• Certified Standard – unless specified in the purchase order, Certified Mixture concentrations are reported utilizing the gravimetric result when the cylinder(s) are filled.  Typically are not analyzed with other laboratory equipment unless they have a reactive constituent or it is requested at the time of order.

  • Primary Standard – Mixture is blended gravimetrically and analyzed utilizing appropriate methods for the gas constituents.

  • EPA Protocol – Mixture is blended and results are reported per EPA 600/R-12/531.

  • ISO 17025 – Mixture blend is analyzed and reported per 17025 guidelines and is NIST traceable.

Tier 5 Mix Type Specifications: 

Concentration Range of Smallest ComponentCertified StandardPrimary StandardEPA ProtocolISO 17025:2005
Blend ToleranceAnalytical ToleranceBlend ToleranceAnalytical ToleranceBlend ToleranceAnalytical ToleranceBlend ToleranceAnalytical Tolerance
0.1 - 10ppm+/- 20%+/- 10%+/- 10%+/- 10%+/- 20%U < 1%+/- 10%U < 1%
10 - 999ppm+/- 10%+/- 5%+/- 5%+/- 1%+/- 10%U < 1%+/- 1%U < 1%
0.1 - 50%+/- 1%+/- 2%+/- 1%+/- 1%+/- 5%U < 1%+/- 1%U < 1%

If there is a question regarding which mix type is suitable for your customer’s application please do not hesitate to call.