment regardless of full acclimati- 
zation in previous environments. Only subjects fully acclimatized to the given 
environment behave in such a repetitive fashion that they can serve as standardized 
test subjects for the determination of added loads. In the milder environments 
which do not impose a considerable heat load, prolonged acclimatization is not 
necessary. Since the data in this report are for subjects fully acclimatized to 
each environment, the reactions of the men to the clothing heat load are minimizedo 
It was found that in unacclimatized subjects, clothing induced greater physiologic 
changes0 
4, Food and Water 
The men ate field rations, type A, obtained from the company mess. Only 
the mid-day meal was eaten in the hot environment. The amount of food eaten was 
not measured but generally the men ate heartily. 
All drinking water was made up as a 0.]i solution of sodium chloride and 
maintained at a temperature of 35°C. The amount drunk was carefully measured. The 
water intake approximated the sweat loss except in some men in the most severe 
environments. After leaving the hot room, the men drank tap water. 
5. Clothing 
The following types and assemblies of clothing were worn during this study: 
Shoe** 
Service 
Socks* 
Half 
Wool 
Shorts* 
Cotton 
Drawers 
Cotton 
Under- 
shirt 
Cotton 
Jacket 
Trousers 
1 
Hood 
j loves 
Nude 
X 
X 
Herringbone Twill 
Single Layer 
X 
X 
X 
X 
X 
Flameproof Twill 
Single Layer 
X 
X 
X 
X 
X 
Herringbone Twill 
Double Layer 
x 
X 
X 
X 
X 
X 
Flameproof Twill 
Double Layer 
X 
X 
X 
X 
X 
X 
Flameproof Twill 
Gomple \f © Ass ©mb • 
x 
X 
X 
X 
X 
X 
. I 
X 
X 
* These garments were untreated. 
All flameproofed nDH clothing was impregnated with the formula: chlorinated 
paraffin CC-2/zinc oxide/aluminum stearate/acetylene tetrachloride in the following 
proportions by weight 139/139/139/17/1623. The impregnation renders the garment both 
flameproof and gasproof. The amount of impregnite picked up by each article expressed 
as a percentage of its initial weight was as follows: hood, 43$; gloves, 43$; long 
undershirt, 43$; long drawers, 43$; jacket, 47$; trousers, 47$» The 47$ pick-up by the jacket and trousers was considered excessive and was reduced to 38$ by one laundering 
prior to shipment of the clothing to this laboratory* 
Each subject was issued clothing of the best possible fit from the limited 
stocks and always wore his own clothing in all tests* Each subject’s two piece herring- 
bone twill fatigue uniform and two piece flameproofed fatigue uniform were of the same 
size. The clothing was always worn in the same manner; trouser legs tucked inside of 
the pulled up socks, jacket shirt tucked into the waist of the trousers, top button of 
jacket buttoned and sleeves unbuttoned at the wrists* This method of wear was chosen 
as offering the greatest protection against flame. Since it reduces the bellows 
action of the clothing, these tests were carried out with the clothing imposing their 
maximum heat loads, e. 
6, Observations and Data Obtains 
Upon arrival in the morning, the men remained in the control (70-75°F.) room 
until individually called into the hot room approximately 7 to 10 minutes before be- 
ginning to walk. Each man entered the hot room completely nude, urinated, dried off 
any sweat present and was weighed (within 10 grams). Simultaneously the individual 
items of clothing he was to wear (placed in the hot room 30 to 45 minutes earlier) 
were also weighed (within 5 grams). The subject quickly dressed in these garments, 
and stood erect 4 minutes during which the heart rate*, rectal temperature and skin 
temperature radiometrically (5 areas) were determined simultaneously0 He then began 
marching. During the walking period all water drunk, urine voided and vomitus were 
carefully measured. At hourly intervals, the heart rat© and rectal temperature were 
determined. After 4 hours of walking, the subject stood erect while the heart rate, 
rectal temperature and skin temperature were measured. He then stripped completely, 
urinated, dried off all of the sweat and was weighed. At the same time, his removed 
clothing was weighed, item by item. Throughout the entire teat, records were kept of 
symptoms, complaints, general appearances, vigor and alertness of the men. 
The skin temperature of 5 areas of the body, three covered and two uncovered 
(chest, forearm, calf, cheek, palm) were determined with a radiometer. For clothed 
areas, the clothing was opened or pushed aside just sufficiently to permit placing of 
the radiometer. Undue exposure of clothed areas was avoided. The skin temperatures 
of individual areas were integrated into an average skin temperature by the following 
weighting formula based on the original formula of Hardy: chest, 0,44; forearm, 0,14; 
calf, 0,23; cheek, 0,10; palm, 0,09, Henceforth the term skin temperature will refer 
to this weighted average skin temperature. Rectal temperatures were measured with 
calibrated rectal thermometers. 
Whenever a man was forced to discontinue walking before the required four 
hours, the final observations were taken and the time recorded. No man was allowed to 
discontinue unless objective indications necessitated it. 
7, Charting 
The charts numbered 1, 2, 3, U, 3, B, 9, 10 and 11 indicate the physiologic 
* All other heart rates were determined on the men marking time during the first half 
minute following their removal from the track. responses of the men in various environments. Corresponding tables give the indivi- 
dual data so that the range and variability of individual response may be more fully 
appreciated after examining the principles of group behavior presented on the graphs. 
B. RESULTS 
1. general Consideration 
The principles governing the analysis of the data of this study are those 
which have been developed and reported in detail in previous studies of men in the 
heat. Briefly, these are* (l) Unacclimatized men improve greatly in their responses 
to heat from day to day. Only fully acclimatized men have sufficiently constant 
responses to heat to serve as standardized test subjects for the evaluation of added 
factors and loads in the heat. Using such test subjects, the effect of added loads 
will always be presented in the most favorable light. Unacclimatized men subjected 
to thfe same loads will have poorer performances. (2) The man as a whole must be 
considered and evaluated with proper weight given to phenomena which cannot be repre- 
sented by a number. Appearance, behavior, complaints, vigor, alertness, morale and 
performance must be given due weight. This weighting depends on the experience of 
the observer. It may equal or even exceed the weight given to such numerically 
representable phvsiologic data as rectal temperature, heart rate, sweating rate, skin 
temperature. (3) Since the physiologic data can be represented numerically and 
graphically, most of the following analysis is in these terms. It is to be understood 
that these serve as gross indices and are valid only when they are consistent and 
representative of the picture in the man as a whole. The data here presented are to 
be considered so consistent. (4) Individual subjects exposed to similar heat stresses 
vary considerably in their responses. Therefore, the averaged data for a group has 
been graphed while individual data appears in tablese 
The subjects were divided into two groups of five (5) men each. These two 
groups (henceforth designated A and B) were made as comparable as possible on the basis 
of age, physical characteristics and physiologic responses to work in the heat. 
TABLE 2 
PHYSICAL CHARACTERISTICS OF THE TWO TSST GROUPS 
GROUP 
NAME 
ACE 
WEIGHT 
HEIGHT 
SURFACE AREA 
Pounds 
Inches 
Sq. Meters 
DIM 
21 
140 
68 
1*75 
szu 
23 
144 
69 
1.80 
k 
MAR 
20 
153 
70 
1.86 
LIN 
20 
169 
72 
lo99 
KNB 
20 
168 
72 
1.99 
AYG 
21 
155 
70 
1.88 
LOW 
20 
141 
64 
1.69 
MIC 
20 
145 
69 
1.80 
B 
HIL 
24 
150 
67 
1.78 .< 
| 
I 
KAC 
24 
171 
71 
Tt.97 
SCO 
21 
178 
71 
__ 
na 
22 
157 
68 
1.8^ Additional data on the comparability of the two groups in each environment 
was always established by the day of working nude. This day also afforded a base 
line of response with which the performance in the two types of clothing could be 
compared. 
2. Heat Load - Single and Double Layer Clothing Assemblies; Bnvironmenta 
Simulating Naturally Occurring Hot Climates, 
a. Hot Temperate Climates - DJ3. 100°F, W.3, 80°?, R,H0 92% 
Although the men complained that the single layer flameproofed clothing 
was ‘’hotter1* and provided less ventilation than the single layer herringbone twill, 
the thermal stress imposed by these environments was of such a low order of magnitude 
that the physiologic changes induced in the men were slight regardless of what they 
wore. This is indicated by the observations made on a group of four (4) men working 
in an environment of D.B, 100°F, W.B, 8Q°F, R.H, 1+2% on one occasion nude, on another 
in single layer flameproofed clothing, on a third in double layer flameproofed cloth- 
ing and finally in the full flameproofed assembly (Chart 1 and Table 3)» It is 
apparent that the addition of clothing induced very few physiologic changes; the 
performance, rectal temperature and heart rates remained practically identical. The 
final skin temperature did not fall to as great an extent when additional layers of 
clothing were worn. The values were still within a normal range. The sweating rate 
increased progressively as clothing was added and in the full impregnated assembly 
it was double that in the nude. This is of significance from the standpoint of troop 
water requirements * 
* In the absence of sufficient thermal stress differences, the potential heat 
loads of clothing do not become apparent unless they are very marked. 
