AS/NZS 60079.2:2002

1 - AS/NZS 60079.2:2002 ELECTRICAL APPARATUS FOR EXPLOSIVE GAS ATMOSPHERES - PRESSURIZED ENCLOSURES 'p'
4 - PREFACE
5 - CONTENTS
9 - 1 Scope
9 - 2 Normative references
10 - 3 Terms and definitions
10 - 3.1 alarm
10 - 3.2 containment system
10 - 3.3 dilution
11 - 3.4 dilution area
11 - 3.5 enclosure volume
11 - 3.6 flammable substance
11 - 3.7 hermetically sealed device
11 - 3.8 ignition-capable apparatus (ICA)
11 - 3.9 indicator
11 - 3.10 internal source of release
11 - 3.11 leakage compensation
11 - 3.12 overpressure
11 - 3.13 pressurization
11 - 3.14 pressurization system
12 - 3.15 pressurized enclosure
12 - 3.16 protective gas
12 - 3.17 protective gas supply
12 - 3.18 purging
12 - 3.19 routine test
12 - 3.20 static pressurization
12 - 3.21 type px pressurizing
12 - 3.22 type py pressurizing
12 - 3.23 type pz pressurizing
12 - 3.24 type test
13 - 4 Protection types
14 - 5 Constructional requirements for pressurized enclosures
14 - 5.1 Enclosure
15 - 5.2 Materials
15 - 5.3 Doors and covers
15 - 5.4 Mechanical strength
15 - 5.5 Apertures, partitions, compartments and internal components
16 - 5.6 Insulating materials
16 - 5.7 Sealing
16 - 5.8 Spark and particle barriers
17 - 6 Temperature limits
17 - 6.1 General
17 - 6.2 For type px or type py
17 - 6.3 For type pz
17 - 7 Safety provisions and safety devices (except for static pressurization)
20 - 8 Safety provisions and safety devices for static pressurization
21 - 9 Supply of protective gas
21 - 9.1 Type of gas
21 - 9.2 Temperature
21 - 10 Pressurized apparatus with an internal source of release
21 - 11 Release conditions
21 - 11.1 No release
22 - 11.2 Limited release of a gas or vapour
22 - 11.3 Limited release of a liquid
22 - 12 Design requirements for the containment system
22 - 12.1 General design requirements
23 - 12.2 Infallible containment system
23 - 12.3 Containment system with a limited release
23 - 13 Protective gas and pressurizing techniques
23 - 13.1 General
25 - 13.2 Pressurization with leakage compensation
25 - 13.2.1 No release
25 - 13.2.2 Limited release of a gas or liquid
25 - 13.3 Pressurization with dilution
25 - 13.3.1 No release
25 - 13.3.2 Limited release of a gas or vapour
25 - 13.3.3 Limited release of a liquid
25 - 14 Ignition-capable apparatus
26 - 15 Internal hot surfaces
26 - 16 Type verification and tests
26 - 16.1 Maximum overpressure test
26 - 16.2 Leakage test
27 - 16.3 Purging test for pressurized enclosures with no internal source of release (pressurization technique may be leakage compensation or continuous flow) and filling procedure test for static pressurization
27 - 16.3.1 Pressurized enclosure where the protective gas is air
27 - 16.3.2 Pressurized enclosure where the protective gas is inert
27 - 16.3.3 Pressurized enclosure where the protective gas may be either air or an inert gas with density equal to air ±10%
27 - 16.3.4 Filling procedure test for a pressurized enclosure protected by static pressurization
27 - 16.4 Purging and dilution tests for a pressurized enclosure with an internal source of release
27 - 16.4.1 Test gas
28 - 16.4.2 Pressurized enclosure where the flammable substance has less than 2% (V/V) oxygen and the protective gas is inert
28 - 16.4.3 Pressurized enclosure with pressurization by continuous flow, containment system with less than 21% (V/V) oxygen ...
29 - 16.4.4 Pressurized enclosure where the flammable substance is not a liquid, pressurization by continuous flow and the prote
29 - 16.5 Verification of minimum overpressure
29 - 16.6 Tests for an infallible containment system
30 - 16.6.1 Overpressure test
30 - 16.6.2 Infallibility test
30 - 16.7 Overpressure test for a containment system with a limited release
30 - 16.8 Verifying ability of the pressurized enclosure to limit internal pressure
30 - 17 Routine tests
30 - 17.1 Functional test
31 - 17.2 Leakage test
31 - 17.3 Tests for an infallible containment system
31 - 17.4 Test for a containment system with a limited release
31 - 18 Marking
33 - Annex A - Purging and dilution tests
33 - A.1 General
33 - A.2 Criteria for compliance where the protective gas is air
33 - A.3 Criteria for compliance where the protective gas is inert
34 - Annex B - Examples of functional sequence diagram
36 - Annex C - Examples of the changes in pressure in ducts and enclosures
41 - Annex D - Information to be provided to the user
41 - D.1 General
41 - D.2 Ducting of protective gas
42 - D.3 Power for protective gas supply
42 - D.4 Static pressurization
42 - D.5 Enclosures with a containment system
42 - D.6 Enclosure maximum overpressure
43 - Annex E - Classification of the type of release within enclosures
43 - E.1 General
43 - E.2 No normal release, no abnormal release
43 - E.3 No normal release, limited abnormal release
43 - E.4 Limited normal release
44 - Annex F - Examples for the use of the dilution area concept
46 - Annex G - Infallibility test for containment system
47 - Bibliography

Specifies the requirements for the construction and testing of electrical apparatus with pressurized enclosures, of protection type 'p', intended for use in explosive gas atmospheres. This Standard is identical with and has been reproduced from IEC 60079-2:2001.

1.1 This part of IEC 60079 contains the specific requirements for the construction and testing of electrical apparatus with pressurized enclosures, of protection type p, intended for use in explosive gas atmospheres.The requirements contained in this standard are supplementary to those in IEC 60079-0.1.2 This standard specifies requirements for pressurized enclosures containing a limited release of a flammable substance.1.3 This standard does not contain the requirements for pressurized enclosures where the containment system may releasea) air with an oxygen content greater than normal, orb) oxygen in combination with inert gas in a proportion greater than 21%.1.4 This standard does not contain requirements for pressurized rooms or analyser houses; see IEC 60079-13 and IEC 60079-16.1.5 Due to the safety factors incorporated in the type of protection, the uncertainty of measurement inherent in good quality, regularly calibrated measurement equipment is considered to have no significant detrimental effect and need not be taken into account when making the measurements necessary to verify compliance of the apparatus with the requirements of this standard.1.6 When the user acts in the role of the manufacturer, it is the users responsibility to ensure that all relevant parts of this standard are applied to the manufacturing and testing of the apparatus.

First published as AS/NZS 60079.2:2002.