Shenzhen ZhongNuo Testing Technology Co., Ltd. specializes in the calibration, verification, and measurement services for gas alarms, combustible gas detectors, toxic and harmful gas detectors, and other equipment in various locations. We hold the necessary qualifications to serve nationwide, addressing clients' electrical safety and explosion-proof fire prevention concerns, and contributing to safe production.
Key Technical Requirements for Regular Calibration of Flammable Gas Detectors (Shenzhen ZhongNuo Inspection Technology Co., Ltd.)
1. Power-on self-test function: The instrument should have an automatic self-test function upon startup, and a manual self-test function should be set for alarm components.
2. Specified 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 hypoxia alarm setting is 19.5% VOL, and the hyperoxia alarm setting is 23.5% VOL (refer to GB 8958-2006 "Operation Procedures for Oxygen Deficiency Hazardous Work," GB 30871-2022 "Special Operation Regulations for Hazardous Chemical Enterprises").
The first-level combustible gas alarm setpoint is not greater than 25% LEL, and the second-level alarm setpoint 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 sets clear requirements for the instrument's indication error, drift, and repeatability. For example, the indication error for flammable 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 established calibration programs and corresponding interfaces 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 certification.
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 or initiating an exhaust system, etc.
9. Power Requirements: Specific requirements are set for the power voltage and continuous operating time 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 voltage resistance, temperature, constant humidity and heat, electromagnetic interference resistance, steam interference resistance, vibration and drop resistance, and functional aspects.

How often should various gas detectors be periodically calibrated and tested?
The recalibration period for instruments is typically one year, subject to the testing unit's determination based on actual usage. During the secondary calibration process, recalibration is required if there are doubts about the instrument's test data, if the main components of the instrument are replaced, or if recalibration is necessary after repairs.

Regulatory Content for Periodic Inspection of Gas Alarms
Installation spacing of inspection (probe) points
2. Installation Height of the Detector
3. Indicated Error (Concentration)
Repetitive (Concentration)
5. Alarm Error (Concentration)
6. Response Time (Seconds)

Gas Standard Material
We use gas standard substances of the same type as the gas measured by the instrument, such as methane or ethane, or gas standards can also use isopropanol, etc. If the instrument does not indicate the type of gas being measured, the concentration of the gas at the set point is approximately 60% of the full scale, using a standard substance. The expanded uncertainty of the standard gas generating gas is not significant (%), and the standard gas standard substance is greater than ±1%. The flow indication error of the repetitive dilution device should not be greater than 0.%. The concentration unit of the dilution device for standard gas standard substances should be converted to the same as the indicating unit of the tested instrument when in use.
Shenzhen Zhongnuo Testing Technology Co., Ltd. is a third-party institution specializing in electrical safety, electrical explosion-proof services, including regular inspections, metrological measurements, and calibrations for gas detectors and toxic/hazardous gas alarm instruments. We hold the necessary qualifications to assist clients in addressing fire and explosion prevention issues.