5O3.3-10

lEIHDD 503.3

тшшшггпт moot sBcmcxi II

ii-i яррмвкгаз

П-1.1 Tteit faciliiieg

a. Tb* required pparetue eonaiete of t R> dtaebere or cabineta in i<ii tbe test conditiona can be eatabliabed and aaiintained. №1е 8 otbenri.se apecified, tba diaabers oust be equipped so that, after transfer of tbe test Iteai. tbe test

eonditiis within the стёшвг cwi be stabilised п.thin five ninutes. Materiel-handling equipaant nay be necessary for transfer of tbe test Itea between cftaaibers.

b. lbs chaabers shall be equipped dth aiatiliary Instnaantatlcn сцмЬХе of

inaintaining and continuoualy aonitoring the test conditiona tfaroiighout an envelope of air stiprounding the test itemCa). (General Bequireaanta, 5.1.1a.)

11-1.2 Controla

a. TeBmeratta. Onleaa otherwiae specified in the test plan, if any action other than test item operation laudti as opening of tbe diaaft>er door, except at transfer tine) results in a significant change (more than (3.6°F)) of the test item teBperat-ore or chad r air tsjsrattjrs, the test it i mil be stabilized at the required temperattsre before continuation.

b. Air velocity. Air velocity in tbe vicinity of tbe test itea 11 not exceed 1.7 пк/s (325 ft/min) to provide standard testing conditions, unless Justified by the test item platform environment.

e= an8fer tiaB. Tre sfer the test item between the two envirenasnts (high and low tenperatures) as rapidly as possible but in no more than five adnutea (unless the test item is large and requires handling equlpnant).

II-1.3 Test interru>tien (General Bequirements, 5.2.4).

a. taadertest tnterrtytfton. If, before tha topsrature sStssigs, an ussidssduled test intemiptlon occurs that causes th* test conditions to exceed allcasle tolerances toward standard aabiant teaperature*, th* teat auat ba reinitiated at the point of interruption and the test item reestablished at the test ocndltion. If tha interruption occura dwing the transfer, the test item oust be reestabliahed at the previous tenperature and then tranaferred.

Ъ. Overtest IntrmMttiona. Any Interrtjption that results In more extreme ехроешч of tbe test item than required by the equipment specification should be followed by a cosplete physical examination and operational check of tbe test item lahare poasibie) before any contintmtion of testing- Tbis ia especially trus sfeara a safety prcblas oculd exist, such as with suniticns. If a prcblea> is disoayered the preferle course of itlon is to stop thm test and start over wltb a new test item. If this is not done and test item failure occurs during tbe remainder of the test, the test results could be invalid dxje to the overtest condition. If no problem is discovered, reestablish preintemtion oondltions and continue from the point viiere Uie test toleranoaa ware exceeded.

II-2 FSS m€S T

II-2.1 Preliminary steos. Before initiating any testing, tron the test plan:

a. Deteneine the test teiqperature levels

b. Dstaresine the test item configuration.

c. Determine the operational requirements.

d. Estimate the time required at each tenperature. (Install tenperature sensors if necessary.)

II-2.2 Pretest standard aafcient checkout. All test items reqjire a pretest checkotst at standard anbient conditions so that baseline data can be established. Munitions and other items, viiere applicable, shall also be examined by nondestrijctive examination methods. (Conduct the checkout as follows:

Step 1. Stabilize the test item at standard aroient conditions ((Seneral Bsquirantsr.ts, 5.1a).

Step 2. Conduct a conplete visual examination of the test item with special attention to stress areas such as comers of molded areas and interfaces between different materials.

Step 3. Docunent the results.

Step 4. Prepare the test item in accordance with General Bequirente, 5.2,2, and required test item configuration.

Step 5. (Conduct an operational checkout in accordance with the approved test

plan.

Step e. Becord results for conpliance with (Beneral Bequirements, 5.2.1.

tCL-Sro-eiCE

Step 7. If the test item operates satisfactorily, proceed to step 1 of procedia I. If not, resolve the problens and restart at step 1, above.

