Shenzhen ZhongNuo Testing Technology Co., Ltd. specializes in the calibration, verification, and measurement services of equipment such as gas alarms, combustible gas detectors, and toxic gas detection instruments for various locations. We hold qualifications to serve nationwide, addressing a range of electrical safety and explosion-proof fire prevention issues for clients, and contributing to safe production.
Standard for calibration and verification of flammable and toxic gas detectors:
GB/T 50493-2019 "Design Standard for Detection and Alarm Systems of Combustible and Toxic Gases in Petroleum and Chemical Industries"
GB12358-2006 General Technical Requirements for Environmental Gas Detection and Alarm Instruments in Workplace
JJG693-2011规程 for the Verification of Combustible Gas Detectors and Alarms

Gas Detector Alarm Calibration Standard Requirements
"Article 5.5 of the "Regulation for Verification of Flammable Gas Detectors" (JJG693-2011) states: The verification cycle for flammable gas detection and alarm instruments: the verification cycle of the instrument shall generally not exceed one year. If there is any suspicion about the instrument's measurement data, or if the instrument has been replaced with major components or repaired, it should be submitted for verification promptly."
Section 3.5 of "Regulations for the Use of Combustible Gas Detection and Alarm Systems" (SY6503-2000) stipulates: Combustible gas detection and alarm systems in use shall be calibrated regularly as per regulations.
Occupational Health Service - Technical Regulations for the Installation of Toxic Gas Devices (GBZ/T223-2009) Article 7.2.1 stipulates: Calibration of detection and alarm devices should be carried out regularly according to the manufacturer's specified time and procedures.
Regulation 3.4 of the "Standard for the Use of Flammable Gas Detectors and Alarms" (SY6503-2000) stipulates that flammable gas detectors and alarms for installation and use should have measuring instruments manufactured by recognized institutions with **metering** and **explosion-proof** performance.

Gas Standard Material
We use gas standard substances of the same type as the gas measured by the instrument, such as methane or ethane, or gas standards can also use isopropanol, etc. If the instrument does not specify the type of gas being measured, the concentration of the gas at the set point, such as methane, ethane, or警设定点, is approximately 60% of the full-scale. The uncertainty of the expanded gas standard substance is not more than % (k-Body standard substance greater than ±1%). The flow indication error of the repetitive dilution device should not be higher than the concentration of the gas standard substance. The concentration unit of the dilution device for the gas standard substance should be converted to the same unit as the measuring instrument when in use, and the deviation should not be greater than 0.%.

Gas alarm regular inspection content
Installation spacing of inspection (probe) points
2. Installation Height of the Detector
3. Indicated Error (Concentration)
4. Repeatability (Concentration)
5. Alarm Error (Concentration)
6. Response Time (seconds)
Shenzhen ZhongNuo Inspection Technology Co., Ltd. is a third-party institution that provides regular calibration, measurement, and certification services for electrical safety, electrical explosion-proofing, gas alarms, and toxic/hazardous gas detectors. We have the资质 to address fire and explosion prevention issues for our clients.