Shenzhen ZhongNuo Testing Technology Co., Ltd. specializes in the calibration, certification, and metrological services for gas alarms, flammable gas detectors, toxic and harmful gas detectors, and other equipment at various locations. We provide services nationwide, addressing electrical safety and explosion-proof fire prevention issues for customers, and contributing to safe production.
Standard for certification and metrological calibration of flammable and toxic gas detectors:
GB/T 50493-2019 "Design Standard for Detection and Alarm of Combustible and Toxic Gases in Petroleum and Chemical Industries"
GB12358-2006 General Technical Requirements for Environmental Gas Detection and Alarm Instruments in Workplaces
JJG693-2011规程 for the Verification of Combustible Gas Detectors and Alarms

Gas Standard Material
We use gas standard substances with the same type of gas as the instrument measures, 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 at the alarm set point should be approximately 60% of the full scale. The expanded uncertainty of the standard gas generating gas is not significant (%), and the standard gas substance should have a repeatability of more 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 measurement unit of the inspected instrument when in use.

Calibration Method
Appearance and structure
Inspect visually and by touch according to the requirements of 4.1
Logos and Branding
Inspect according to the requirements of 4.2 using visual inspection.
Power-on inspection
Inspect visually and by touch, checking the alarm function and alarm action values according to the requirements of 4.3.
Introduce a standard substance of gas with a concentration greater than the alarm setting point, causing the instrument to trigger an alarm. Observe if the instrument's sound and light alarms are functioning properly and record the readings at the time of the alarm. Repeat the measurement three times; the arithmetic mean of the three readings is the instrument's alarm trigger value.

Gas Detector Alarm Calibrator Specification Requirements
Regulation 5.5 of the "Regulation for the Verification of Combustible Gas Detectors" (JJG693-2011) stipulates: The verification cycle for combustible gas detection and alarm instruments: Generally, the verification cycle of the instrument should not exceed one year. If there is any doubt about the measurement data of the instrument, or if the instrument has been replaced with major components or repaired, it should be promptly sent for verification.
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 required.
Occupational Health Service Station Toxic Gas Device Installation Specification (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.
Section 3.4 of the "Regulations for the Use of Combustible Gas Detectors" (SY6503-2000) stipulates: Combustible gas detectors for installation and use shall have measurement instruments manufactured by an institution recognized for their**explosion-proof performance**.
Shenzhen Zhongnuo Testing Technology Co., Ltd. is an independent third-party institution specializing in electrical safety, electrical explosion prevention, gas alarm, and toxic and harmful gas alarm instrument regular calibration, measurement, and certification services. We provide qualifications to help customers address fire and explosion prevention issues.