Shenzhen ZhongNuo Testing Technology Co., Ltd. specializes in the calibration, verification, and measurement services for gas alarms, combustible gas detectors, and toxic gas analyzers for various locations. We hold the necessary qualifications to serve nationwide, addressing electrical safety and explosion-proof fire prevention issues for clients, and contributing to safe production.
Combustible Gas Detector Alarm Regular Inspection Content and Methods
Annual inspections of industrial and commercial alarm sensors are conducted regularly, primarily to check for the accuracy, repeatability, drift, and response time of the alarms against standards. Additionally, the suitability of the alarm installation location and any interference from other equipment are also assessed.

Key Technical Requirements for Regular Calibration of Flammable Gas Detectors (Shenzhen ZhongNuo Testing Technology Co., Ltd.)
1. Self-check Function at Startup: The instrument should have an automatic self-check feature upon startup, and a manual self-check function should also be set for the 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 Code for Hypoxia Hazardous Work" and GB 30871-2022 "Special Operation Code for Hazardous Chemical Enterprises").
The first-level combustible gas alarm setpoint does not exceed 25% LEL, and the second-level alarm setpoint does 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, with established calibration procedures and corresponding interfaces 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 cutting off power supply or initiating the 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 bearing, 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 functionality.

Appearance and structure
The instrument should not have any appearance damage that affects its normal operation. The surface of newly manufactured instruments should be smooth and glossy, with an even paint and plating coating, free of peeling or rusting.
The instrument's connections are reliable, and all dials or buttons should operate and control normally.
Logos and branding
Instrument name, model, manufacturer, production date, serial number, explosion-proof markings and numbers, as well as the manufacturing measurement instrument license mark and number for domestic instruments should be clear.

What factors can affect the calibration cycle of a combustible gas detector alarm?
Manufacturer Requirements: Different manufacturers may have varying inspection cycle requirements for flammable gas detectors. Therefore, when purchasing equipment, carefully review the product manual to understand the specific requirements of the manufacturer.
Equipment Operating Environment: The operating environment of the alarm can directly affect its inspection cycle. If the equipment is frequently exposed to high concentrations of harmful gases, high or low humidity, or high or low temperatures, its inspection cycle may be accordingly shortened.
‌Equipment Maintenance Status: The condition of equipment maintenance is also a significant factor affecting the inspection cycle. If the equipment faces issues such as battery depletion and sensor aging over a long period, the inspection cycle will accordingly be shortened.
Shenzhen ZhongNuo Testing Technology Co., Ltd. is a third-party institution specializing in electrical safety, electrical explosion prevention, gas alarm systems, and toxic and harmful gas alarm instruments for regular verification, measurement, and calibration services. We are qualified to provide solutions for fire and explosion prevention issues for our clients.