Shenzhen ZhongNuo Testing Technology Co., Ltd. specializes in the calibration, verification, and measurement services for gas alarms, combustible gas detectors, toxic and harmful gas detectors, and other equipment in various locations. We hold the necessary qualifications to serve nationwide, addressing clients' electrical safety and explosion-proof fire prevention issues, and contributing to safe production.
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.

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 an additional manual self-check function for alarm components.
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: The standard specifies specific alarm value settings for different gases.
For example, the oxygen deficiency alarm setpoint is 19.5% VOL, and the oxygen enrichment alarm setpoint is 23.5% VOL (refer to GB 8958—2006 "Operation Code for Oxygen Deficiency Hazardous Operations," GB 30871—2022 "Special Operations Code for Chemical Hazardous 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 the 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 a set calibration program and corresponding interface to ensure the accuracy of its measurement results.
6. Explosion-proof Performance: Equipment for explosive environments must have explosion-proof performance in accordance with relevant regulations and obtain an explosion-proof certification.
7. Audio-Visual Alarm Devices: The audio-visual alarm devices of the alarm should meet specific visibility and sound pressure level requirements to ensure 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 Supply Requirements: Specific requirements are outlined for the supply voltage, continuous operating time, etc., of both 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, electromagnetic interference resistance, steam interference resistance, vibration and drop, and functionality.

Regular Testing Content and Methods for Flammable Gas Detectors
Annual inspections of industrial and commercial alarm sensors are conducted regularly, primarily to check if the alarm sensors' indication errors, repeatability, drift, and response times comply with standards. Additionally, the suitability of the alarm sensor's installation location and any interference from other equipment are inspected.

Which gas detectors require regular calibration and verification?
Fixed-install, handheld, and portable gas detectors, gas alarm instruments, toxic and harmful gas detectors/alarm systems, flammable gas detectors with alarms, gas analyzers, etc.
Shenzhen ZhongNuo Testing Technology Co., Ltd. is a third-party institution specializing in electrical safety, electrical explosion-proof, gas alarm, and toxic and harmful gas alarm instrument calibration, regular inspections, and metrological services, providing qualifications to solve fire and explosion prevention issues for clients.