Environmental Testing for Electric and Electronic Products — Part 2: Test Methods — Test L: Dust and Sand
1 General
This part describes the general structure of the dust/sand tests. The structuring and a summary of the characteristics of the different tests are given in Figure 1 and Table 1. The dust test of IEC 60529 has its equivalent in the proposed method La2. See Annex A.
1.1 Scope
This part specifies test methods to determine the effects of dust and sand suspended in air, on electrotechnical products.
The test methods of this part are not intended for the testing of air filters. Only method Lc2 is suitable for the simulation of the erosion effects of high velocity (more than 100 m/s) particles.
1.2 Description of Test L
The dust and sand test is structured into three groups:
La: non-abrasive fine dust. A test which is primarily oriented towards investigation of the seals of the test specimen. The test specimen is exposed to a very fine dust in the form of talc or an equivalent. The effects of temperature cycling resulting in a pressure difference between the inside and outside of the specimen may be reproduced.
Lb: free settling dust. A test which is oriented towards investigation of the effects when simulating conditions at sheltered locations. The test specimen is exposed to a low-density dust atmosphere created by the intermittent injection of a small quantity of dust which is allowed to fall by gravity onto the specimen.
Lc: blown dust and sand. A test which is oriented towards investigation of the seals and the effect of erosion when simulating outdoor and vehicle conditions. The test specimen is exposed to either a turbulent or a laminar air flow to which is added a quantity of dust, sand or a dust/sand mixture.
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2 Normative References
The following normative documents contain provisions which, through reference in this text, constitute provisions of this part. For dated references, subsequent amendments (excluding corrections), or revisions, of any of these publications do not apply to this standard. 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, the latest edition of the normative document referred to applies.
GB/T 4797.6-1995 Environmental Conditions Appearing in Nature for Electric and Electronic Products — Dust, Sand, Salt Mist (neq IEC 60721-2-5:1991)
IEC 60529:2001 Degrees of Protection Provided by Enclosures (IP code)
3 Terms and Definitions
For the purposes of this part, the following terms and definitions apply.
3.1
dust
particulate matter of unspecified origin or composition whose size ranges from 1 μm to 150 μm
3.2
dust conentration
total mass of dust particles per unit volume of air
3.3
humidity
relative humidity is defined as the ratio of the actual vapour pressure in the air at any temperature to the maximum of saturation vapour pressure at the same temperature
3.4
hygroscopic
having a tendency to absorb moisture
3.5
partical size
general dimension of the dust and sand particles based on the premise that the particles are spheres; commonly measured by sieving, by calculating settling velocities, or by determining areas of microscopic images
3.6
sand
grains vary from spherical to angular whose size lies between 100 μm and 2 000 μm, but for environmental testing, the range is usually restricted from 150 μm to 850 μm
3.7
sieve (square-meshed)
intended for the particle size analysis of the material to be sieved, which conforms to a test sieve standard specification
4 Test La: Non-abrasive Fine Dust
Foreword II
Introduction III
1 General
2 Normative References
3 Terms and Definitions
4 Test La: Non-abrasive Fine Dust
5 Test Lb: Free Settling Dust
6 Test Lc: Blown Dust and Sand
Annex A (Informative) General Guidance
A.1 Characteristics of test dust
A.2 Other dusts
A.3 Effect of humidity on test dust
A.4 Effects on electrotechnical products
A.5 Safety precaution
A.6 Test L and IEC 60529 comparison
Annex B (Informative) Bibliography
