DISTRIBUTED BY: National Technical Informatio Service U. S. DEPARTMENT OF COMMERCE 5285 Port Royal Road, Springfield Va

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1 - wt-- AD COLD WATER EVALUATION OF ENVIRONMENTAL MARINE DIVING SUITS James H. Veghte, et al Aerospace Medical Research Laboratory Wright-Patterson Air Force Base, Ohio November , A II DISTRIBUTED BY: National Technical Informatio Service U. S. DEPARTMENT OF COMMERCE 5285 Port Royal Road, Springfield Va ~ - ~ I. la

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3 I ~NOTICIA L ~~~When US Government drawings, speclllcatloms or other data ame =We for-m ONy O Mceot thar, F: adefinitely related Government procuremtert, operation, the Govern, t thd*b nus n epn a~~ibit -nor any obligation Whatsoever, agd the frac thalt the GovethVIC1t 442:Y hae kwmfe, furnished, or in any way supplied the smid dravdngs SpeelfCatlon3, or ouwe data, 1A not to ba regarded by implication or otherwize, o4 in any mnner U~efislng the hold=r or any eojthr* person or corporation, or conveying any rlghts or =M!01 to maitofacture. use, cinch any ýjtenwe Invention that may in any way be related thereto. Organizations and individuals receiving aniwonncemoe~ts or repofts via the Aer p=c Wedicaj- Ho- ;~~ i ~ search Laboratory automatic maiiglift ~ i~i subitw the add orew iaestnpo h report envelope or refer to -the code number ýwhtu COrrespdlnf about chdlmeof ad&reo Or cancellation. Do not return this copy. Retain or destroy. Please do not, request copies of this report from Aerobpw ceffcd'neseaý TAbM ZiW-77 copies mayv be purchasd from: - AMAtIA IIJ AIR FORCE/56780/12 Oftembr i079;-' 100 'j 1=12

4 Security Classification DOCUMENT CONTROL DATA - R & D (Security classification 01 title, body of abstrect and Indexing annotation must be entered when the overall report It claeetiled) I. ORIGINATING ACTIVITY (CoI/orSeIeuthla) 2a. REPORT SECURITY CLASSIFICATION Aerospace Medical Research Laboratory, Aerospace Unclassified Medical Division, Air Force Systems Command, Wright- b. CROUP Patterson Air Force Base, Ohio REPORT TITLE Cold Water Evaluation of Environmental Marine Diving Suits 4. DESCRIPTIVE NOTES ( r)pa of ceport end Inclusive dates) S. AUTHOR(SI Fiert nea., middle Initial, last name) James H. Veghte, Lt Colonel, USAF Fritz K_ K. g m N.On G. REPORT DATE 7d. TOTAIL NO. OF PAGES 7b. NO. OF REtS November a. CONTRACT OR -RANT NO. S.. ORIGINATOR-% REPORT NUMBER(S) b. PROJECT NO AMRL-TR c. Task No Sb. OTHER A[PORT NOTS) (Any othetrlnusbere that may be asigtned tistereport) d. 4ork Unit No n2 1O. DISTRIBUItON STATEMENT Approved for public release; distribution unlimited II. SUPPLEMENTARY NOTES I 12. SPONSORING MILITARY ACTIVITY Aerospace Medical Research Laboratory,. TAMD, AFSC, Wright-Patterson AFB, 1Ohio i 13. ABSTRAC T Two 24-hour cold water immersion - life raft exposures were conducted in our laboratory test facility involving three subjects in each exposure. Physiologic data were obtained during these exposures to discern the better cold water protective capabilities of two environmental marine diving suits. The Swedish Unisuit proved thermally superior to the Dunlop suit. Several recommendations are made. DD,FNO Security Classification A

5 -. w - U Security Classification I4. LINK A LINK 6 LINK C KEY WOROS ROLE WT ROLE WT ROLE WT Cold Water Immersitn Coldwater-Raft Protection Coldwater Protection Coldwater Tolerance I Security Classification -A.OLt -... i.,, l I. [ i I

