AS/NZS 61241.2.1:2000

1 - AS/NZS 61241.2.1:2000 ELECTRICAL APPARATUS FOR USE IN THE PRESENCE OF COMBUSTIBLE DUST - TEST METHODS- METHODS FOR DETERMINING..
4 - PREFACE
5 - CONTENTS
6 - INTRODUCTION
7 - 1 Scope
7 - 2 Normative references
8 - 3 Definitions
8 - 3.1 dust:
8 - 3.2 ignition of a dust layer:
8 - 3.3 minimum ignition temperature of a dust layer:
8 - 3.4 ignition of a dust cloud:
8 - 3.5 ignition temperature of a dust cloud:
8 - 4 Method A: Dust layer on a heated surface at a constant temperature
8 - 4.1 Preparation of dust sample
8 - 4.2 Test apparatus
9 - 4.2.1 Heated surface
9 - 4.2.2 Dust layer thermocouple
9 - 4.2.3 Temperature measurements
9 - 4.2.4 Ambient temperature measurements
9 - 4.2.5 Dust layers
10 - 4.2.6 Formation of dust layer
10 - 4.3 Procedure
10 - 4.3.1 General
11 - 4.3.2 Method
11 - 4.3.3 Results
12 - 4.4 Test acceptance criteria
12 - 4.5 Reporting of results
12 - 4.6 Application of results
13 - 5 Method B: Dust cloud in a furnace at a constant temperature
13 - 5.1 Preparation of dust sample
13 - 5.2 Test apparatus
13 - 5.3 Procedure
13 - 5.3.1 Setting-up
13 - 5.3.2 Determination of minimum ignition temperature
14 - 5.3.3 Mass of dust
14 - 5.3.4 Air pressure
14 - 5.4 Criterion of ignition
14 - 5.5 Minimum ignition temperature of a dust cloud
14 - 5.6 Reporting of results
15 - ANNEX A - Method A - Construction of a heated surface and measurement of temperature distribution on the surface
21 - ANNEX B - Construction of a constant temperature furnace

Specifies two test methods for determining the minimum ignition temperatures of dust. This Standard is identical with and has been reproduced from IEC 61241-2-1:1994.

This part of AS/NZS 61241 specifies two test methods for determining the minimum ignition temperatures of dust.The methods are not suitable for use with substances having explosive properties.Method A (clause 4) is applicable to the determination of the minimum temperature of a prescribed hot surface which will result in the decomposition and/or ignition of a layer of dust of a specified thickness deposited on it. The method is particularly relevant to industrial equipment with which dust is present on hot surfaces in thin layers exposed to the atmosphere.Method B (clause 5) is applicable to the determination of the minimum temperature of a prescribed hot surface which will result in the ignition of a cloud of a given sample of dust or other particulate solid. The test is intended to be carried out as a complementary test after determining the minimum ignition temperature of a dust layer by method A of this standard.NOTES concerning method B1 Because the method of operation of the furnace gives short residence times for dust particles within it, this method of test is applicable to industrial equipment where dust is present as a cloud for a short time. This method of test is of small scale and the results are not necessarily representative of all industrial conditions.2 The method is not applicable to dusts which may, over a longer period of time than provided for in the test method, produce from deposits gases generated during pyrolysis or smouldering.

First published as AS/NZS 61241.2.1:2000.