MbTriOD 510.3 SMD AND DUST

РАЖ

SECTION 1

I-l PURPOSE ...................... 510.3-1

1-2 EKVIBONSENTAL EFFEXTTS............... 510.3-1

1-3 GUIDELINES FOR DETERMINING TEST

PROCEDURES AND TEST CONDITIONS .......... 510.3-2

1-4 SPECIAL CONSIDERATIONS............... 510.3-5

1-5 REFERENCES ..................... 510.3-7

SECTION II

II-l APPARATUS ..................... 510.3-8

II-2 PREPARATION FOR TEST................ 510.3-12

II-3 PROCEDURES ..................... 510.3-13

11-4 INFORMATION TO BE RECORDED............. 510.3-14

I-l PURPOSE. This test method is divided into two procedures. The snal 1-particle procedure (dust, fine sand) is performed to ascertain the ability of equipment to resist the effects of dust particles which may penetrate into cracks, crevices, bearings, and joints. The blowing sand test is performed to determine whether materiel can be stored and operated under blowing sand (149 to в50р m particle size)

reliability, naintainabl 1 Ity du© to the abrasion (erosion) ФГ Clogging effect of

large, sharp-edged particles.

1-2 ENVIRONMENTAL tjyECTS. An airborne samd and dust environment, associated most often with the hot-dry regions of earth, exists seasonally in other regions. Naturally occurring sand and dust storrfB are an inportant factor in the deployment of nateriel. but with the Increaaed meehanlzation of military operations, these cause less of a problem than does sand and dust associated with mans activities. Exanples of some problems that could occur as a result of exposure of materiel to blowing sand and dust are:

a. Abrasion of Suafaces.

b. Penetration of seals.

c. Erosion of surfaces.

d. Degradation of electrical circuits.

№TH0D 510.3

coatin* OTi, or severe abrasion of, a test it-esH; *iich csuld Influence the reeulte of other MIL-STD-e 10 ntethods such as FungiiS (Method 508.4), Humidity (507.3), and Salt Fog (509.3). Therefore, this method should be applied following such tests. Additionally, this method should follow method 501.3 (High Tenperature), since the tenperature derived is used in this msthod.

d. Test variations. The variables associated with the blowing sand and dust test procedures include:

(1) Air velocity.

(2) Tenperature.

(3) Test item configuration and orientation.

(4) Sand dust conposition.

(5) Sand dust concentration.

(6) Test duration.

1-3.1 Choice of test procedures. Two test procedures are included in this method: blowing dust and blowing sand. Based on the test items deployment expoeure, and function, determine v iether both procedures are applicable.

e. Clogging of openings and filters.

f. Physical interference with mating parts.

g. Fouling of Enoving parts.

h. Exothermal reaction (thermite effects) of clay particles (with aluminum oxide) at high temperatures, producing heat nAich could cause high-tenperature corrosion and produce extremely hard, erosive particlee.

1-3 CRJIDELINES FOR DETERMINING TEST PROCEDURES ДТО TEST COMDITIOMS

NOTE: The tailoring process as described in Section 4 of this docxjment should be used to determine the appropriate tests and test variables.

a. Application. This method is applicable to all mechanical, electrical,

electronic, elsctrccheniical, and electroznechanical devices for vbich eqpcsure to tbs effects of a dry sand- or dust-laden at-nsDSphere is anticipated.

b. Restrictions. This method does not apply to any chemical reaction that nay оссгдг in the presence of moisture.

(1) The smal 1-particle (blowing dust) procedure may be condxjcted wfith either of the following dust oonfwsitions, by weight.

(a) Bed china clay is common throiighout much of the world and

contains:

Solubilities < 2%, PK between 6 and 8 5%

Ferric oxide (FegCK) 10 ±5%

Aluminxnn oxide (AljOj) 20 ±.10X

Silicon dioxide (Si02 Silicon dioxide and

reKalning iHpuritlej

i/ From MIL-STD-210.

1-3.2 Choice of related feat conditiona. After chooeing the teat procedure, choose the values of the test variables and decide whether or not the test item is to operate during the test. The specific test conditions to be used in these tests should be baised on field data (Seneral Reqxiirements, 4.3). If field data are not

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requirsmsnts docurasr.ts. If this infcrsstion is not available, the following may be xjsmd as guidance.

a. Teaperatige. Ortless otherwise specified, these tests should be conducted at the operating or storage teiqperature obtained from the teofwrature response of the test item from method 501.3

b. Rslativs huad-dity. High levels ef relative hjnidity saay cause caking of dist pas*tlcles. Consequently, test chuber Ш should not exceed 30%.

c. Mr vylociy.

(1) BlowinS dust. Tha air velocities used in the blowing duat (smal 1 pvticle) test praceduS include a nuLninSun sir velocity to maintain test conditions (1.5 va/s or 300 ft/min) and a higher air velocity typical of desert tdnds (8.9 m/s or 1750 ft/min) that shall be used for most tests. Other air velocities may be used, but test chanber limitations must be considered. Excessively high air velocities may lessen the caking or clogging caused by lower air velocities.

