Shenzhen Zhongnuo Testing Technology Co., Ltd. specializes in the calibration, verification, and metrological services for equipment such as gas alarms, combustible gas detectors, and toxic and harmful gas detectors for various locations. We hold qualifications to serve nationwide, providing solutions to electrical safety and explosion-proof fire prevention issues for our clients, contributing to safe production.
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 workspaces.
The standard was published in 1990 and has undergone multiple 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 detection and alarm instruments for flammable gases, toxic and harmful gases, and oxygen in workplace environments.

Gas Detector Alarm Calibration 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: The calibration cycle of the instrument generally should not exceed 1 year. If there is any suspicion about the instrument's measurement data, or if the instrument has been replaced with major components or repaired, it should be promptly submitted for calibration.
Section 3.5 of the "Regulations for the Use of Flammable Gas Detection and Alarm Systems" (SY6503-2000) stipulates: Flammable 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 should be carried out regularly according to the manufacturer's specified time and procedures.
Regulation 3.4 of the "Standard 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 recognized agencies with ** explosion-proof performance **.

Key Technical Requirements for Regular Calibration of Combustible Gas Detectors (Shenzhen ZhongNuo Testing Technology Co., Ltd.)
1. Power-On Self-Check Function: The instrument should have an automatic self-check feature upon startup, with a manual self-check option for alarm components.
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 oxygen deficiency alarm setting is 19.5% VOL, and the oxygen-rich alarm setting is 23.5% VOL (refer to GB 8958-2006 "Operation Procedures for Oxygen Deficiency Hazardous Operations," 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 instruments' indication error, drift, and repeatability. For instance, the indication error for combustible gases, toxic and harmful gases, and oxygen should not exceed 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 a set calibration program and corresponding interface to ensure the accuracy of its measurement results.
6. Explosion-proof Performance: Instruments used in explosive environments must possess explosion-proof performance in compliance with relevant regulations and obtain an explosion-proof certification.
7. Sound and Light Alarm Devices: The sound and light alarm devices of the alarm should meet specific visibility and sound pressure level requirements to ensure 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 or initiating an exhaust system, etc.
9. Power Requirements: Specific requirements are set for the supply voltage, continuous operating time, etc., of battery-powered and non-battery-powered instruments.
10. Other Performance Requirements: Including specifications for azimuth, response time, full-scale indication error, high-speed airflow, long-term stability, insulation withstand voltage, temperature, constant humidity and heat, resistance to electromagnetic interference, resistance to steam interference, vibration and drop, and functionality.

The detection principle of the instruments primarily includes catalytic combustion, infrared absorption, and thermal conductivity types. The sampling methods include diffusion and aspiration. The instruments are mainly composed of detection elements, amplification circuits, alarm systems, and displays, designed for monitoring the concentration of combustible gases in the environment.
Shenzhen Zhongnuo Inspection Technology Co., Ltd. is a third-party institution that offers regular certification, measurement, and calibration services for electrical safety, electrical explosion-proofing, gas alarms, and toxic and harmful gas detection instruments. We hold the necessary qualifications to assist clients in solving fire and explosion prevention issues.