6 FOREWOFRD This research was conducted by persomiel in the Aerospace Medical Research Laboratory, Aerospa.ce Meidical Division, in support of require-- ments for Headquarters Aerospase Rescue and Recovery Service, Scott AFB, Illinois, and the Life Support Systems Program Office, Aeronautical Systems Division, Wright-Patterson AFB, Ohio. This technical report has been reviewed and is approved. CLYDE R. REPLOGLE, PHD Chief Environmental Medicine Division Aerospace Medical Research Laboratory iii

7 SECTION I INTRODUCTION Preliminary physiologic data collected at Eglin Air Force Base, Florida, indicated that the cold water survival clothing for the Skylab program needed future testing. The two dry suits were the Dunlop (NATO) and the Swedish Unisuit assew'ales. The contingency requirement for the Skylab program is to provide pararescue personnel with the capability to withstand 2 hours of cold water immersion with a subsequent 72 hours in a life raft exposed to conditions found in northern latitudes. Therefore, two 24-hour exposures were planned in the laboratory test facility involving three subjects in each exposure. Careful metabolic, heart rate, and thermal data were to be collected during this exposure in an effort to discern the better of the two clothing asremblies. I 1

8 SECTION II EXPERIMENTAL METHOD Six voilateer test subjects were used in the two programmed 24-hour cold water immersion - life raft exposures. Three subjects all wearing identical outer dry suits participated in eaci exposure. clot 0lug The underlying wv.s varied only with the Dunlop suit. The specific clothing and, tulotive values are listed in table 1. The water temperature was maintained at OC while the air temperature was -4C with 30 to 60m/minute wind velocity. underwear. An ECG harness was affixed and the subjects were dressed in thermistor The sensors it, this underwear monitored 17 skin temperatures as well as rectal temperature. telemetered. In both exposures, some physiologic data were After control readings, the subjects walked into the environmental chamber and jumped into a large swimming p-,ol filled with cold water and ice. A seven man insulated Navy raft was afloat in the pool. A real±stic exposure called for one man to stay in the water 45 minutes before being joined by the other two subjects. At the end of a 2 hour water immersion for the first subject, all three clamored aboard the large life raft. The exposures were terminated upon the subject's request or at the monitor's discretion. each teit. Table 2 shows the physical conditions during The telemetry equipment was fabricated by Dr. Marko of tte Labor'.tory and yielded accurate temperature and ECG data. with a total of seven channels: Three units were built each 4 for skin temperatures, 1 for rectal temperature, 1 for calibration and 1 for the ECG signal. was devoted to antenna modification so that it hood of this clothing. A major effort could be placed under the For the ffrst time, reliable metabolic data were obtained by means of a new 102 sensor developed by our laboratory group. This technique represents a major advance in predicting tolerance times during cold water immersion or cold water immersion - raft exposures. 2

9 ----IM F- TABLZ 1 CLOTHING ASSEMBLIES Clothing Worn Clo Value Under Clothing Subject Lest No. (Inside and Outside) Clo Value (Alone) A 1 Theri.tstor Underwear, pr. Waffle Weave pr, Waffle Weave Underwear + Unisuit Und zwear, Unisuit Liner Liner, 2 pr. socks, wool gloves, Unisuit B 1 Thermistor Underwear, pr. Waffle Weave pr. Waffle Weave Underwear + Unisuit Underwear, Unisuit Liner Liner, 2 pr. socks, wool gloves, Unisuit C 1 Thermistor Underwear, pr. Waffle Weave pr. Waffle Weave Underwear + Unisuit Underwear, UnisuiZ Liner Liner, 2 pr. socks, wool gloves, Unisuit D 2 Thermistor Underwear, pr. Waffle Weave pr. Waffle Weave Underwear + Spacer Underwear, Liner Ventile Spacer, 2 pr. wool socks, wool gloves, 2 pc. Dunlop Suit 2 Thermistor Underwear, pr. Waffle Weave pr. Waffle Weave Underwear Underwear, 2 pr. socks, wool gloves, 2 pc. Dunlop Suit F 2 Thermistor Underwear, pr. Waffle Weave pr. Waffle Weave Underwear, Unisuit Underwear, 1 Unisuit Liner, 2 pr. socks, wool gloves, 2 pc. Dunlop Suit 3

