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 at various locations. We hold the necessary qualifications to serve nationwide, addressing all sorts of electrical safety and explosion-proof fire prevention issues for our clients, and contributing to safe production.
GB 12358-2024 "General Technical Requirements for Environmental Gas Detection and Alarm Instruments in Workplace" is an important standard.
Intended to standardize the performance, functions, and testing methods of environmental gas detection and alarm instruments used in work sites.
The standard was issued in 1990 and has undergone several revisions.
The new version is GB 12358—2024, which will be officially implemented on June 1, 2025.
This standard applies to the production and use of detection and alarm instruments for flammable gases, toxic and harmful gases, and oxygen in workplaces.

Gas Alarm Meters Calibration Conditions and Requirements
Environmental Conditions
Ambient Temperature: 0~40℃.
2. Relative Humidity: ≤85%
3. The working environment should not affect the normal operation of the instrument with electromagnetic fields and interfering gases.
Inspection Gauges and Instruments
1) Standard Gas Material
The relative expanded uncertainty of the gas standard substance does not exceed 2% (k=2).
2) Standard Gas Dilution Device: Dilution Error of 1%
3) Stopwatch: Graduation not greater than 0.1s.
4) Flow Control: Flow rate not less than 500 mL/min, flow grade not less than level 4.
5) Zero Point Gas: Purified compressed air.
6) Pressure Relief Valve: A pressure relief valve that matches with the calibrated cylinder.
7) Gas Pipeline: Tube made of materials like polytetrafluoroethylene or stainless steel, which do not affect the concentration of the tested gas.

Combustible Gas Detector Alarm Regular Inspection Content and Methods
Annually, we conduct annual inspections on the sensors of industrial and commercial alarm systems, primarily checking for measurement errors, repeatability, drift, and response time to ensure they comply with standards. Additionally, we verify the appropriateness of the alarm system's installation location and check for interference from other equipment.

How often should various gas detectors be periodically calibrated and tested?
The recalibration time for instruments is typically 1 year, to be determined by the submitting unit based on actual usage. During the secondary calibration process, if there are doubts about the instrument's test data, or if the main components of the instrument are replaced, as well as after repairs, a re-calibration is required.
Shenzhen Zhongnuo Testing Technology Co., Ltd. is an independent third-party service provider specializing in electrical safety, electrical explosion-proofing, gas alarm systems, and toxic/hazardous gas detection instruments. We offer regular inspections, measurements, and calibrations, as well as qualifications to assist clients in addressing fire and explosion prevention issues.