Shenzhen ZhongNuo Testing Technology Co., Ltd. specializes in the certification, calibration, and metrological services of gas alarms, combustible gas detectors, and toxic and harmful gas detectors for various venues. We provide services across the country, addressing customers' electrical safety and explosion-proof fire prevention issues, and promoting safe production.
Which gas detectors require regular calibration and verification?
Fixed-installed, handheld, portable gas detectors, gas alarm instruments, toxic and harmful gas detectors/alarm systems, flammable gas detectors/alarm systems, gas analyzers, etc.

The detection principle of the instrument mainly includes catalytic combustion, infrared absorption, and thermal conductivity types. The sampling methods are diffusion and aspiration. The instrument is mainly composed of detection elements, amplification circuits, alarm systems, and displays, used for monitoring the concentration of combustible gases in the environment.

Gas Detector Alarm Calibrator Specification Requirements
Regulation 5.5 of the "Regulation for Inspection and Verification of Combustible Gas Detectors" (JJG693-2011) states: The inspection period for combustible gas detection and alarm instruments: Generally, the inspection period for the instrument shall 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 inspection 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 periodically as per the regulations.
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 Combustible Gas Detectors" (SY6503-2000) stipulates: Combustible gas detectors for installation and use shall have measurement instruments manufactured by an institution recognized for their**explosion-proof performance**.

Primary Technical Requirements for Regular Calibration of Combustible Gas Detectors (Shenzhen ZhongNuo Inspection Technology Co., Ltd.)
1. Power-On Self-Check Function: The instrument should have an automatic self-check function upon startup, and the alarm components should also be equipped with a manual self-check option.
2. Specify the effective detection distance: The effective detection distance of the non-contact gas alarm instrument shall not be less than 20 m.
3. Alarm Value Settings: The standard specifies specific alarm value settings for different gases.
For example, the hypoxia alarm setting is 19.5% VOL, and the hyperoxia alarm setting is 23.5% VOL (refer to GB 8958—2006 "Operation Procedures for Hypoxia Hazardous Operations" and GB 30871—2022 "Special Operation Regulations for Hazardous Chemical Enterprises").
The first-level combustible gas alarm setpoint does not exceed 25% LEL, and the second-level alarm setpoint does not exceed 50% LEL.
The first and second level alarm settings for toxic and harmful gases are determined based on the OEL (Occupational Exposure Limit) or IDLH (Immediate Danger to Life and Health).
4. Error and Repeatability: The standard specifies clear requirements for the instrument's indication error, drift, and repeatability. For example, the indication error for combustible gases, toxic and harmful gases, and oxygen should be no more than 5%FS, 5%FS, and 2%FS respectively within the normal test range of the instrument's full scale.
5. Calibration and Interface: The instrument should be easy to calibrate, and calibration programs and corresponding interfaces should be set up to ensure the accuracy of its measurement results.
6. Explosion-proof Performance: Equipment used in explosive environments should possess explosion-proof properties in accordance with relevant regulations and obtain an explosion-proof certification.
7. Audio-Visual Alarm Devices: The audio-visual alarm devices of the alarm should meet visibility and sound pressure level requirements under specific conditions, ensuring effective alerting of staff during emergencies.
8. Output Control Function: Instruments with output control capabilities should be able to activate the output control function upon emitting an alarm signal, such as cutting off power supply or initiating the exhaust system, etc.
9. Power Requirements: Specific requirements are outlined for power supply voltage, continuous operating time, etc., for battery-powered and non-battery-powered instruments.
10. Other performance requirements: including requirements for azimuth, response time, full-scale indication error, high-speed airflow, long-term stability, insulation withstand voltage performance, temperature, constant humidity and heat, electromagnetic interference resistance, steam interference resistance, vibration and drop, and functionality.
Shenzhen ZhongNuo Testing Technology Co., Ltd. is an independent third-party service provider specializing in electrical safety, electrical explosion-proofing, gas alarms, and toxic gas detection equipment for regular calibration, measurement, and certification. We hold the necessary qualifications to assist customers in addressing fire and explosion prevention issues.