Shenzhen Zhongnuo Testing Technology Co., Ltd. specializes in the calibration, verification, and measurement services for gas alarms, flammable gas detectors, toxic and harmful gas detectors, and other equipment in various locations. We hold qualifications to serve nationwide, addressing all sorts of electrical safety and explosion-proof fire prevention issues for our clients, and contributing to safe production.
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 clean, with even paint and plating coatings, and free from peeling and rusting.
The instruments are reliably connected, and all dials 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 measurement instrument license marking and number for domestic instruments should be clear.

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 alternative substances like isopropanol can be used. If the instrument does not specify the type of gas being measured, the concentration of the gas, such as methane, ethane, or ethylene, at the set point should be approximately 60% of the full scale. The expanded uncertainty of the standard gas may not be more than % (the expanded uncertainty of the gas standard substance should be 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 should be converted to match the indicating unit of the tested instrument when in use.

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 Usage Environment: The operating environment of the alarm directly affects its inspection cycle. If the equipment is continuously 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 like battery depletion or sensor aging over a long period, the inspection cycle will accordingly be shortened.

Gas Alarm Meter Calibration: Conditions and Requirements
Environmental Conditions
Ambient Temperature: 0~40℃.
2. Relative Humidity: ≤85%
3. The working environment should not interfere with the normal operation of the instrument by electromagnetic fields and interfering gases.
Calibration Tools and Instruments
1) Standard Gas Substance
The relative expanded uncertainty of the gas standard material does not exceed 2% (k=2).
2) Standard Gas Dilution Unit: Dilution Error of 1%.
3) Stopwatch: Graduation not greater than 0.1s.
4) Flow Control: Flow range not less than 500 mL/min, flow grade not less than level 4.
5) Zero Point Gas: Purified compressed air.
6) Pressure Reducing Valve: A pressure reducing valve that matches with the calibrated cylinder.
7) Gas Pipeline: Tubing made of materials like polytetrafluoroethylene or stainless steel that do not affect the concentration of the measured gas.
Shenzhen Zhongnuo Testing Technology Co., Ltd. is a third-party institution specializing in electrical safety, electrical explosion-proofing, gas alarm systems, and toxic and harmful gas alarm instruments for regular inspections, metrological measurements, and calibration services. We are qualified to address fire and explosion prevention issues for our clients.