11-3 PSOuBJJUiiE. Tha foll6 d.nB porOoedis>e provides the basis fw ooliectins the necessary information conoemlng the test item in a severe tenperatu shock environomnt: The procedure Is Mpittm to ataat the iow tMperatvM. - Olamsvmp,

it is permissible to start with high teaperature. and alternate between the two tenperature extrimaa in aequanoe.)

Step 1. With the teat iten in tbe duober, odjuat the cfaaiber air

teaperature tc the 1 ow-teaperature axtrase specified in tba test plan. Maintain this t Dperatts>e for one hour or until the test item has been stabilised, вЦоЬеуег ia longer.

Step 2. Transfer the test item to tbe high-tenperatts environment (as specified in the test plan) in no aore than five minutes. Chaaber control shall be

svdti that after iriser-ticn of the test item, the chaaber teaperatuB shall ba vdthln the specified test tolerance after a period of not ss *e than 5% cf the exposure tims. Cycle the chanber through the appropriate diumal cycle until the text item response tenperattve (from the test plan! has been reacted. Maintain this teaperature uitil the teat item has stabilized. (See (Seneral Bequirements. 5.1.3)

Step 3. Transfer the test item tc the low-taBpsratura envircnaant as above, and stabilise at that tenperature.

ШГЕ: If the test procedure is interrupted dm to work schedules, etc., the test item can be left at the test temperature or returned to standard aabient COTiditlena for the tina required. Before oontinxjing the teat, the test item auat be reatabilised at tbe

tanparat-ure of tba last supcessfully ooopleted period before the Intemtim (see II-

1=3) ,

Step 4. Bepeat ateps 2 and 3. step 5. Repeat step 4.

Step e. Bst<.s<n the test it s to control lad aau;i itt conditions (General Requirements. 5.1b) and stabilize.

Step 7. Operate and inspect the test iten and obtain results in accordance with General Requirements, 5.2.0. Conpare theae data with the preteat data.

П-4 iigOHMjiTTOM TO gg ттгхи?.

a. Teat item identification (manufacturer, aerial niaber, etc.).

b. Previoua test methods to abioh tbe test iten has been siA>Jected.

lETHQD 503.3

SSraDD 503.3

c. BMults of Mcfti parfomanco check and visual examination, and ison wltb tbe failure criteria.

(1) Pretest.

(2) During test.

(3) Post-test.

d. Length of time required for each performance check.

a. Status of tbs test ites for each visual exasiination.

f. Defects noted during visual examinations.

g. Clothing and special equipment used to set цр or dlsassenfole the test item.

h. Test taaaratxa.

i. Duration of each exposure.

J. Appropriate anthropometric measxjrements of personnel performing lipulation testa.

k. Teaperatxare-tias-versus date (test item and chaatMr).

1. Initial analysis of any failure.

tsmHSD SC3.3

1-2.1 Heating effects. The heating effects of solar radiation differ from those of high air teirf>erature alone in that the amoimt of heat absorbed or reflected depends on the rot.ighness and color of the surface on *ilch the radiation is incident. In addition to the differential expansion between dissimilar materials, changes in the intensity of solar radiation вау cause conponents to expand or contract at different rates, which can lead to severe stresses and loss of structural integrity. In addition to those specified in method 501.3, some other exanples of heating effects Include:

Janming or loosening of moving parts.

Weakening of solder joints and glued parts. Change in strength and elasticity.

Loss of calibration or malfunction of linkage devices. Loss of ssal integrity.

Changes in electrical or electronic conponents. Prematvire actuation of electrical contacts.

HETHOD 505.3 SOLAR RADIATION (SuNSHImE)

SECTION I

I-l PURPOSE ...................... 505.3-1

1-2 ENVIRONNENTAL EFFECTS............... 505-3-1

1-3 GUIDELINES FOR DETERMINING TEST

PRucEDUm and T CONDITIOiE.......... 505.3-2

1-4 SPECIAL CONSIDERATIONS ............... 505.3-8

1-5 Hbl-EHSNCES.............. ...... 505.3-9

SECTION II

II-l APPARATUS ..................... 505.3-10

11-2 PREPARATION FOR TEST................ 505.3-13

II-3 PB0CEDUPE3 ..................... 505.3-14

11-4 INFORMATION TO BE RECOPJ)ED............. 505.3-17

SECTION I

I-l PURPOSE. This test is conducted to determine the effects of solar radiation on equipment that may be exposed to sunshine during operation or unsheltered storage on the EiuPths Btrface Or In the lower atraosphere.

a. Fading of fabric color.

b. Checking and fading of paints.

e. Deterioration of .natural sad synthetic elastomirs and polymers throtMh photochemical reactions initiated by shorter wavelength radiation.

