1 - AS 2380.4-1994 ELECTRICAL EQUIPMENT FOR EXPLOSIVE ATMOSPHERES - EXPLOSION-PROTECTION TECHNIQUES - PRESSURIZED ROOMS OR PRESSU
4 - PREFACE
5 - CONTENTS
7 - SECTION 1 SCOPE AND GENERAL
7 - 1.1 SCOPE
7 - 1.2 REFERENCED DOCUMENTS
8 - 1.3 DEFINITIONS
8 - 1.3.1 Air lock
8 - 1.3.2 Continuous dilution
8 - 1.3.3 Enclosure
8 - 1.3.4 Explosive atmosphere
8 - 1.3.5 Flammable material
8 - 1.3.6 Fresh air
8 - 1.3.7 Hazard
8 - 1.3.8 Ignition-capable equipment
8 - 1.3.9 Internal source of flammable gas or vapour
8 - 1.3.10 Lower explosive limit (LEL)
8 - 1.3.11 Opening
8 - 1.3.12 Pressurization
8 - 1.3.13 Pressurization by circulation of protective gas
8 - 1.3.14 Pressurization with leakage compensation
8 - 1.3.15 Pressurized enclosure
8 - 1.3.16 Protective device
9 - 1.3.17 Protective gas
9 - 1.3.18 Purging
9 - 1.3.19 Room
9 - 1.3.20 Self-revealing fault
9 - 1.3.21 Type of protection ‘p’
9 - 1.4 TEMPERATURE LIMITS
9 - 1.5 GROUPING OF EQUIPMENT
9 - 1.6 PRESSURIZATION PRINCIPLE
11 - SECTION 2 GENERAL CONSTRUCTIONAL REQUIREMENTS
11 - 2.1 SCOPE OF SECTION
11 - 2.2 ELECTRICAL PERFORMANCE OF EQUIPMENT
11 - 2.3 CONSTRUCTION MATERIALS
11 - 2.4 PROTECTION AGAINST ENVIRONMENT
11 - 2.5 PRESSURIZATION
11 - 2.5.1 Overpressure requirements
11 - 2.5.2 Dual pressurization
11 - 2.6 INLET AND OUTLET APERTURES
11 - 2.7 ALTERNATIVE SOURCES OF PROTECTIVE GAS
12 - 2.8 INTAKE DUCTING
12 - 2.9 ELECTRICAL CONNECTIONS TO ENCLOSURES
12 - 2.10 ENTRY OF ELECTRICAL AND OTHER SERVICES TO ROOMS
12 - 2.11 DOORS AND COVERS
12 - 2.12 POSSIBLE SOURCES OF IGNITION
12 - 2.13 ENCLOSED COMPONENTS
12 - 2.14 PRESSURE OR FLOW ACTIVATED DEVICES
13 - 2.15 SUPPLY OF PROTECTIVE GAS
13 - 2.15.1 Type of gas
13 - 2.15.2 Temperature
13 - 2.16 ROTATING MACHINES
13 - 2.17 PROTECTION REQUIREMENTS
13 - 2.17.1 General
13 - 2.17.2 Electrical supply
13 - 2.17.3 Switching off electrical supply
13 - 2.17.4 Failure of pressurization
14 - 2.17.5 Separate rooms or enclosures
14 - 2.17.6 Other protective measures
14 - 2.18 INSPECTION DOORS
15 - SECTION 3 ENCLOSURES HAVING NO INTERNAL SOURCE OF FLAMMABLE MATERIAL
15 - 3.1 GENERAL
15 - 3.2 LEVEL OF OVERPRESSURE
15 - 3.3 PROTECTION REQUIREMENT
15 - 3.3.1 Switching off electrical supply
15 - 3.3.2 Alarm
16 - SECTION 4 ROOMS HAVING NO INTERNAL SOURCE OF FLAMMABLE MATERIAL
16 - 4.1 GENERAL
16 - 4.2 LEVEL OF OVERPRESSURE
16 - 4.3 PROTECTIVE GAS FLOW
16 - 4.4 PROTECTION REQUIREMENT
16 - 4.4.1 General
16 - 4.4.2 Rooms located within Class I Zone 1 areas
17 - 4.4.3 Rooms located within Class I Zone 2 areas
17 - 4.4.4 Rooms located within Class II areas
18 - SECTION 5 ENCLOSURES HAVING AN INTERNAL SOURCE OF FLAMMABLE GAS OR VAPOUR
18 - 5.1 GENERAL
18 - 5.2 DESCRIPTION OF TECHNIQUES
18 - 5.2.1 Continuous dilution with air
18 - 5.2.2 Pressurization with inert gas
18 - 5.3 LEVEL OF OVERPRESSURE
18 - 5.4 OUTLET APERTURES
18 - 5.5 ASSESSMENT OF THE INTERNAL RELEASE
18 - 5.5.1 General
18 - 5.5.2 Type and magnitude
19 - 5.5.3 Combinations of release
19 - 5.6 PROTECTION REQUIREMENTS
19 - 5.6.1 Energizing.
19 - 5.6.2 Switching off electrical supply
20 - 5.6.3 Alarm only
20 - 5.7 SUPPLY OF PROTECTIVE GAS
22 - SECTION 6 ASSESSMENT AND TESTS
22 - 6.1 GENERAL
22 - 6.2 TYPE VERIFICATION AND TESTS
22 - 6.3 PRESSURIZATION TEST
22 - 6.4 MINIMUM OVERPRESSURE TEST
22 - 6.4.1 Test conditions
22 - 6.4.2 Number of tests
22 - 6.5 IMPACT TEST
23 - SECTION 7 MARKING
24 - APPENDIX A - DUCTS FOR PROTECTIVE GAS SUPPLY
27 - APPENDIX B - GUIDELINES FOR ASSESSING THE TYPE OF RELEASE WITHIN ENCLOSURES
27 - B1 GENERAL
27 - B2 NO NORMAL RELEASE
27 - B3 LIMITED NORMAL RELEASE
28 - B4 LIMITED ABNORMAL RELEASE
28 - B5 UNLIMITED ABNORMAL RELEASE
29 - APPENDIX C - DISCUSSION OF PROTECTION REQUIREMENTS FOR CONTINUOUS DILUTION
29 - C1 SCOPE
29 - C2 PRINCIPLE
29 - C3 NORMAL INDUSTRIAL IGNITION-CAPABLE ELECTRICAL EQUIPMENT IN ZONE 2 OR A NON-HAZARDOUS AREA
29 - C3.1 Equipment with no normal release
29 - C3.2 Equipment with normal release
29 - C4 NORMAL INDUSTRIAL IGNITION-CAPABLE ELECTRICAL EQUIPMENT IN ZONE 1
30 - C5 EQUIPMENT WITH NO SOURCE OF IGNITION IN NORMAL OPERATION, IN CLASS I ZONE 2 OR A NON-HAZARDOUS AREA
30 - C6 EQUIPMENT WITH NO SOURCE OF IGNITION IN NORMAL OPERATION IN ZONE 1 AREAS