10 TABgE PHYSICAL TEST CONDITIONS, CLOTHING AND TEST DURATION Test Date/ Air Temp Water Temp Wind Velocity Divers Suit Time (Minutes) Subject TA (C) Tw (C) Wv (M/min) Worn In Water In Raft Total 8 Dec 71 A Unisuit B C Dec 71' D E Dunlop F Km /

11 SECTION III RESULTS Individual skin, core temperature, and heart rate changes during the exposures are plotted in figures 1-6. No data were available during the water immersion portion of the Unisuit test because of failure of prototype telemetry equipment. None of the physiologic data indicatedthermal difficulty. The three subjects in the Unisuit tests maintained rectal temperatures above 36.6C, well above the critical level of 35.OC. These core temperatures stabilized after the first hour in the raft. With this same clothing, no serious temperature levels of the extremities were reached with the lowest value of 14.3C recorded for the feet. Temperature changes during the Dun3op tests were somewhat more serious. Subject D asked to be removed after only 442 minutes in the raft because of discomfort resulting from the extreme cold. His rectal temperature of 35.3C verifies his subjective feelings. There was no problem with his extremity temperatures. The other two subjects were able. to go on and asked to be removed after 1020 minutes in the raft becatue of intolerable cold. At the end of the test, their core temperatures had dropped to 35.3C and 35.7C. Extremity temperatures were maintained above 13.OC. Heart rates in all cases were within normal limits for sedentary, resting individuals. Mezabolic aata are presented in figures 7 and 8. There is a marked difference between the metabolic ra es of subjects dressed in the Unisuits and Dunlop suits during the cold water immersion phase. average values of an exercising man in water wearing the Unisuit is about 65 to 75 Kcal/m2 hr - a moderate level - compared to the 90 to 140 Kcal/m 2 hr levels of the subjects wearing the Dunlop suits. Note Subject F's response. In the raft, the metabolic levels of subjects dressed in the Dunlop assemblies were somewhat higher on the average than those wearing the ITnisuits. All levels were below 80 Kcal/m2 hr and usually below 70 Kcal/m2 hr. Air temperatures within the raft varied from 10 to 20C higher than ambient air temperatures. by the life raft is shown in table 3. The A physical analysis of the insulation afforded this raft, checked by two techniques, was 1.67 clo. The functional insulative value of Figure 9 presents a theoretical calculation of total insulation for comfort with various numbers of occupants in this raft at various air temperatures. 5

12 - - - ICI0 La-., C>- C> 0 43 mc (NW/SV83 INH 0 13 *Oct FIGUE 1 PHSIOLGICL RSPOSES F SBJET AWHIL WERIN TH UNIUI NIUI WTHA LNE 6%I

13 0 /. LAJ I-I co 0 w cr-- wo 7~J {NIN/SIV381 31VU 1N 3H (301)d31 FIGURE 2. PHYSIOLOGICAL RESPONSES OF SUBJECT B WHILE WEARING THE UNISUIT WITH A UNISUIT LINER

14 -- -w.8 -- i ii I I&Iw \Q ti I - o o o oc o~o o o o L:VH(3 NNR1I3)3V du3 FIUE3 HYILGCL EPNE O UJC HL ERN H UNISIT WTH UNIUIT IN( /

15 100 IN WATER ~90! 80 m ~60 5o IN RAFT TR T RATES70 b "HANDS 10 I0I T I M E - HOURS FIGURE 4. PHYSIOLOGICAL RESPONSES OF SUBJECT D WHILE WEARING THE DUNLOP SUIT WITH 1 PAIR WAFFLE WEAVE UNDERWEAR AND AN EXPERIMENTAL SPACER LINER 9I ME MMAMM-

16 'Row 0! / - 'AL 1- M // // - "(NIM/SM381 31VS 18M3 (0) )dn3_ FIGURE 5. PHYSIOLOGICAL RESPONSES OF SUBJECT E WHILE WEARING THE DUNLOP SUIT AND 2 PAIR OF WAFFLE WEAVE UNDERWEAR

