National Physical Laboratory



Sulphur odorants

Sulphur-containing compounds are added to natural gas to provide a distinctive odour, thus allowing any potentially hazardous leaks to be detected. The very low odour thresholds of these compounds enable detection by the human nose at minute concentrations.

NPL's sulphur odorant standards are available as either binary or multi-component mixtures, in a matrix of methane or nitrogen. The range of standards covered by NPL's UKAS accreditation is shown in the table below:

Component Amount fraction
range (µmol/mol)
Hydrogen sulphide 0.4 to 5000
Carbonyl sulphide 0.4 to 5000
Carbon disulphide 0.4 to 200
Dimethyl sulphide 0.4 to 200
Ethyl methyl sulphide 0.4 to 200
Diethyl sulphide 0.4 to 200
Component Amount fraction
range (µmol/mol)
0.4 to 200
Ethanethiol 0.4 to 200
2-propanethiol 0.4 to 200
1-propanethiol 0.4 to 200
2-methyl-2-propanethiol 0.4 to 200
Tetrahydrothiophene 0.4 to 200

Non-sulphur odorants

NPL also supplies a range of non-sulphur odorant mixtures in order to provide traceability for the measurement of components which are increasingly being used to odorise natural gas across Europe. Standards are available containing the components most commonly used as non-sulphur odorants: methylacrylate, ethylacrylate and 2-ethyl-3-methylpyrazine.


Please email or telephone Customer Services on +44 20 8943 6151.

Last Updated: 22 Sep 2016
Created: 18 Sep 2013


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