Gas Safety (Management) Regulations (Northern Ireland) 1997

Part I Requirements under Normal Conditions

1.  The content and characteristics of the gas shall be in accordance with the values specified in the following table.

Content or characteristic	Value
hydrogen sulphide content	≤ 5 mg/m3;
total sulphur content (including H2S)	≤ 50 mg/m3;
hydrogen content	≤ 0.1% (molar);
oxygen content	≤ 0.2% (molar);
impurities	shall not contain solid or liquid material which may interfere with the integrity or operation of pipes or any gas appliance (within the meaning of regulation 2(1) of the 1997 Regulations) which a consumer could reasonably be expected to operate;
hydrocarbon dewpoint and water dewpoint	shall be at such levels that they do not interfere with the integrity or operation of pipes or any gas appliance (within the meaning of regulation 2(1) of the 1997 Regulations) which a consumer could reasonably be expected to operate;
WN	(i) ≤ 51.41 MJ/m3, (ii) ≥ 47.20 MJ/m3;
ICF	≤ 0.48
SI	≤ 0.60

2.  The gas shall have been treated with a suitable stenching agent to ensure that it has a distinctive and characteristic odour which shall remain distinctive and characteristic when the gas is mixed with gas which has not been so treated, except that this paragraph shall not apply where the gas is at a pressure of above 7 barg.

3.  The gas shall be at a suitable pressure to ensure the safe operation of any gas appliance (within the meaning of regulation 2(1) of the 1997 Regulations) which a consumer could reasonably be expected to operate.

4.—(1) Expressions and the abbreviations used in this Part shall have the meanings assigned to them in Part III.

(2) ICF and SI shall be calculated in accordance with Part III.