Shenzhen ZhongNuo Testing Technology Co., Ltd. specializes in the calibration, certification, and metrological services for gas alarms, combustible gas detectors, toxic and harmful gas detectors, and other equipment at various locations. We offer nationwide services, addressing clients' electrical safety and explosion-proof fire prevention issues, and contributing to safe production.
Regulatory Content and Methods for Regular Detection of Flammable Gas Detectors
Annual inspections are conducted on the sensors of commercial and industrial alarm systems, primarily checking for measurement errors, repeatability, drift, and response time to ensure they meet standards. Additionally, the suitability of the alarm system's installation location and any interference from other equipment are assessed.

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

Flammable and toxic/hazardous gas alarm detectors calibration and measurement standards:
GB/T50493-2019 "Design Standard for Detection and Alarm Systems of Combustible Gases and Toxic Gases in Petroleum and Chemical Industries"
GB12358-2006 General Technical Requirements for Environmental Gas Detection and Alarm Instruments in Workplace
JJG693-2011规程 for the Verification of Flammable Gas Detectors and Alarms

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 an additional manual self-check function 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 Setting: Specific alarm value settings are stipulated for different gases according to the standard.
For example, the hypoxia alarm setpoint is 19.5% VOL, and the hyperoxia alarm setpoint is 23.5% VOL (refer to GB 8958-2006 "Operation Procedures for Hazardous Work of Hypoxia" and GB 30871-2022 "Special Operation Regulations for Hazardous Chemical Enterprises").
The first-level flammable gas alarm setpoint is no greater than 25% LEL, and the second-level alarm setpoint is no 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 be no more than 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, and calibration programs and corresponding interfaces should be set up to ensure the accuracy of its measurement results.
6. Explosion-proof Performance: Equipment used in explosive environments must have explosion-proof performance in compliance with relevant regulations and obtain an explosion-proof certificate.
7. Audio-Visual Alarm Device: The audio-visual alarm device of the alarm should meet specific visibility and sound pressure level requirements to ensure effective notification of staff during emergencies.
8. Output Control Function: Instruments with output control functions 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 the supply voltage, continuous operating time, etc., for battery-powered and non-battery-powered instruments.
10. Additional Performance Requirements: Includes specifications for bearing, 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 resistance, and functionality.
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 help customers address fire and explosion prevention issues.