Page 93 - Praxair - Specialty Gases and Equipment Reference Guide

Grade Specifications

Mixture Order Mixture Component Blend Pre- Analytical
Grade Reference Concentration Range Tolerance Uncertainty
EV – Environmental Grades (1)
NTRM T N/A N/A ± 1%
EPA Protocol E 2 - 25 ppm ± 10% ± 1%
25.1 - 49.9% ± 5% ± 1%
Primary Master PM 1 - 9.9 ppm ± 10% ± 0.1 ppm
10 - 25 ppm ± 10% ± 1%
25.1 - 9999 ppm ± 5% ± 1%
1.0 - 49.9% ± 2% ± 1%
Certified Master CM 1 - 9.9 ppm ± 20% ± 0.2 ppm
10 - 25 ppm ± 20% ± 2%
25.1 - 9999 ppm ± 10% ± 2%
1.0 - 49.9% ± 5% ± 2%
Dynamic Blend DM 1 - 99.9 ppm Zero ± 2%
Master 100 ppm - 49.9% Zero ± 1%
Dynamic Blend D 1 - 99.9 ppm Zero ± 5%
Standard 100 ppm - 49.9% Zero ± 2%
ST – Standard Grades
Primary Standard P 1 - 9.9 ppm ± 10% ± 0.1 ppm
10 - 25 ppm ± 10% ± 1%
25.1 - 9999 ppm ± 5% ± 1%
0.1% - 49.9% ± 2% ± 1% or 0.02% abs*
Certified Standard C 1 - 99.9 ppm ± 20% ± 5%
100 - 999 ppm ± 10% ± 2%
0.1 - 49.9% ± 5% ± 2%
Non-Certified U 1 - 999 ppm ± 20% N/A
Standard 0.1 - 49.9% ± 10%
Custom Standard Z 1 ppm - 49.9% TBD TBD
* Whichever is smaller.
(1) All Environmental Grades are NIST traceable. Actual ranges, blend tolerance, and analytical uncertainty are based on available
National Institute of Standards and Technology (NIST) SRM concentrations. Please see individual components for specific information.
Note: For all mixtures, blend tolerance and analytical uncertainty specification may vary depending on the chemical characteristics of
the component and the cylinder size. For mixtures outside of these ranges, please contact your local Praxair representative.

Blend Tolerance
s s
Requested Concentration

Example: Relative Absolute s 5.10% 5.20%
Value Value
Blend ± 5% of minor ± 0.25%
Tolerance component
Analytical ± 2% of minor ± 0.10% 4.75% 5% s 5.25%
Uncertainty component Reported
Concentration
Certification
Accuracy
Section C – Mixtures
s s

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