Shenzhen ZhongNuo Testing Technology Co., Ltd. specializes in the calibration, verification, and measurement services for gas alarms, flammable gas detectors, toxic and harmful gas detectors, and other equipment in various locations. We hold the necessary qualifications to serve nationwide, providing solutions to electrical safety and explosion-proof fire prevention issues for our clients, and contributing to safe production.
Measurement Instrument Control
Instrument control includes calibration, follow-up calibration, and in-service inspection.

Regular Inspection Content for Gas Alarm Systems
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)

Key Technical Requirements for Regular Calibration of Flammable Gas Detectors (Shenzhen ZhongNuo Inspection Technology Co., Ltd.)
1. Power-On Self-Check Function: The instrument should have an automatic self-check function upon startup, with a manual self-check function for alarm components as well.
2. Specify the effective detection distance: The effective detection distance of the non-contact gas alarm instrument shall not be less than 20 m.
3. Alarm Value Setting: Specific alarm value settings are stipulated for different gases according to the standard.
For example, the oxygen deficiency alarm setting is 19.5% VOL, and the high-oxygen alarm setting is 23.5% VOL (refer to GB 8958-2006 "Operation Procedures for Oxygen Deficiency Hazardous Work" and GB 30871-2022 "Special Operation Regulations for Hazardous Chemical Enterprises").
The first-level flammable gas alarm setpoint is not greater than 25% LEL, and the second-level alarm setpoint is not greater than 50% LEL.
The first and second level alarm settings for toxic and harmful gases are determined based on OEL (Occupational Exposure Limit) or IDLH (Immediate Danger to Life and Health).
4. Error and Repetition: The standard specifies clear requirements for the instrument's indication error, drift, and repeatability. For instance, the indication error for combustible gases, toxic and harmful gases, and oxygen should not exceed 5% FS, 5% FS, and 2% FS respectively within the normal test range of the instrument's full scale.
5. Calibration and Interface: The instrument should be easy to calibrate, with established calibration procedures and corresponding interfaces to ensure the accuracy of its measurement results.
6. Explosion-proof Performance: Instruments used in explosive environments must possess explosion-proof performance in accordance with relevant regulations and obtain an explosion-proof certificate.
7. Sound and Light Alarm Devices: The sound and light alarm devices of the alarm should meet visibility and sound pressure level requirements under specific conditions, ensuring effective alerting of staff during emergencies.
8. Output Control Function: Instruments with output control capabilities should be able to activate the output control function upon emitting an alarm signal, such as cutting off power supply or initiating an exhaust system, etc.
9. Power Requirements: Specific requirements are outlined for the supply voltage, continuous operating time, etc., of battery-powered and non-battery-powered instruments.
10. Other Performance Requirements: Including requirements for azimuth, response time, full-scale indication error, high-speed airflow, long-term stability, insulation withstand voltage performance, temperature, constant humidity and heat, resistance to electromagnetic interference, resistance to steam interference, vibration and drop, and functionality.

Appearance and structure
The instrument should not have any appearance damage that affects its normal operation. The surface of newly manufactured instruments should be smooth and clean, with a uniform paint and coating without any peeling or 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, manufacturing date, serial number, explosion-proof marking and number, as well as the manufacturing metrological instrument license mark and number for domestic instruments should be clear.
Shenzhen Zhongnuo Testing Technology Co., Ltd. is a third-party institution providing regular certification, metrological testing, and calibration services for electrical safety, electrical explosion-proofing, gas alarms, and toxic/hazardous gas alarm instruments. We hold the necessary qualifications to address fire and explosion prevention issues for our clients.