Shenzhen Zhongnuo Testing Technology Co., Ltd. specializes in the certification, calibration, and metrological services for equipment such as gas alarms, combustible gas detectors, and toxic gas detection instruments for various locations. We hold qualifications to serve nationwide, addressing clients' electrical safety and explosion-proof fire prevention issues, and contributing to safe production.
Gas Detector Alarm Calibration Specification Requirements
Regulation 5.5 of the "Regulation for Calibration of Combustible Gas Detectors" (JJG693-2011) states: The calibration cycle for combustible gas detection and alarm instruments: generally, the calibration cycle of the instrument shall not exceed 1 year. Instruments with suspected measurement data, replaced major components, or repaired should be promptly submitted for calibration.
Section 3.5 of the "Regulations for the Use of Flammable Gas Detection and Alarm Systems" (SY6503-2000) stipulates: Flammable gas detection and alarm systems in use shall be calibrated regularly as per the regulations.
Occupational Health Service - Code for the Installation of Toxic Gas Equipment (GBZ/T223-2009), Article 7.2.1 stipulates: Calibration of detection and alarm devices shall be performed regularly according to the manufacturer's specified time and procedures.
Regulation 3.4 of the "Code for the Use of Combustible Gas Detectors and Alarms" (SY6503-2000) states: Combustible gas detectors and alarms for installation and use shall have measurement instruments manufactured by an approved institution and **explosion-proof performance**.

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 even paint and coating, without any flaking 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 marking and number, as well as the domestic instrument's manufacturing measurement equipment license marking and number, should be clear.

Gaseous Alarm Detector 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.
Calibration Tools and Instruments
1) Certified Reference Materials for Gases
The relative expanded uncertainty of the gas standard substance 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 is compatible with the calibrated cylinder.
7) Gas Pipeline: Tubing made of materials like polyethylene or stainless steel, which do not affect the concentration of the measured gas.

Measurement Equipment Control
Instrument control includes calibration, follow-up calibration, and in-service inspection.
Shenzhen ZhongNuo Inspection Technology Co., Ltd. is a third-party service provider specializing in electrical safety, electrical explosion-proof, gas alarms, and toxic and harmful gas detectors for regular inspections, metrological measurements, and calibration. We are certified to address fire and explosion prevention issues for our clients.