- Men worked in both the two layer herringbone twill and the two layer flame- 
proofed assemblies with equal ease and Chart 2 and Table 4 indicates that the physio- 
logic changes induced by the two types of clothing were minimal and practically 
identical. Moreover, insofar as the heart rate and rectal temperature are concerned, 
the physiologic changes in the clothed and nude men were essentially the same. The 
clothed man exhibited an average sweat rate 10C$ above the nude. There was no fall 
in skin temperature such as occurred in the nude men. 
b. Very Hot Temperate Climate - D.B. XOO°F, W.B. 86°F, R.H. 57* 
This environment differed from the previous one by an increased humidity. 
The men worked in this environment for one day only; one group in two layer herring- 
bone twill, the other in two layer flameproofed assembly. Chart 3, Table 5 indicates 
that the physiologic responses of the two groups were very similar. In all measure- 
ments, however, the response of the group wearing flameproofed clothing was insignifi- 
cantly greater than that for the group wearing herringbone twill, With large numbers 
of men, these differences would have probably been statistically significant. There 
was, however, one striking difference in the two groups. One man wearing flameproofed 
clothing was completely exhausted at the end of two hours and was forced to drop out. 
Indeed,his rapid heart rate of 1?1 per minute is largely responsible for the difference 
in the two curves of heart rate. The poor performance and exaggerated physiologic 
responses of this one subject in the presence of the relatively good responses of his 
colleagues is not explained. 
6 c. Hot. Humid (Tropical) Climate - D„B. 90°F, W0B. 88°F, R.H. 93* 
This almost saturated environment is equivalent to that found under 
severe jungle conditions. Here again the men worked for one day only, half of the 
group wearing two layer herringbone twill and the other half wearing two layer flame- 
proofed assemblies. The clothing imposed no handicap to effective work, the physio- 
logic responses in the two groups of men being almost identical (Chart 4 and Table 6), 
The pulse rate and final skin temperatures in men wearing the flameproofed assembly 
are in agreement with the previous indications of the greater load of this assembly. 
SUMMARY 
The studies in these environments have not demonstrated any real differences 
in the heat load imposed by the flameproofed and herringbone twill clothing. These 
experiments indicate that clothed men can work effectively in severe naturally occur- 
ring environments. 
3* Heat Load - Single Layer Clothing Assemblies 
a. Environments Simulating Those Within Tanks in Hot Climates 
D,Bo 120UP, W,B. 88°F, BoH.' 28% 
This environment is representative of the extreme of conditions found 
in the driving compartments of buttoned-up M4A3 tanks operating in midday in mid- 
summer at Camp Polk, La. It imposes a marked thermal stress which can be tolerated 
only after considerable acclimatization. Because of the severity of this stress, the 
studies in this environment were limited to the heat loads imposed by single layer 
assemblies of clothing. Under these conditions, differences in various types of 
clothing were demonstrated0 
Chart 5 and Table 7 show that well acclimatized, fit men can, both nude 
and clothed, work effectively for at least four (4) hours in such an environment» How 
ever, the "cost,” measured in terms of the severity of the physiologic responses was 
greater for clothed men than for nude men. Except for a material increase in the 
sweating rate, the physiologic changes when wearing herringbone twill were only slight* 
ly greater than when the men were nude. When the men wore flameproofed clothing, the 
physiologic changes were greater. The elevated rectal and skin temperatures were 
indications that the clothing offered a considerable barrier to the dissipation of 
heat. However, the sweating rates were identical whether herringbone twill or flame- 
proofed twill was wom0 At D.B. 120°F, W„B. 88°F, the heat load of the herringbone 
twill clothing is still easily tolerated but the load imposed by the flameproofed 
clothing begins to approach undesirable proportions. 
b. Environments at the Upper Limits Tolerated by Working ken 
(1) D.B, 120°F, W.B. 90°F, R.H, 31? 
(2) D.B. 120° F, W.B. 92°F, R.Hw 35? 
(3) D.B. 93°P, W.B. 92°F, R.H. 97? 
(4) D.B. 95°F, W.B. 94°F, R.H. 97? 
The criteria for the upper environmental limits for work in the heat 
utilized in this study were described in detail in a previous report and are briefly 
restated. Environments are considered Relatively easy" when all men finish the 
required four (4) hours of work in good spirits, without difficulty or complaints 
7 and with physiologic changes no greater than those seen in acclimatized men working 
in typically desert or tropical heat; i.e,, group average rectal temperatures under 
101°F and group average heart rates less than 130 beats per minute. Environments 
are considered "difficult" when all men still finish the required four (4) hours of 
work bit now with much effort, many complaints, lack of alertness, approaching 
exhaustion and with physiologic changes exceeding in severity those usually encounter- 
ed in acclimatized men working in hot climates; i0e,, group average rectal tempera- 
tures between 101°F and 102°F and heart rates between 130 and 145 beats per minute. 
Occasionally one man may fail to finish. Environments are considered "impossible* 
when the group as a whole fails to finish the required four (4) hours of walkingo 
The men suffer from many distressing and severe symptoms and many fall out during 
the second hour of effort. Few are capable of finishing the four (4) hours of work. 
The group average rectal temperature exceeds 102°F, and the group average heart rate 
averages 150 beats per minute. Critical judgment must be employed with these "rules 
of thumb" and attention must be given to the over-all picture without focussing on 
other e0g,, physiologic responses. Since these "rules of thumb" are based 
on group phenomena, they can never be used to predict individual performance0 
‘The "second-wind" improvement discussed in the previous report was again 
encountered. This subjective improvement usually occurred late in the second or 
early,in the third hour of work and was again associated with the.approach of an 
equilibrium state. In the clothed men, it also seemed to be associated with the wet- 
ting of the clothing with sweat. As the garments became progressively wetter, the 
men remarked that they felt "cooler"-and they worked more easily. 
The present experiments were designed only to bracket the upper limits and 
delineate the least severe environments in which the men could not work and the most 
severe environments in which they qould work. Only environments of two extreme types 
were studied; i.e,. 
(a) A humid atmosphere with D0B, 93 - 95°F. 
(b) A relatively dry atmosphere with a D,B, of 120°P, 
The environments lore re kept as close to the limit as possible and no work was done to 
define the "relatively easy" environments. Neither was work done to re-study the 
upper limits for the nude men. The environments were always picked with regard to the 
clothed state, "Impossible" in this report is equivalent to the "impossible" in the 4 
previously reported study and upper limit in this report to "difficult" in the pre- 
vious study. 
Charts 6 and 7 indicate the effect of the two types of clothing on the upper 
environmental limits at which men can work. Clothing lowered the upper limit to the 
extent of reducing the limiting wet bulb temperature of the environment by 2°F to 4°F, 
This reduction occurred at both the "upper limit" (Chart 6) and the "impossible" levels 
(Chart 7). Wearing herringbone twill lowered the limiting wet bulb temperature by 2°F 
for both the saturated and the hotter dr£er environments, However, when wearing flame- 
proofed clothing, the limiting wet bulb temperature was lowered by 2°F for saturated 
environments and by 4°F for environments with a D.B. 120°F. This is consistent with 
the greater barrier to evaporation imposed by the flameproofed clothing and hence its 
greater heat load in environmsnts where evaporation is the sole means of losing heat 
and maintaining thermal equilibrium. Its heat load is not as great where evaporation 
is not as significant an avenue of heat loss (saturated environments). -£QMFIps« i-i-£ h 
Analyses of the performances and physiologic responses of the men in these 
"upper limits” environments in the nude, wearing herringbone twill or flameproofed 
clothing are presented in Charts 8, 9, 10 and 11 and in Tables 8, 9, 10 and 11, A 
uniformity of response along a definite pattern is apparent. When clothed in flame- 
proofed garments, the overall response is always the poorest and when nude the 
response is the best} wearing herringbone twill gives an intermediate response0 
Increasing the wet bulb temperature from 88°F to 9CPF when the dry bulb was 
12CPF served to separate the two clothing issues more clearly from the standpoint of 
their respective heat loads. Ifen clothed in herringbone twill were all able to com- 
plete four (4) hours of work whereas half of the men in flameproofed clothing dropped 
out (compare Chart 5 and 8), When the thermal stress of the surroundings became very 
marked (D.B. 120°F, W.B. 92°F and D.B. 95°F, W.B. 94°F) this stress was in itself so 
great that men with both types of clothing were quickly forced to fall out and a 
determination of the added loads of the two garments became difficult as their indivi- 
dual loads were submerged in the greater environmental load (Charts 9, 11). 
4* Physical Characteristics of the Clothing 
a. Gross Characteristics 
The flameproofed twill garments were heavy, thick, stiff, coarse, rough 
and waxy. The men objected mildly to these characteristics. With repeated wear, 
the cloth became more pliable and less coarse but never?as soft and flexible as 
herringbone twill. Its weight remained constant throughout the study indicating that 
the ImpVegnite had not leached out (Table 12). 