(2/ В1 ctrinjt send. An air velocity In the range cf IS tc 29 m/s (3540 tc 57(Ю ft/min) is sigested fcr nsst blowing sand 1 ications. Wnds of 18 m/e that would blow the large particles are conmon, and gusts ш to 29 m/s are not xsiconmon. Other air velocities may be used if the induced flow velocity around the equipment in its field application is known.

d. Sand and duet corooslbion

eL-STO-eiOE 14 JIILY 1989

(Ъ> Silicon Hour tud been widely used in diat testing end contains 97 to 99 percent (ty weight) silicon dioxide (SiO- ТЬе following size distribution applies to both red china clay and silicia flour:

100 percent shall pass tiiroijgh a 100 sssh screen.

98 ±2 percent shall pass through a 140 niesh screen.

00 ♦г percent shall pass through a 300 sash screen.

75 ±2 percent shall pass thrcvh a 325 aesh screen.

(2) Unless otherwise specified, the sand suggested to be vaed in tbe large

particle test is silica sand and (at least 05% by weight SiOg). The aaoxstt l.OX 1.0.5% of the sand shal 1 be retained by a 20 mesh screen (вбОу m), 1.7% l0.8% by a 30 mesh screen (590p m). 14.8% 1.1% by a 40 mesh screen (420P m.). 37.0% 1.1% by a 50 mesh screen (2Э7 pm). 28.6% ii% by a 70 mesh screen (210м m). 12.7% ♦!% by a 100 mesh screen (149 iim), and 5.2% 1.1% shall pass a 100 assh screen. The sand shall be of subangular structvB wdth a mean №>unbein nunber (roundness factor) eqwl to 0.2 and a hardness factor of 7 mobs.

e. Sand and dust concentrations

(1) The dust eoneentration for the bloinLng dxat test shall be maintained at 10.6 17 g/m (0.3 lP.2 g/ft) unless otherwise specified. This figure is not uireallstic and le taed because of the llBKltatlons of most chaiibers.

(2) The sand concentrations 3/ shall be as follows unless otherwise

specified.

(a) For test items likely to be ised close to aircraft (suc. as helicopters) operatir,g over unpavsd surfaces: 2.2 te lp.5 g.m (0.0623 ±0.015 g/ft-*) .

(b) For test items never used or never exposed in close to operalng aircraft, but whichmay be found near operating surface vehicles: 1.1 lP.25 g/m** (0.033 ip.0075 g/ft).

(c) For test items that will be subjected only to natural conditior,s: 0.177 g/m (0.0050 g/ft *).

f. Test item confilturation. The configuration of the test item met reproduce, as closely as technically possible, tbe config\s>atlon that it would assisne during storage or use, such as:

2/ Naval Weapons Center Large Particle Blowing Sarxi Procedure 3/ MIL-STD-210. ЬеТЮО 510.3

vemoD 510.3

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

(2) Protected or not protected.

(3) Deployed realistically or with restraints, such as with openings that are normally covei*ed.

g. Orientation. The test item should be so oriented vdth respect to the blowdng Bond that the DOst Vulnerable Bwfacevs) faces the blowing sand. The test item Bssy be reoriented at 90-rainute intervals.

h. patlons

(1) For blowing sand tests, 90 minutes per face is considered to be a minimLiB (see I-3.2g).

(2) For biowring diet teetS; siv hows at 23°0 (73°F) and six hours at the high storage or operating tenperature are required. Additionally, sxifficient time nust be allowed at the low air velocity to stabilize the test item at the higher tenperature.

NOTE: The period of tins that the test item is exposed to the environmental condltione may be ae eitfriifiQ it as the Conditions thesselves. The length cf time spent at the extreme conditions of each procedure should be at least long enough to Insure stabilization of the test item at the specified conditions.

i. Operation durin* test. Operation of the test item during the test period should be basou on the use requiresoBnte of the Bpecifio test iteoL For exasple, envircnssntal control equi; &snt would be operated while exposed tc extreme anbient environments, whereas certain equipment, although exposed to severe environments, might be operated only in an environmentally controlled shelter. If operation of the test item during the test is required by the reqiiirements docunent, the test plan shall contain a schedule describing the time periods of operation, the settings ef oontrole, uid the types and ашйшЪв of stresses to be placed on the teat item during testing. This schedule shall contain at least one 10-minute period of continuous operation of the test item during the last hour of the test.

1-4 eiAL OOiBlDmATlOMS

1-4.1 Failure arAlvsis. The failure of a test item to meet the requireasnts of the equipment specification nust be analyzed, and related Information mmt be considered, such as:

a. Degradation allowed in operating characteristics wfclle at the extreme conditions.

Test procedure. Test tenperature.

Belative hunidity.

Air velocity.

Sand or dust conposition.

Sand or dust concentration.

