GJB 150.12A-2009 Laboratory environmental test methods for military materiel — Part 12: Sand and dust test
1 Scope
This part specifies the purpose and application, tailoring guidelines, information requirements, test requirements, test process and result analysis of sand and dust test carried out in military materiel laboratory.
This part is applicable to the sand and dust test of military materiel.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of this part. For dated reference, subsequent amendments (excluding corrections), or revisions, of any of these publications do not apply to this part. However parties to agreements based on this part are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references or references with version not indicated, the latest edition of the normative document referred to applies.
GJB 150.1A-2009 Laboratory environmental test methods for military materiel - Part 1: General requirements
GJB 150.3A-2009 Laboratory environmental test methods for military materiel - Part 3: High temperature test
GJB 4239 General requirements for materiel environmental engineering
3 Purpose and application
3.1 Purpose
3.1.1 Small dust particles (diameter ≤149μm) procedures, which are designed to evaluate the resistance of materiel to dust that may block openings and penetrate cracks, bearings and joints; it is also used to evaluate the operating efficiency of the filter device.
3.1.2 Sand blowing (diameter 150μm to 850μm) procedures, which are designed to evaluate whether the materiel can be stored and operated under sand blowing conditions.
3.2 Application
This test is applicable to evaluate the adaptability of all mechanical, optical, electrical, electronic, electrochemical and electromechanical devices that may be exposed to dry sand-blowing, dust-blowing or dust-falling conditions.
3.3 Restriction
This test is not applicable to determine the problem of abrasion of onboard equipment in flight (because of the different impact velocities of sand particles), nor to determine the accumulation effect of static charges. In addition, this test is not applicable to outdoor use because it is not easy to control.
4 Tailoring guidelines
4.1 Selection of test methods
4.1.1 General
Analyze the requirements of relevant technical documents, apply the results obtained by implementing GJB 4239 in the ordering process of materiels (products), determine the stage of sand and dust environment in the service life of materiel, and determine whether this test is necessary according to the following environmental effects. When it is necessary to carry out this test through determination and the same test piece is used for this test and other environmental tests, the sequence of this test and other tests shall also be determined.
4.1.2 Environmental effect
Natural sand and dust environments are usually associated with hot and dry areas, but they also exist seasonally in most other areas, so naturally generated dust storms are an important factor to be considered when using materiel. But as military operations have become more mechanized, they have caused more problems than natural sand and dust environments. To help determine whether this test is appropriate for the materiel to be tested, at least the following typical effects shall be considered:
Contents
Foreword II
1 Scope
2 Normative references
3 Purpose and application
3.1 Purpose
3.2 Application
3.3 Restriction
4 Tailoring guidelines
4.1 Selection of test methods
4.2 Selection of test procedures
4.3 Determination of test conditions
5 Information requirements
5.1 Information required before test
5.2 Information required during test
5.3 Information required after test
6 Test requirements
6.1 Test apparatus
6.2 Test control
6.3 Test interruption
7 Test process
7.1 Test preparation
7.2 Test procedure
8 Result analysis
8.1 Overview
8.2 Dust-blowing and dust-falling tests
8.3 Sand-blowing test