The flameproofed clothing was resistant to wetting. (Photograph 1) 
The garments appeared wettest where the clothing came into direct contact with skin 
(shoulders, upper back, anterior surface of the thighs). Unless rubbed directly into 
the cloth, the sweat tended to roll on the clothing like ’’water on a duck's back," 
(Figure X). As a consequence, the sweat was funnelled along the inner surface of 
the clothing, dripping out of the sleeves and running into the socks and out of the 
shoes. With repeated wearing, the flameproofed garments wetted to a greater degree 
than on initial wear, but even so the wetting was not uniform and did not approach the 
water uptake of herringbone twill (Figure 12, Photograph 2). 
b. Absorption of Water 
(1) Uptake of Sweat During Walk 
The reduced capacity of flameproofed clothing to absorb water was 
quantitatively demonstrated. After having been dried for at least fourteen (14) hours 
(sufficient to evaporate the sweat absorbed during the previous day's wear), the 
individual items of clothing were weighed in the hot room, within $ grams, immediately 
before and after walking,. Table 13 indicates that the flameproofed garments absorbed 
less than half as much sweat (water) as the herringbone twill garments. Furthermore, 
this difference in water uptake was the same in both the saturated and the more dry 
environments (Table 13). Since the total sweat output of the men was the same when 
wearing both types of clothing, equal opportunities for the absorption of water were 
presented to both garments. It also appeared that most of the water taken up by the 
flameproofed garments waa absorbed early for the increase in weight of the clothing of 
men dropping out in one or two hours almost equalled that of the clothing of the men who completed four (4) hours of work. 
The water repellancy of the flameproofed clothing decreased with wear 
(Table 14). However, this clothing never absorbed more than one-half as much water 
as the herringbone twill. The increase in water absorbing capacity was not due to 
the leaching out of the flameproofinp compound since the weight of the flameproofed 
garments did not decrease with wear (Table 12). 
Determinations of the absorption of water by the flameproofed long cotton 
underwear were few, but indicated that (l) when relatively small amounts of sweat are 
present, the flameproofed underwear takes up as much sweat as the cotton underwear 
and (2) when larger amounts of sweat are present the uptake falls progressively below 
that for the untreated cotton (Table 15). 
(2) Uptake of Water on Iromersio: 
The absolute differences in the total water absorbing capacities of 
herringbone twill and flameproofed twill were determined by weighing the two types 
of clothing before and after immersion in water. The individual items of clothing 
were dried, weighed, and then immersed in water at 72°F (22°C) for both four and forty- 
five hours, removed and hung individually. The clothing was reweighed when the drip- 
page rate was 4 drops per minute. It was again hung and then reweighed at intervals 
to determine the drying rate. This was determined in two environments: (1) D.B. 72°F, 
W.B. 65°F and (2) D.B. 120°F, W.B. 68°F. 
Table 16 indicates that herringbone twill jackets and trousers absorbed 
water in amounts equal to their initial dry weights; whereas similar flameproofed 
garments absorbed only about one-*half of their dry weight. However, in terms of 
water absorbed, the actual uptake by the flameproofed garments was approximately two- 
thirds of the uptake by the herringbone twill garments. Similarly, flameproofed long 
cotton underwear absorbed but 75# to 85# as much water as regular cotton long under- 
wear. A comparison of Table 16 with Tables 13 and 14 indicates that during wear, 
herringbone twill garments absorbed sweat in amounts approximating 95# of the total 
water absorptive power of the cloth. On the other hand, during wear, flameproofed 
garments absorbed 50# to 60# of the water they were capable of absorbing. Determina- 
tions of the amount evaporated per unit time from the two types of clothing indicated 
that they were approximately the same. However, since the flameproofed clothing had 
absorbed less water (Chart 12), it became dry more rapidly than the herringbone twill. 
c. Effect of Clothing on the Evaporation Gradient Between Skin and Air 
7 \ It appeared that the flameproofed clothing imposed a greater barrier to 
the evaporation of sweat than did the herringbone twill, A series of experiments were 
designed to test this hypothesis and quantitate the effect of clothing on the evapora- 
tive gradient between skin and air. 
These tests were made in an environment of D.B. 120°F, W.B. 92°F on two 
men of similar physical characteristics and with essentially identical physiologic 
responses to work in the heat. The two men were studied nude, in herringbone twill, 
in flameproofed twill and in prewetted flameproofed twill. The standard conditions 
consisted of having the men stand for one-half hour in a wide pan containing mineral 
oil under which unevaporated sweat collected. The subject’s dry clothing, a thermo- 
couple harness, a ’’test*’ towel and the pan were weighed while the man dried himself thoroughly with a "discard” towel, The pan was placed on the weighing platform, 
the subject quickly donned the harness and test clothing, then stepped into the 
pan. The weight of clothed man plus pan was obtained at the beginning and end of 
30 minutes. The change in weight indicated evaporated sweat. During the stand, the 
skin temperature (by thermocouple from 4 areas) and the surface temperature (by 
radiometer from 5 areas) were determined five times. When the man was nude, skin 
temperature readings were made by radiometer. Dry and wet bulb temperatures of 
the air at the subjects chest level were determined 3 times during the stand and 
the heart rate and rectal temperature were taken at the beginning and end. At the 
end of 30 minutes, the final weight and temperature data were taken, the subject 
undressed, dried in the "test" towel following which the removed clothing and 
harness, towel and pan were weighed. 
From this data were calculated the total sweat loss, the evaporated sweat 
and its heat equivalent, the mean (average) skin temperature, the vapor pressure 
of the air, the vapor pressure of water at the temperature of the skin, and the 
change in body heat content (heat storage). Coefficients used in the storage 
calculations were 0,33 for skin temperature and 0,67 for rectal temperature and 
0,83 for the specific heat of the body. 
Table 1? presents the derived data of these experiments. It indicates 
the extent to which clothing imposed a barrier to evaporative cooling for the 
standing Subject, Flameproof twill imposed a greater barrier than herringbone 
twill as shown by the smaller volume of sweat evaporated and the decreased heat 
lost by its evaporation. Herringbone twill cloth decreases the total evaporative 
heat loss observed in the nude subject by and flameproofed twill cloth by 27/£, 
The evaporative gradient (Calories of heat lost per square meter of body surface 
per mm Hg difference in vapor pressure of the water at the temperature of the skin 
and air) follows the same pattern being lowered 13$ by herringbone twill and 2 
by flameproofed twill (nude, 9o9> herringbone twill, 8,6; flameproofed twill, 7»1). 
The physiologic implications of these clothing barriers to evaporative 
cooling are the progressively higher skin and rectal temperatures and the gain in 
body heat content as the men went from the nude state to herringbone twill to 
flameproofed clothing. For example, when nude, the men were in thermal equilibrium 
and stored no heat; when wearing herringbone twill, they stored heat at the rate of 
8o2 and when in flameproofed twill, their heat storage was about 
twice as great, being 14<>4 Calories/ii^/Hour, 
Wearing flameproofed garments which had been previously wetted by immersion 
yielded total evaporative heat losses and evaporative gradients which closely approxi- 
mated those for the nude state (Table 17). However, it is likely that they do not 
represent the actual heat loss from the body for a considerable amount of the evapora- 
tion probably took place at the surface of the clothing and not at the skin surface. 
Evaporation at the clothing surface may not be as beneficial in cooling the body. 
That this may indeed have been the case is indicated by a definite heat storage of 
6,2 during wearing of the prewetted garments; whereas no heat storage 
occurred in the nude state where similar evaporative heat losses and evaporative 
gradients were obtained. 
An evaluation of the real meaning of the evaporative gradients here determin- 
ed is complicated by the progressive wetting of the clothing during the test period. 
Hence the gradient is in a sense a mixed one, pertaining neither to dry clothing nor 
11 to wet clothing, but to sin indefinite state of the clothing which is progressively- 
changing from dry to wet. 
5. Toxic Sffecta 
No toxic effects attributable to the impregnation were encountered during 
this study in which some men wore the flaraeproofed garments as many as 18 times 
for a total of 46 hours of wear. The garments were not worn continuously through- 
out the day, but rather intermittently during test periods varying from 1 to 4 
hours in length. Neither generalized systemic effects nor cutaneous toxic reactions 
resulting from direct contact were seen. 
However, an erythematous and maculo-papular dermatitis was noted in some 
subjects when wearing either herringbone twill or flameproofed garments. These 
resulted from the mechanical irritation of the cloth, being localized to areas 
where rubbing occurred, such as the groins, anterior surface of the thighs, the 
upper thorax, the belt line and, lower legs. 
The intermittent and relatively short duration of wear of these garments 
did not constitute an entirely satisfactory test of the toxic potentialities of 
the impregnite. Nevertheless, acute toxicity can be excluded by these experiments. 
6. Flame Resistance of the Clothing 
This has been reported separately,* 
*N0R,C. Project Q.M.C. Ho, 27, Preliminary Report, Sub-Project 27-A5-X-2, 
dated 30 April 1945* o 
3 
SKIN 
TEMP. 
WEIGHT LOSS 
RECTAL TEMPERATURE °F 
PULSE RATS/™ 
o 
(AvgoWtg0) 
(Sweat) 
M 
sc 
cu 
£ 
S 
o 
3 
3 
Hours 
Hours 
Gr/Hr. 
