Shenzhen ZhongNuo Inspection & 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 in various locations. We serve nationwide, providing solutions for electrical safety and explosion-proof fire prevention issues, and contributing to safe production.
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, and the alarm components should also be equipped with a manual self-check option.
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 by the standard 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 Work" and GB 30871-2022 "Special Operation Regulations for Hazardous Chemical Enterprises").
The first-level flammable 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 setpoints for toxic and harmful gases are determined based on 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, with a set calibration program and corresponding interface 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 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 capabilities should be able to activate the output control function upon emitting an alarm signal, such as shutting off power supply or initiating exhaust systems, etc.
9. Power Requirements: Specific requirements are outlined for the power supply voltage, continuous operating time, etc., for both 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, temperature, constant humidity and heat, resistance to electromagnetic interference, resistance to steam interference, vibration and drop, and functionality.

Which gas detectors require regular calibration and verification?
Fixed-install, handheld, and portable gas detectors, gas alarm instruments, toxic and harmful gas detectors/alarm systems, flammable gas detectors/alarm systems, gas analyzers, etc.

Gas Detector Alarm Calibration Specification Requirements
Regulation 5.5 of the "Regulation for Calibration of Combustible Gas Detectors" (JJG693-2011) states: The calibration cycle for combustible gas detection and alarm instruments: Generally, the calibration cycle of the instrument shall not exceed one year. If there is any doubt about the measurement data of the instrument, or if the instrument has been replaced with major components or repaired, it should be sent for calibration promptly.
Section 3.5 of "Regulations for the Use of Flammable Gas Detectors and Alarms" (SY6503-2000) stipulates: Flammable gas detectors in use should be calibrated regularly as per the regulations.
Section 7.2.1 of "Code for the Setting of Toxic Gas Equipment in Workplaces" (GBZ/T223-2009) stipulates: Calibration of detection and alarm devices shall be carried out regularly according to the manufacturer's specified time and procedures.
Section 3.4 of the "Regulations for the Use of Combustible Gas Detectors" (SY6503-2000) stipulates: Combustible gas detectors for installation and use shall have measurement instruments manufactured by an institution recognized for their **manufacturing** and **explosion-proof** performance.

Recurrent Testing Content and Methods for Flammable Gas Detectors and Alarms
Annually, we conduct annual inspections 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, we verify the appropriateness of the alarm installation locations and whether they are subject to interference from other equipment.
Shenzhen ZhongNuo Testing Technology Co., Ltd. is a third-party institution that provides regular certification, metrological verification, and calibration services for electrical safety, electrical explosion-proof equipment, gas detectors, and toxic and harmful gas alarm instruments. We hold the necessary qualifications to help customers address fire and explosion prevention issues.