This standard specifies the technical requirements, preparation, value determination, inspection rules, marking, packaging, transportation and storage of methane calibration gas in air. This standard applies to methane calibration gas in air. MT 423-1995 Technical conditions for methane calibration gas in air MT423-1995 Standard download decompression password: www.bzxz.net

Coal Industry Standard of the People's Republic of China
Technical Conditions for Methane Calibration Gas in Air
Subject Content and Scope of Application
MT423-1995
This standard specifies the technical requirements, preparation, value determination, inspection rules, marking, packaging, transportation and storage of methane calibration gas in air. This standard applies to methane calibration gas in air. 2 Reference Standards
GB10628 Comparative Method for Determination of Composition of Standard Mixed Gas for Gas Analysis
3 Terminologywww.bzxz.net
3.1 Methane Calibration Gas in Air
Methane calibration gas in air (hereinafter referred to as calibration gas) is a methane and air mixture prepared by units, personnel, devices and methods confirmed by the technical supervision department of the Ministry of Coal Industry, and is used for routine calibration of methane measuring instruments based on the catalytic combustion principle. 4 Technical Requirements
4.1 The methane concentration range of the calibration gas is 1.00×10-2～3.00×10-2. The uncertainty of the calibration gas shall not exceed 5×10-2.4.2
4.3 The maximum relative difference between the methane concentration of the calibration gas prepared and the methane concentration required by the user is 5×10-2.5 Preparation
The calibration gas shall be prepared by a unit confirmed by the technical supervision department of the Ministry of Coal Industry. 5.1
5.2 The raw gas used for preparation shall not contain sulfides, and the methane concentration shall not be less than 99.9×10-2.6 Fixed value
The calibration gas shall be determined by comparison method according to Article 3.1 of GB10628. 6.1
6.2 The uncertainty of the standard mixed gas for fixed value shall not exceed 2×10-2.6.3 The methane concentration in the calibration gas shall be calculated according to formula (1) in GB10628. Each calibration gas shall be measured at least 3 times and the average value shall be calculated. 6.4 The uncertainty of the calibration gas shall be calculated according to formula (2) in GB10628. 6.5 The relative difference △c between the methane concentration prepared by the calibration gas and the methane concentration required by the user is calculated as follows: Ac = × 100
Wherein: c1-
-methane concentration required by the user, %; methane concentration prepared by the calibration gas, %.
6.6 Data processing:
6.6.1 The calculation result of the standard value of the methane concentration of the calibration gas shall be rounded to 3 decimal places and rounded to 2 decimal places. 6.6.2 The calculation result of the uncertainty of the calibration gas and the relative difference between the prepared methane concentration and the methane concentration required by the user shall be rounded to 2 decimal places and rounded to 1 decimal place. Approved by the Ministry of Coal Industry of the People's Republic of China on October 5, 1995 and implemented on December 1, 1995
7 Inspection rules
7.1 Factory inspection
MT423-1995
7.1.1 The calibration gas shall be inspected by the quality inspection department of the preparation unit. It can only be shipped after passing the inspection and issuing a certificate of conformity. 7.1.2 Factory inspection items include: standard value of methane concentration of calibration gas and container filling pressure. 7.1.3 The contents of the factory inspection certificate include: container number, standard value of methane concentration in mixed gas, filling pressure, set value date, validity period, person in charge of preparation, inspection and calibration and the preparation unit. 7.1.4 After the calibration gas passes the factory inspection, its validity period shall be no less than six months. 7.2 Supervision inspection
The quality of the calibration gas shall be supervised and inspected by the metrology technical organization authorized by the technical supervision department of the Ministry of Coal Industry. 8 Marking, packaging, transportation, storage
8.1 The marking of steel cylinder containers shall comply with the following provisions a.
The shoulder of the steel cylinder is sprayed red, accounting for about 1/4 of the height of the steel cylinder, and the rest is sprayed black; b. The words "methane calibration gas in air" are painted white on the black part; a self-adhesive "certificate of conformity" with black words on a white background is affixed to the steel cylinder. c.
8.2 Packaging
8.2.1 The calibration gas prepared by the partial pressure method is filled with steel cylinders. 8.2.2 The calibration gas prepared by the static volume method or the dynamic volume method is recommended to be filled with steel cylinders. 8.3 Transportation
The calibration gas filled in the steel cylinder should be shipped as dangerous goods during transportation. 8.4 Storage
The calibration gas should be stored in a special room at room temperature and away from heat sources. Additional remarks:
This standard was proposed by the Coal Mine Safety Standardization Technical Committee of the Ministry of Coal Industry. This standard is under the jurisdiction of the Coal Mine Gas Detection and Rescue Equipment Branch of the Coal Mine Safety Standardization Technical Committee of the Ministry of Coal Industry. This standard is drafted and interpreted by the Fushun Branch of the China Coal Research Institute. The main drafter of this standard is Yang Wenzheng.
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