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IGEM - SR/25 SUPP 1

Hazardous area classification of installations using Hydrogen or blends of up to and including 20% by volume Hydrogen in Natural Gas

active, Most Current
Organization: IGEM
Publication Date: 1 November 2022
Status: active
Page Count: 73
scope:

This Supplement to IGEM/SR/25 complements BS EN 60079-10-1 by providing detailed requirements for the hazardous area classification of permanent and temporary hydrogen or NG/H blend (as defined in Sub-Section S2.3) installations. A hazardous area is an area in which explosive gas/air mixtures are, or may be expected to be, in quantities such as to require special precautions for the construction, installation and use of electrical apparatus or other sources of ignition.

Note: Releases of heavier-than-air or neutrally-buoyant gases and vapours are covered by EI IP-MCSP-P15.

This Supplement to IGEM/SR/25 applies to all hydrogen or NG/H blend (as defined in Sub-Section S2.3) installations. However, for any installation downstream of an emergency control valve (ECV), other Standards may more readily be applied, as follows (the user to check whether the Standard has been revised or a corresponding Supplement has been issued to cover hydrogen or NG/H blends):

• for primary and secondary meter installations in industrial and commercial premises, where the equipment has been installed in accordance with IGEM/GM/5, IGEM/GM/6, IGEM/GM/8 or BS 6400 and has been tested to, and complies with IGE/UP/1, IGE/UP/1A, IGEM/UP/1B or IGEM/UP/1C (as appropriate), IGEM/GM/7A and IGEM/GM/7B may be applied rather than this Supplement to IGEM/SR/25 but this Supplement to IGEM/SR/25 has to be applied to installations where any one of the following apply:

• ventilation is of the forced type

• maximum operating pressure (MOP) exceeds 75 bar

• creep relief vents terminate within the installation enclosure

• the installation is at a remote, unmanned, site

• it is considered that leaks may go undetected

• unodourised gas is metered

• a competent person considers there to be unusual site circumstances.

• for industrial and commercial installations downstream of the primary meter installation, or downstream of the ECV if a meter installation is not installed, where the installation has been installed in accordance with IGEM/UP/2, IGEM/UP/3, IGEM/UP/6, IGEM/UP/9, IGEM/UP/10 or IGEM/UP/12 and tested in accordance with IGE/UP/1 or IGE/UP/1A the new Standard, IGEM/UP/16 will apply. However, this Supplement to IGEM/SR/25 may still have to be applied to, for example higher pressures; non-standard designs and hazardous areas created by other energy sources, etc.

In general, this Supplement to IGEM/SR/25 will not be less conservative than these other Standards and, therefore, it may be used for any hydrogen installation. If the Standards listed above are not relevant to, or have not yet been updated for, hydrogen and/or NG/H blends then this Supplement is to be applied.

Note 1: It is recognised that there are other techniques available to enable the management of risk, for example dilution ventilation.

Note 2: IGEM/GM/7A contains specific procedures relating to electrical connections to gas meters.

Note 3: It would not be normal to apply IGEM/SR/25 to a single domestic gas installation.

This Supplement applies to:

• pure liquid-free hydrogen with gas quality specification in accordance with IGEM/H/1;

• liquid-free 20% hydrogen / 80% natural gas by volume (referred to in this Supplement as 20% NG/H blend) with gas quality specification for hydrogen in accordance with IGEM/H/1 and gas quality specification for NG in accordance with IGEM/SR/25.

The ambient and gas storage temperature ranges used for hydrogen and NG/H blends are as given in the current version of IGEM/SR/25, Section 2.3 for NG. Zoning distances for fixtures and fittings are given up to an operating pressure of 100 bar for NG/H blends and up to 200 bar for pure hydrogen, recognising the potential for higher pressure hydrogen storage systems.

A zone of negligible extent is only applicable in this Supplement to:

• pure hydrogen installations of MOP not exceeding 2 bar

• 20% NG/H blend installations of MOP not exceeding 10 bar.

This Supplement applies to any potential release of hydrogen except those that may be caused by catastrophic failure such as the rupture of a process vessel or pipeline, component failure and similar rare events that are not predictable.

Certain aspects of the design of new plant and equipment can affect significantly the nature and severity of the eventual hazardous area classification.

This Supplement to IGEM/SR/25 is not intended to provide design details for equipment. However, compliance with the general principles of design set out in Section 4 and Appendix 4 will help minimize the severity of the hazardous area classification.

Gases are classified according to the ignitability of the gas/ air mixture as defined in BS EN 60079-20-1 (i.e. IIA, IIB, IIC). Equipment protection ratings are suitable for the NG/H blend and/ or pure hydrogen installation.

For a process map, which may assist the user in understanding the complexities of undertaking hazardous area classification. See Appendix 11 of the main Standard.

All pressures quoted are gauge pressures unless otherwise stated.

Italicised text is informative and does not represent part of a formal Supplement.

Appendices are informative and do not represent part of a formal Supplement unless specifically referenced in the main sections via the prescriptive terms "must", "shall" or "should".

Document History

SR/25 SUPP 1
November 1, 2022
Hazardous area classification of installations using Hydrogen or blends of up to and including 20% by volume Hydrogen in Natural Gas
This Supplement to IGEM/SR/25 complements BS EN 60079-10-1 by providing detailed requirements for the hazardous area classification of permanent and temporary hydrogen or NG/H blend (as defined in...
August 1, 2013
Hazardous area classification of Natural Gas installations
This Standard applies to all Natural Gas installations and complements BS EN 60079-10-1 by providing detailed requirements for the hazardous area classification of permanent and temporary Natural Gas...

References

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