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SSTHDD 505.3

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0300 0600

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1200 вОО

Т!МЕ Of BAY {HRS)

FIGURE 505.3-3- Q1t rartlntlon ете1е.

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liiL-sro-eios

14 JULY 18

II-3.2 Ppocsd-js II - Steady atata for prolor.ged aetinle effectg

Step 1. AdJU8t tbe solar radiation source to a radiant energy rate of 1120 ±A7 Wv? (355 ±1* Btu/ft/b). or as specified in the equipment specification, and a tenperature of 4в* С (120 >F).

Step 2. Sblntain these Gcnditlcr.s for 20 hours. 1/

Step 3. Measure and record the test item tenperatures.

Step 4. Turn off the solar radiation source for four hours.

Step 5. Repeat steps I tluugh 4 for the пшЬег or cycles specified in tha test plan.

Step 6. Condiict a perfoi>mance check and visual examination as in II-2.2, steps 2 and 5 and document the results.

Ii-4 HgOHMRTlOw TO BE ЙЕ501шы)

a. Test item identification (nanufacttsr, aerial nunber, etc.).

b. Previous test methods to which the test item has been subjected.

c. Test procedure.

d. Besults of each performance ehe<dc.

e. Besuuts of each vistjal examination (and photographs, if applicable).

f. Location of tenperature sensors on the test item.

g. Test item taeratm*es td хровш-в periods.

h. Solar lanp baiik Identification. 1. Additional data as required.

1/ If required, operational checks should be conducted during the last

four hours of each 20-hour exposure when test tenperatures are maximized.

MIL-STD-SlOE 14 JTJLY 1089

505.3-18

leiKX) soe.3

BAIH

sscncw I

I-l FQBFOSK......................500.3-1

1-2 атвсшвт/Лл effects...............5oe.3-i

1-3

Ш1даЛШ FOB ШШЕайШЮ TEST

FSOCEDliHES AS!D TEST С(Яа>1Т1(ЯБ.......... 505.3-2

1-4 SPECIAL ССЙЕ1!ЖВ*Т10Ш............... 506.3-5

1-5 mFEBEHCES............ ........ 806.3-7

ЗВСТКЖ II

II-l AFPABATIB..................... 506.3-8

Ii-2 rSSFiSSSiaS FOB TSST................ 506.3-10

II-3 PBOCEDUHES...................... 506.3-10

11-4 IHPOBM&TION TO BE RECORDED............. 506.3-12

SBCTIOM I

I-l PUHP03E. Tb* p*ln teat la conducted to datamina the followlhg:

I a. Tbe effectiveneas of protective covers or cases in preventing the penetration

of reiin.

b. The capability of the test item to satisfy its performance requirements during and after exposiare to rain.

c. Tbe physical deterioration of the test item causedby tbe rain.

1-2 EWVIBOiaCTTAb FgyrS. Rain ( ien falling, upon inftact. and as deposited (aater) has a variety of effects on materiel.

a. In tbe atmosphere, it:

(1) Interferes with or degrades radio comnunication (reference d) .

(2) Limits radar effactivaness (reference d).

(3) LlsLw air@>aft operations by r-eatricting visibility (refereriGe d}.

(4) Damages aircraft in flight.

(5) Affects artillery and missile launching.

(6) Degrades or negates optical surveillance.

(7} Decreases effectiveriess cf perscnnel in exposed activities.

(8) Causes sone fuzes to fuiction preaaitiB*ely.

(9) Inhibits visibility through optical devices.

b. On lipact, it erodes surfaces.

c. After deposition, it:

(1) Degrades the strength of som aaterials.

(2) Proaotes corrosion of aatals.

(3) Deteriorates siirface coatings.

(4) Can render electrical or electronic apparatxjs inoperative or dangerous.

d. After penetration into containers, it:

(1) Gatses sal function cf electritssl equipssnt.

(2) May freeze Inside equipaant. vtiich aay cause delayed deterioration and malfunction by aval ling or cracking of parts.

(3) Causes high hxsnidity. ш1сЬ can, in tina. encoxirage corrosion and fungal

growth.

(4) Causes slower bianiing of propellants.

№УГЕ: lbs tailoring pFotss as described in section 4 of this dosissnt should ba xsed to determine th* appropriate tests and test v *ii!les.

a. Application. This method is afqpllcable to equipaant Aioh may be expoaed to rain under aervic* conditions.

b. Bestrietions. isre a requiresent exists for dateraining tha affects of rain erosion on rsdosas, nose cones, fuses, etc.. a vodsst sled test facility or other sush facility should be considered. Since any teat procedise Involved would be oontingent on requlremente peculiar to the teat item and the facility eoployed, a standardised test procedure for rain eroaion ia not included in thla test method. Becauae of tbe finite aize of the test facilities, atmospheric rain effects sxjch as electromagnetic propagation may not be determined with thla method. Thia test method is not intended for use in evaluating the adequacy of aircraft windshield rain reaoval provisions. Additionally, this method nay not be adequate for determining th* ffects of extended p*riods of exposxjre to rain.

