Shenzhen Zhongnuo Testing Technology Co., Ltd. specializes in the calibration, verification, and measurement services for equipment such as gas alarms, flammable gas detectors, and harmful gas analyzers for various locations. We hold the necessary qualifications to serve customers nationwide, addressing all kinds of electrical safety and explosion-proof fire prevention issues, and promoting 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 and alarm instruments used in workplace operations.
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 gas detection and alarm instruments for flammable gases, toxic and harmful gases, and oxygen in workplace environments.

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 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: The standard specifies specific alarm value settings for different gases.
For example, the oxygen deficiency alarm setting is 19.5% VOL, and the enriched 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 combustible gas alarm setting is not greater than 25% LEL, and the second-level alarm setting 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 (Immediately Dangerous to Life and Health concentration).
4. Error and Reproducibility: The standard specifies clear requirements for the instrument's indication error, drift, and reproducibility. For instance, the indication error for flammable 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 Interfaces: 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: Equipment used in explosive environments should possess explosion-proof capabilities in compliance with relevant regulations and obtain an explosion-proof certification.
7. Audio-Visual Alarm Device: The alarm's audio-visual alarm device must meet visibility and sound pressure level requirements under specific conditions to ensure effective alerting of staff during emergencies.
8. Output Control Function: Instruments with output control functionality should be capable of activating 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 both battery-powered and non-battery-powered instruments.
10. Additional Performance Requirements: Including specifications for direction, response time, full-scale indication error, high-speed airflow, long-term stability, insulation voltage resistance, temperature, constant humidity and heat, electromagnetic interference resistance, steam interference resistance, vibration and drop, and functional aspects.

Regulatory Content and Methods for Regular Inspection of Combustible Gas Detectors
Annual inspections are conducted on the sensors of commercial and industrial alarm systems, primarily checking for the accuracy, repeatability, drift, and response time of the alarms to ensure they meet standards. Additionally, the suitability of the alarm installation location and any interference from other equipment are assessed.

Flammable and toxic gas alarm detectors calibration and metrological verification according to standards:
GB/T50493-2019 "Design Standard for Detection and Alarm Systems of Combustible Gases and Toxic Gases in Petroleum and Chemical Industry"
GB12358-2006 General Technical Requirements for Environmental Gas Detection and Alarm Instruments in Workplace
JJG693-2011 "Regulation for Calibration of Combustible Gas Detectors"
Shenzhen Zhongnuo Testing Technology Co., Ltd. is a third-party institution specializing in electrical safety, electrical explosion-proofing, gas alarm systems, and toxic/hazardous gas detection instruments for regular inspections, metrological surveys, and calibration services. We are qualified to address fire and explosion prevention issues for our clients.