Shenzhen ZhongNuo Testing Technology Co., Ltd. specializes in the calibration, certification, and metrological services for gas alarms, combustible 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 clients, and contributing to safe production.
Primary Technical Requirements for Regular Calibration of Combustible 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 manual self-check capabilities for alarm components as well.
2. Specified effective detection distance: The effective detection distance of the non-contact gas alarm instrument shall not be less than 20 meters.
3. Alarm Value Setting: The standard specifies specific alarm value settings for different gases.
For example, the oxygen deficiency alarm setting is 19.5%VOL, and the oxygen-rich alarm setting is 23.5%VOL (refer to GB 8958-2006 "Operation Procedures for Oxygen Deficiency Hazardous Operations," 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 Repeatability: The standard specifies clear requirements for the instrument's indication error, drift, and repeatability. For example, the indication error for flammable 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, and calibration programs and corresponding interfaces should be set up to ensure the accuracy of its measurement results.
6. Explosion-proof Performance: Equipment used in explosive environments should have explosion-proof performance in compliance with relevant regulations and obtain an explosion-proof certification.
7. Sound and Light Alarm Devices: The sound and light alarm devices of the alarm should meet specific visibility and sound pressure level requirements to ensure effective alerting of staff in emergency situations.
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 or initiating an exhaust system, etc.
9. Power Requirements: Specific requirements are set for the power voltage, continuous operating time, etc., for battery-powered and non-battery-powered instruments.
10. Additional Performance Requirements: Includes specifications for bearing, response time, full-scale indication error, high-speed airflow, long-term stability, insulation withstand voltage, temperature, constant humidity and heat, electromagnetic interference resistance, steam interference resistance, vibration and drop, and functional aspects.

Routine Inspection Items for Environmental Gas Detection and Alarm Equipment in Workplaces:
Alarm sound and light (if applicable)
2. Low response value
3. Indicating 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-operated instruments)
8. Response Time
9. Status Indicator (with Wireless Communication Function)

Regular Calibration Content for Gas Detectors
Installation spacing of testing points
2. Installation Height of the Detector
3. Indicated Error (Concentration)
Repetitive (Concentration)
5. Alarm Error (Concentration)
6. Response Time (Seconds)

The calibration cycle for flammable gas detectors is typically once a year.
In accordance with the standard JJG 693-2011 "Flammable Gas Detectors," the calibration cycle for flammable gas detectors generally does not exceed one year. This means that under normal circumstances, a comprehensive calibration and testing of the flammable gas detectors should be conducted annually to ensure their performance meets the relevant requirements.
Shenzhen Zhongnuo Testing Technology Co., Ltd. is a third-party service provider specializing in electrical safety, electrical explosion-proofing, gas alarms, and toxic and harmful gas alarm instruments for regular verification, metrological calibration, and other services, qualified to address fire and explosion prevention issues for clients.