Shenzhen ZhongNuo Testing Technology Co., Ltd. specializes in the calibration, verification, and measurement services for gas alarms, combustible gas detectors, toxic and harmful gas detectors, and other equipment at various locations. We hold the necessary qualifications to serve nationwide, addressing clients' electrical safety and explosion-proof fire prevention issues, and contributing to safe production.
Which gas detectors require regular calibration and verification?
Fixed-install, handheld, portable gas detectors, gas alarm instruments, toxic and harmful gas detectors/alarm, flammable gas detectors/alarm, gas analyzers, etc.

Power-on inspection
After power on, the instrument should operate normally with clear and complete display sections. Check the alarm function and alarm trigger values.
Alarm function and alarm action value verification
The instrument's sound and light alarm should be functioning normally. Insulation resistance
Insulation resistance for instruments using alternating current power should be no less than 20MΩ.

GB 12358-2024 "General Technical Requirements for Environmental Gas Detection and Alarm Instruments in Workplace" is an important standard.
Intended to standardize the performance, functions, and testing methods of environmental gas detection alarm instruments used in work sites.
The standard was issued in 1990 and has undergone several revisions.
The new version is GB 12358—2024, which will be officially implemented on June 1, 2025.
This standard applies to the production and use of gas detection and alarm instruments for flammable gases, toxic and harmful gases, and oxygen in workplace environments.

Primary Technical Requirements for Regular Calibration of Flammable Gas Detectors (Shenzhen ZhongNuo Inspection & Testing Technology Co., Ltd.)
1. Power-On Self-Check Function: The instrument should have an automatic self-check function upon startup, with a manual self-check function for alarm components as well.
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 Setting: Specific alarm value settings are stipulated for different gases in accordance with the standard.
For example, the oxygen deficiency alarm setting is 19.5% VOL, and the high-oxygen alarm setting is 23.5% VOL (refer to GB 8958-2006 "Operation Procedures for Oxygen Deficiency Hazardous Operations" and GB 30871-2022 "Special Operation Regulations for Hazardous Chemical Enterprises").
The first-level flammable gas alarm setpoint is not greater than 25% LEL, and the second-level alarm setpoint is not greater than 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 indicating error, drift, and repeatability of the instrument. For instance, the indicating error for flammable 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, with established calibration procedures and corresponding interfaces to ensure the accuracy of its measurement results.
6. Explosion-proof Performance: Equipment for explosive environments must have explosion-proof performance in compliance with relevant regulations and obtain an explosion-proof certification.
7. Sound and Light Alarm Device: The sound and light alarm device of the alarm should meet visibility and sound pressure level requirements under specific conditions, ensuring effective alerting of staff in emergency situations.
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 set for the power voltage, continuous operating time, etc., of 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 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 provide资质 services to address fire and explosion prevention issues for our clients.