scope:

This Standard covers new and existing gas pipework installation, controls and associated gas appliances including appliance connections and pipework with a nominal OP not exceeding 2 bar installed downstream of the primary meter installation in industrial and commercial premises. ⮞It is also applicable to parts of common pipework within multi-occupancy domestic premises; for example, between pipework risers downstream of the meter installation and also to the central boiler plant (see Figure 2).⮜ For hazardous area analysis of installations outside the scope of this Standard, reference may be made to IGEM/SR/25.

Note 1: "Installation pipework" includes appliance connection, pipe joints and fittings. Appliance pipework located within appliance casings or integral with the appliance is subject to the requirements of appliance Standards and thus outside the scope of IGEM/UP/16.

Note 2: In this Standard where the term "joint" is used, it refers to all joints other than welded, soldered or brazed joints.

Note 3: Gas appliances (where the gas is at a temperature of 15 °C under a pressure of 1 bar) which are used for cooking, heating, hot water production, refrigeration, lighting or washing; and have, where applicable, a normal water temperature not exceeding 105 °C are excluded from hazardous area classification. Industrial process plant will need a DSEAR risk assessment.

Note 4: This Standard may also be applied on process applications without a primary meter.

This Standard covers gas installations containing predominantly methane such as Natural Gas. It applies to all gases, including landfill or biogases, with a combined proportion of methane-plus-inerts of greater than 89 % by volume; a gross calorific value not exceeding 45 MJ m^-3; molecular weight not exceeding 20 kg kmol^-1; Lower Flammability Limit (LFL) of not less than 4.4 %; a temperature range of -20 °C to 50 °C and specific gravity (SG) not exceeding 0.8. Ambient temperatures are assumed to be in the range -20 °C to 35 °C.

Note: The general principles in this document may be applied to other gases. Zone classifications and zoned extents are not covered by this document. Reference to be made to the fuel supplier or appropriate reference documents, such as EI 15 and 'New Methods for Hazardous Area Classification for explosive gas atmospheres'" SANTON R., IVINGS M.J., WEBBER D.W. and KELSEY A. Hazards XXIII, 12-15 Nov 2012".

This Standard provides basic design information which will help designers and those undertaking risk assessments (including those required by DSEAR) to achieve a gas installation that will achieve a hazardous area classification of Zone 2 NE permitting the use of standard electrical equipment and other potential ignition sources. The description of this topic is given in Appendix 3. A description of duties under DSEAR is given in Sub-Section 3.2.2.

Note 1: Zone 2 NE is defined as an area in which an explosive atmosphere consisting of a mixture of air with gas, vapour or mist is not likely to occur in normal operation, but if it does occur, will exist for a short period only before detection and repair and would be of negligible extent. The resultant ignition, if it did occur, would be such that it would be unlikely to injure persons or damage buildings.

Note 2: Zone 2 NE is achieved when the background concentration in the enclosure is less than 10 % Lower Explosive Limit (LEL).

Note 3: RR630 and IGEM/SR/25 introduced a criteria by setting an upper limit of 1 g/s for allowing a Zone 2 NE classification.

Note 4: There will be areas which in general will not be classified as NE, such as terminations i.e. vent outlets, pipe vents and relief valves. 

The following are not covered by this Standard:

• ⮞installation pipework downstream of the Emergency Control Valve (ECV) within a domestic dwelling⮜

• any part of a primary meter installation (see IGEM/GM/7B).

Note: ⮞Installation pipework may fall within the zone classification of the meter installation. Reference will need to be made to the primary meter risk assessment and IGEM/GM/7B as appropriate.⮜

Pressures quoted are gauge pressures unless otherwise stated.

This Standard considers the specific gravity of air to equal 1.

Italicised text is informative and does not represent formal requirements.

Appendices are informative and do not represent formal requirements unless specifically referenced in the main Sections via the prescriptive terms "must", "shall" or "should".

Note: Unusual site circumstances would include the presence of persons, processes or conditions that have potential to increase the risk of an incident.