Shenzhen ZhongNuo Inspection & Technology Co., Ltd. specializes in the calibration, certification, and metrological services for gas alarms, combustible gas detectors, and toxic and harmful gas detectors in various locations. We offer national services to address a range of electrical safety and explosion-proof fire prevention issues, promoting safe production.
How often should various gas detectors be calibrated and tested?
Instrument recalibration is typically every 1 year, determined by the submitting unit based on actual usage. During the secondary calibration process, recalibration is required if there are doubts about the instrument's test data, if the main components of the instrument are replaced, or if recalibration is needed after repairs.

Gas Detector Alarming Device Verification Specification Requirements
Regulation 5.5 of the "Regulation for Calibration of Combustible Gas Detectors" (JJG693-2011) stipulates: The calibration cycle for combustible gas detection and alarm instruments: Generally, the calibration cycle of the instrument should not exceed one year. If there is any doubt about the instrument's measurement data, or if the instrument has been replaced with major components or repaired, it should be sent for calibration promptly.
Section 3.5 of the "Regulations for the Use of Combustible Gas Detection and Alarm Systems" (SY6503-2000) stipulates: The combustible gas detection and alarm systems in use shall be calibrated regularly as required.
Occupational Health Service (GBZ/T223-2009) Article 7.2.1 stipulates: Calibration of detection and alarm devices shall be carried out regularly according to the manufacturer's specified time and procedures.
Section 3.4 of the "Regulations for the Use of Flammable Gas Detectors and Alarms" (SY6503-2000) stipulates that flammable gas detectors and alarms installed and used should have measurement instruments manufactured by an institutionally recognized manufacturer, with explosion-proof performance.

Gaseous Alarm Meters Calibration Conditions and Requirements
Environmental Conditions
Ambient Temperature: 0~40℃.
Relative Humidity: ≤85%
3. The working environment should not interfere with the electromagnetic fields and disturbance gases that affect the normal operation of the instruments.
Inspection Gauges and Instruments
1) Certified Reference Materials for 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: Graduation not greater than 0.1s.
4) Flow Control: Flow rate not less than 500 mL/min, flow grade not lower 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 certification and metrological calibration of flammable and toxic gas detectors:
GB/T 50493-2019 "Design Standard for Detection and Alarm Systems of Combustible Gases and Toxic Gases in Petroleum and Chemical Industries"
GB12358-2006 General Technical Requirements for Environmental Gas Detection and Alarm Instruments in Workplaces
JJG 693-2011 "Regulation for Calibration of Flammable Gas Detectors"
Shenzhen Zhongnuo Testing Technology Co., Ltd. is a third-party institution specializing in electrical safety, electrical explosion-proofing, gas alarms, and toxic and harmful gas alarm instruments for regular inspections, metrological measurements, and calibrations. We are qualified to address fire and explosion prevention issues for our clients.