Test item configuration.

b. Mecesaity for use of special operating procedures or special kits during extreme conditions.

c. Tbe test item shall be considered to have failed the dust (fine sand} test

wtian:

(1) Dust has penetrated the test item in sufficient quantity to cause binding or blocking of moving parts, nonoperation of contacts or relays, formation of electrically conductive bridges with resulting shorts, clogging, or the accuaulation of dust which wrt.ll act as a nix;leus for the collection of wmter vapor.

(2) The performance results obtained in accordance wdth ths test plan are not within the t-olerance limits estliisd.

d. The test item shall be considered to have failed the large-particle test

wtien:

tl) Abrasion of the test item exceeds the anoxjnt described in its rsquirsmer.ts document.

(2) ТЬл test item does not perform safely or operate adequately as described in its requirements docunent.

NOTE: The test plan shall contain procedures for determining the test items degradation dm to abrasion. These procur-es shal 1 deecriba parassaters (suc. as ancunt cf wear or loss of wjeight) or observable attributes (sxjsb as change of shape) which, if not within specified limits, are indications that the test item has failed because of abrasion effects. The permissible tolerances of the parameters and attrlbiites shall be provided.

1-4.2 Sunmrv of teatnforBati6n required. The following informatien is required in the test plan for adequate conduct cf the tssts cf sscticn II.

КЕТЮО 510.3

h. Operational requirements.

i. Test item orientation and tine of exposur-e per orientation. J. Mditional giiidelinee.

1-5 аапахЕясЕЗ

a. Hafer. Carl A., A Survey and Study of the Factors which Aiiect

the Dust Environment Created bv a Vehicle Qperatinii Over Unsurfaced Terrain Southwest Research Ir.stitute, Contract DA-23-072-OSD-1210 final report.

b. Kuletz, Edward, and Schafer, Howard, Survey ar>d Study on Sand and Dust. Naval Wbapons Center Report NWC TPS170, August 1971.

c. TbDust Environnient and its Effects on Dust Penetration. wADC 7K 56-556. DTIC nistber AD-110-472.

d. MIL-STD-210, Clinatic Information to Determine Design and Test Requirements for Mllltarv Systems and Equipment. 9 January 1987.

e. Synopsis of Baciotround Material for MiL-STD-210. Climatic Bctremes for Militarv-ECTuipffisnt. Bedford, MA: Air Force Caafcridge P,esearch Laboratories, January 1974, DTIC nunber AD-780-508.

f. Industrial Ventilation. A Manual of Recoinnended Practice. Comnittee on Industrial Ventilation, Box 16153, Lansing. MI 48901.

KETHOD 510.3

SECrriOK II SAND AND DUST

II-l APPARATUS II-l.l TBBt fBcmby

II-l.1.1 Plowing JSt

a. The test facility shall consist of a chani>er and accassories to control dust concentration, velocity, tenperature, and hunidity of dust-laden air. In order to provide adequate circulation of the dxjst-laden air, no more than SO percent of the cross-sectional area tnomal to airf lovw and 30 percent sf the voliase cf the test chan4>€r shall be occupied by the test iteasCs). The chaa* r shall be provided trtth

a means of maintaining and verifyiTtg the dust concentration in circulation. A mininun acceptable means for doing this is by use of a properly calibrated smoke meter and standard light source. The dxjst-laden air shall be Introdixwd into the test space in such a manner as to allow Uie air to become approximately laminar in flow before it strikes the test item.

WARNIM3 ЮТЕ: Silica floxs- may present a health hazard. Wien using silica flour, assure that the chanber is functioning properly and not leaking; if a failure of containment is noted and people night have been elфosed air saaples riiould be obtained and conpared to the current threshold limit values of the Anerican Conference of €k>vemment axxi Industrial ibgienists. Chanber repair and/or other appropriate action should be taken before continuing use of the chanber. Care should be taken dis>ing all stape ftiere ехровш of people to the silica dust is possible.

b. The dust used in this test shall be as outlined in I-3.2d(l). II-l.1.2 glowing imn4

a. The required apparatisi consists of a chaaber or cabinet, together with necessary air conditioning and circulation eqxiipoant with its axjxiliary control instrunentation, sand storage and moving equipaant, and sand concentration measuring equipment, capable of maintaining and continuously monitoring tb* required conditions throughout an envelope of air surroiSKiing the test Item(s). (See (General Bequlr-effiBnts, 5.1.1.) Figures 510.3-1 and 510.3-2 are scheaatic dlagraas ef typical facilities for Hiia test.

b. A data collection system, separate from the chanber controllers, shall be enployed to measure test space conditions. Readout charts shall be readable to

within at least 0.в°С (1**F).

SAND

y y i

lllllllllllll

-CREW-TYPE SAND FEEDER

TEST

AIR CONDITIONING COILS

FLOW

STRAIGHTENERS

VARIABLE-SPEED FAN

SAND-AIR MIXTURE

CYCLONE SAND

SEPARATOR

SAND COLLECT

FIGURE 510.3-1. Rloulng 8iind teat facility (vertical flQttl