ЬЕГЮО 508.3

(1) Bain can penetrate the enclosure of the test item while it is in

(2) The test item can meet its performance specifications during and after exposure to rain.

(3) Bain causes physical deterioration of the test item.

(4) Thm rain and eolleeted rainieifcer renoval systene are effective.

b. Selection of the test procedure. Three test procedures are included within method 50в.З: blowdng rain, drip, and watertightness. Select the procedure that presents the most severe exposure anticipated for the test item.

(1) Pfocedts, I,..-..Blowing rain. Procedure I is applicable for equipment lAich will be deployed out-of-doors and viiioh will be tsiprotected from blowing rain. The acconpanying wind velocity can vary from almost calm to extremely high. Test items which cannot be adeqviately tested with this procedure because of their large size should be considered for testing under procedure III.

(2) Procedure II - Drip. Procedure II is appropriate viier. equisent is normally protected from rain but may be expoeed to falling water from condensation or leakage from upper surfaces.

c. SeqiMnce. (See General Requlremente, 5.1.4.) This method is юрИсаЫе at any stage In the test program, but its effectiveness as a test method is maximized if it is performed after the dynamic tests.

The leakage test (method 512.3) is normal ly considered to be more severe than the rain test for dstsrmlnirtg the psnstrability of the test iters. EqpjipBssr.t that passes

t-he laaVatfa test Шу HOt reqwslr* хроя\в>т to the rain teat if Its configuration IS

unchanged and the effects of penetration are the main concern.

d. Test variation.. This method is conprised of three rain-related test procedures. Before the test is conducted, a determination must be made of Mhich test proovuVBrmm ало test conditlone are appropriate. I>etersinaticn cf related test ccnditicr.s that are used during the test are based cn:

(1) The test item configuration.

(2) The operational pxirpose of the test item. 1-3.1 (atoice of test procedure(s)

a. Test objectives. The primary objectives of the rain test are to determine

mh-STD-BioE 14 JTiY iS88

(3) Pfogadtxaa TTT - ifcterti*htRegg. Procedure III should be considered viien large (shelter-size) equipment Is to be tested and a blowing-rain facility is not available or practical. This procedure is not intended to sisulate natural rainfall but will provide a high degree of confidence in the eatertlghtness of a piece of equipment.

1-3.2 Choice of relate;; test csnditicrj. Varlablss under each test procedure include the test item configwation, rainfall rate; wind velocity teat item expom r siirfaces, water pressure, and any additional appropriate guidelines in accordance with the requirements document.

a. Test itepi coniiauration. The test item should be tested in al 1 the

ccnfiguratlor.s in shich it can be placed during its life <-ele. As a ш1п1шш, the following configurations should be considered:

(1) In a shipping/storage container or transit case.

(2) Protected or not protected.

(3) In its operational configiaration.

(4) Modified with kits for special ц>р1ieatlons.

b. Bainfall rate. The rainfall rate used in procedure I may be tailored to the

anticipated deplojrmsnt locale and duration. An instantaneoijs rainfall rate equivalent to 0.30 ssn/ssin (l.S@ In./h) occurs fftiisss?n 1 у in areas of heavy rainfall, but a minlmLin rate of 10 em/hr (4 in/h) is recoaaoended, aince it la not an uncommon occurrence and would provide a reaaonable degree of confidence in the test iteat Asia, for exanple. is known to have high rainfall intensltlea. The highest recorded intensity for one minute occurred In Mazyland and ams 31.3 am/rain (1.33 in./mln.).

i-or testing purposes, the fOl lOmng table of rminfml 1 rmteS (Гаш SuL,-alv-2IG) far

worldwide expected durations of exposure (EDS) frcxn 2 to 25 years is sore realistic.

TABLE 50e.3-I. Expected rainfall ratea for different axpospf jyyrttons.

