Shenzhen Zhongnuo Testing Technology Co., Ltd. specializes in the calibration, certification, and measurement services for gas alarms, flammable gas detectors, toxic gas analyzers, and other equipment in various locations. We are licensed to serve nationwide, providing solutions to electrical safety and explosion-proof fire prevention issues for clients, promoting safe production.
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 (e.g., methane, ethane, etc.) set at the alarm point is approximately 60% of the full scale. The uncertainty of the expanded gas standard substance is not significant (%). The repeatability of the dilution device's flow indication error should not be greater than 0.1%. The concentration unit of the dilution gas standard substance should be converted to match the unit of the tested instrument when in use, and the difference should not exceed 0.1%.

Verification Method
Appearance and structure
Inspect and feel according to requirements of Section 4.1
Logos and branding identifiers
Inspection to be conducted according to the requirements of Section 4.2.
Power-on inspection
Inspect visually and by touch, checking the alarm function and alarm action values as per the 4.3 requirements.
Introduce a standard substance of gas at a concentration greater than the alarm set point, causing the instrument to trigger an alarm. Observe if the instrument's audio-visual alarm is functioning properly and record the instrument's reading 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.

Standard for inspection and calibration of flammable and toxic gas detectors:
Standard GB/T50493-2019 "Design Standard for Detection and Alarm Systems of Combustible Gases and Toxic Gases in Petroleum and Chemical Industries"
GB12358-2006 General Technical Requirements for Environmental Gas Detection and Alarm Instruments in Workplaces
JJG 693-2011 "Regulation for Calibration of Combustible Gas Detectors"

Gas Alarm Detector 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 Testing Technology Co., Ltd. is a third-party service provider specializing in electrical safety, electrical explosion-proofing, gas detectors, and toxic gas alarm instruments, offering regular inspections, metrological measurements, and calibration services. We are qualified to assist clients in solving fire and explosion prevention issues.