3 
0 
1 
2 
3 
4 
0 
1 
2 
3 
4 
Init 
Final 
Kac 
98.4 
99 ol 
99.1 
99.1 
99 oO 
99 
99 
105 
102 
102 
94.8 
92=3 
448 
B 
Sco 
99 = 2 
100=3 
100.1 
100 oO 
99=7 
102 
105 
108 
105 
102 
95=7 
92=4 
639 
M 
Mic 
98.6 
99 o3 
99-1 
98.9 
99=0 
93 
90 
93 
90 
87 
95 = 5 
94=3 
451 
| 
Low 
98.6 
99.6 
99 o3 
99 =1 
99 oO 
105 
108 
102 
99 
99 
96.4 
93 = 5 
520 
AVG. 
98=7 
99 o 5 
99=4 
99=3 
99=2 
100 
100 
102 
99 
98 
95.6 
93=1 
514 
6 
Kac 
98.6 
99=0 
98o9 
98o9 
99=0 
99 
120 
108 
105 
108 
93 o 5 
93.6 
709 
tM 
B 
Sco 
98=7 
99=7 
100o0 
99.6 
99 = 5 
96 
99 
102 
99 
96 
95=9 
92=8 
938 
32 
Mic 
98.6 
99 ol 
99=3 
99.3 
99 =4 
90 
96 
99 
96 
99 
97 = 5 
93 = 5 
759 
cC Ctj 
Low 
98.9 
99.4 
99.6 
99=3 
99 o 5 
93 
93 
102 
105 
93 
94=7 
94.1 
857 
fxl 3 
3 
M 
CO 
AVG. 
98o7 
99 o3 
99.5 
99 =3 
99 =4 
95 
102 
103 
101 
99 
95=4 
93.5 
816 
e 
>-» 
Kac 
98=7 
99o4 
99.6 
99=2 
99=1 
96 
102 
99 
102 
105 
94=0 
94=2 
759 
q3 
B 
Sco 
99o2 
100 o0 
100 o0 
99.8 
99=9 
114 
108 
99 
105 
102 
94=9 
95=1 
1357 
til 
Mic 
98.5 
99o2 
99.2 
99ol 
99.2 
99 
96 
96 
102 
96 
94.4 
94.3 
1051 
O, _) 
■>:§ 
Low 
98.6 
99o4 
99=9 
99=5 
99 =4 
84 
102 
93 
102 
93 
94.8 
94.1 
877 
8 
AVG. 
98.8 
99o5 
99=7 
99=4 
99.4 
98 
102 
97 
103 
99 
94=5 
94.4 
1011 
Kac 
98.2 
99ol 
98 o9 
99 oO 
99=1 
111 
114 
102 
108 
108 
94=9 
94 o 8 
850 
Q jH *-3 
B 
Sco 
99oO 
100o5 
100=6 
99=8 100.I 
93 
123 
114 
111 
105 
95,8 
94=2 
123? 
S 
Mic 
98.9 
99 o 5 
99=4 
99=1 
99 ol 
111 
114 
99 
90 
96 
95=3 
94,8 
1055 
Ct 
* JS CO 
Low 
98,8 
99=7 
99.6 
99=3 
99 o 5 
105 
117 
105 
108 
102 
95.8 
95=4 
831 
98=7 
*4 
AVG. 
99 o7 
99.6 
99.3 
99.5 
105 
117 
105 
104 
103 
95.4 
94=8 
992 
TABLE 3 
The Physiologic Responses of Working Men Wearing 
Increasing Amounts of Flameproofed Twill 
D.Bc 100°Fo - W,B. 80°Fo CLOTHING 
GROUP 
NAME 
* 
RECTAL TEMPiiEATUEE °F 
PULSE RATE/MIN 
SKIN TEMP. 
(AvgoWtg,) 
°F 
WEIGHT LOSS 
(Sweat) 
G*n/Hr0 
0 
1 
Hours 
2 
3 
4 
0 
1 
Hours 
2 
3 
4 
Inito 
Final 
Lin 
98 = 7 
100 02 
100 o3 
100.2 
100 o 2 
102 
117 
108 
102 
105 
95.2 
94.6 
502 
A 
Kne 
98o9 
99o7 
99.1 
99.0 
99.0 
96 
96 
84 
87 
87 
94.4 
93=0 
560 
w 
ri 
Mar 
98.6 
99ol 
99.4 
99.3 
99.1 
102 
111 
102 
96 
99 
95=4 
93.2 
549 
23 
Dim 
98=7 
99o7 
99 o3 
99.4 
99.4 
96 
105 
99 
99 
96 
95=6 
93 = 5 
433 
AVGa 
98=7 
99=7 
99=5 
99.5 
99.4 
99 
107 
98 
96 
97 
95=1 
93.6 
511 
Kac 
98 o A 
99.1 
99.1 
99.1 
99.0 
99 
99 
105 
102 
102 
94=8 
92 =3 
448 
D 
Sco 
99.2 
100*3 
100.1 
100o0 
99=7 
102 
105 
108 
105 
102 
95=7 
92.4 
639 
w 
D 
Mic 
98=6 
99 o3 
99 ol 
98o9 
99 o0 
93 
■90 
93 
90 
87 
95 = 5 
94=3 
451 
I 
Low 
98=6 
99.6 
99.3 
99.1 
99=0 
105 
108 
102 
99 
99 
96.4 
93 = 5 
520 
AVG. 
9807 
99=6 
99=4 
99.3 
99=2 
100 
101 
102 
99 
98 
95.6 
93=1 
514 
Lin 
98.9 
99.6 
99.6 
99 o 5 
99 = 5 
78 
93 
108 
96 
96 
95=0 
94=2 
1155 
• 
Kne 
99ol 
99=4 
99 o2 
99.3 
99.2 
105 
108 
87 
108 
84 
94=4 
94=i: 
956 
H 
o 
A 
Mar 
98o4 
99.3 
99.8 
99.8 
99.6 
84 
96 
99 
117 
105 
94=3 
95 =7 
859 
CQ 
• 
X 
Dim 
98 o8 
99 o 5 
99.8 
99=9 
99.8 
87 
93 
87 
108 
96 
94.8 
93=8 
823 
AVGo 
98.8 
99=5 
99.6 
99.6 
99 = 5 
89 
98 
95 
107 
95 
94.6 
94=5 
948 
Kac 
98=7 
99o4 
99.6 
99.2 
99.1 
96 
102 
99 
102 
105 
94=0 
94=2 
759 
p * 
Sco 
99=2 
lOOoO 
lOOoO 
99.8 
99=9 
114 
108 
99 
105 
102 
94=9 
95=1 
1357 
Q 
Mic 
98 = 5 
99 o2 
99.2 
99.1 
99=2 
99 
96 
96 
102 
96 
94=4 
94=3 
1051 
• 
a. 
• 
Low 
98=6 
99.4 
99.9 
99.5 
99=4 
84 
102 
93 
102 
93 
94.8 
94=1 
877 
f*4 
AVGo 
98.6 
99.5 
99.7 
99.4 
99=4 
98 
102 
97 
103 
99 
94=5 
94=4 
1011 
TABLE 4 
The Physiologic Responses of Working Men Wearing 
Two Layer Flameproofed Twill and Herringbone Twill 
D.B. 100°Fo - W.B. 80°Fe CiJ 
25 
SKIN 
TEMP. 
HEIGHT LOSS 
RECTAL 
TEMPERATURE c 
*F 
PULSE RAT^MIN 
o 
(Avg. 
Wtg.) 
(Sweat) 
E 
ft. 
as 
3 
op 
O 
Hours 
Hours 
Gm/Hr, 
o 
S 
sc 
0 
1 
2 
3 
4 
0 
1 
2 
3 
4 
Init, 
Final 
Lin 
99*1 
100 02 
100.6 
100.3 
100.0 
93 
126 
105 
126 
117 
96=2 
94=8 
2no 
A 
Kne 
98.5 
100.0 
100 o0 
99.4 
99.3 
102 
129 
.99 
120 
in 
95=8 
94.3 
1457 
A 
Mar 
98 o 2 
100 o0 
100 o 2 
100.1 
100.2 
105 
144 
138 
135 
126 
96=1 
95.7 
1362 
E-^ 
CQ 
• 
Dim 
98=5 
99.9 
100.5 
100.2 
100.2 
90 
132 
129 
120 
120 
95.4 
94=6 
1281 
K 
AVG. 
98.6 
100o0 
100.3 
100,0 
99*9 
98 
133 
118 
125 
119 
95.9 
95.0 
1552 
Kac 
98.4 
99 o7 
99 o9 
99 = 8 
99=8 
96 
144 
132 
129 
120 
94 o9 
94.9 
1213 
B 
Sco 
9808 
100.3 
101 o0 
100 o3 
100.4 
120 
147 
156 
141 
129 
95.6 
95.2 
2005 
/-N 
r-* 
Mic 
98.4 
100.0 
101,0* 
- 
- 
117 
153 
171* 
- 
- 
- 
- 
2198 
• 
cu 
Low 
98=6 
100ol 
100.4 
100.4 
100.3 
105 
129 
132 
120 
129 
96=0 
95.8 
1321 
Uh 
AVG. 