1-3 ampELiMBS for оегевмидю -rasr pbdcbdcbbs ш> test oomditioms

liuTE: The tailoring process as described in section 4 cf this decfassnt should be used to determine the propriat9 tests шуЛ test variables.

a. AppIication. This method is leed ймп the test item is likely to ba elфosed to solar radiatim in the open, in hot cliaates during its life cycle, and the effects mentioned in 1-3.1 and 1-2.3 are of concern. In most cases, this asatbed aooUid

replace method S01.3 (high taaparatura).

b. Bestriotions. This method is not to be used to siюulate the beating effects that result from enclosed or covered storage conditiona. live aolar spectrua and energy levels are those that are received at sea level. Tb* ultraviolet portion is simulated only in a general way, but is considered adeqxjately representative of levels in most geographic

c. Sequence. (See Gleneral Requirements, 5.1.4) Tbe solar radiation test be applied at any st4ige in tbe teat program,

d. Test variations. This mathod is coBpo**d of two solar radiation tests: procedures I кСусИс) and II (Steador state).

кеТКЮ 505.3

h. Fading of colors of color-coded cospoiiante.

i. Changes in characteristics of elastomers and polymers.

j. Blistering and peeling of paints and other finishes.

k. Softening of potting c< pounds.

1-2=2 Actinie effects. In addition to the heating effects of 1-2.1, **ich are caused by the infrared portion of the solar spectnsa, certain degradation from solar energy may be attributable to other portions of the spectrua. particularly the ultraviolet. Since the rate at 4tich these reactions will occur generally increases as the tenperature rises, the full spectrum mLJSt be tised to adequately simulate the actinic effects of solar radiation. Some escasples of dsterioration amim d by actinic effects

шь-гпьвюЕ 14 JULY loeo

(1) Tarn duoiem of tmwt proorndxisrS is based <m tha fclloielng: 1тЛ Tbm ntieinat d axpoavipa ciX4nmBtanc e.

(b) The expected problem areas vdthin the test item.

(c) Tbe duraticm ox exposure to solar radiati.

(2) The related test conditions that are used during the test are

deterned by:

(a) The anticipated areas of deployment.

(b) The test item configuration. 1-3.1 Qtojg* Pi tesfc ptpgrnojgrn

a. Operational purpose of ,the test item. Prom the requirements doctsnents, determine the furtction(s) to be performed by the test item during or after exposure to direct solar radiation.

b. Test objectives. Tbe primary objectives of the test are to determine if:

(1) Tbe test item can satisfy its operatlmal requirements during and after exposure to solar radiation.

(2) Tbe physical degradation *iich occurs during exposure prodxicma adverse effects en the test iteat Based on this infornatlon and the ршфове of the test item, determine 4iat test data are necessary to evaluate the required performance of the test item during and after exposure to solar radiation.

c. Selection of the test procedure. Tm> test procedxss are included d.th this method. Based on the test data reqxiirwaents, datermiris hl > of tha test procedis is appli sble.

(1) Procedure I - CvclinS for heat effects. This test procedure is used if the test item is expected to ithstand the heat from exposure in the open in hot climates and still be able to perform without degradation both during and after expostsre. Tbe solar radiation test (as opposed to the high teeratvs>e test, method 501.3) should be used vftien the test item could be affected (see 1-2) by differential heating or Aen the heating caused by solar radiation is unknown. After the induced teeperatis and tenperature effects have been determined to be ooaparable to the tenperature and tenperature effects that could be prodiieed by method 901.3 (high tenperature) , the latter could (for economic reasons) be sxibstitiited for this solar radiation test.

