BS EN ISO 6145-8:2008

BS EN ISO 6145-8:2008 Gas analysis. Preparation of calibration gas mixtures using dynamic volumetric methods. Diffusion method

BS EN ISO 6145-8 specifies a dynamic method for the preparation of calibration gas

mixtures using diffusion. It covers calibration gas mixtures containing component mole fractions ranging from 10−9 to 10−3.

The method specified in BS EN ISO 6145-8 also provides a relative expanded uncertainty of measurement.

The method can be applied for the generation of low-concentration calibration gases of organic components that are liquid at room temperature, with boiling points ranging from about 40 °C to 160 °C.

BS EN ISO 6145-8 applies to the generation of calibration gas mixtures of a wide range of hydrocarbons at ambient and indoor air concentration levels. It also applies to the generation of low-concentration gas mixtures of water.

Contents of BS EN ISO 6145-8

Introduction

Scope

Normative references

Principle

Reagents and materials

Apparatus

Procedure

Preliminary checks and operating conditions

Determination of mass loss

Expression of results

Calculation

Sources of uncertainty

Practical example of a diffusion cell calibrator configured for evaluating speed of response in a hygrometer

Example of performances of diffusion cells for toluene and trichloromethane

Example of uncertainty calculations for a periodic weighing system

Bibliography