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APPROVED FOR PUbLIC RELEASE Report No. 87-R-0I.DISTRIBUTION UNLIMITED AFPEA Project No. 86-P-3ii

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SUSAN M. UDRY

PACKAGING SPECIALIST DTICAUTOVON 787-3362 ELECTE

Commercial (513) 257-3362 FE826 :-D "D

Final Report

of

Free Breathing Static Dehumidification Systems

4-

HQ AFLC/DSTZ

L , AIR FORCE PACKAGING EVALUATION AGENCY.cight-Patterson AFB OH 45433-5999

January 1987

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ACKNOWLEDGMENTS

HQ AFLC/DSTZ, Air Force Packaging Evaluation Agency (AFPEA),Wright-Patterson AFB OH 45433-5999 appreciates the cooperationand positive attitudes of all personnel who have contributedtheir time and effort to this project.

Additionally, a special expression of thanks to the followingpersonnel for their extra effort in this endeavor:

Carl Fixman, AGM Container Controls, Inc., Tucson AZ

Michael Miller, SM-ALC/DSTD, McClellan AF8 CA

George Isley, SM-ALC/MMCGE, McClellan AFB CA

USAF Det-8-17th Weather Squadron, McClellan AFB CA

Mark Boals, HQ AFLC/DSTZD, Wright-Patterson AFB OH

Eileen Foley, ASD/YYC, Wright-Patterson AFB OH

Ed Kowalski, Retired -- HQ AFLC/DSTZ, Wright-Patterson AFB OH

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NOTICE

When government drawings, mp..ricatios, or other datai are used for any purpose other than in connectionwith a definitely related government procurement operation, the United States Government thereby incur, no responsi-bility whatsoever; and the fact that the government may have formulated, furnished, or in any way supplied the saiddrawings, specifications, or other data, is not to be regarded by implication or otherwise as in any manner licensing theholder or any other person or corporation, or conveying any rights or permission to manufacture, use, or sell any patentedinvention that may in any way he related thereto. Thi. report is not to be used in whole or in part for advertising or salespurposes.AFPEA PROJECT NO. 86-P-311TITLE: Engineering Support for the Free Breathing Static

Dehumidification (FBSDH) SystemABSTRACT

Deterioration of maLeriel from moisture induced corrosion in

shelter/trailers/vans (S/T/Vs) during shipping/storage led to thedevelopment of -a self-contained system designed to maintain; arelative humidity (RH) of 40 percent or less within a S/i'/V for aperiod of two years without desiccant changes. This particularsystem i:- static because there is no external means to generateits operation of maintaining the RH of 40 percent or less.

Six prototype FBSDH systems were fabricated under contract number33700-81-C-0074. Five units were placed in a field-service testat SM-ALC/DSTD, McClellan AFB CA and one unit was placed in afield service test at HQ AFLC/DSTZ, Wright-Patterson AFB OH. Thefield test operation was established to verify the prototypedesign and to determine the actual life of the desiccant charge.

The field test data shows that the prototype FBSDB systex. did notverify the design requirement of maintaining a 40 percent or lessRH in the interior of the S/T/Vs. However, it is anticipated thatthe FBSDH system will maintain the 40 percent or less RH levelwhen properly installed in equipment or containers that aredesigned to meet the requirement of 2.0 inches of water pressure(0.072 pounds per square inch) for 60 minutes.

PREPARED PUBLICATION DATE:

Susan .drPackaging Specialist JAN 1987

REVIEWED DY:.-7 APPROVED BY: -'~3/

. ALAPH ZYDJCKE1Ch, Design-Branc DcAFPEA

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TABLE OF CONTENTS

Acknowledgments ~ ~ ~ ~ ~ ~ ~ P ......................

Acknowldct en................................................1

Table of Contents.......................................... iii

Executive Summary............................................ 1

Introduction.................................................. 2

Background............................................... 2

Purpose................................................... 2

Test Specimens............................................... 3

Test Outline and Test Equipment.............................. 3

Test Procedure and Results................................... 4

Cost.......................................................... 9

Conclusion................................................... 10

Recommendations............................................. 12

Appendix A, Installation of FBSDH- System in SIT/V ..........13

Appendix B, FBSDH- System.................................... 15

Appendix C, Testing S/T/V for Tightness Prior to Useof FBSDI System........................................... 17

Appendix D, Draw-Down Procedure in Preparation of SIT/Vfor Field Service Testing................................. 20

Appendix E, Preparation and maintenance of FBSDH Systemfor Field Service Testing................................. 21

Table I, Interim Reporting.................................. 24

Table II, Pressure/Vacuum Test.............................. 25

Table Ill, Draw-Down Data Before Start of Field ServiceTesting.................................................... 26

Figure 1, FBSDH System....................................... /

TABLE OF CONTENTS (Cont'a)

Page

Figure 2, Front View, FBSDH System ......................... 28

Figure 3, Back View, FBSDH System, Cartridges in ServiceConfiguration ........................................... 29

Figure 4, FBSDH System Cartridge .......................... 30

Figure 5, Back View, FBSDH System, Cartridges in Draw-

Down Configuration ...................................... 31

Figure 6, FBSDH System, Flow Schematic .................... 32

Figures 7, 8, and 9 Pressure/Vacuum Test Equipment ........ 33

Figure 10, Humidity Indicator, Remote ..................... 36

Figure 11, Template for Installation of Remote Humidity

Indicator ............................................... 37

Figure 12, Field Layout of Shelter Positions, SM-ALC/

DSTD ...... .............................................. 38

Figure 13, Field Layout of Shelter Position, HQ AFLC/

DSTZ .................................................... 39

Figure 14, SM-ALC Internal Environment, Shelter No. I,1985, Relative Humidity ................................... 40

Figure 15, SM-ALC Internal Environment, Shelter No. 1,1986, Relative Humidity ................................. 41

Figure 16, SM-ALC External Environment, 1985,Temperature ............................................... 42

Figure 17, SM-ALC External Environment, 1985, RelativeHumidity ................................................ 43

Figure 18, SM-ALC Internal Environment, Shelter No. 2,

1985, Relative Humidity ................................. 44

Figure 19, SM-ALC External Environment, 1986,Temperature .... .......................................... 45

Figure 20, SM-ALC Internal Environment, Shelter No. 2,1986, Relative Humidity ................................... 46

iv

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TABLE OF CONTENTS (Cont'd)

Page

Figure 21, SM-ALC Internal Environment, Shelter No. 3,1985, Relative Humidity ................................. 47

Figure 22, SM-ALC Internal Environment, Shelter No. 3,1986, Relative Humidity ................................... 48

Figure 23, SM-ALC Internal Environment, Shelter No. 4,1985, Relative Humidity ................................. 49

Figure 24, SM-ALC Internal Environment, Shelter No. 4,1986, Relative Humidity ................................. 50

Figure 25, SM-ALC Internal Environment, Shelter No. 5,

1985, Relative Humidity ................................... 51

Figure 26, SM-ALC Internal Environment, Shelter No. 5,1986, Relative Humidity ................................... 52

Figure 27, AFPEA Internal Environment, 1985, RelativeHumidity ................................................ 53

Figure 28, AFPEA External Environment, 1985, RelativeHumidity ................................................ 54

Figure 29, AFPEA Internal Environment, 1986, RelativeHumidity ................................................ 55

Figure 30, AFPEA External Environment, 1986, RelativeHumidity ................................................ 56

Figure 31, AFPEA External Environment, 1986,

Temperature ............................................. 57

Figure 32, Template for Installation of FBSDH System ...... 58

Distribution List ........................................... 59

V

,I

EXECUTIVE SUMMARY

The Air Force has long recognized the need fuL environmentalprotection of materiel in shelters/trailers/vans (S/T/Vs) during

shipping/storage. Deterioration of materiel from corrosion, dueto the presence of excessive moisture in S/T/Vs results in highmaintenance costs to the US Government.

