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 for various locations. We serve nationwide, addressing clients' electrical safety and explosion-proof fire prevention concerns, and contributing to safe production.
Gas Standard Material
We use gas standard substances with 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 alarm set point is approximately 60% of the full scale. The uncertainty of the expanded gas standard substance is not significant (%). The standard gas concentration should not exceed 0.1% of the repeatability dilution device's flow indication error. The concentration unit of the dilution device for gas standard substances should be converted to match the measurement unit of the tested instrument, and it should not be greater than 0.1%.

Appearance and structure
The instrument should not have any surface damage that affects its normal operation. The surface of newly manufactured instruments should be smooth and glossy, with even paint and plating coatings, free of peeling and rusting.
The instrument's connections are reliable, and all dials or buttons should operate and control normally.
Logos and Branding
Instrument name, model, manufacturer's name, date of manufacture, serial number, explosion-proof marking and number, as well as the manufacturing metrological instrument license marking and number for domestic instruments, should be clear.

Regular inspection contents for gas alarm detectors
Installation spacing of inspection (testing) points
2. Installation Height of the Detector
3. Indication Error (Concentration)
4. Repeatability (Concentration)
5. Alarm Error (Concentration)
6. Response Time (Seconds)

Routine Inspection Items for Environmental Gas Detection and Alarm Equipment in Workplaces:
1. Alarm sound and light (if applicable)
2. Low response value
3. Indicated Error (for Gas Detectors/Gas Detector Alarms)
4. Instrument Drift (in Portable Instruments)
5. Alarm Error (for Gas Detection Alarm/ Gas Alarm)
6. Pump-actuated instrument gas collection distance and flow rate (for pump-actuated instruments)
7. Power Supply (for battery-powered instruments)
8. Response Time
9. Status Indicator (with Wireless Communication Function)
Shenzhen ZhongNuo Testing Technology Co., Ltd. is an independent third-party service provider specializing in electrical safety, electrical explosion prevention, gas alarms, and toxic/hazardous gas alarm instrument calibration, regular verification, and metrological services, with qualifications to assist customers in addressing fire and explosion prevention issues.