Accredited Gas Mixtures [ Return towards Emissions Monitoring ]

A Comprehensive Range of Gases in Accordance to ISO17025

It is a requirement of both ISO 17025, and MCERTS accreditations that calibration gases used for the quantification of emissions are traceable. It means that there is an auditable chain of direct measurements linking the value of the calibration gas back to primary standard gas mixtures and ultimately to the SI units.

Understanding the legislative demands, Air Liquide has the solution, by offering a comprehensive range of calibration gases that are certified in accordance to ISO17025 in our calibration laboratory in Gellep. The traceability, accuracy and stability of our gas mixtures ensure that the user has a quality product fit for purpose.

Conversion Factors (0ºC and 101.kPa) ppm / mg Nm³
NO	NO₂	SO₂	CH₄	CO	CO₂	NH₃	HCl	HF
1.340	2.054	2.860	0.716	1.250	1.965	0.760	1.628	0.893

Binary Gas Mixtures
Gas	Matrix	Concentration Range	Relative Uncertainty (95% level of confidence)
Carbon Monoxide	Nitrogen or Air	10ppm – 20%	+/-1%
Carbon Dioxide	Nitrogen or Air	10ppm – 20%	+/-1%
Methane	Nitrogen or Air	1ppm – 100ppm	+/-1% (<10ppm +/-2%)
Propane	Nitrogen or Air	1ppm – 1%	+/-1%
Sulphur Dioxide	Nitrogen	20 – 5000ppm	+/-1%
Nitrogen Dioxide	Nitrogen	3 - 1000ppm	+/-1% (<10ppm +/-2%)
Nitric Oxide	Nitrogen	1 – 4500ppm	+/-1% (<100ppm +/-2%)
Oxygen	Nitrogen	1 – 25%	+/-1%

Quaternary Gas Mixtures
Gas	Matrix	Concentration Range	Relative Uncertainty (95% level of confidence)
Carbon Monoxide Carbon Dioxide Propane	Nitrogen	0.2 – 5% 1.5 – 18% 150 – 1000ppm	+/-1% +/-1% +/-2%
Carbon Monoxide Carbon Dioxide Propane	Nitrogen	0.2 – 5% 1.5 – 18% 1000 – 5000ppm	+/-1% +/-1% +/-1%

Download DKD Scope of Accreditiation Certificate..

International Recognition & European Co-operation

In the course of proceeding globalisation and a coalescing Europe the mutual recognition of national calibration certificates is essential.

In Europe this is done by multilateral agreements (MLA) within the European co-operation for Accreditation (EA), which in the meantime almost all European accreditation bodies for calibration and testing laboratories as well as certification bodies belong to.

Mutual recognition is based on:

- A harmonisation of the accreditation criteria and procedures
- EA interlaboratory comparisons
- evaluations of the accreditation bodies by international peer teams

The European standards for accreditation bodies of calibration and testing laboratories as well as their assessment and evaluation provide the basis for this.

Worldwide the national accreditation bodies have syndicated in the International Laboratory Accreditation Cooperation (ILAC), whose main objective is the creation of a network of agreements for the mutual recognition of calibration certificates and test reports of accredited laboratories.

This network is to improve above all the acceptance of these certificates and reports by member states of the World Trade Organization (WTO) within the scope of the agreement on the removal of technical barriers to trade (TBT Agreement) of 1995. ILAC thus supports the work of the respective regional organizations, e. g. EA and APLAC (Asia Pacific Laboratory Accreditation Co-operation). DKD is a member of ILAC and belongs to the signatories of the "ILAC Mutual Recognition Arrangement" for the mutual recognition of calibration certificates and test reports (further details see EA or ILAC).

Calibration Gases...

	Austria BMWA
	Belgium BKO/OBE
	Denmark DANAK
	France COFRAC
	Germany DKD
	Greece ESYD
	Italy SIT
	Netherlands RVA
	Portugal IPQ
	Spain ENAC
	Sweden SWEDAC
	Switzerland SAS
	UK UKAS