The moisture problem has been addressed at various times in the

past years; however, the goals to meet the operating and designrequirements have fallen short of providing state-of-the-artenvironmental protection for equipment. Variables such as thequantity of desiccant required, the effective placement ofdesiccant, and the service life of the desiccant, have nct beenfully explored.

A self-contained, modular unit was developed xiide toprovide a dry storage environment for materiel inside of S/T/Vsby maintaining a relative humidity (RH) of 40 percent or less fora period of two years without desiccant changes.

Field test operations were established with five shelters at SM-ALC/DSTD and one shelter at HQ AFLC/DSTZ to verify the prototypedesign and to determine the actual life of the desiccant charge,,It should be noted that the S/T/Vs used at SM-ALC/DSTD were notnew shelters, but were reconditioned in an extensive sealingoperation to reduce the amount of leakage into the S/T/V. Conse-quently, the field test operation was initiated with less thanideal S/T/Vs with the best effort conditions.

Results of the field test, 15 Jan 85 through 31 Oct 86, lndicatethat the design of the prototype FBSDH system did not verify thedesign requirements by maintaining a RH of 40 percent or less inthe S/T/Vs. However, it is anticipated that the FBSDH systemwill maintain the 40 percent or less RH level when properlyinstalled in equipment of containers that are designed to be airtight and can meet the requirement of 2.0 inches of water pres-sure (0.072 pounds per square inch) Ifor 60 minutes.

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INTRODUCTION

BACKGROUND: During storage and transportation of SIT/IVs, propercorrosion control is not always accomplished, resulting inrepair/replacement of electronic items in S/T/Vs. A prototypeFBSDH system has been developed under contract to reduce humidityand prevent water induced corrosion of electronic equipmenthoused in S/T/Vs.

Preliminary design parameters for the FBSDH system wereestablished from published literature on dehumidification sys-tems. The conceptual design was developed and laboratory testedto verify design criteria. An estimated two year service lifefor the desiccant charge was derived from the laboratory tests.To determine the actual service life of the desiccant, field testoperations were established at SM-ALC/DSTD, McClellan AFB CA andHQ AFLC/DSTZD, Wright-Patterson AFB OH.

The FBSDH system was designed to be effective for a S/T/V size of8'x8'x10' (640 cu ft). The FBSDH system is a self-containedmodular unit which allows air flow through the unit when placedin a sealed S/T/V during shipment/storage. This air flow (orbreathing) is created by changing environmental conditions. TheFBSDH system is a static system because air is not circulated bydynamic dehumidification machines or fans.

The components of the system are suitable for use in an environ-ment of -40 degree F (-40 degree C) to +155 degree F (+68 degreeC). The system is designed for a breathing cycle of 90 degree Fat 95 percent RH to +120 degree F at 40 percent RH with fivehours of in-breathing and five hours of out--breathing during each24 hour period.

For a FBSDH system to work, all breathing air in and out of theS/T/V must pass through the FBSDH system. Therefore, the S/T/Vmust be adequately sealed to ensure that all breathing in and outof the S/T/V is only through the FBSDH system.

The FBSDH system is designed to be easily installed and removedfrom a S/T/V (see Appendix A). The only modification required toa S/T/V is to cut a hole in the wall or door to install the FBSDHsystem. Also, the system can be completely serviced withoutopening the S/T/V.

PURPOSE: The purpose of the field service test project was toverify the prototype design of the FBSDH system and to determinethe actual life of the desiccant charge.

2

TEST SPECIMENS: Six systems (Figures 1 through 6 and Appendix B)were fabricated under Air Force contract number 33700-81-C-0074by AGM Container Controls, Inc., 3526 E. Lowell Road, P.O. Box40020, Tucson AZ 85717-0020. Five systems were installed inshelters at SM-ALC/DSTD, McClellan AFB CA 95652 and one systemwas installed in a shelter at HQ AFLC/DSTZ, Air Force PackagingEvaluation Agency (AFPEA), Wright-Patterson AFB OH 45433-5999.

The interior of the walls and roof of shelters 1, 2, 3, and 4 atSM-ALC/DSTD are foam and beam construction, while shelter number5 is constructed of paper honeycomb materials. The interior ofthe shelter at HQ AFLC/DSTZ is not insulated and the walls androof are constructed of sheet metal.

Test Outline and Test Equipment

Equipment used to monitor the interior relative humidity (RH) andtemperature (T) of the shelters during the field service test isas follows:

a. Probes for Humidity and Temperature MeasurementVaisala, Model HMP 23 UT(T = -20 degree C to +80 degree C/-4 degreeF to +176 degree F)

b. TransmittersVaisala, Model HMT-13B(T = -20 degree C to +80 degree C and RH 0 to100 percent) with 4-2OmA output signal for both RH andT.

c. Data Logger, Precision DigitalModel No. 1045-FTM-MA-N-NSerial No. 208666

The shelter tightness test for air and water leakage was conduc-ted in accordance with the methods in Appendix C, and performedon the S/T/Vs prior to installation of the FBSDH system (seeFigures 7, 8, and 9). At this time, an extensive sealingoperation was necessary with a polysulfide compound to eliminatethe excessive air leakage. No requirement for the pressure/vacuumdecay rate had been established at this time. Equipment used forthis test was fabricated by AFPEA personnel in accordance withFi,'ire 7 and was forwarded to SM-ALC/DSTD for their use in the1, -paration of the shelters for the field service tests. L

After the shelter tightness tests were completed, a araw-downtest was performed to dehumidify the interior atmosphere of theshelter(s). To lower the RH in these shelters, draw-downcartridges from the FBSDI! system were installed to expose thesilica gel (desiccant) to the shelter environment. In the

3

. . . -- - 4 - . . .

draw-down configuration (Figures 1, 5, and P.psnaix D), approxi-mately 84 percent of surface area of the sili,-i gel is exposedto the internal S/T/V environment, promoting th.c absorption ofexcessive moisture from the shelter interior into the silicagel.

Upon completion of the draw-down phase, the draw-down cartridgeswere removed and service-phase cartridges were placed into thehousing to start the field service tests (Appendix E).

The remote humidity indicator (Figures 1, 10, and 11) is used todisplay the percentage of interior humidity in the S/T/V andshould be observed at frequent intervals.

Layout of the shelter positions in the field test operations ar1shown in Figures 12 and 13 at SM-ALC/DSTD, McClellan AFB CA anduHQ AFLC/DSTZ, Wright-Patterson AFB OH, respectively.

Table I outlines the interim reporting for the data obtained from.

the field service testing.

Test Procedures and Results

Irispection

Six systems were shipped frot the contractor AG1 Container Con-trol, Inc., to SM-ALC/DSTD. Visual inspection of the exterior andinterior surfaces, markings, hardware, strapping, and seals. Anymanufacturing imperfections were noted by engineering personnelfrom SM-ALC/DSTD.

Results: Results of the visual inspection was satisfactory.Workmanship on the systems was classified as excellent.

S/T/V Tightness Test

The S/T/V tightness test was conducted in accordance with methodsin Appendix C.

Results: Results of the pressure/vacuum tests are annotated inTable II and indicate that 2.0" Water Pressure (NP) held forapproximately 30 minutes or less in each of the shelters, withthe exception of shelter No. 1 at SM-ALC/DSTD. These resultsconclude that the shelters were not very air tight (excludingNo. 1 at SM-ALC/DSTD). All shelters required an extensive sealingoperation to establish the values in Table II and were consideredsatisfactory to initiate further testing. A pressure/vacuum decayrate had not been established; therefore, the data was retainedto determine the decay rate criteria for the S/T/Vs.

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Draw-Down Procedu.e

The draw-down procecure to pre-dry the shelteL6 was conducted inaccordance with the methods in Appendix D.

Results: Results of the draw-down are annotated in Table III.The shelters at SM-ALC/DSTD were below 30 percent RH for thedraw-down phase and were put into their service mode immediately.Also, more than 40 hours were required for the draw-down period.The draw-down phase at HQ AFLC/DSTZ reached 10.4 percent RH, butthis figure may be erroneous because of problems with therecording equipment. However, since this is the only RH valueavailable on the shelter interior, after 4 days in the draw-downphase, it was considered satisfactory and FBSDH system was putinto its service mode.

