Shenzhen Zhongnuo Testing Technology Co., Ltd. specializes in the calibration, certification, and measurement services for gas alarms, flammable gas detectors, toxic and harmful gas detectors, and other equipment for various locations. We offer services nationwide, addressing clients' electrical safety and explosion-proof fire prevention issues, and supporting safe production.
How often should various gas detectors be periodically calibrated and tested?
Instrument recalibration is typically every 1 year, determined by the submitting unit based on actual usage. During the secondary calibration process, if there are doubts about the instrument's test data, or if the main components of the instrument are replaced, or if recalibration is needed after repairs.

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 published 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 workplaces.

Key Technical Requirements for Regular Calibration of Flammable 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, and a manual self-check function should also be set for the alarm components.
2. Specified Effective Detection Range: The effective detection range of non-contact gas alarm instruments shall not be less than 20 meters.
3. Alarm Value Setting: The standard specifies specific alarm value settings for different gases.
For example, the hypoxia alarm set value is 19.5%VOL, and the hyperoxia alarm set value is 23.5%VOL (refer to GB 8958-2006 "Operation Code for Hypoxia Hazardous Work" 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 (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 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 Interface: The instrument should be easy to calibrate, with set calibration procedures and corresponding interfaces to ensure the accuracy of its measurement results.
6. Explosion-proof Performance: Instruments for use in explosive environments must have explosion-proof performance in accordance with relevant regulations and obtain an explosion-proof certificate.
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 notification to 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 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, resistance to electromagnetic interference, resistance to steam interference, vibration and drop, and functionality.

Standard for Verification and Calibration of Combustible and Toxic Gas Detectors:
GB/T 50493-2019 "Design Standard for Detection and Alarm of Combustible and Toxic Gases in Petroleum and Chemical Industries"
GB12358-2006 General Technical Requirements for Environmental Gas Detection and Alarm Instruments in Workplace
JJG 693-2011 "Regulation for Calibration of Flammable Gas Detectors and Alarms"
Shenzhen ZhongNuo Testing Technology Co., Ltd. is a third-party institution providing regular certification, measurement, and calibration services for electrical safety, electrical explosion-proofing, gas detectors, and toxic and harmful gas alarm instruments. We have the qualifications to solve fire and explosion prevention issues for our clients.