EffecTech’s Stack Emissions Proficiency Testing Scheme has been described as “excellent all round” and has participants in the UK and Ireland as well as in the rest of Europe and Asia.

 2023 SEPTS scheme

  • The 2023 SEPTS scheme is now closed for applications. The forms for the next round will be available in early 2024
  • Alternatively, you could participate in an on-demand proficiency testing scheme,  in which gas mixtures are provided for ‘blind’ measurement. On-demand schemes are available for sulphur, hydrocarbons and emissions testing.

For more information, please contact us

More information about SEPTS

   SEPTS frequency and benefits

The 2023 SEPTS report can be downloaded here:

 SEPTS Final Report 2023

Mixture types Amount fraction range (%mol/mol)
oxygen in nitrogen 2 to 14
carbon dioxide in nitrogen 1 to 10


Mixture types Amount fraction range (μmol/mol)
sulphur dioxide in nitrogen 10 to 200
propane in 10% oxygen / nitrogen 5 to 50
nitric oxide in nitrogen 10 to 500
carbon monoxide in nitrogen 20 to 500
NO/NO2 in nitrogen Nitric oxide (NO) 20 to 400
Nitrogen oxides (NOx) 25 to 500

Participants are required to report the composition and an estimate of the uncertainty of the gas where appropriate using the reporting template.


Evaluation will be using ISO 17043 approved methods including En ratio and Z scores.


As mandated by ISO 17043, all data including participants and performance will be kept strictly confidential. Only the submitting laboratory will receive feedback on their performance. Performance data will be reported to the whole group anonymously.