Field Service Test

The field service test was conducted in accordance with methodsin Appendix E.

Results: The field service test results at SM-ALC/DSTD aredisplayed in Figures 14-26 and are as follows:

Shelter No. I: From Table III, the draw-down phase obtained aminimum RH reading of 28.8 percent. From the follow-on data,Figure 14, the interior RH continued to increase as the fieldservice test was continued. No effort was made, however, torestart the field service test since the data was required forevaluation of the FBSDH System. Figures 14 and 15 indicate thatthe interior maximum RH for each day throughout the field testremained above the 40 percent level. When the draw-down phasewas initiated, little temperature cycling occurrea (see Figure16) under high RH environmental conditions (see Figure 17).Therefore, it has been determined that these conditions contri-buted to the FBSDH system's inability to maintain the internaimaximum RH of 40 percent or less. In addition, it has been oeter-mined that moisture may have been trapped in the interior wallsof the shelter. The sealing operation on the outer surface onlyallowed the moisture to migrate into the shelter interior andresulted in the high RH readings (see Figures 14 and 15).

The field service test was discontinued after 21 Jan 86 becausethe silica gel reached saturation and could not reactivate it-self. The cartridges were removed and weighed. The cartridgesabsorbed 13.65 pounds ot moisture and lost their eftectiveness.Subsequently, the FBSDH system was removed from the shelter anosent to HQ AFLC/DST7, Wcight-Patterson AFB OH. Visual inspectionof the shelter revealed broken exterior sealed areas. Thisprobably resulted from external weather conditions, such as thehot sun and rain.

Shelter No. 2: The draw-down phase, Table IIl, obtained a mIinlubLiRH reading of 11.9 percent and was consioece , satisractory to

start the service phase. The data from Figure 18 displays theinterior maximum RH for 1985 below the 40 percent level onlyafter the draw-down phase and throughout the month of Aug. Thisindicates that the draw-down phase did reduce the interior RH andthat moisture migrated from the interior of the wails ano wasabsorbed by the FBSDH system. This resultea in the nigher inter-nal RH readings for the first 3 months or 1985 (see FCiure 16).However, from Apr-Aug 85 greater temperature cycling occurred,

promoting the FBSDH system to reactivate itself and- oissipate theabsorbed moisture into the external environment. Ihis was evidentin the below 40 percent readings throughout Aug (see F'igure 18,Julian date z13-244). From Sep 85 to May 86, the externaltemperature difference tor each day decreased (see Figure L6,Julian dates 244-365 and Figure 19, Julian dates 1-121), whichindicateE, ie ss breathing. This caused the internal RH to increase(see Figure 18, Julian aates 244-365 and Figure 20, Julian dates1-121). Visual examination of the snelter exterior did notreveal any deteriocation to the sealed areas.

On 14 May 86, -he cartridges were removed and weighed. The FBSDHsyster, had absorbed 13.75 pounds of moisture. The unit hadreached saturation and could not reactivate itself. Inspectionof the shelter interior revealed condensed moisLure on the walls.The sheiter was aired out for two weeks and the cartridges werereinstalled on 31 May 86, to determine whether the FBSDH systemcould reactivate itself during the summer months. Afterreinstalling the cartridges into the shelter, the internal maxi-mum RH increasea to approximately 70 percent. Tnis level wasmaintained from Jun-Sep 86 (see Figure 20, Julian dates 152-244).In Sep 86, the internal maximum RH increased to approximately 60percent (see Figure, Julian date 244). This level of humiditymaintaineo itself in the 70-80 percent range until 31 Oct 86,when the field test was concluded. During Sep-Oct 8o, the exter-nal temperature cyclinq decreased (see Figure 19, Julian dates

244-304). It has been determined that the lack of temperature

cycling contriouted to the high internal :iaximum RH.

On 4 Nov 86, pcessu-e and vacuum test were conducted with the

following results; 1.0 minutes and 1.3 minutes, respectively. Inaddition, each cartridge was weighed with a total weight gain of

11.3 pouno.s of moi'sture. The shelter interior did not reveal thepresence of condensation. The FBSDH system was then removed,

packaged, and returned to HQ AFLC/DSTZ.

Shelter ND. 3: 'ine draw-down phase, Table III, obtiined minimumRH reading c 13-.5 percent and was considered satisfactory toinitiate the setrvice phase. Figure 21 displays the draw-downphase, 5-13 Fe; L;'), reouced Ltri internal maximum RH to 22.3

percent. In the service phase, the maximum \L[ ,radually increaseJto the 35-45 percent level and maintained tnat. level until theend of Nov 85 (see Figure 21, Julian dates 325-335). At the enaof November, the internal maximum RH decreased to 30 percent. Atthe beginning of December, the maximum internal RH increased toapproximately 38 percent due mainly to high external RH condi-tions caused from rain. From the end of Dec 85 - mid-Feb 86 theinternal maximum RH remained below 40 percent (see Figure 22).From Feb-May 86, the internal RH rapidly increased (see Figure22, Julian dates 40-134). It appeared that the FBSDH system wassaturated and unable to rejuvenate itself.

On 14 May 86, the cartridges were removed and weighed. The threecartridges in total absorbed 12.10 pounds of moisture. Theinterior was observed and condensation was evident on the shelterwalls and floor. The shelter was aired out for two weeks, thenthe cartridges were reinstalled on 31 May 86. Shortly after thecartridges were reinstalled, the internal maximum RH increased toapproximately 90 percent and maintained that level through 31 Oct86. The performance of the FBSDH system throughout 1985 wassatisfactory. However, in 1986 the FBSDH system performed verypoorly, especially after February. During Feb 86, Sacramentoexperienced rain and may have contributed to the high internalmaximum RH readings. The saturation appeared to be so severethat the FBSDH system could not reactivate itself, even duringthe summer months.

On 4 Nov 86, pressure and vacuum tests were conducted with theresult of 1.5 minutes and 3.5 minutes, respectively. Additional-ly, each cartridge was weighed, with a total weight gain of 14.6pounds of moisture. Some condensation was present on the inter-ior of the shelter. The FBSDH system was then removed, packaged,and shipped to HQ AFLC/DSTZ.

Shelter No. 4: The draw-down phase, Table III, obtained a ini- ,mum RH of 20.7 percent and was considered satisfactory to ini-tiate the service phase. Figure 23 displays the dcaw-down phase,15-17 Jan 85, reduced the internal maximum RH to 33 percent. Tneinternal maximum RH gradually increased to the 55-60 percentlevel until mid-Jun 85 and remained at that level until the endof Nov 85. it had been determined that moisture migrated fromthe interior of the shelter walls and was absorbed by the FBSDHsystem. Thi6 resulted in the 55-60 percent RH level from Jun-Nov85. At the beginning of December, the internal maximum RH ue-creased gradually over a two week period to approxiuately 45percent, then increased to approximately 52 percent (bee Figure23). This increase in internal RH corresponds to an increase inthe environmental RH and rainy conditions (see Figure I?).Throughout 1986, the internal maximum RH graaually' increased from42 percent in January to 72 percent in August. The internalmaximum RH maintained that level until the end of AuYLst and

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gradually decreased to 65 percent in Octoj)_r It has oeen deter-mined that the cartridges gradually became 6aturated during thefield test. The FBSDH system was not able t? reactivate itself,which resulted in the internal maximum RH rcdings in the rangeof 40-60 percent throughout most of the fielo test (see Figures23 and 24).

On 4 Nov 86, pressure and vacuum tests were conducted with thefollowing results of 9.5 minutes and 7.0 minutes, respectively.Additionally, each cartridge was weighed, with a total weightgain of 10.0 pounds. Moisture was not present on the shelterinterior. The FBSDH system was then removed, pacKaged, andshipped to HQ AFLC/DSTZ.