EDE ! Bate

2 -4.0 * 10

I 5 ! 4.7 ! 12 !

i 10 : 5.2 I 13 :

i 25 I 5.8 : 15 t

c. Droplet gise. Soiair.al drep-sise spsctra exist for ir.stsntsneous rainfall rates, but, according to MIL-STD-210, for the long-term rainfal 1 rates they axe meaninglesa. since rates are made up of many different instantaneous ratea posseasing

тГЯЮ 508.3

50e.3-4

nEthOD 506.3

different spectra. For these tests, droplet sizes should not be sneiller than approxinately Q.B mn in diameter. I/ *iieh is considered to be ndst or drizzle rather than rain (reference е.), or larger than 4.5mra.

d. Wind velocity. High rainfal 1 intensities accoiipanied by winds of 18 m/s (40 nph) are not unconnion during storms. Unless otherwise specified, this velocity is reconuided for ргОсеоШ^ I tests, winds of 35 т/в (75 sph) are the threshold for hurrlcans-forcs winds.

e. Test item exposure surface. Wind-driven rain will usually have more of an effect on vertical surfaces than on horizontal surfaces, and vice versa for vertical or near-vertical rain. Al 1 surfaces onto which the rain could fal 1 or be driven nust be exposed to the test conditions.

f. Wter pressure. Procedure III relies on pressxirized water. The pressure may be varied according to the requirements docunents, but a minimum value of 377 kPa (40 pslg) nozzle pressure is given as a guideline based on past experience. This value will produce water droplets traveling at approximately 64 km/h (40 raph) wiien a nozzle as specified in in Il-l.ie is used.

g. Additional guide 1 i. .es. P.eview the requirerosnts docunsnts for a.iy additicmal guidelines.

1-4 SPECIAL (X>N5IDERATI0NS

Y a 1 v?i- j < 1 .

X-m.i raiAurg апа.АУДд.в

1-4-1.1 Operational requirements. The failure of the test item to satisfy the requirements of the equipment specification must be analyzed carefully, and related information nust be considered, such as:

a. Deadatlon allowed in the performBnoe characteristiCB Ьесаше of rainfall exposure.

b. Necessity for special kits for special operating procedures.

c. Safety of operation.

1-4.1.2 Whiter penetration. Based on the individual test item and the

requiraBBnts for its попвхрояш в to wrater, determine if one of the following is 4iplioable:

a. Ohconditional failure. Any evidence of water penetration into the test item oiclosure following the rain test shall be considered a failure.

1/ Observations show that there are no drops of less than roughly 0.5 die>ing intense rains (reference c).

b. Acceptable watw pwHitpatlon. ШХтг penetration of not nore than 4 ояР per 28,000 си? (1 ft *) of teat item encloeuee 2/ ahall be acceptable, provided the

following conditions are met:

(1) Ihere.is no iBBsdiate effect cf tba rater cn t! sratien cf the test

item.

(2) The test item in its operational configisation (transit/atorage oasa open or removed) shall successfully cooplete the induced tei]9erature/huaidity procedure ox method 307.3 for the geographical area in iii<3i it la dealgnad to be

deplc-ad.

1-4.2 Tenperature. Experlenoe has sho s) that a teaperature differential between the test item and the rainwater can affect the outeoaa (leakage) of a гл1п test. It is recoamnnded that whenever possible, the test item teaperature be at least

10°C (18 higher than the rain teoperatuope at the beginning of eaoi 30-

minute exposure period to produce a negative pressure differential inside the test

item.

1-4.3 Sunmarv of test information required. The following infoiwtion is required in the test plan for adequate conduct of the tests of section II:

a. Test procedure(s).

b. Test item configuration.

c. Bainfall rate.

d. Test item Reheat teaperatts.

e. Exposure surfaces/durations.

f. Wind velocity.

g. Wtter pressure.

h. HJiLter tenerature.

i. Additional guidelines.

Z/ This quantity of water (4 cor) is proxinately the quantity required to raise

the relative hussidity cf 1 cubic foot cf air at standard anbient coiiticns (50% BH at 2lOc (70°F) to saturation at 49°C (120* F)). The 4в°С value is realiatie for equipment expoaed to higher tenperattjrea and aolar radiation effecta.

a. AR 70-38. Baseareh. PevelopmBnt. Teat and Evaluation of Jfateriel for Extraae Climatic Oonditiona. 1 August 1979.

b. ШЬ-8Т1>-210. Climatic Informpition to petapqine Pesjgn anc Tat Baoxiiraments for IHlitarv Systems and Kouipmant. 9 January iSS7.

c. Synopsis of BadotrotSKl Ifciterial for 1ДЬ-8П>-21<Ж. Cllmatic-Extrames

for Milityy EfjniiBment. Bedford, MA: Air Force Casbridge Besearch Laboratories, 1974, OTIC mmber AD-780-508.

d. Amy Materiel Command Pamphlet АМ-70б-11в, Butineerlnit Design Handbook. Environmental Factors.

e. ShiSchke, R. E. (ed.). aiegawv of Meteorology. Boston: American Meteorological Society, 1970.

f. MIL-S-5S286. Shelter. Electrical EauiPMnt S-280( )/0.

g. MIL-3-55541, gelter. gler-t.r1.-i) fiTilrJspnt g-250C jJQ

h. КГСАЛХЫбО. Environmental Conditions and Test Procedures for Airborne finiicment. Janxjary 1980.