98.6 
100 o0 
100 c6 
100.2 
100.2 
no 
143 
148 
130 
126 
95.5 
95.3 
1634 
*Unab 
)le to 
continue after 
two (2) hours of walking. 
TABLE 5 
The Physiologic Responses of Working Men Wearing Two layer 
Flameproofed Twill and Herringbone Twill 
D.B. 100°F, - W.B. 86°F. o 
SKIN 
TEMP, 
WEIGHT LOSS 
S85 
M 
RECTAL TEMPERATURE °F 
PULSE RATEA(IN 
• 
(Avg.Wtg,) 
(Sweat) 
E 
0- 
o 
Op 
3 
s 
3 
Hours 
Hours 
Grn/Hr. 
o 
o 
0 
1 
2 
. 3 
4 
0 
1 
2 
3 
4 
Init 
. Final 
Lin 
99oO 
100,2 
100 o 2 
100,0 
100,1 
99 
102 
102 
117 
117 
96.2 
95=2 
2026 
A 
Kne 
98„9 
lOOoO 
99o8 
99.4 
99.6 
102 
104 
93 
108 
117 
95=7 
95=4 
1230 
A 
Mar 
99 o0 
100 o3 
100,4 
100,0 
100,3 
129 
117 
117 
120 
123 
96.4 
95.6 
1150 
♦ 
CQ 
Dim 
98*2 
100,0 
100,7 
100,5 
100,9 
69 
102 
120 
120 
132 
94.6 
95 = 5 
1117 
X 
AVGo 
98,8 
100,1 
100,3 
lOOoO 
100,2 
100 
106 
108 
116 
122 
95=7 
95=4 
1381 
Kac 
98,8 
99.6 
99o8 
99.9 
100,0 
114 
117 
126 
132 
141 
95 = 1 
96.2 
1113 
B 
Hil 
99.1 
99,8 
100,1 
99.7 
100.1 
99 
102 
114 
123 
120 
95.9 
96.3 
1218 
Mic 
99 o0 
99.9 
100,0 
100,2 
100,3 
111 
102 
126 
138 
144 
95.2 
96.8 
1653 
Q 
• 
cu 
Low 
98.5 
99 o7 
100,0 
100.2 
100.4 
111 
114 
120 
135 
141 
94.5 
96.3 
1201 
• 
AV£. 
98o8 
99o8 
100.0 
100,0 
100,2 
109 
109 
122 
132 
137 
95.2 
96.4 
1296 
TABLE 6 
The Physiologic Responses of Working Men Wearing 
Two Layer Flameproofed Twill and Herringbone Twill 
D.B. 90°F. - W.B. 88° CLOTHING 
GROUP 
RECTAL TEMPERATURE °F 
PULSE RATS/MIN 
SKIN TEMP, 
(AvgoWtg,) 
Op 
WEIGHT LOSS 
(Sweat) 
Gm/Hr. 
NAME 
0 
1 
Hours 
2 
.3 
4 
0 
1 
Hours 
2 
3 
4 
Init. 
Final 
Dim 
99.1 
lOOol 
100,0 
100 02 
100 oO 
99 
114 
120 
108 
99 
97,6 
96.9 
1024 
Szu 
98o7 
99o2 
99,3 
99.2 
99 o3 
108 
111 
105 
99 
114 
97.2 
97 oO 
909 
A 
Mar 
98.5 
99 o 5 
99o7 
99.6 
99.6 
96 
102 
111 
105 
120 
97 08 
97,7 
1054 
Lin 
98,4 
99,7 
99.6 
99.6 
99.8 
84 
96 
105 
102 
105 
97,1 
96.0 
1444 
§ 
Kne 
98,5 
99.1 
99 o3 
99 oO 
99oO 
93 
111 
120 
84 
87 
97o4 
97.2 
1005 
AVGo 
98,6 
99o5 
99.6 
99 o 5 
99 o5 
96 
107 
112 
100 
105 
97,4 
97,0 
1087 
Low 
98.5 
99,9 
100 oO 
100 o0 
lOOol 
96 
108 
105 
108 
120 
97,7 
98o2 
1148 
Mic 
98.8 
99.6 
99.6 
99.6 
100 oO 
126 
129 
126 
123 
135 
96.3 
96.2 
1062 
B 
Hil 
98.3 
99 o*5 
99,4 
99.6 
99,8 
102 
120 
111 
103 
126 
96.5 
96.9 
1022 
Kac 
98.6 
99.6 
99,5 
99.6 
99o7 
99 
108 
117 
120 
126 
97.0 
97,7 
982 
§ 
Sco 
98,8 
99 o9 
100,1 
100,2 
100.0 
114 
117 
117 
99 
105 
99,1 
96.7 
1388 
> 
AVG0 
98.6 
99 o7 
99,7 
99.8 
99 o9 
107 
116 
115 
112 
122 
97,3 
97,1 
1120 
Low 
98,7 
100o3 
100,6 
101,0 
100o5 
120 
135 
138 
129 
126 
98,6 
98 oO 
1812 
Mic 
99 oO 
99.8 
99 o9 
99,7 
99.7 
99 
123 
132 
123 
123 
98.7 
97,1 
1756 
• 
B 
Hil 
98.6 
100o2 
100.4 
100 o 5 
100,5 
105 
141 
135 
135 
126 
96.6 
97,1 
1544 
£H 
e 
Kac 
98.6 
100 02 
100,2 
100 o3 
100o2 
123 
135 
132 
132 
126 
96o6 
97,2 
1499 
CP 
• 
ac 
Sco 
98.6 
100,6 
100 o4 
100o2 
100 o0 
117 
138 
117 
111 
129 
98.4 
96,7 
2039 
AVGo 
98,7 
100 02 
100 o3 
100 o3 
100 o 2 
113 
134 
131 
126 
126 
97,8 
97,2 
1730 
Dim 
98.4 
101 o 3 
101,6 
101 o3 
101,0 
81 
135 
132 
129 
132 
97.2 
97.8 
1701 
Seu 
98.4 
100.6 
101,4 
101 o4 
101 o 4 
99 
129 
135 
138 
129 
97,7 
98 o7 
1482 
A 
Mar 
98.6 
101 o 2 
101.5 
101,3 
101,0 
111 
153 
153 
153 
144 
97,8 
98,0 
1752 
• 
Lin 
98.8 
101 o 7 
102 o 3 
102 o 4 
102 o 5 
96 
120 
117 
126 
123 
97,7 
99,7 
2040 
Cu 
• 
Kne 
98,8 
100.8 
101 o 5 
101,6 
101 o 5 
102 
123 
117 
108 
117 
97c2 
99,1 
1755 
AVGo 
98.6 
101,1 
101.7 
101.6 
101 o 5 
98 
132 
131 
131 
129 
97 0 5 
98.7 
1746 
TABL3 7 
The Physiologic Responses of forking Men Wearing 
Flameproofed Twill and Herringbone Twill 
D.3. 120°Fo - W.B. 88°F0 o 
9 
SKIN 
TEMP. 
WEIGHT LOSS 
2S 
M 
RECTAL TEMPERATURE °F 
PULSE RATE/MIK. 
(AvgoWtg.) 
(Sweat) 
e 
CU 
3 
c 
T 
o 
Hours 
2 
Hours 
2 
Gm/Hr o 
3 
O 
o 
g 
i 
S5 
i 
0 
1 
3 
4 
0 
1 
3 
4 
Initc 
Final 
Dim 
4=0 
99 o0 
100.2 
100.4 
100.4 
100.4 
90 
117 
120 
117 
n7 
96.9 
96.8 
1477 
Szu 
4=0 
99=1 
99.8 
99 o7 
99.6 
99=8 
111 
in 
114 
n? 
114 
97.9 
96.7 
1616 
A 
Mar 
4.0 
98.0 
10C.1 
100.9 
100.2 
100.4 
105 
141 
123 
129 
123 
97=0 
96.8 
1725 
Lin 
4.0 
99.0 
100.5 
100.7 
100.5 
100.4 
96 
in 
123 
n7 
n? 