Shelter No. 5: The draw-down phase, Table III, obtairied a mini-mum internal RH of 19.6 percent and was considered satisfactoryto start the service phase. Figure 25 oisplays the draw-downphase had reduced the internal maximum RH to 39 percent. In theservice phase, the internal maximum RH followed the externalmaximum RH trends (see Figure 17) throughout 1985 except forNovember and December. This correspcndence between internal andexternal maximum RH was anticipated because of the poor sheltercondition and the inability of the shelter to hold pressure or avacuum (see Table II). It appears from Figures 25 arid 26 (Juliandates 315-365 and 1-40, respectively) that the FBSDH system oeganto reactivate itself during Nov 85 - Feb 86. For the remainderof 1986, the internal maximum RH gradually increase to the the50-60 percent range and maintained that level (see Figure 26).It appears from the data that the cartridges had absorbed mois-ture, but were not saturated. The FBSDH system in Shelter No. 5had the best results in the field test. but the internal Rfi didexceed the 40 percent level.

On 4 Nov 86, pressure and vacuum tests were conducteu and theresults were 1.0 minutes and 1.3 minutes, respectively. Inaddition, the cartridges were removed and weighed. The totalweight gain of the cartridges was 12.10 pounds of moisture. Theinterior of the shelter revealed that condensation was not pre-sent. The FBSDH system was then removed, packaged, and returnedto HQ AFLC/DSTZ.

Results of the field service test, Figures 27-31, at HQ AFLC/DSTZare as follows:

Shelter No. 1: The draw-down phase, Table III, obtained a mini-mum internal RH of 2.9 percent, but this value may be erroneousdue to problems with the recording equipment. However, since thisis the only RH value available on the shelter interior, it wasconsidered satisfactory and the FBSDH system was put into itsservice operation. Figure 27 displays the draw-down phase, 8-13Aug 85, obtained a internal maximum RH of 38.2 percent. In 1985,

z2 Mr h

the internal maximum Rd remained below tht 36 oercent levelexcept on 12-15 Sep, 20-21 Nov, and 2-3 Dec. These results arefavorable, since the internal humidity was kept below the levelof the external conditions (see Figure 28). The internali maximumnRH for 1986 gradually rose from approximately 60 percent inJanuary to approximately 93 percent in mid-February (see Figure29, Julian dates 1-40). During this period, the external maximumRH also was increasing (see Figure 30). As 1986 continued, thetemperature cycling increased (see Figure 30) and the FBSDHsystem began to slightly reactivate itself. This was evident inthe decreasing trend in the internal maximum RH frcm 'Feb-Auj 86(see Figure 29, Julian dates 40-243). The high internal maximumRH readings appeared to correspond to the external RH, mainly duefrom the uninsulated walls and roof of the shelter.

On 4 Sep 86, pressure and vacuum tests were conducted. Theshelter could not maintain a pressure or vacuuti for any length oftime. The cartridges were removed and weighed, with a totalweight gain of 7.91 pounds. fhe interior of the sheiter revealedno condensation.

Cost:

Cost studies for production quantities have been completed caidare summarized as follows:

MULTIPLE UNIT PRICE ESTIf"ATE

NU[IBER OF FIBSDH SYSTEMS PRICE PLR MBSD[i SkY'ST

10 - 25 $340026 - 50 $240051 - 100 $1700101 - 500 $1300501 - 1000 $10001000 or more $950

NOTES:

1. A FBSDH systeii consists of one (1) hcusing, one (I) re.oteindicator tube, two (2) relative humidity indicatocs aic t.rCee(3) cartridges filled with silica gel.

2. Prices include preservation packayin, for tnk cactcidgis iiiaccordance with MIL-P-116, Submethod IA-14 and cof:,mercial packin U2for the complete system.

3. Prices are foc planning purposes in 1984 dollars.

9

Conclusion:

Results of the field service test, 15 Jan 85 - 31 Oct 36, did not

verify the design of the prototype FBSDH system by maintaining a

40 percent or less RH in the interior of the S/T/Vs. S/T/Vs used

in the field test operation at SM-ALC/DSTD were not new and

required an extensive sealing operation on the doors, fasteners,

gaskets and any other openings to prevent air leakage. The shel-

ter at AFPEA was not insulated and had a wooden floor; therefore,

the floor required the application of a water-barrier laminate.

Consequently, the field test operation was initiated with less

than ideal S/T/Vs and with best effort refurbishing conditions.

All shelters acquired the 40 percent or less RH requirement forthe draw-down phase, but when the service phase began the RHgradually increased above the 40 percent level. During 1985,three of the five shelters at SM-ALC/DSTD (No.s 3, 4 and 5) had

coinciding internal maximum RH, but at slightly differenthumidity levels. Also, four of the five shelters at SM-ALC/CSTD(No.s 2, 3, 4 and 5) obtained similar internal maximum RH trerndsduring the summer months (Nay-Aug 85). During 1986, all shelters

had their internal maximum RH remain above the 40 percent level,

except shelters 3, 4, and 5 from I Jan-15 Feb. Shelter No. 1at SM-ALC/DSTD remained consistently above the 40 percent levelin its service mode. The shelter at AFPEA also went above the 40percent level during its service phase. The internal maximum Rh

remained constantly above 40 percent throughout the field test.

The various RH trends were created by the different S/T/V condi-tions. It has also been determined that moisture in the interiorof the walls of the shelters at SM-ALC/DSTD migrated into theshelter interior and was absorbed by the FBSDH system at differ-ent rates and resulted in greater than 40 percent R11 throughoutthe field test.

Further examination of the data indicate more emphasis is

required in the followinq areas:

I. A method to detect localized water-intrusion through theexternal surface of the shelter structured panel (from TO 35E4-1-162, paragraph 4-29) will be conducted prior to the pres-

sure/vacuum test to help determine the condition of the S/T/V:

a. DETECTION OF LOCALIZED WATER-INTRUDED AREAS. If, during

periodic inspection, delamination is suspected on an externalsurface of the shelter structural panel, the panel must befurther examined to determine possible causes before repair ismade. The most reliable and efficient method of detecting delam-inations and/or voids is to use the coin-tap method. The extentof the delamination and/or void must be markeo with chalk or amarking pen. Before repair, reinspect the area within the

10,

9 "!

marked outline for any possible holes, riveted doublers, orbolted fittings which either lack sealant or where sealant hascracked or peeled away. If sealant is defective or missing, itis almost certain that water has intruded inside the panel anddamaged the core material.

Refer to the appropriate procedure in TO 35E4-1-162 for the typeof repair that is required. (Appendices C, The S/T/V TightnessTest, and D, The Draw-Down Procedure, must be changed to reflectthis procedure.)

2. The S/T/V housing the FBSDH system must have a pres-sure/vacuum decay rate that will hold 2.0" WP (0.072 psi) for 60minutes (Appendix B, The Prototype Unit, paragraph 1.4 and Appen-dix C, The S/T/V Tightness Test, paragraphs 3.6 and 4.2, must bechanged to indicate this decay rate).

3. The draw-down RH of 40 percent or less must be held for a 24hour period to ensure that the maximum RH level for that day isactually below the 40 percent or less level. (Appendices D, TheDraw-Down Procedure, and E, The Preparation and Maintenance ofthe FBSDH System, paragraph 2.1, must be changed to indicatethis.)

4. The service phase must be initiated after a proper draw-downphase (see #2), between 1200 and 1600 hours, when the externalRH is approaching its lowest level of the day. (Appendix E, ThePreparation and Maintenance of the FBSDH System, paragraph 2.1,must be changed to reflect this.)

5. Value engineer the FBSDH System with the following:

a. Desiccant cartridges:

(1) Design seals into housing.

(2) Change material to polymer or polymer/metal.

(3) Eliminate nylon bag.

(4) Eliminate guides and stops.

b. Housing:

(1) Change door design to use hinges.

(2) Design housing internal symmetrically.

(3) Design extruded seal that can be used as a cartridgeand door gasket.

