Shenzhen Zhongnuo Inspection & Technology Co., Ltd. specializes in the calibration, verification, and measurement services for gas alarms, combustible gas detectors, and toxic gas analyzers for various locations. We are licensed to serve nationwide, addressing electrical safety and explosion-proof fire prevention issues for our clients, and contributing to safe production.
How often should various gas detectors be periodically calibrated and tested?
The recalibration period for instruments is typically one year, which is determined by the sending unit based on actual usage. During the secondary calibration process, if there are doubts about the instrument's test data, or if the main components of the instrument are replaced, or if recalibration is needed after repair.

Gas Detector Alarm Calibration Specification Requirements
Regulation 5.5 of the "Regulation for the Verification of Combustible Gas Detectors" (JJG693-2011) stipulates: The verification cycle for combustible gas detection and alarm instruments: Generally, the verification cycle of the instrument should not exceed one year. Instruments with suspected measurement data, instruments that have replaced major components, or instruments that have been repaired should be sent for verification promptly.
Section 3.5 of the "Regulations for the Use of Flammable Gas Detection and Alarm Systems" (SY6503-2000) stipulates: The flammable gas detection and alarm systems in use shall be calibrated regularly as required.
The Regulation of Toxic Gas Device Installation in Workplaces (GBZ/T223-2009) Article 7.2.1 stipulates: Calibration of detection and alarm devices should be carried out regularly according to the manufacturer's specified time and procedures.
Section 3.4 of the "Code for the Use of Combustible Gas Detectors and Alarms" (SY6503-2000) stipulates: Combustible gas detectors and alarms for installation and use should have measurement instruments manufactured by an authorized body and **explosion-proof performance**.

Gas Alarm Meters Calibration Conditions and Requirements
Environmental Conditions
Ambient Temperature: 0~40℃.
2. Relative Humidity: ≤85%
3. The working environment should not affect the normal operation of the instrument with electromagnetic fields and interfering gases.
Calibration Tools and Instruments
1) Certified Reference Gases
The relative expanded uncertainty of the gas standard material does not exceed 2% (k=2).
2) Standard Gas Dilution Unit: Dilution Error of 1%.
3) Stopwatch: Resolution not greater than 0.1s.
4) Flow Control: Flow range not less than 500 mL/min, flow grade not less than level 4.
5) Zero Point Gas: Purified compressed air.
6) Pressure Reducing Valve: A pressure reducing valve that matches with the calibrated cylinder.
7) Gas Pipeline: Tubing made of materials like polytetrafluoroethylene or stainless steel that do not affect the concentration of the measured gas.

Standard for calibration and verification of combustible and toxic gas detectors:
GB/T 50493-2019 "Design Standard for Detection and Alarm of Combustible Gases and Toxic Gases in Petroleum and Chemical Industries"
GB12358-2006 General Technical Requirements for Environmental Gas Detection and Alarm Instruments in Workplace
JJG693-2011规程 for Calibration of Combustible Gas Detectors and Alarms
Shenzhen ZhongNuo Inspection & Technology Co., Ltd. is an independent third-party service provider specializing in electrical safety, electrical explosion-proof, gas detectors, and toxic and harmful gas alarm instruments for regular calibration, measurement, and certification. We offer qualifications to help customers address fire and explosion prevention issues.