1 - AS/NZS 60079.:2007 Explosive atmospheres Part 2: Equipment protection by pressurized enclosure ‘p’
4 - PREFACE
5 - CONTENTS
7 - INTRODUCTION
9 - 1 Scope
9 - 2 Normative references
10 - 3 Terms and definitions
12 - 4 Protection types
13 - Table 1 – Determination of protection type
14 - Table 2 – Design criteria based upon type of protection
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
16 - 5.5 Apertures, partitions, compartments and internal components
16 - 5.6 Insulating materials
17 - 5.7 Sealing
17 - 5.8 Spark and particle barriers
17 - 5.9 Internal batteries
17 - 6 Temperature limits
17 - 6.1 General
17 - 6.2 For type px or type py
18 - 6.3 For type pz
18 - 7 Safety provisions and safety devices ( except for static pressurization)
18 - 7.1 Suitability of safety devices for hazardous area
18 - 7.2 Integrity of safety devices
18 - Table 3 – Safety devices based upon protection type
18 - 7.3 Provider of safety devices
18 - 7.4 Sequence diagram for type px
19 - 7.5 Ratings for safety devices
19 - 7.6 Purging automated for type px
19 - 7.7 Purging criteria
19 - 7.8 Requirements when a minimum flow rate required
20 - 7.9 Safety devices to detect overpressure
21 - 7.10 Value of overpressure
21 - 7.11 Pressurizing multiple enclosures
21 - 7.12 Safety devices on doors and covers
21 - 7.13 Protection types that may remain energized
21 - 7.14 Protection types permitted within type py
22 - 8 Safety provisions and safety devices for static pressurization
22 - 8.1 Suitability of safety devices for hazardous area
22 - 8.2 Protective gas
22 - 8.3 Internal sources of release
22 - 8.4 Filling procedure
22 - 8.5 Safety devices
22 - 8.6 Protection types that may remain energized
22 - 8.7 Overpressure
22 - 9 Supply of protective gas
22 - 9.1 Type of gas
23 - 9.2 Temperature
23 - 10 Pressurized equipment with an internal source of release
23 - 11 Release conditions
23 - 11.1 No release
23 - 11.2 Limited release of a gas or vapour
23 - 11.3 Limited release of a liquid
24 - 12 Design requirements for the containment system
24 - 12.1 General design requirements
24 - 12.2 Infallible containment system
24 - 12.3 Containment system with a limited release
25 - 13 Protective gas and pressurizing techniques
25 - 13.1 General
25 - Table 4 – Protective gas requirements for a pressurized enclosure with a containment system
25 - 13.2 Pressurization with leakage compensation
26 - 13.3 Pressurization with dilution
26 - 14 Ignition- capable apparatus
26 - Table 5 – Protection types permitted within the dilution area
27 - 15 Internal hot surfaces
27 - 16 Type verification and tests
27 - 16.1 Maximum overpressure test
27 - 16.2 Leakage test
28 - 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
28 - 16.4 Purging and dilution tests for a pressurized enclosure with an internal source of release
29 - 16.4.3 Pressurized enclosure with pressurization by continuous flow, containment system with less than 21 % ( V/ V) oxygen and the protective gas is inert
30 - 16.5 Verification of minimum overpressure
31 - 16.6 Tests for an infallible containment system
31 - 16.7 Overpressure test for a containment system with a limited release
31 - 16.8 Verifying ability of the pressurized enclosure to limit internal pressure
32 - 17 Routine tests
32 - 17.1 Functional test
32 - 17.2 Leakage test
32 - 17.3 Tests for an infallible containment system
32 - 17.4 Test for a containment system with a limited release
32 - 18 Marking
32 - 18.1 Identifying as pressurized
32 - 18.2 Warnings
32 - 18.3 Supplementary marking
33 - 18.4 Internal source of release
33 - 18.5 Static pressurization
33 - 18.6 Pressurization systems
33 - 18.7 Warnings required in other clauses
33 - 18.8 Overpressure limited by user
33 - 18.9 Inert gas
33 - 19 Instructions
34 - Annex A (normative) Purging and dilution tests
35 - Annex B (informative) Examples of functional sequence diagram
37 - Annex C (informative) Examples of the changes in pressure in ducts and enclosures
42 - Annex D (informative) Information to be provided to the user
44 - Annex E (normative) Classification of the type of release within enclosures
45 - Annex F (informative) Examples for the use of the dilution area concept
47 - Annex G (normative) Infallibility test for containment system
48 - Annex H (informative) Introduction of an alternative risk assessment method encompassing “equipment protection levels” for Ex equipment
52 - Bibliography