Specifies requirements for the design, construction and testing of rooms and enclosures of electrical equipment in which the entry of flammable gas or vapour is prevented by maintaining the air (or other non-flammable gas) within the room or enclosure at a specified pressure above that of the external atmosphere. Requirements for the use of pressurized rooms and enclosures in Class II, combustible dust areas are also included.

This Standard specifies requirements for the design, construction and testing of pressurized rooms or pressurized enclosures, type of protection 'p', intended for use in Class I, Zone 1 and Zone 2 or Class II explosive atmospheres. While this standard covers enclosures with an internal release of flammable gas or vapour, it does not cover rooms with such a release, e.g. analyser houses nor rooms or enclosures with an internal release of combustible dust.The requirements contained in this Standard are supplementary to those in AS 2380.1.NOTES:1 The classification of explosive atmospheres, termed hazardous areas, is dealt with in AS 2430. Further guidance may be obtained from Handbook SAA HB13.2 Equipment with large areas which are subjected to pressures in excess of 1 kPa (e.g. sheet metal switchboard enclosures) may require approval from the relevant authority responsible for pressure vessel legislation in the State or Territory in which the enclosure is to be installed.3 Rooms in which there is an internal release of flammable gas or vapour e.g. analyser houses are covered by IEC 79-16.4 Areas not covered by this standard may be treated by protection by ventilation in accordance with AS 1482.5 To minimise the risk of failure of an enclosure due to rupturing arc faults safeguarding against potential fault currents of an installation, especially where levels exceed 6 KA, should be provided.

First published in part as AS C377-1969.AS 1021 first published 1971.AS C377-1969 revised and redesignated AS 1825-1976.Second edition AS 1021-1980.Second edition AS 1825-1982.AS 1021-1980 and AS 1825-1982 revised, amalgamated and redesignated AS 2380.4-1994.Reconfirmed 2013. First published in part as AS C377-1969. AS 1021 first published 1971. AS C377-1969 revised and redesignated AS 1825-1976. Second edition AS 1021-1980. Second edition AS 1825-1982. AS 1021-1980 and AS 1825-1982 revised, amalgamated and redesignated AS 2380.4-1994.