97.7 
96.9 
2245 
Kne 
4=0 
98.3 
99o9 
100,1 
99o9 
99*9 
99 
126 
117 
117 
123 
97*0 
97 o 5 
1662 
AVGo 
98.7 
100.1 
100.4 
100.1 
100.2 
100 
121 
n9 
n9 
n9 
97*3 
96.9 
1741 
Low 
4=0 
98.4 
99.6 
100.2 
99o9 
100.2 
96 
114 
120 
120 
117 
96.5 
97.8 
1665 
Uic 
4.0 
98.5 
100.0 
100.5 
100.4 
100.3 
117 
126 
129 
123 
123 
97.6 
96.8 
1901 
W 
B 
Hil 
4o0 
96o7 
99o7 
100.0 
99 o9 
99=9 
108 
123 
111 
in 
117 
96.5 
96.6 
1477 
Kac 
4=0 
98.6 
99=7 
99.8 
99=7 
99.8 
102 
123 
123 
120 
114 
96.3 
97 o2 
1421 
z 
Sco 
4.0 
99 o0 
100.4 
100.3 
99=9 
100.1 
111 
129 
126 
123 
123 
97*7 
96.9 
2239 
AVG, 
98.6 
99o9 
100.2 
100.0 
100.1 
107 
“ 123 
122 
n9 
119 
96.9 
97 o0 
1737 
Low 
6.0 
98.4 
100.7 
101.2 
100.9 
100.8 
96 
120 
129 
132 
135 
97 <>3 
97*9 
1543 
Mic 
4.0 
98.3 
100.7 
101.2 
101.0 
101.0 
102 
120 
153 
138 
138 
97*3 
97=3 
2123 
• 
B 
Hil 
4=0 
99 o3 
100.6 
101.0 
100.1 
100.0 
102 
117 
126 
123 
117 
97*1 
97=3 
1859 
6-* 
a 
Kac 
4o0 
98o4 
100.4 
100.7 
100.3 
100 „0 
111 
135 
129 
123 
132 
97 o3 
97o2 
1711 
m 
• 
Sco 
4.0 
98.7 
100.8 
100.6 
100.3 
100.2 
105 
123 
135 
126 
120 
98.2 
97*1 
2693 
AVG. 
98.6 
100.6 
100.9 
100.5 
100.4 
103 
123 
134 
128 
128 
97.4 
97=4 
1986 
Dim 
2.0 
98.5 
100.9 
101.8* 
.. 
_ 
96 
126 
141* 
— 
«> 
98,1 
97.6* 
1863 
Szu 
4.0 
98o4 
100.4 
100.6 
101.0 
,100.6 
108 
126 
144 
144 
126 
96.9 
98.2 
1988 
Q 
A 
Mar 
2.4 
98.6 
101.5 
102.9 
102.8* 
- 
117 
138 
156 
156* 
- 
97.8 
97 ol* 
2376 
4ft 
Oh 
Lin 
4.0 
98.8 
101.4 
102.0 
101,9 
101.8 
102 
147 
150 
138 
153 
97.7 
98.1 
3121 
• 
Kne 
2o7 
98.8 
101.1 
101.8 
102.0* 
- 
114 
123 
145 
147* 
- 
97*0 
98.7* 
2231 
AVG. 
98.6 
101.1 
101.8 
101.4 
101.2 
107 
132 
147 
141 
140 
97o5 
98.2 
2312 cr 
*D* 
ita t 
aken at time of cessation of w&lki 
ng - 
not used in averages 
fcr that hour. 
TABLE B 
The Physiologic Responses of Working Men 
Wearing Flameproofed Twill and Herringbone Twill 
D.B. 120°F. - W.B. 90°Fo CLOTHING 
GROUP 
H 
HRS. WALKED 
RECTAL TEMPERATURE °F 
PULSE RATE/MIN 
SKIN TEMP. 
(Avg.Wtg.) 
°F 
WEIGHT LOSS 
(Sweat) 
Gm/Hr. 
0 
1 
Hours 
2 
3 
4 
0 
1 
Hours 
2 
3 
4 
Init, 
Final 
Dim 
4.0 
98.8 
100o9 
101,0 
100.9 
101,1 
93 
135 
132 
120 
120 
97.5 
97.6 
1790 
Szu 
4.0 
98,9 
100,2 
100.1 
100,8 
100,9 
105 
129 
123 
129 
126 
97.6 
98.6 
1747 
w 
A 
Mar 
4.0 
97.8 
100.4 
100.5 
100,7 
100.6 
99 
141 
123 
126 
120 
97.4 
97.8 
2325 
g 
Lin 
4.0 
99.2 
101,2 
101.2 
101.0 
101.1 
96 
126 
126 
117 
123 
97,6 
98,6 
2294 
ss 
Kne 
4o0 
98,4 
100,2 
100,3 
100,2 
100,9 
87 
123 
99 
123 
120 
96,8 
99.1 
1949 
AVGo 
98.6 
100.6 
100,6 
100,7 
100,9 
96 
131 
121 
123 
122 
97.4 
98,3 
2021 
Low 
4.0 
98,6 
100,1 
101.4 
101.7 
102,1 
102 
144 
129 
120 
132 
98,1 
99.4 
1396 
Mic 
4.0 
98,8 
100.3 
100,4 
100,5 
101,0 
105 
126 
150 
123 
126 
97,8 
98,7 
2071 
w 
B 
Hil 
4.0 
98 o4 
100,4 
100,4 
100,4 
100,6 
87 
111 
102 
117 
111 
97.2 
98,7 
1562 
g 
Kac 
4.0 
98,6 
100,0 
100,0 
100,2 
100,7 
96 
120 
120 
132 
123 
97.1 
98,5 
1684 
25 
Sco 
4.0 
99.3 
101,4 
101,2 
101,2 
101,5 
in 
156 
123 
120 
126 
97,8 
98,2 
2543 
AVG. 
98 o7 
100,4 
100,7 
100,8 
101,2 
100 
131 
125 
122 
124 
97,6 
98.7 
1851 
Low 
2,4 
98,9 
102,0 
103.1 
103.2* 
- 
105 
144 
144 
150* 
98.0 
H* 
O 
O 
0 
1589 
Mic 
2,7 
98,8 
101,3 
101,8 
102,4* 
- 
129 
147 
141 
156* 
- 
98,3 
99,6* 
2063 
o 
E- 
B 
Hil 
4.0 
98,2 
100,8 
101 o 7 
101,7 
102,0 
102 
129 
in 
147 
123 
97.9 
99.4 
1688 
ft 
m 
Kac 
4.0 
98o7 
101,2 
102,0 
102,0 
101.8 
105 
150 
147 
141 
150 
97.2 
99.3 
1774 
• 
ac 
Sco 
4.0 
99.0 
102.0 
102,3 
102,4 
102,5 
n4 
147 
132 
132 
126 
98,1 
99.2 
2477 
AVGo 
A 
98 o7 
101,5 
102,2 
102,0 
102.1 
m 
143 
135 
140 
133 
97,9 
99.3 
1718 
Dim 
106 
98.6 
102,2 
103o4* 
— 
<» 
105 
141 
132* 
97.4 
99,8* 
1957 
Szu 
2.0 
98.8 
101.6 
102,9* 
- 
- 
U7 
138 
135* 
- 
- 
98.7 
100.5* 
1955 
Q 
A 
Mar 
1.2 
97.8 
102.1 
102,8* 
- 
- 
99 
180 
168* 
- 
- 
97,5 
ioa3* 
2397 
ft 
(X 
Lin 
1,6 
99.1 
102,8 
103,6* 
- 
- 
108 
141 
129* 
- 
- 
98.2 
100,4* 
2569 
ft 
Ct* 
Kne 
4o0 
98,6 
102,0 
103.5 
103*7 
103.4 
102 
141 
141 
138 
141 
97.9 
100,8 
1824 
AVG, 
98.6 
102,1 
103.2 
103.7 
103.4 
106 
148 
138 
138 
141 
97.9 
100,8 
2140 
*Data taken at time of cessation of walking 
- not used in averages for 
that hour. 
TABLiS 9 
The Physiologic Responses of Working I'en 
Wearing Flam©proofed Twill and Herringbone Twill 
D.B. 120°F, - W.B. 92°F. CLOTHING 
GROUP 
NAME 
RECTAL 
TEMPERATURE °F 
PULSE RATE/MIN 
c 
SKIN TEMP. 
(Avg.Wtg,) 
°F 
WEIGHT LOSS 
(Sweat) 
Gm/Hr, 
0 
1 
Hours 
2 
3 
4 
0 
1 
Hours 
2 
3 
4 
Init, 
Final 
Dim 
98.8 
100 o0 
100,4 
100,6 
100,6 
93 
129 
114 
123 
117 
95.3 
96.4 
1706 
Szu 
98.0 
99.4 
99.5 
99.8 
99,8 
87 
108 
120 
123 
123 
95«2 
96.8 
1705 
A 
Mar 
98,4 
100.3 
100.7 
100.8 
100.6 
120 
150 
153 
141 
138 
95,3 
96.7 
1791 
w 
Lin 
99o7 
100 <>7 
100.6 
100,7 
100,6 
93 
117 
108 
117 
126 
96.4 
96.5 
1908 
1 
Kne 
98.4 
99.8 
100,1 
100,4 
100,3 
90 
114 
117 
117 
120 
94.8 
97,0 
1848 
AVG, 
98.7 
100.0 
100o3 
100,5 
100.4 
97 
124 
122 
124 
125 
95.4 
96.7 
1792 
Low 
98.6 
100.4 
100,7 
101,0 
101,2 
90 
150 
129 
120 
126 
93*0 
97,3 
1466 
Mic 
98.6 
99.9 
100 o 6 
100,5 
100,6 
114 
132 
153 
129 
126 
95ol 
96.8 
1836 
B 
Hil 
93.6 
99.6 
99o9 
100,0 
99=.9 
93 
99 
114 
126 
105 
95,0 
96.8 
1483 
w 
Q 
Kac 
99o3 
100 o 2 
100,3 
100,7 
101,4 
102 
126 
126 
138 
129 
94.6 
97 ol 
1148 
5 
ss 
Sco 
98o8 
100 o 5 
100 o 8 
100,8 
101 ol 
105 
141 
123 
126 
129 
95.8 
96,6 
2458 
AVGo 
98 08 
100,1 
100.5 
100.6 
100.8 
101 
130 
129 
128 
123 
94,7 
96,9 
1678 
Dim 
98.5 
101o0 
101.1 
101,3 
101,4 
93 
135 
135 
123 
132 
95.6 
97.8 
1760 
Szu 
98o7 
100.6 
101.5 
101,0 
100,7 
105 
129 
141 
132 
123 
95*9 
97.9 
1760 
o 
A 
Mar 
98.1 
100o9 
101.6 
101.3 
101.6 
102 
141 
144 
150 
156 
95o9 
97,6 
2244 
Eh 
• 
Lin 
99 o4 
101,7 
102,3 
102,0 
102,1 
105 
135 
126 
144 
144 
96,6 
98,1 
2353 
OQ 
• 
Kne 
98o5 
100 o 9 
101,2 
101.0 
101,0 
108 
120 
129 
129 
123 
95*8 
98.2 
1824 
AVG. 
