DECLARATION OF EQUIVALENCE

 

 

 

Chemical Science and Technology Laboratory

National Institute of Standards and Technology - NIST

Gaithersburg, MD., United Stated of America

 

and

 

Nederlands Meetinstituut,

 Van Swinden Laboratorium - NMi - VSL

Delft, The Netherlands

 

 

NIST and NMi declare that on July 1, 2004 the suites of primary standard gas mixtures developed and maintained in both the Institutes, comprising a range of analyte concentrations in the stated diluent gas as listed in Annex 1, can be considered as equivalent within the stated uncertainties. This declaration shall expire on July 1, 2005 at which time a new declaration shall take effect.

 

This declaration is based on the results of intercomparisons carried out between the two Institutes. A continuous program of intercomparisons has been agreed to in order to maintain this declaration and is outlined in a mutual Memorandum of Cooperation, effective July 1, 1999.

 

 

Signed By on August 9, 2004:

 

Willie E. May, Chief                    

Analytical Chemistry Division

Chemical Science and Technology Laboratory

National Institute of Standards and Technology

Gaithersburg, MD 20899 USA

01-301-975-3108

 

Signed By on July 26, 2004:

 

Ed W.B. de Leer                         

Scientific Director                                                              

Nederlands Meetinstituut

Van Swinden Laboratorium B.V.

Delft, The Netherlands

31 15 2691 500

 

 

Annex 1:         NIST and NMi Primary Standard Gas Mixture Suites which are declared to be equivalent

 

 

 

Component

 

Molar Fractions (mol/mol)

 

Maximum allowable difference

 

 

Date of Reassessment

 

 

Carbon Dioxide in Nitrogen

 

 

 

10·10-6  to 20·10-2

 

 

0.3 % relative

 

 

2007

 

 

Carbon Dioxide in Air

 

 

 

100·10-6  to 500·10-6

 

 

0.5 % relative

 

 

2007

 

 

Carbon Monoxide

in Nitrogen / Air

 

 

 

10·10-6 to 10·10-2

 

 

0.3 % relative

 

 

2005

 

 

Ethanol in Nitrogen / Air

 

 

 

75·10-6 to 500·10-6

 

 

1 % relative

 

 

2005

 

 

Oxygen in  Nitrogen

 

 

 

0.1·10-2 to 25·10-2

 

 

0.3 % relative

 

 

2006

 

 

Propane in Nitrogen / Air

 

 

 

10·10-6 to 1·10-2

 

 

0.3 % relative

 

 

 

2006

 

 

Nitric Oxide in Nitrogen

 

 

 

0.1·10-6 to1·10-2

 






0.5% relative

 

 

2007

 


Nitric Dioxide / Air

 

 

10·10-6 to1·10-2

 






1% relative

 

 

2006

 

 

 

Sulfur Dioxide in Nitrogen

 

 

 

100·10-6 to 1·10-2

 

 

0.5 % relative

 

 

2004

 

 

VOC’s (ethane, propane, propene, isobutane, isobutene, n-butane, isopentane, n‑pentane, n-hexane, n‑heptane, benzene, toluene, n-octane, o-xylene) in nitrogen

 

 

 

1·10-9 to 1·10-6

 

 

2 % relative

 

 

2006

 

Natural gas

CH4, C2H6, C3H8,

n-C4H10, i-C4H10, n-C5H12, neo-C5H12, n-C6H14, CO2, N2, He

 

 

Typical

 

0.5 % relative

(CH4 0.3 % relative)

 

 

2005

 

Hydrogen Sulphide in Nitrogen

 

10·10-6 to 1000·10-6

 

2 % relative

 

2005