Shenzhen ZhongNuo Testing Technology Co., Ltd. specializes in the certification, calibration, and metrological services for gas alarms, combustible gas detectors, toxic and harmful gas detectors, and other equipment in various facilities. We hold qualifications to serve nationwide, addressing clients' electrical safety and explosion-proof fire prevention issues, and contributing to safe production.
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. Specify Effective Detection Range: The effective detection range of non-contact gas detectors must 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 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 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 OEL (Occupational Exposure Limit) or IDLH (Immediate Danger to Life and Health).
4. Error and Reproducibility: The standard specifies clear requirements for the instrument's indication error, drift, and reproducibility. 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 for use in explosive environments must possess explosion-proof performance in accordance with relevant regulations and obtain an explosion-proof certificate.
7. Audio-Visual Alarm Device: The audio-visual alarm device of the alarm should meet visibility and sound pressure level requirements under specific conditions, ensuring 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 Requirements: Specific requirements are outlined for power supply voltage, continuous operating time, etc., for battery-powered and non-battery-powered instruments.
10. Additional Performance Requirements: Includes specifications for direction, 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.

Measurement Instrument Control
Instrument control includes calibration, follow-up calibration, and in-service inspection.

Regulatory contents for regular gas alarm inspections
Installation spacing of inspection (probe) points
2. Installation Height of the Detector
3. Indicated Error (Concentration)
4. Repeatability (Concentration)
5. Alarm Error (Concentration)
6. Response Time (Seconds)

Standard for certification and metrological calibration of flammable and toxic gas detectors:
Standard for Design of Detection and Alarm Systems for Combustible and Toxic Gases in Petroleum and Chemical Industry - GB/T50493-2019
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 service provider specializing in electrical safety, electrical explosion-proofing, gas alarms, and toxic and harmful gas detectors for regular calibration, measurement, and verification. We offer qualifications to solve fire and explosion prevention issues for our clients.