Ii%

-~~~~~. V.'..-%- s

(4) Change material to codted steel.

c. Remote humidity indicator tube:

(1) Eliminate machined tube and use flat plate.

(2) Change material to polymer.

The test data displays that the FBSDH system could not maintain40 percent or less RH and control the internal environment of theS/T/Vs; therefore, the FBSDH system should not be installed intoS/T/Vs. The FBSDH system may have possible application withequipment or containers that have the minimum requirement ofholding 2.0" WP (0.072 psi) for 60 minutes.

Recommendations:

1. If SIT/Vs were modified to meet pressure requirements than anoperational test and evaluation of the FBSDH system should beattempted.

2. Upon successful completion of the FBSDH system in air tightequipment or containers, suggested design changes and/or improve-ments should be added to reduce the cost of the FBSDH 3ystem (Seepoint 5 of the Ccnclusion).

. ,1

* *~.*,,.

. . . . . . . . . . . . . . . . . . .

~ .IL.d - .k,

APNDiLtX A

INSTALLATION OF A FREE BREATHER STATIC DEHUMIDIFICATIONSYSTEM AND HUMIDITY INDICATORS IN A SHELTER/TPAILER/VAN

1.0 INTRODUCTION

1.1 Two humidity indicators ace used with the installation ofthe FBSDH system. One humidity indicator is installed in thecover of the FBSDH system and the other is installed through thewall of the S/IT/V ii a location away from the FBSDI s6ystem. Th=humidity indicator installed in the cover of the FBSDH system isa guide to the conditiori of the desiccant in the FBSD1I system.The humidity indicator located away from the FBSDH system is aguide to the RH in the S/T/V.

1.2 The humidity indicators contain a color change disc whichchanges from blue to lavender to pink as the RH increases andturns back to blue as the RH decreases.

1.3 Each color change disc is divided into four segments, thesesegments correspond to 30, 40, 50, and 60 percent RH respec-tively. For example, if the 40 percent segment of the disc islavender or pink, the humidity indicator is indicating a RH ofover 40 percent. But it is also indicating that the R11 is lessthan 50 percent.

1.4 The FBSDH system is a self-contained modular unit. TheFBSDH system is designed to be easily mounted and/or removeo frohthe exterior wall/door of a S/T/V.

1.5 The air inlet tube to the FBSDH system is designed toprotect against the ingress of blowing snow, rain, dirt, insects,animals, birds and/or other foreign materials.

1.6 Each FBSDH system module was designed to hold enough unitsof desiccant for a service life of two years ano should maintainthe RH of 40 percent or less in a S/T/V that is 8'x8'xlO' when inaccordance with £IL-STD-210B, Table V.

2.0 INSTALLATION OF FBSDH SYSTEM

2.1 The FBSDH system is to be installed in the main structure ofthe S/I/V.

2.2 The separate humidity inaicator is to be installed in thestructure of the S/T/V as described in paragraph 2.7.

2.3 Select a location in the structure of the S/T/V for instal-lation of the FBSDH system. Check carefully for clearance around

13 ..

V-~~~~ 7-7-7- T .7 -Y, " -7 -r

the FBSDH syste., dnd particularly the cled~ace For pc)truionl ,.the FBSDH system into the S/V/V. In the UL~w-&owrj configurationa clearance of 14 inches is required arounu the cartridges. TheFBSDH system cover umust be accessible frcoii t! - exterioc S/I/V rurservicing while the S/T/V is in storage. A ,)or of the S/T/V isthe preferred location.

2.4 Using the template shown in Figure 32, cut tne rqcuired.opening for the installation. If the cut is in nroneycomb orsandwich construction, seal the tiller oetween the inside andoutside sheathing with a polysulfide compound (conforming to iiIL-S-81733, Type [-2, solvent) in a well ventilated area. Refer t, ,TO 35E4-1-162, paragraphs 4-15, 4-16 and 4-17 for further in-struction5 on application procedures.

2.5 Apply a thin coatinq of sealer (polysulfide compound) to theinside surface of the mounting flange on the FbSDH syutem hous-ing, and attach the FBSDH housing to the S/T/V using rivets ordrive sc-ews. Remove excess sealer.

2.6 Check the installed FBSDH system for clearance and roo forprotrusion of the cartridges into the S/T/V.

2.7 Select a location for the separate humidity indicator tube.This location snouli be remote from the FBSDH system main unit.The opposite end of the S/T/V is the preferred location; however,-the separate humidity indicator may be installed at any locationmore than five feet away from the FBSDH and about four feet abovethe bottom ot cne S/i/V. The separate humidity indicat-oc shouldbe installed in a location that can be viewed when Lne S/T/V isin storage.

2.8 Using the template shown in Figure 11, cut an opening for-the separate humiidity indicator tube. Seal the opening cut andthe flange of the holder as described in paragraphs 2.4 and 2.5.

2.9 Tihoroughly -lean the inside of the S/I/V. Nipe allsurfaces clean and free of visible moisture. Close and secureall accesses, doors and openings in the S/T/V. Install ahumidity indicator in the hole provided in the upper rioht handcorner of the FBSDH system cover and install the FBSUH systeitcover. Install a humidity indicator in the holder installed inparagraph 2.7 and 2. ,,.

p.

p,%

APPENDIX B

FREE BREATHING STATIC DEHUMIDIFICAT.i SYSTEi.,(PROTOTYPE UNIT)

1.0 INTRODUCTION

1.1 The FBSDH system is intended to provide a dry storageenvironment for materiel inside of SIT/V by maintaiiing a relci-tive humidity of 40 percent or less during the diurnal oreathinycycles.

1.2 Changes in the atmospheric temperature will create changesin the air flow through the FBSDH system. As the interior temper-ature of the S/T/V will increase, the interior pressure will tendto increase causing the air in the S/T/V to flow out. As theinterior temperature in the S/T/V decreases, the interior pres-sure decreases tending to cause air to flow in. These dailychanges in atmospheric conditions is called the diurnal cycle. Inthe inflowing phase of the diurnal cycle, the air is usuallyhumid. This inflow of humid air raises the RH in the S/T/V andcauses deterioration of materiel inside the S/T/V. The FBSDHsystem is designed and installed so that the flow of air into andout of the S/T/V will flow through the FBSDH system thus (!ry.uiiJthe air and preventing the increase in RH in the S/T/V fromexceeding 40 percent.

1.3 The FBSDH systei is used initially for reducing the t H below40 percent in the Si/TV (called the draw-down pndse) jn6a,,i o formaintaining the RH in the S/T/V below 40 percent (cal.)d tht!service phase).

1.4 The FBSDH system is intended only for installation in S/T/Vthat are designed and fabricated to have an establisht: ipressure/vacuum decay rate that will be detcrLmined fs a tiii.field test operation.

2.0 DESCRIPTION OF' FBSDH SYSTEMI

2.1 A schematic diagram of the FBSDH system i s shown in ?i u r- .

1. It consists of a major unit to be mounted ii a wall r dcorof a SiT/V and a separate humidity indicator to be muntedremotely from the major unit to monitor the atmosphere inside uf .-the S/T/V. The major unit contains three (.j) -eplaccablc desi2-cant cartridges.

2.2 The major unit of the FBSDH System is a housing 28"" riiijh x15-1/2" wide x 9" deep and weighs 14 pounds. T£h nousi:,J .struction includes a flange. The flange contains 2S 1/4"diameter holes to be used for imouting the CBSDH 'slte.. on thcS/T/V. Inside of the housin, i a uaffle system which conti1_;no

15

'4-%"

chambers for installation of desiccant cartridces. The bafflesystem includes a breathing tube and passage to direct the flow

of breathing air through the desiccant cartridges. The majorunit is provided with a cover which is attached to the housingwith 22 captive screw type fasteners. In the upper right handcorner of the cover is a HuF,.i-,t'Y I."'-icator used to monitor thecondition of the desiccant charge. An inlet elbow is attached tothe lower right hand corner of the cover. A rubber plug for theinlet opening is attached to the cover by a chain.

