Shenzhen ZhongNuo Testing Technology Co., Ltd. specializes in the calibration, verification, and measurement services for equipment such as gas alarms, combustible gas detectors, and toxic gas analyzers in various locations. We hold the necessary qualifications to serve nationwide, providing solutions for electrical safety and explosion-proof fire prevention issues, and contributing to safe production.
Gas Alarm Detector Regular Inspection Content
Installation spacing of testing points
2. Installation Height of the Detector
3. Indicated Error (Concentration)
4. Repeatability (Concentration)
5. Alarm Error (Concentration)
6. Response Time (seconds)

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 be expanded with isopropanol, etc. If the instrument does not specify the type of gas being measured, the concentration of the gas at the set point (e.g., 60% of the full scale) is approximately the concentration of the standard substance. The uncertainty of the expanded gas standard substances is not significant (%). The flow rate indication error of the repetitive dilution device should not be greater than 0.1% for gases with higher concentrations. The concentration unit of the gas standard substances should be converted to match the unit of the inspected instrument during use, and the deviation should not exceed 0.1%.

Verification Method
Appearance and structure
Inspect and feel according to the requirements of 4.1
Logos and branding
Inspection to be conducted in accordance with requirement 4.2.
Power-on Inspection
Inspect visually and by touch according to 4.3 requirements to check the alarm function and alarm action values as per 5.3.4.
Introduce a standard gas substance with a concentration exceeding the alarm set point, causing the instrument to trigger an alarm. Observe whether the instrument's audio-visual alarm is functioning normally and record the instrument's reading at the time of alarm. Repeat the measurement three times; the arithmetic mean of the three readings is the instrument's alarm action value.

Standard for inspection, verification, and calibration of combustible and toxic gas detectors:
GB/T50493-2019 "Design Standard for Detection and Alarm Systems of Combustible and Toxic Gases in Petroleum and Chemical Industry"
GB12358-2006 General Technical Requirements for Environmental Gas Detection and Alarm Instruments in Workplace
JJG 693-2011 "Regulation for Calibration of Combustible Gas Detectors"
Shenzhen Zhongnuo Testing Technology Co., Ltd. is a third-party institution specializing in electrical safety, electrical explosion-proofing, gas detectors, and toxic gas alarm instruments for regular inspections, metrological measurements, and calibration services. We provide qualifications to solve fire and explosion prevention issues for our clients.