Shenzhen ZhongNuo Testing Technology Co., Ltd. specializes in the certification, calibration, and metrological services for gas alarms, flammable gas detectors, and toxic gas analyzers, catering to various venues. With qualifications to serve nationwide, we address electrical safety and explosion-proof fire prevention issues for clients, contributing to safe production.
Gas Detector Alarm Calibration Specification Requirements
Regulation 5.5 of the "Regulation for Calibration of Combustible Gas Detectors" (JJG693-2011) stipulates: 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 instrument's measurement data, or if the instrument has been replaced with major components or repaired, it should be sent for calibration promptly.
Section 3.5 of the "Regulations for the Use of Combustible Gas Detection and Alarm Systems" (SY6503-2000) stipulates: The combustible gas detection and alarm systems in use shall be calibrated regularly as required.
Occupational Health Service (GBZ/T223-2009) Article 7.2.1 stipulates: Calibration of detection and alarm devices should be carried out regularly according to the manufacturer's specified time and procedures.
Section 3.4 of the "Regulations for the Use of Flammable Gas Detectors and Alarms" (SY6503-2000) stipulates: The flammable gas detectors and alarms installed and used should have measurement instruments manufactured by an institutionally recognized manufacturer, and should possess explosion-proof performance.

Gas Standard Material
We use gas standard substances of the same type as the gas measured by the instrument, such as methane or other gases, where gas standards can also be ethyl alcohol, etc. If the instrument does not specify the type of gas being measured, the concentration of the gas with a 60% increment in the alarm set point is approximately the full-scale value of the standard substance. The uncertainty of the expanded gas standard substance is not significant (%). The repeatability of the dilution device should not exceed ±1%. The flow value error of the dilution device should not be greater than 0.%. The concentration unit of the gas standard substance should be converted to match the indicating unit of the tested instrument when in use.

Power-on inspection
The instrument should operate normally after being powered on, with the display sections being clear and complete. Check the alarm function and alarm trigger values.
Alarm function and alarm action value verification
The instrument's sound and light alarm should be functioning normally. Insulation resistance
Insulation resistance for equipment using AC power should not be less than 20MΩ.

Key Technical Requirements for Regular Calibration of Combustible Gas Detectors (Shenzhen ZhongNuo Testing Technology Co., Ltd.)
1. Self-check Function at Startup: The instrument should have an automatic self-check function upon startup, and a manual self-check function should also be set 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 meters.
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-rich 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 combustible gas alarm setting should not exceed 25% LEL, and the second-level alarm setting should not exceed 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 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 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: Instruments used in explosive environments must possess explosion-proof capabilities 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 functions should be able to activate the output control feature upon emitting an alarm signal, such as cutting off power supply or initiating the exhaust system, etc.
9. Power Requirements: Specific requirements are set for the power voltage, continuous operating time, etc. of 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, electromagnetic interference resistance, steam interference resistance, vibration and drop, and functionality.
Shenzhen ZhongNuo Testing Technology Co., Ltd. is an independent third-party institution providing services such as periodic inspection, measurement, and calibration for electrical safety, electrical explosion-proof equipment, gas detectors, and toxic and harmful gas alarm instruments, as well as资质 certifications to address fire and explosion prevention issues for clients.