Shenzhen Zhongnuo Testing Technology Co., Ltd. specializes in the certification, calibration, and metrological services for gas alarms, flammable gas detectors, and toxic and harmful gas detectors at various locations. We hold qualifications to serve nationwide, addressing electrical safety and explosion-proof fire prevention issues for clients, and contributing to safe production.
Regulatory Content and Methods for Regular Inspection of Combustible 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 in compliance with standards. Additionally, the suitability of the alarm system's installation location and any interference from other equipment are assessed.

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 a uniform paint and plating layer, free of peeling and rusting.
The instrument's connections are reliable, and all knobs or buttons should operate and control normally.
Logos and Branding
Instrument name, model, manufacturer's name, date of manufacture, serial number, explosion-proof marking and number, as well as the manufacturing metrological instrument license marking and number for domestically manufactured instruments should be clear.

Power-on inspection
After power is applied to the instrument, it should operate normally with clear and complete display. Check the alarm function and alarm action values.
Alarm function and alarm action value verification
The instrument's acoustic and visual alarms should function normally. Insulation resistance
Insulation resistance for instruments using AC power should not be less than 20MΩ.

Gas Standard Material
The gas standard substance used should be of the same type as the gas measured by the instrument, such as methane or ethane, or a gas standard can be isopropanol, etc. If the instrument does not specify the type of gas being measured, the concentration of the gas at the alarm set point is approximately 60% of the full scale. The uncertainty of the expanded gas standard substance is not more than % (k-1 standard substance greater than ±1%). The flow indication error of the repetitive dilution device should not be greater than 0.%. The concentration unit of the gas standard substance diluted by the dilution device should be converted to the unit of the instrument being tested when in use, and the unit should not be greater than 0.%.
Shenzhen ZhongNuo Testing Technology Co., Ltd. is a third-party institution that specializes in electrical safety, electrical explosion-proofing, gas alarms, and toxic gas detection equipment for regular inspections, calibration, and metrological services. We provide资质 to help clients address fire and explosion prevention issues.