AS/NZS 61241.3:1999

1 - AS/NZS 61241.3:1999 ELECTRICAL APPARATUS FOR USE IN THE PRESENCE OF COMBUSTIBLE DUST - CLASSIFICATION OF AREAS WHERE ...
4 - PREFACE
6 - CONTENTS
9 - 1 General
9 - 1.1 Scope
10 - 1.2 Normative references
10 - 2 Definitions
10 - 2.1 area:
10 - 2.2 normal atmospheric conditions:
10 - 2.3 hybrid mixtures:
10 - 2.4 dust:
10 - 2.5 conductive dust:
10 - 2.6 explosive dust atmosphere:
10 - 2.7 combustible dust:
10 - 2.8 classified area (dust):
10 - 2.9 non-classified area (dust):
11 - 2.10 zones:
11 - 2.11 zone 20:
11 - 2.12 zone 21:
11 - 2.13 zone 22
11 - 2.14 source of dust release:
11 - 2.15 extent of zone:
11 - 2.16 normal operation:
12 - 2.17 abnormal conditions:
12 - 3 Area classification and safety
12 - 3.1 Safety principles
12 - 3.2 Area classification objectives
13 - 3.3 Area classification principles
13 - 4 Procedure for area classification
13 - 4.1 General
13 - 4.2 Identification of sources of release
14 - 4.3 Likelihood of the occurrence of sources of release
14 - 4.4 Identification of the possibility of formation of potentially hazardous dust layers
15 - 4.5 Examples of designation of zones
16 - 4.6 Extent of zones
18 - 5 Documentation
18 - 5.1 General
18 - 5.2 Drawings, data sheets and tables
20 - ANNEX A - Practical examples

Provides classification of areas where explosive dust/air mixtures and combustible dust layers are or may be present, in order to permit the proper selection of electrical apparatus for use in such areas. This Standard is identical with and has been reproduced from IEC 61241-3:1997.

This part of AS/NZS 61241 is concerned with the classification of areas where explosive dust/air mixtures and combustible dust layers are or may be present, in order to permit the proper selection of electrical apparatus for use in such areas.This standard is intended to be applied where there can be a risk due to the presence of explosive dust/air mixtures or combustible dust layers under normal atmospheric conditions. It does not apply to: underground mining; the processing and manufacture of explosives; areas where a risk can arise due to the presence of hybrid mixtures;catastrophic failures, which are beyond the concept of abnormality dealt with in this standard (see note 1);ignition sources other than those associated with electrical apparatus (see note 2);any risk arising from an emission of flammable or toxic gas from the dust.This standard is generally applicable to apparatus suitable for use and storage at ambient temperatures between –20°C and +40°C inclusive. It is also applicable to apparatus for use in specific applications with different temperature ranges.This standard does not take into account the effects of consequential damage following a fire or an explosion.NOTES1 Catastrophic failure in this context is applied, for example, to the rupture of a storage silo or a pneumatic conveyor.2 In any process plant, irrespective of size, there can be numerous sources of ignition apart from those associated with electrical apparatus. Appropriate precautions will be necessary to ensure safety in this context, but these are outside the scope of this standard.

First published as AS 2430.2-1981.
Second edition 1986.
Jointly revised and redesignated as AS/NZS 61241.3:1999.