2.3 Three cartridges of silica gel are provided with each FBSDHsystem. Each cartridge contains approximately 17 pounds of silicagel MIL-D-3716, Type II, grade H. The total of 51 pounds ofsilica gel is equivalent to approximately 600 units of desiccant.The top, bottom, and three sides of the cartridges are of perfor-ated aluminum alloy. The fourth side or edge of the cartridge issolid (unperforated). The rubber strip in the cartridgeconstruction is to seal the cartridge to the baffle assemblywhen the cartridges are installed in the housing. Figure 4 showsa cartridge.

2.4 The cartridges are designed to be installed with the unper-forated surface facing outside the S/T/v for the draw-down phase(Figure 5). In this configuration a large area of desiccant isexposed to the humid air inside the S/T/V. For the service phasethe cartridges are installed with the unperforated surface facinginside the S/T/V. In this configuration the breathing air flowsthrough the cartridges.

2.5 A charge of silica gel in the FBSDH system is used to adsorbmoisture from the inbreathing humid air. The outbreathing airfrom the interior of the S/T/v flows through the charge of silicagel in a path that it will remove some of the absorbed moisturefrom the silica gel (Figure 6), and dissipate it into the exter-nal environment.

2.6 Pressure drop of the air flow through the system is 0.01inches of water. (It should be noted that the lower the pressuredrop through the system, the more likely it is that breathing airwill flow through the system, rather than leaking into the S/T/Vthrough some other path).

16

A .

APPENDIX C

TESTING SHELTER/TRAILER/VAN FOR TIGHTNESS PRIOR TO USE OF THEFREE BREATHER STATIC DEHUMIDIFICATION SYSTEM

1.0 INTRODUCTION

1.1 It is important that the structure of an S/T/V, in which aFBSDH system is installed, be air tight. Leakage of humid air andwater into the S/T/V must be eliminated for the breathing cyclesto pass through the FBSDH system.

1.2 Since our concern is the leakage of air, a method of testingusing air is required. A pressure/vacuum decay rate has not beenestablished; therefore, it is essential to retain all data todetermine the decay rate criteria.

1.3 The first step in the air tightness test is to stabilize theS/T/V for 12 hours in an environment that is not in directsunlight. The environment stabilizing the S/T/V must also nothave changed more than 10 degrees F during this stabilizationtime.

1.4 The second step in the air tightness test is a thoroughvisual internal and external check of the condition of theSIT/V. Warped doors, small openings, missing fasteners anddeteriorated gaskets and seals should be repaired during thischeck.

1.5 Since the FBSDH system will be placed in service as soon asthe tightness test is completed, the interior of the S/T/V shouldbe clean, dry and ready for installation. Equipment in the S/T/Vshould be properly secured. Required documentation such as aT.O., shipping instruction, etc., for the equipment in the S/T/Vshould be checked.

1.6 The method of testing shall consist of applying low pressureair to the insiae of the S/T/V and checking the outside of theS/T/V for leakage using a soap bubble test. When all leaks havebeen corrected, a vacuum shall be applied to the S/T/V. Finally,the differential pressure, between the inside and the outside ofthe S/T/V, shall be measured and recorded along with the timerequired to hold the 2.0" WP.

1.7 The pressure test is used to apply a pressure to the insideof the S/T/V so that leaks can be found using the soap bubblemethod. The vacuum test is used as a final test.

2.0 TEST EQUIPMENT N

17 Ii

2.1 it Th Lu±; d LUC Lflte LO ,L i. ~ 2seIL consistLs of c Vc,/Bluwer a test idiicmfQiu, ~ nhu;.es to conriccL tt,- teal_ e,,uipa,!nL Lu theLU C, Uc 11

Vac/lalow(:r.

2.2 The Vac/ilower Lu.1e ht:: )ositive ires~urck1= >

pre~33ure test and thu vocua,. foc the va.cuui, tes.3-

2.3 The iianioireter is usca toQ m~easure- ulhic Lte;:.ane2 the -i: t whl*,ini mi eta c c~

2.4 Thin lidfl&xible cuohiesu nosze i- ue,. to -mu ~ Lt.Vac/fllowec to the arm1fifold arid thme itian. l--ld toth, iiilet of trm 2FB 0" 1) H Hose cldwmps v.ill oe reuiCI o the end'; of ch is ms,:prevent leakaqe.

3.0 PRLSSURE 1.1'Z2'

3.1 Connect the te.:t iSf1 fold to the Ft3SDIH, ,3 ufo. n ?t ,uc.-9. CloSe ValvC, "A." Conn ct tn - VaC/iBlower Eur sc:cthe mianifold.

3.2 Start tie Vac/ichzv-c.

3.3 SlowlY op enl dIlVe "A" wh Ie Oi)aerviinj thme pcess3uredifferential on) the mnoer. If the imanolliterC i.S sL.n2.0" '. P restrict the openinj to obtain 2.0" 4,P.

3.4 Usinj a soap 6olution check all potential bso-rc;E~ WI lcI'in the S/I/v. So urces ofic6kajz would cce joi L,doorG jask,2L, end,( 6ii ' ~ IijC.- Duri 11 th K_, te6t, C'I- _ c 1.

connection between th-e tanifild aind- the r'tSLD[I t. iKk.are found they should ;.e correctedi or f1rc oc

3.5 Coirrect' leilks Oy use- o;f ap'proved su 1w o e' ma. -3t, Z:r i C

iiaterials and tapec-. kecoiiuuend :d ;a A coii.)Oulit I.1

cpurt, P-do wi ich i s j i acIc"ordanICe wi th '' -

1 -2 (so lvent) Tlhi1z: shfould bx2 aL.Ll ied Ii well, vci mt iIiK,:f ec to TO 35E4 -1032, parea, aphs 4- L5~ 1 16 ,n~d 4- 1instruction& onl application procedures.

.6 Clo0Se Vav V k2 ObSoCLV( th.l-cc; o imC.mnnomme te . The pressure- differ-eni-lal shoculd c .! I~ 1de rthe tii e recuireo to rnuid 2.0" W,-P.

4 U VAC-UJII TEST'

4. L Con.nect the Vac,/Blowec?: forc succioni oni thi: s;

CoeValve "A". Start thez Vac/;Ki wer.

4.2 Sluwly Open V-,lvC-_ "A" Wi 1,2 L~C k ic - L

% % %18

.7 .7-.

pcLes~iuCe Lcduij , thai wldifold. Ui~C~tt: LJ IL;IU 2

Uri-,uce tile s/&/v uoLs 11ot iC&It.

5 .) DATA TU BEL H.LU-Ot<L'J

5 .1 A C,.-Ctification dn-let showingy that thtz tu2Ls Ln,:a ic-DiPlet'aa -,uU16 e .ept Oil file.

5.2 A recoro Oif tCiie, cepaic iiido drid tue codiirLon -

iiu1u 1oeL T In Lji.,.

olf Ja." e uo rflu 31/ nuticzabie deter iOcut..on thf SL1L s CoIn

stcuctul:,2 of the -/i/v or wtodificationLr to Lln S/i/V1.

6.2 ii. preh, UL~ alia, Vacuu.l test-z snould c:jetoi

ShO'W :Tt Ch,3eica~ GfL-dLU i 3Cxddt. in; .hctctthan cx~lccte&-.

1. Ln. AiatL 1y ueon satisfactor 2 co ~ e~c WiU A ~ tn-S~n ~rn~ ~shculcd LD, put in zc\cv ice in th - uc W-uowui '. .

APPENDIX D

DRAW-DOWN PROCEDURE IN PREPARATION OF SiiF]b RS/TRAILERS/VANSFOR FIELD SERVICE TESTS

1 .0 INTRODUCTION

1.1 The S/T/V must be pre-dried to 40 percent or less RH andmust not contain visible moisture in the fori,; of condensation .rpuddles. Further the pre-drying or draw-down operatiou mustensure that moisture absorbed on the surfaces of the interior ofthe S/T/V, and its contents, is removeo.

