AS/NZS 2430.3.4:1997

1 - AS/NZS 2430.3.4:1997 CLASSIFICATION OF HAZARDOUS AREAS - EXAMPLES OF AREA CLASSIFICATION-FLAMMABLE GASES
4 - PREFACE
5 - CONTENTS
6 - 1 SCOPE
6 - 2 REFERENCED DOCUMENTS
6 - 3 DEFINITIONS
7 - 4 GAS INDUSTRY CODES-CONSUMER INSTALLATIONS
7 - 4.1 Scope
7 - 4.2 Classification of hazardous areas within consumer premises
7 - 4.2.1 Relief device and vent pipe discharge points
7 - 4.2.2 Pits
7 - 4.2.3 Cylinders
7 - 4.2.4 Compressors
8 - 4.2.5 Natural gas cylinder filling hoses
8 - 4.2.6 Other areas
8 - 5 GAS INDUSTRY CODES-DISTRIBUTION SYSTEMS
8 - 5.1 Scope
8 - 5.2 Classification of hazardous areas within gas distribution systems
8 - 5.2.1 Relief device discharge points
8 - 5.2.2 Above ground enclosure containing distribution gas pressure control equipment
8 - 5.2.3 Pits
8 - 5.2.4 Other areas
8 - 6 LIGHTER-THAN-AIR FLAMMABLE GASES-OTHER INSTALLATIONS
8 - 6.1 Scope
8 - 6.2 Classification of hazardous areas
8 - 6.2.1 Pressure storage tank, inadequately ventilated
9 - 6.2.2 Tank filling or discharge connections, inadequately ventilated
9 - 6.2.3 Gas equipment in adequately ventilated locations
11 - 6.2.4 Pits
11 - 6.2.5 Gas equipment in inadequately ventilated locations
11 - 6.2.6 Compressed gases in cylinders
12 - 7 HEAVIER-THAN-AIR FLAMMABLE GASES-OTHER INSTALLATIONS
12 - 7.1 Scope
12 - 7.2 Classification of hazardous areas
12 - 7.2.1 Pressure storage tank, other than buried or mounded tanks
12 - 7.2.2 Tank filling or discharge connections
12 - 7.2.3 Gauging (ullage) vent valve on tank
13 - 7.2.4 Tank safety relief valves
13 - 7.2.5 Hydrostatic relief valves
13 - 7.2.6 First stage regulator in connection with tank
13 - 7.2.7 Valve, flange or screwed connection
13 - 7.2.8 Pumps
14 - 7.2.9 Compressors in adequately ventilated locations
14 - 7.2.10 Vaporizers
14 - 7.2.11 Bleed vent or drain valve in liquid piping system, in adequately ventilated locations
14 - 7.2.12 Pits containing pumps, compressors, regulators or valves in liquid or vapour lines
14 - 7.2.13 Cylinder filling (other than in situ)
17 - 7.2.14 Cylinder filling (in situ)
17 - 7.2.15 Cylinders installed for use in inadequately ventilated locations
17 - 7.2.16 Cylinders, adequately ventilated, whether in storage or installed for use, exchange type
17 - 7.2.17 Cylinders, whether in storage or installed for use, adequately ventilated, in situ fill type (with limited gas bleeding f
18 - 7.2.18 Bulk cylinder storage, inadequately ventilated structure

Provides guidance on the classification of areas associated with the production, processing, handling and storage of heavier-than-air and lighter-than-air flammable gases. It includes specific examples of classification for such areas. To be read in conjunction with AS/NZS 2430.3.1:1997.

This Standard provides examples of area classification for areas associated with the production, processing, handling and storage of heavier-than-air and lighter-than-air flammable gases. It is part of the AS/NZS 2430.3 series which recommends the classifications of several commonly occurring situations and should be read in conjunction with AS/NZS 2430.3.1.Caution should be exercised when considering lighter-than-air gases with densities close to that of air, or any lighter-than-air gas which may be cooled substantially below ambient air temperature (e.g. by expansion from a compressed liquefied, or refrigerated liquefied state); such gases may actually be heavier-than-air gases, or their behaviour may be sufficiently close to that of heavier-than-air gases and therefore those Clauses pertaining to heavier-than-air gases should be used.For flammable gases in refineries and major processing plants reference should be made to AS/NZS 2430.3.5, which uses the Generalized Method of classification.

First published in Australia in part as part of AS 1076.2-1977.
AS 2430.1 first published 1981.
AS 1076.2-1977 and AS 2430.1-1981 revised, amalgamated and designated AS 2430.1-1982.
AS 2430-1-1982 revised and redesignated in part as AS 2430.3-1987.
Second edition 1991.
First published in New Zealand as part of NZS 6101P:1972.
Revised and redesignated in part as NZS 6101.3:1991.
AS 2430.3-1991 and NZS 6101.3:1991 revised, amalgamated and redesignated in part as AS 2430.3.4:1997.