GB/T 5275.7-2025 Active
GB/T 5275.7-2025 Gas analysis—Preparation of calibration gas mixtures using dynamic methods— Part 7:Thermal mass-flow controllers
Abstract
GB/T 5275 is a series of documents describing various dynamic methods for preparing calibration gas mixtures. This document describes a method for continuously preparing calibration gas mixtures using a thermal mass flow controller and pure gases or gas mixtures. This document is applicable to gas mixtures in which the components do not react with the materials constituting the flow path of the thermal mass flow controller or auxiliary equipment.
The best achievable level of calibration gas mixtures prepared using the methods described in this document is as follows: the relative measurement expansion uncertainty (obtained by multiplying the standard uncertainty by the inclusion factor k=2) U is no greater than 2%.
General Product Information
| Document Type | National standards |
|---|---|
| Standard Status | Active |
| Standard Code | GB/T 5275.7-2025 |
| CCS | Industrial gases and chemical gases |
| ICS | Industrial gases |
| Implement Date | 2026-05-01 |