98.6 
101.0 
101.5 
101.3 
101,4 
103 
132 
135 
136 
136 
96.0 
97.9 
1988 
Low 
98.6 
101,3 
101,7 
102,0 
102,1 
93 
129 
147 
135 
138 
96.2 
98,7 
1476 
Mic 
98,6 
100,8 
101,4 
101.3 
102,0 
108 
138 
135 
144 
153 
96.2 
98,1 
1961 
Q 
B 
HU 
98.5 
100o8 
101,5 
101.3 
101,4 
99 
132 
129 
123 
126 
95.1 
98.1 
1650 
o 
Kac 
99.3 
101 o0 
101,8 
102,2 
102,4 
105 
129 
150 
153 
150 
95.7 
98.8 
I486 
cu 
• 
pt, 
Sco 
98.6 
101,0 
101.7 
101,7 
101,7 
102 
147 
159 
135 
147 
96.4 
98,5 
2914 
AVG. 
98,7 
101.0 
101.6 
101,7 
101,9 
101 
135 
144 
138 
143 
95*9 
98,4 
1897 
TABLE 10 
The Physiologic Responses of Working Men bearing 
Flameproofed Twill and herringbone Twill 
D.B. 93°Fo - W.B. 92°F0 CLOTHING 
GROUP 
NAME 
HRS.MLKED 
* RECTAL TEMPERATURE °F 
PULSE RATE/MIN 
• 
SKIN TEMP, 
(Avg.Wtg,) 
°F 
WEIGHT LOSS 
(Sweat) 
Gffl/Hr, 
0 
1 
Hours 
2 
3 
4 
0 
1 
Hours 
2 
3 
4 
Init. 
Final 
Dim 
AO 
98.6 
100.6 
101.4 
101.1 
101,0 
96 
132 
129 
120 
120 
94 o9 
96,8 
1833 
Szu 
4«0 
98.0 
99*8 
100.6 
100,9 
101,0 
105 
123 
138 
123 
123 
95*3 
97 ol 
2256 
W 
A 
Mar 
U) 
98.5 
100,3 
101,5 
101.6 
101,5 
114 
162 
159 
150 
159 
95*1 
96.9 
2265 
§ 
Lin 
4o0 
98.6 
100 08 
102.0 
101.7 
102.1 
90 
126 
135 
132 
144 
95*0 
97*1 
2626 
S5 
Kne 
4*0 
98,9 
100 o0 
100,7 
100,8 
101,2 
105 
129 
135 
138 
129 
96.0 
97.3 
1818 
AVG0 
98.5 
100 o3 
101,2 
101,2 
101,4 
102 
134 
139 
133 
135 
95*3 
97 oO 
2160 
Low 
4*0 
99*1 
100.8 
101.6 
102,2 
102,6 
108 
132 
135 
138 
141 
96.4 
98,1 
1771 
Mic 
4*0 
100X> 
100ol 
101,0 
101,0 
101.4 
102 
129 
132 
138 
144 
95c5 
97*4 
2500 
cq 
B 
HU 
4<0 
98,7 
100.4 
101,3 
101.1 
101.1 
96 
114 
132 
132 
123 
95.4 
96,8 
1306 
Kac 
4o0 
98 o4 
100 o0 
100.8 
100,7 
101,0 
1U 
141 
147 
135 
156 
95.6 
97.2 
1600 
se 
Sco 
4c0 
99.1 
100,4 
lOlcl 
101,7 
101,5 
105 
138 
144 
138 
132 
94*7 
97*2 
3087 
AVG, 
99 a 
100,3 
101,2 
101,3 
101,5 
105 
131 
138 
136 
139 
95*5 
97 *3 
2153 
Low 
208 
99 a 
102,2 
103,5 
103.4* 
* 
1U 
156 
156 
150* 
.. 
96,7 
99*1* 
1626 
Mic 
lo8 
98.6 
101.6 
102,9* 
- 
- 
120 
162 
144* 
- 
- 
96.4 
98,3* 
2356 
• 
Eh 
6 
Hil 
2,2 
99o0 
101 o 7 
102.8 
102,7* 
- 
114 
144 
135 
150* 
- 
96.6 
98.4* 
1804 
• 
CQ 
Kac 
2,0 
98.6 
101,3 
102.7* 
- 
- 
114 
159 
171* 
- 
- 
96.1 
98.3* 
2243 
♦ 
tc 
Sco 
4o0 
98.8 
101.7 
102.6 
103 oO 
102,9 
108 
150 
153 
150 
156 
95*9 
99.2 
2586 
AVGo 
98.8 
101.7 
102,9 
103.0 
102,9 
114 
154 
154 
150 
156 
96.3 
99*2 
2123 
Dim 
lo8 
99*0 
102,1 
103,9* 
_> 
_ 
92 
159 
156* 
1770 
Szu 
1.7 
98 a 
101 ol 
101,8* 
- 
- 
111 
144 
144* 
- 
- 
96.3 
98,5* 
2073 
Q 
A 
Mar 
1*5 
98.6 
102.3 
103,4* 
- 
- 
114 
165 
180* 
- 
- 
96,6 
99 oO* 
2113 
♦ 
0, 
Lin 
2o0 
98.6 
102,2 
103,9* 
- 
- 
105 
150 
147* 
- 
- 
96.4 
98.5* 
2980 
• 
fx. 
Kne 
lo6 
98,9 
102 o0 
102,8* 
- 
- 
111 
159 
144* 
- 
96.0 
99.3* 
2005 
AVG. 
98.6 
101,9 
103.9 
- 
- 
107 
155 
147 
- 
- 
96.3 
- 
2188 
. 
*Dat< 
i taken at time of cessation of wa 
Iking 
- not used in averages for that hour. 
