MIL-STD-202H.pdf - 第69页

MI L - S TD - 202 -1 10 6. NOTE S (This secti on contain s i n f or m at i on o f a g ener al or ex pl anat or y nat ur e t ha t m ay be he l pf ul , b u t is not man datory.) 6.1 Supers ession data . T he m ai n b ody a…

MIL-STD-202-110

4.2. Procedure

Place the test item in the chamber, positioned as near the center of the chamber as practicable. If more than one

item is being tested, there shall be a minimum clearance of 4 inches between surfaces of test items or any other

material or object capable of furnishing protection. Also, no surface of the test item shall be closer than 4 inches from

any wall of the test chamber. Orient the item so as to expose the most critical or vulnerable parts to the dust stream.

The test item orientation may be changed during the test if so required by the component specification.

Step 1 - Set the chamber controls to maintain an internal chamber temperature of 23°C (73°F) and a relative

humidity of less than 22 percent. Adjust the air velocity to 1,750 ±250 feet per minute. Adjust the

dust feeder to control the dust concentration at 0.3 ±0.2 grams per cubic foot. With test item

nonoperating, maintain these conditions for 6 hours.

Step 2 - Stop the dust feed and reduce the air velocity to 300 ±200 feet per minute. Raise the internal

chamber air temperature to 63°C (145°F) and adjust humidity control to maintain a relative humidity of

less than 10 percent. Hold these conditions for 16 hours.

Step 3 - While holding chamber temperature at 63°C (145°F) adjust the air velocity to 1,750 ±250 fpm,

maintain a relative humidity of less than 10 percent. Adjust the dust feeder to control the dust

concentration at 0.3 ±0.2 grams per cubic foot. With the test item nonoperating, maintain these

conditions for 6 hours.

Step 4 - Turn off all chamber controls and allow the test item to return to standard ambient conditions.

Remove accumulated dust from the test item by brushing, wiping, or shaking, care being taken to

avoid introduction of additional dust into the test item. Under no circumstances, shall dust be

removed by either air blast or vacuum cleaning.

NOTE: 1. This test specimen may be operating during either or both of the 6-hour test periods (step 1 or 3)

if so required by the component specification.

2. When the component specifications reference test conditions A, B, or C of the previous version of

this test method, steps 1 through 4 of this test will be used unless otherwise specified.

5. DETAILED REQUIREMENTS

5.1 Summary. The following details are to be specified in the individual specification:

a. Change in orientation during test, if required.

b. Whether component is to operate during test and length of time required for operation and measurements.

c. Whether the second 6-hour test at 63°C (145°F) shall be performed immediately after reaching

stabilization in step 2.

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MIL-STD-202-110

6. NOTES

(This section contains information of a general or explanatory nature that may be helpful, but is not mandatory.)

6.1 Supersession data. The main body and 38 parts of this revision of MIL-STD-202 replace superseded MIL-STD-

202.

Custodians: Preparing activity:

Army - CR DLA – CC

Navy - EC

Air Force - 85 (Project 59GP-2015-014)

DLA - CC

Review activities:

Army - AR, AT, AV, CR4, MI, SM, TE

Navy - AS, OS, SH

Air Force - 19, 99

NSA - NS

NOTE: The activities listed above were interested in this document as of the date of this document. Since

organizations and responsibilities can change, you should verify the currency of the information above using the

ASSIST Online database at https://assist.dla.mil/

北测（上海）电子科技有限公司

联系方式：xuyj@beice-sh.com 13917165676

INCH-POUND

MIL-STD-202-111

18 April 2015

SUPERSEDING

MIL-STD-202G

w/CHANGE 2 (IN PART)

28 June 2013

(see 6.1)

DEPARTMENT OF DEFENSE

TEST METHOD STANDARD

METHOD 111, FLAMMABILITY (EXTERNAL FLAME)

AMSC N/A FSC 59GP

北测（上海）电子科技有限公司

联系方式：xuyj@beice-sh.com 13917165676