CF₄ and SF₆ are the global warming chemicals that are used in semiconductor companies. In the Kyoto protocol on climate change in 1997, those chemicals were included in the items for which quantified emission limitation and reduction commitments were required. Accordingly for the measurement of these gases, it is necessary that measurement results are accurate and traceable, in particular because of the fact that CF₄ and SF₆ are global warming source gases.

This part of the project focuses on a comparison of measurement capability for measuring CF₄ and SF₆ at emission level. This key comparison will cover the comparability of the gas CRMs at the emission level (10 × 10^-6 mol/mol – 100 mmol/mol in nitrogen or air) of the following chemicals: CF₄, C₂F₆, CHF₃, SF₆ and NF₃.

There is good agreement between the results of the key comparison participants in this comparison for both CF₄ and SF₆. The results for CF₄ agree within 0.5% relative, and for SF₆ they agree within 0.1% relative. Even though the concentration is as low as 100 µmol/mol, the comparability between participants on gravimetric preparation plus comparison analysis is excellent for the laboratories that are participating in this key comparison.

Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.

The final report has been peer-reviewed and approved for publication by the CCQM.