TABLE 11 
The Physiologic Responses of Working Men 
Wearing Flameproofed Twill and Herringbone Twill 
D.B. 95°F0 - WoB» 94°Fo TABLE 12 
Weight of Test Clothing Before the First 
and After the Last Wear 
(Data are the Average of Ten Uniforms) 
JACKET 
TROUSERS 
Herringbone Twill 
Initial Weight (CM) 
740 
656 
Final Weight (GM) 
773 
684 
Flameproof Twill 
Initial Weight (GM) 
1098 
960 
I Final Weight (Oil) 
1106 
980 TABLE 13 
The Sweat Absorbed by Flameproofed and Herringbone 
Twill Two-Piece Fatigue Uniforms During Work in Hot Environments 
(Data are the Average for the Clothing of Five Men) 
ENVIRONMENT AND TYPE OF GARMENT 
DoBo 120°F=, 
H„B„ 90°Fo 
D,B. 93°F,, 
W0B„ 92°Fo 
Flameproofed 
Twill 
Herringbone 
Twill 
Flameproofed 
Twill 
Herringbone 
Twill 
Hours of Wear 
3<>5 
4o3 
4.2 
3o9 
Water Absorbed (Grams) 
Jacket 
306 
697 
370 
719 
Trousers 
305 
697 
381 
721 
Assembly 
611* 
1394 
751 
1440 
Total Sweat of Subjects 
(Grams) 
8182 
8486 
8040 
6640 
* The clothing assembly of the two men who walked for the entire period 
had an average water uptake of 663 grams, while the clothing of the 
remaining three men, walking an average of 2C4 hours, had an uptake 
of 577 gramso TABLE U 
The Increased Uptake of Sweat by Flameproofed Garments 
During Repeated Wear in Hot Environments 
(Data are the Average for the Clothing of 5 Men) 
ENVIRONMENT AND TYPE OF GARMENT 
• 
D.B,120°F.,W.B,88°P,> 
DoBc120°Fo,WoBo88°Fo 
D.B,120°F.,WoB„90°R 
Flameproofed 
Twill 
Flameproofed 
Twill 
Flameproofed 
Twill 
No0 of Hours Previous 
Wear 
0 
4©6 
23 o3 
Hours of Wear 
3o6 
4o2 
3o5 
Water Absorbed (Grams) 
Jacket 
130 
184 
306 
Trousers 
123 
182 
305 
Assembly 
253 
366 
611* 
Total Sweat of Subjects 
(Grams) 
5427 
7080 
8182 
*See Footnote in Table 13. •TABLE 15 
The Sweat Absorbed by the Individual Layers of the 
Two Layered Flameproofed and Herringbone Twill 
Fatigue Uniform During Work in Moderately 
Hot Environments 
(Data are the Average for the Clothing of 4 Men) 
ENVIRONMENT AND TYPE OF GARMENT 
DcBo 100°Fo t 
WoBo 80°Fo 
D.Bo 100°F., 
W.B, 86°F, 
Flameproofed 
Not 
Flameproofed 
Flameproof ed 
Not 
Flameproofed 
Hours of Wear 
Water Absorbed (Grams) 
4o3 
4o3 
4o3 
4c2 
Twill Outer Garments 
208 
609 
30?* 
1175 
Cotton Under Garments 
550 
507 
844* 
U06 
Total Sweat of Subjects 
(Grams) 
4330 
4040 
£492* 
6652 
*Data on 3 men only - the data of the one man who failed to finish 
four hours of walking excluded. TABLE 16 
The Water Uptake by Individual Items of the Two 
Layered Flameproofed and Herringbone Twill 
Uniforms Immersed in Tap Water 
(Data is the Average of Two Sets of Clothing) 
Weight o^ 
Water Uptake 
Water Uptake 
Garments in 
After Soaking in 
After Soaking in 
Equilibrium at 
Water (72°Fo) for 
Water (72°F0) for 
Four 
Hours 
Forty-five Hours 
TYPE OF GARMENT 
D.B0 
120°Fo 
• 
W.Bo 
78°Pt, 
(Gra 
m«) 
(Gra 
me) 
(Grams) 
OUTER GARMENTS 
Jacket 
Trousers 
Jacket 
Trousers 
Jacket 
Trousers 
Herringbone Twill, Unworn 
778 
615 
749 
682 
864 
700 
Flameproof Twill, Unworn 
1123 
888 
506 
362 
559 
384 
Herringbone Twill, Worn 
778 
670 
854 
777 
835 
747 
Flameproof Twill, Worn 
1123 
955 
562 
509 
664 
513 
Under- 
Under- 
Under- 
LONG UNDERGARMENTS 
shirt 
Drawers 
shirt 
Drawers 
shirt 
Drawers 
Cotton Regular, Unworn 
265 
236 
543 
430 
591 
514 
Cotton Flameproof, Unworn 
348 
313 
441 
281 
525 
323 
Cotton Regular, Worn 
225 
240 
607 
473 
708 
595 
Cotton Flameproof, Worn 
380 
339 
596 
445 
504 
456 TABLE 17 
Quantitative Determination of the Reduction in Evaporative 
Heat Loss Due to Flameproofed and Herringbone Twill 
Uniforms, in a Hot Environment 
D.B. 120°Fo, W.Bo 92°F„ 
(Average of Two Subjects) 
• 
NUDE 
1ERRINGB0NE 
TWILL 
FLAMEPR00FED 
TWILL 
PRE-WETTED 
FLA^EPROOFED 
TWILL 
Evaporative Heat Lose 
Cal/iP/Hr. 
160,7 
133*2 
117.7 
163,4 
Evaporative Heat Loss 
CalAr/Hr0 per mmHg 
Vapor Pressure (s~a)* 
9.9 
8,6 
7.1 
9.7 
Change in Heat Content 
CalA[2/Hr. 
-2*4 
802 
14o4 
602 
Air Tempa D.B, °F« 
121 o 6 
120.0 
121.1 
120.2 
Vapor Pressure of Air, 
inmHga 
29o2 
30o2 
30.2 
30o5 
o 
Final Rectal Temp0 F, 
100o9 
101 o 5 
101,6 
100o8 
0 
Average Skin Temp, F, 
97 0 7 
97.7 
98.4 
98o9 
Vapor Pressure at 
Skin Temp, (s«a) nmHg. 
16,5 
15,6 
16,5 
17 oO 
Sweat, Gn/Hr. Total 
1920 
1548 
1899 
1833 
Sweat, Gm/HTo Evaporative 
550 
458 
106 
568 
*s - skin temperature 
a = air temperature CHART I 
AVERAGE PHYSIOLOGIC RESPONSE OF WORKING MEN WEARING 
INCREASING AMOUNTS OF FLAMEPROOFED TWILL 
D.B. IOO°F - W.B. 80°F 
-KEY- 
NUDE 
SINGLE LAYER FP (D) 
TWO LAYER FP (D) 
TWO LAYER FP PLUS 
HOOD AND GLOVES CHART 2 
AVERAGE PHYSIOLOGIC RESPONSE OF WORKING MEN WEARING 
TWO LAYER FLAMEPROOFED TWILL AND HERRINGBONE TWILL 
D. B. 100° F-W.B. 80° F 
- KEY- 
FLAMEPROOFED ( D) 
HERRINGBONE 
TWILL (HBT) 
NUDE CHART 3 
AVERAGE PHYSIOLOGIC RESPONSE OF WORKING MEN WEARING 
FLAMEPROOFED TWILL AND HERRINGBONE TWILL 
D. B. 100° F-W. B. 86° F 
- KEY- 
FLAMEPROOFED(D) 
HERRINGBONE 
TWILL (HBT) CHART 4 
AVERAGE PHYSIOLOGIC RESPONSE OF WORKING MEN WEARING 
TWO LAYER FLAMEPROOFED TWILL AND HERRINGBONE TWILL 
D.B. 90° F- W.B. 88° F 
- KEY- 
FLAM EPROOFED (D) 
HERRINGBONE 
TWILL (HBI) CHART 5 
AVERAGE PHYSIOLOGIC RESPONSE OF WORKING MEN WEARING 
FLAMEPROOFED TWILL AND HERRINGBONE TWILL 
3 
D.B. 120° F- W.B. 88° F 
-KEY- 
FLAMEPROOFED (D) 
HERRINGBONE 
TWILL (HBT) 
NUDE d3AV~l 319NIS 111 Ml Q3dOOdd3W Vld = dd 
H3AV1 339NIS 11IM1 3NO09MHd3H = 10 H 
CHART 6 
UPPER ENVIRONMENTAL LIMITS AT WHICH MEN CAN 
COMPLETE FOUR HOURS OF CONTINUOUS WALKING H.B.T = HERRINGBONE TWILL SINGLE LAYER 
FP (D) = FLAMEPROOFED TWILL SINGLE LAYER 
CHART 7 
THRESHOLD ENVIRONMENTAL LIMITS 
MEN CANNOT WALK FOR FOUR CONTINUOUS HOURS 
AT OR ABOVE ENVIRONMENTS DESIGNATED 
* ESTABLISHED BY PREVIOUS STUDY CHART 8 
AVERAGE PHYSIOLOGIC RESPONSE OF WORKING MEN WEARING 
FLAMEPROOFED TWILL AND HERRINGBONE TWILL 
D.B. I20°F-W.B. 90° F 
-KEY- 
FLAMEPROOFED (D) 
HERRINGBONE 
TWILL (HBT) 
NUDE CHART 9 
AVERAGE PHYSIOLOGIC RESPONSE OF WORKING MEN WEARING 
FLAMEPROOFED TWILL AND HERRINGBONE TWILL 
D. B. 120° F-W.B. 92° F 
-KEY- 
FLAMEPROOFED (D) 
HERRINGBONE 
TWILL (HBT) 
NUDE CHART 10 
AVERAGE PHYSIOLOGIC RESPONSE OF WORKING MEN WEARING 
FLAMEPROOFED TWILL AND HERRINGBONE TWILL 
- KEY- 
FLAMEPROOFED(D) 
HERRINGBONE 
TWILL (HBT) 
NUDE CHART II 
AVERAGE PHYSIOLOGIC RESPONSE OF WORKING MEN WEARING 
FLAMEPROOFED TWILL AND HERRINGBONE TWILL 
D.B. 95° F- WB. 94° F 
-KEY- 
FLAMEPROOFED ( D) 
HERRINGBONE 
TWILL ( HBT) 
NUDE CHART 12 
THE DRYING RATE OF FLAMEPROOFED AND HERRINGBONE TWILL 
UNIFORMS AFTER IMMERSION IN 72° WATER FOR 45 HOURS 
DRYING CHAMBER: D.B. 72°F.,W.B. 65°F. 
DATA FROM ONE SET OF CLOTHING 
INITIAL DRY WEIGHT FOR H.B.T. = 1383 GRAMS 
INITIAL DRY WEIGHT FOR F. R = 2011 GRAMS HBT HBT FPT 
The sweat uptake of herringbone twill and flameproofed twill garments on first wearing. 
The nee herringbone twill garment in the center is worn by a subject who did not walk. 
ARMORED MEDICAL RESEARCH LABORATORY 
T t FORT KNOX, KY. _ . ' 
»o. T-5 Photograph #1 HBT FPT *3>" 
Appearance of herringbone twill garment during twelfth wearing compared 
with that of flameproof twill during fifth wearing. 
ARMORED MEDICAL RESEARCH LABORATORY 
Project T-5 FORT KNOX, KY. Photograph # 2