2.0 ACTIVATION OF FBSDH SYSTEM FOR DRAW DOWN

2.1 Prepare to remove the cover of the FBSDH system and insertthe desiccant cartridges. Three cartridges will be installed.The operation of unpacking the cartridges, inserting thei. and

reinstalling the FBSDH system cover should be accomplished in asshort a time as possible to reduce exposure cf the cartridges to

humid air. Examine Figure 4 which shows the cartridge. N'ote thestops and guides on the top and bottom of the cartridges. Notealso that one vertical face of the cartridge is unperforated.

2.2 Cartridges can most easily he inserted in the housing bytilting the top slightly outward, lifting the cartridge highenough so that the guides on the bottom of the cartridges can beplaced on the lower horizontal baffle in the housing, thenstraightening the cartridge and pushing it at top ano oottoatinto the housing chamoec, cartridges are a snug fit in thechambers.

2.3 Procedure.

2.3.1. Remove the FBSDI. cover, unpack three cartridges, notaand record their serial number and weight arid insert then inthe housing.

2.3.2. Each cartridges should be inserted witn its uiiperfo-atec .face out. The cartridges should oe inserted about 7 inchesinto the chambers and firmly against the stops.

2.3.3. iieinstali the FBSDH system cover. Check to be sure thatall of the captive fasteners ace securely tightened. Do notinstall the rubber plug.

2.4 The draw down phase Figure 5 is now in operation and should L

take about 40 hours, according to MIL-P-116.

.-.

°-

2-0

D~i.~.±~l~'2A1rowSiSIEMS FO)R CIELID O'Lr'V ICL ii ~

J1 . l.'OU CTi W.

1. The FBSDH Systei is intencied to provice a dry st rja:Lllivironi~~t ror . iatt criei iniue df 3/1/Vs ol ii~ii~ i .L4U percent or less durinj the diurnal breathin~j cycj-zC.

i . The FESi30 Dy_,teL 4~a" aesiynCd for a service- iljtc DL 2 pyear.,In an eiivironmint of -40 ce .jre eL (-40 uejrute C) tc i-1%, oe,,.)

(+30 j oaee C) wha-n i c~z;tallie( in a S/T/V s i ze of L; 'x 'x 10'.Duriny tni;s _)eciod nD uiaintenance should be C~~.O

2 . AC2iIVAI1LO 0z: FI3SL)L SYS'rE.j FOR SERVICE

2. t'Tin draw down Ohase has rocen c_:- tc when thc-o~it

* hui ,dity indi cator Ceddus 40 -3cent or less. 'rho 4:3a/.tservice ?hase is; ready t7. jejin.

2.2 Prepare for cep!_accw_.e- *'it.i esicccanL sarl ri.-en~ucin( that three sealad packad3es of desiccant cartc s s areready forc installation.

*2.3 Reriove thle cover by loosenin5 the screw fast nc-s. that hioldthe cover to the housing. Reitove the desiccant atie nawere, us~ed for draw oveni. Iiiiiediately install thnree ne~w uScant cartridges. Trie cartridges are to be iistal'_ c. _Li ttitcperforacted face out. .:hen -;roperly isai tne carcriajeswill be flush with the outside of the touzin 5 (&± ui ) in..

cartrid. es ace dtuai~ned to be a sriu~ fit in tne bathf It-Lic h-a iib (, c i. The car triuy,. seal r. i 3t be rorc.:o ovef c to C)).-the nousirig oaffle assembly.

2.4 Cloac_ anc secure tha FBSuii zsystem houisin~j y

2.5 Do niot discard thie desiccant cartriddco_, usedl 1-uc tie u

du.4n pnaot!. They way be2 refillca or reactivated, ccf .cparagaphj.u fof proce;aure.

-.0 :llLz'N~ a: v ;Di :Y.ILil

3.1i At iritor vail . t9c .wt atLuIuL yi. .~

3.2 Iti the nUJI.uI ty ilIwJ L il~t. thE C-Ver ofE th _ FW.3H JLa.shows anl U of oo.4u 111p c~L d L It_ CQiOLtc illu .cuL'r 6ilhcWS a.,.RH of isore than 40 ~.ecit& / 1~i6 n~nJ.PtrL1. Ksurc_ of the 11;a . aio; l..fjcuccL ol ~t.t tK,: W/

described in Appendix C and repeat the draw ,'wI as describea inAppendix D.

3.3 If the humidity indicator in the cover snows an RZd of gcpat-er than OL cual to 40 percent and tt'2 , inc .: . how ai

RH of 40 percent or less, the desiccant cartridges should bereplaced. During this period, monitor the remote indicator twicedaily. If the RH at the indicator does not exceed 40 percent, itis not necessary to repeat the draw-down phase. If the RH at theremote indicator exceeds 40 percent, the S/T/V is leaking. Deter-mine the source of leakage and make corrections. Retest theS/T/V arid repeat draw-down.

4.0 REACTIVATION OF THE FBSDH SYSTEM CARTRIDGES

4.1 Desiccant cartridges may be reactivated by placiny them ina dry vented oven which has oeen heated to 260 degree F. Beforeactivation the cartridge should be weighed and the weightrecorded. The cartridge should remain in the oven for 48 hours.Remove the cartridge, and record the weight. The weight of thereactivated cartridge assembly should be close to that marKed onthe cartridge naie plate. IL the weight ot the cartridge anodesiccaiit exceeds the weight marKed on the cartridge label plateby more th-an 2 pounus, return the cartridge to the oven foranother 48 hours. When the weight condition had been achieved,mark the weight on the proper line on the cartridge name plate.If the cartridge is not to be placed in service immediately, itshould be packaged according to MIL-P-l16, submethod 1A-14. Tagthe package to indicate date of reactivation and weight.

4.2 Cartridges may be disassembled and desiccant reactivated.To disassemble a cartridge, remove the eight flat head machinescrews holding thc cartridge top to the sides of the cartridges.Note how the cartridge seal is assembled between the cartridgesolid edge and the cartridge top. This seal must be reassembledin the same fashion. If any part of the cartridge seal isdamaged, the cartridge should be returned to a repair base forrepairs.

4.3 Open the nylon baj containing the desiccant and pour thedesiccant into a clean container. Examine the nylon baJ. Ifthe bag is torn, J.t may be .epaired by patching. Retain thenylon bag for reuse.

4.4 Weigh the desiccant and spread it on a clean flat metalpan. Place the ,an in a dry, vented oven at a temperature of2bO degree F. The desiccant should be allowed to remain in theoven for 24 hours. Remove the pan and desiccant and weigh thedesiccant. The weight of the desiccant should be close to thatshown on the cartridge nameplate. If the weight exceeds thename plate weight by more than 2 pounds, the desiccant should be

-----------------------------------:,.

: *- ": '- ' - " .- -: , ---. * *' ', * - - . -- ' . - - . -- ,- .* . , k : -. 2 , . . . % '

returned tu the oven for another 24 hours, w. ntil tne weightcondition has been achieved.

4.5 Prepare the cartridge for refilling by insertinj the nylonnag carefully into the aluminum cartridge canister. The bottomof the bay should oe pushed to the bottom of the canister and thebag spread to the insides of the canister. Pour the reactivateddesiccant carefully into the nylon bay. Close the top of the bai-with staples or by sewing. picc the top of the cartridgeexercising caution to ensure that the top portion of tiie gasketseal is properly installed. Note the weight of the cartridge andmark the cartridje name plate accordingly. If the cartridge isnot to be placed in service immediately, it should be packagedaccording to MIL-P-116, submethod 1A-14. Tag the package with theweight and date of rechar-in-. .

5.0 REFILLING OF DESICCANT CARTRIDGES WITH DESICCAJT"

5.1 Cartridge may be refilled with fresh desiccant. Remove thetop of the cartridge in accordance with paragraph 4.2. Open thenylon bag and discard the desiccant. Note: The desiccant ma,,be saved by reactivation as described in paragraph 4.4. Chec .the nylon bag as described in paragraph 4.3 and 4.5. R{efill tfhecartridge with silica gel, MIL-D-3716 SPEC, Type iI, Gcrane H.

