Shanghai Gas Alarm Detector Inspection Frequency ZhongNuo Inspection

Shenzhen ZhongNuo Testing Technology Co., Ltd. specializes in the calibration, verification, and measurement services for gas alarms, flammable gas detectors, toxic and harmful gas detectors, and other equipment in various locations. We hold the necessary qualifications to serve nationwide, addressing electrical safety and explosion-proof fire prevention issues for our clients, and 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 and alarm instruments used in work场所.
The standard was issued 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 workplaces.

Key Technical Requirements for Regular Calibration of Combustible Gas Detectors (Shenzhen ZhongNuo Testing Technology Co., Ltd.)
1. Self-check function upon startup: The instrument should have an automatic self-check function when turned on, and the alarm components should also be equipped with a manual self-check function.
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 oxygen enrichment alarm setting is 23.5% VOL (refer to GB 8958-2006 "Operation Procedures for Oxygen Deficiency Hazardous Work" and GB 30871-2022 "Special Operation Regulations for Hazardous Chemical Enterprises").
The first-level alarm setting for flammable gases 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 (Immediate Danger to Life and Health).
4. Error and Repetition: The standard specifies clear requirements for the instrument's 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 Interfaces: 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: Instruments used in explosive environments must have explosion-proof performance in compliance with relevant regulations and obtain an explosion-proof certification.
7. Audio-Visual Alarm Devices: The audio-visual 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 supply or initiating an exhaust system, etc.
9. Power Supply 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: Includes specifications for orientation, response time, full-scale indication error, high-speed airflow, long-term stability, insulation withstand voltage performance, temperature, constant humidity and heat, resistance to electromagnetic interference, resistance to steam interference, vibration and shock resistance, and functional aspects.

Power-on inspection
The instrument should operate normally and the display should be clear and complete after being powered on. Check the alarm function and the alarm action values.
Alarm function and alarm action value verification
The instrument's sound and light alarm should be normal. Insulation resistance.
Insulation resistance for equipment using AC power should be no less than 20MΩ.

The calibration cycle for flammable gas detectors is typically once a year.
In accordance with the standard JJG 693-2011 "Flammable Gas Detectors," the calibration period for flammable gas detectors generally does not exceed 1 year. This means that under normal circumstances, a comprehensive calibration and testing of the flammable gas detectors should be conducted annually to ensure their performance meets the relevant requirements.
Shenzhen Zhongnuo Testing Technology Co., Ltd. is a third-party institution specializing in electrical safety, electrical explosion-proofing, gas alarm systems, and toxic gas detection instruments, providing regular inspections, metrological services, and calibration. We are qualified to address fire and explosion prevention issues for our clients.