КЕТЮО 505.3

(2) Ргосеауге II - Stsadv tftata for prolongad actinie effeetB. This procedijre is шей irfien the principal concern is the possibility that ler.g periods of exposure to sunshine will result in detrimental actinic effects. Because actinic effects do not usually occur unless the exposure is prolonged, it is inefficient to use the cycling test of procedure I, tdiich could conceivably take months to conduct. The approach, therefore, is to use an accelerated test which is designed to redixse the tims to reprodiice integrated effects of long periods ox exposure. The key to using this prccedxire successfully is maintalnir.g encxgh cooling air to prevent the test item from exceeding tenperatures that would be attained under natural conditions (six;h as the cycling test simulates), so that there will not be an exaggerated test which unfairly penalizes the test item. However, there should not be enough cooling air to produce unrealistic cooling. Since the actinic effects are highly dependent apor, the solar radiation spectrvni (as well as intensity and duration), the spectrum nust be as close as possible to that of natural sunlight.

The 4-hour lights-off* period of each 24 hour cycle allows for test item conditions (physical and chemical) to retin*n toward normal* and provide some degree of thermal stress exercising.

1-3.2 (loice of related test conditior,s. Having chosen the test proeedure, it is necessary to choose the dliB*nail cycle, test duration, test item configuration, relative humidity, and any additional a4>ropriate conditions.

a. Diurnal cycle. For Procedure I. two high tuperature diurnal cycles are provided in table 505.3-1 with the sane solar radiation conditions for both. The first cycle (Hot Dry) has a peak tenperatin of 49C (120 and 1120 w/m (355 Btu/ft/hr) and represents the hottest conditions exceeded not more than one percent of the hours in the most extreme month at the most severe locations in those portions of the earth under consideration. This cycle is used *ien there is a requirement for the test item to perform satisfactorily worldwide. The second cycle (Basic not) is less severe and peaks at an air tenperature of 43 C (110

and a solar radiation intensity of 1120 H/m. This cycle is used *ien there is a requirensnt for ths test item tc perfors asithout dsgradation in many geogr-aphical areas of the world that extend outward from the Hot Dry* reglmts of thm United States, Mexico, Africa. Asia and Australia, southern Africa. South America, southern Spain and Southwest Asia. (See Method 501.3. for area descriptions.) This cycle is also used aiien special precaxitlons are taken to provide protection against the s\m% in hot. wry veas (such as with nutitions).

b. Test .duration

(1) Procedure I. The test item shal 1 be exposed to continuous 24-houp cycles of controlled sinulated solar radiation and dry bulb teaperatta>e as indicated In table 505.3-1 or as spc cified in the requirements documents. The nuaber of cycles performed shall be either the mininun necessary to produce the peak isponse

tenperatiBe of the test items critical conponent(s) (within 2* {3.S°F) of

the peak response tenperature achieved dvrlng the previous 24-hour cycle) er three

ecntinusue cy-clas, bichever is longer. It is suggested that, for nssst applications, Ше ssxisun test duration should be seven cyoles.

(2) Procedure II. (See figure 505.3-2.) Procedure II will give an acceleration factor of approxinately 2.5 as far as the totalenergy received by the test itea is concerned. Eight hours of exposure to 1120 W/in (355 Btu/ft/h), as in the steady-state test, is ec[ual to 24 hours or the cycling test (20 hours of light and 4 bo-ura of no light per cycle). Л duration of ten 24-hour cycles is suggested for equlpsisnt nEich is occasionally > ed outdoors, su as portable test Itene, etc. For equlpnnnt continuously exposed to outdoor conditions, a test duration of 56 cycles or longer is suggested. Increasing the irradiance above the specified level is not reconmended, because of the danger of overheating, and there is presently no indication that attenpting to accelerate the test in this way gives results that correlate with equlpnaent response under natural solar radiation conditions.

TABLE 505.3-1. Tens?erature/8olar radiation diurnal cycles 1/

i Hue

i Шп

120 90

i 43

! 30

110 86

1120

О

355 0

1/ Salaeticn of tassperatur-e ccriditicns depends cn the requiresssnts dccxsasntCs) and the condition to *iich the pticular item will be subjected during normal \ age.

ftETHDD 505.3