Replace the top, checking the gasket seal and mark the cartriayg .name plate as necessary. Package the cartridge, accoLding t-MIL-P-116, submethod 1A-14 if it is not to be put into scrviceimmediately.

b .U TAKING FBSD[i SYSTEM OUT OF SERVICE

U.1 'i'he FBSDH system is taken out of service by installing theplug into the inlet elbow at the lower right hana corner of thePBSDH system cover. Desiccant cartridges may he removed orretainea in the housing.

7.0 REMOVAL OF FBSDH SYSTEM

7.1 The FBSDH system may be removed from the S/T/V by unboltingthe FBSDH system housing flange. The remote separate.[ R-indicator tube may be removed by unbolting the flai.ge from theS/T/V.

7.2 Blank the openings in the S/T/V with suitable oei.al plate,properly sealed.

Lk

TABLE I

INTERIM REPORTING

1. Type A: Telephonic Communication

Frequency: Once per week for four weeks

Contents: Review of performance of FBSDH during tne previouaseven days.

2. Type B: Written Report

Frequency: Once per month for duration of project

Content:

a. It should be noted that data was cecorded cdch day,every hour within the 24-hour period, for each of the fiveshelters.

b. Exterior temperature and relative humidity readinjscorrespond to 0400 and 1600 hours denoting the maximum-environmental changes in the SM-ALC area according to data from -the USAF weather station.

c. General weather conditions for each 7-day period.

d. This report will also include all pertinentinformation that the engineers of record regard as a ijn4f citcontribution to the document of this field test.

3. As the project goes forward, reporting procedures wil beadjusted as required.

2-4

.

24

TABLE II

PRESSURE/VACUUM EiST*

Shelter No. Pressure VacuLUn Date

SM-ALC/L)Si'U

120.0 Min 120.0 Min 8 Nov 84

16.0 Min 10.0 Min 23 Aug 841.0 Min 1.3 Min 4 Nov 8b

3 10.0 Mi 10.0 Min 11 Oct 641.5 Min 3.5 Min 4 Nov 8u

4 30.U Min 6.0 Min 2o Sep 844 9.5 Min 7.0 Min 4 Nov 8o

5 2.U Min 2.0 Min 30 Oct 84

5 1.0 Min 1.3 MIn 4 Nov o-

HQ AeLC/DSTZ

1 0.0 Min 0.0 Min Aug 6SO.0 Min U.o Min 4 Sep db

*1ime is in minuts for pressure/vacuum decay tcom 2.0" WP t

0.0" WP. No pressure/vacuum decay rate was establmsnea when tnefield test opecation was initiated; therefore, [iyultiple trialswere performed on =ach shelter during the sealing operation. .When the Dest possaie decay time was reco-ded on any yavenshelter, the sealing process was discontinued.

**FBSDH System was taken out of the shelter on 2L Jan bu. A

final pressure/vacuum test was not conducteo.

25

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DISTRIBUTION LIST

Dr'ICA'uAC 12Cameron StationAlexandria VA 22304-b145

HQ Ar'LC/DSI'Z Library 20Wriyht-Patterson AF'B OH 45433-5999

HQ) AeLC/DSTP IWriyht-Patterson AF8 OH 45433-599 ;

HQ USAeLE11 IWash DC 20330

HQ Ar'SC/LG' I

O)C-ALC/DSTTinker Ar'B OK 73145

U0-ALC/ OST 1Hill AFB UT 84406

SA-ALC/DST i I.

Kelly AeBN TIX 78241

SM-ALC/DST/DS'fD I eaMcClellan AF'8 CA 95652

WR-ALC/DSlRobbins AFB GA 31098 -

ASD/AWLWri(,ft-Patterson AFB O11 45433

DLSIL/AMXMCUSA Loy isitic5 Myt CtcF't Lee VA 23801

US AMC iPackaying, Storage, ariaIContainerization C(-ritec/SDSTO0-T

Tooynianna PA 184u6

US Army N'atick Labb/STRN&C-ESINatick MA OI7oU

NAVSUPSYSCMO/SUP-U32 IA IWash DC 2037/6

59

77.

DISTRIBUTION LIST (Cont'd)

CoilulanderNaval Supply Systems CoimandAttn: N. Karl (SUP 061lF)Washington, DC 20376-5000

ComananaerNaval Air Systems CowianoAttn: E. Panigot (AIR 41212A)Washinyton, DC 20361

CommanderSpace and Naval Warfare Systems ComimanoAttn: T. Coroe (Code 8218)Washington, DC 20360

CommanderNaval Facilities Engineering ComanaHofiikmn Bldu. #2, Room 12S21Attn: C. Manwarriny (PAC 0644)Alexandria, VA 22332

Coiutanciny Of ficer %Naval Construction Battalion CenterAttn: K. Pollock (Code 15611K) %Port lueneme, CA 93043

Co-unanaerNaval Sea Systems Corino %Attn: G. Mustin (SEA bGb3)Washington, DC 20302

ComaanaerNaval Sea Systems CommandAttn: F. Basford (SEA 05M3)Washinyton, DC 20362

Colianaing OfficerNaval Aviation Supply Office700 ROboins AvenueAttn: J. lannello (Cos tPP-A)Pnilaoelpnia, PA 19111-5u98

Comianaing Of icer

Navy Snips Parts Control CenterP.O. Box 2020Attn: F. Sechrist (Code Ub41)Mechanicsourg, PA 1-/055-0788

60

DISTRIBUTION LIST (ConL'd)

Cotunandiny Otticec 1Naval Air Enyineerinyq CenterAttn: F. Maynitico (SESD Code 9321)

Lakehurst, NJ 08733-5100

ASO/TEP-A 1700 Robuins AvePhiladelphia PA 19111

US Army AMCCOM/SMCAR-AEI) 1Dover NJ 01801-5001

GSA, Office ot Engineering Myt IPackayiny DivisionlWash DC 2U406

HiQ ULA/OWO ICameron StationAlexandria VA 22304-b14b

ASL)/ALXP 2

Wrignt-Patterson At'b OH 45433

AFSC AL/IYNP/YNEP I eaE~jln AFB Fl, 32!542

HIQ AFLC/DS/DS1 2 eaWriyht-Patterson AFB Oh 45433

HQ AFCC-/MMA 2Wriyht-Pattersofl AF1 Oil 45433

A1'ALC/C V 2Wrignt-Patterson Ar'B 0il 45433

AFALC/OA 2

wriyflt-Patter~on AFt8 OHl 45433

AFLC LOC/CV 24Vijt-Pattevxson Ar'b OH 45433

AeLC LOC/TL 2Wrijt-PattcrCson AUi3 Oki 4t433

ASD/IAM/TAIL 2 ea

Wryht-Patterson AF8 OH- 45433

61

DISTRIBUTION LIST (Cont'a)

LSD/XRMS 2Hanscom AFB MA 01731Attn: Major Roln Eye

SM-ALC/DSQ6McClellan AFB CA 95652

SM-ALC/MMLT (John WasKewicz)McClellan AFB CA 966Q52

SM-ALC/MfCGE 2McClelldn AFB CA 95652Attn: Geoyce Isley

SM-ALC/MAIPG Ir(Cie-ilan AFB CA 95652

AGM Container Contc-is Inc. 33526 E. Ft. Lowell RoadPC Box 40020Tucson AZ 85717-0020Attn: Royer Stewart

U.S. Army Research, Development, 2Enyineeriny Centec/STRNC-UST-

Attn: Nick PatavNatick MA 01756-5000

General Dynamics 2Attn: Lorraine DixonWLC LiuracyLdna Sytteus DivisionP0 Box 52/

vccrren MI 48090

-

62

*- - .%- .- ..-. -.- - -.. * %-*.*.** . , _ . . . . .. . -- . -. -.. .. .. . -. -. -. . .. ., ~ ., -. . .. .

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