17 IAI / 0 ; i i 1 I //,1 ~(NIN/ISL8) 31VH 18tV3]H (3 ) dm31 S~UNISUIT 6. PHYSIOLOGICAL SFIGURE RESPONSES OF SUBJECT F WHILE WEARING THE DUNLOP SUIT WITH 1 PAIR OF WAFFdLE W EAVE UNDERWEAR AND THE LINER

18 I+ (nwuu HH (O OD Cr. o1 Z-- FIGUR 7.NEMTBLI.EPNEO SUICSWAIN H NS 121 iu 121 FIG~tE7. METAOLIC TH ESPONE OF UBJECS WEAINGTELNSI

19 S ' ' -- i Q 1 IQ;I a: _. 0"I Elf a ItI,"/- / " '=,8-. S..!S 1 USH an /1034 S~FIGURE 8. THE METABOLIC RESPONSE OF SUBJECTS WEARING THE S~DUNLOP ASSEMBLIES 13 k_ 0

20 TABLE 3 Insulation Values for the 7-man Navy Insulated Life Raft Thermal Insulation - Procedure Mean Mean Manikin Ambient I R Temp (C) Temp (C) Total (I) (Ig) RaftTotal method 1 Use of Copper Manikin TEST Clo MEAN TOTAL = Igarment + Iaraft + Iraft + Ia IRAFTTOTAL + ITotal - Igarment Methjd 2 Conductances Insulative Values Use of Heaters Cloa 1 in Raft k x 0.18 Kcal/m 2 hrc Clo value 1. Floor Floor Ceiling Ceiling Side walls Side walls End walls End walls Inside air Inside air to 1.67 to outside air - outside air 6. Inside wall to 5.13 (effective insulation) outside wall - 6. Inside wall to 1.08 outside wall (Insulation of raft per se) 14

21 6 -COMFOT TOTAL INSULATION FOR 44 > I -JN - 2 so I * l '40!i AIR TEMPERATURE ( C) FIGURE 9. PREDICTIVE CLO VALUES REQUIRED FOR COMFORT IN A 7-MAN 2 LIFE RAFT. THE AVERAGE METABOLIC RATE OF 50 Kcal/M HR IS BASED ON DATA OBTAINED IN THIS STUDY. 15 /

22 DISCUSSION Thesc test data indicate the Unisuit is thermally superior to that of the Dunlop suit. The use of the Unisuit liner greatly enhances thermal equilibrium. Subject F wearing this liner under the Dunlop suit showed a marked reduction in metabolic rate during cold water immersion. This is supported by the clo value of this assembly shown in table 1. Most subjects requested to be removed from the exposure b"'ause of long term shivering, discomfort, and boredom. Thermally, all of the persons wearing the Unisuit could tolerate longer exposures without serious physiological problems. Those subjects wearing the Dunlop suit reached tolerable limits. Heater pads were given to the subjects wearing the Duiiov suits with favorable response. Perceptible heat is generated for approximately 10 minutes. Subjective comments concerning the Unisuit were favorable with slight bouts of shivering reported with the most discomfort relating to tight booties and face seals. In the actual case, these suits would bc tailor fitted and constrictive spots could be alleviated by cutting the outer material. Booties were cut in the Dunlop suit exposure to alleviate constriction. Subjects wearing the Dunlop suit complained of water leakage at the wrists and cold feet during water immersion. The feet did aot rewarm while in the raft. Fiugers were also cold and numb during zold water immersion. The Unisuit mittens afforded better protection. 16 /

23 SECTION IV CONCLUSIONS 1. Thermally, the Unisuit is superior to the Dunlop suit when identical underclothing is worn. 2. The ventile spacer garment is a detriment, thermally, and should be discarded. 3. Pararescue personnel wearing the Unisuit with approprfate underclothing could tolerate 2 hours of cold water exposure and subsequently several days in an insulated raft. Cold sea survival training is necessary. 4. A telemetry system has been fabricated to obtain limited physiologic data in field environments. SECTION V RECOMMENDATIONS The Unisuit should be modified to meet the pararescue requirements, i.e., opening parachute shock. Physiologic data can be obtained during the final field testing of the modified suit to provide a broader data base. 11 ii S17 *U.S.Governmont Printing Office: / ~-~ ~ * --