Dominion Gas, A Praxair Company

Reference and certified standards are manufactured using gravimetric techniques with high accuracy balances traceable to NPL standard masses.

The widely acknowledged superiority of the gravimetric method of production over manometric techniques ensures that mixtures are manufactured consistently to the highest possible accuracy. Mixture purity and composition is verified by analysis and certification following a thorough homogenization process.

More complex and reactive mixtures are analysed several times over a period of days or even weeks to guarantee their final stability and quality.