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 concerns, and contributing to safe production.
Measurement Instrument Control
Instrument control includes calibration, follow-up calibration, and in-service inspection.

The calibration cycle for flammable gas detectors is typically once a year.
According to the standard JJG 693-2011 "Flammable Gas Detector Alarms," the calibration cycle for flammable gas detectors typically does not exceed 1 year. This means that under normal circumstances, a comprehensive calibration and test of the flammable gas detector should be conducted annually to ensure its performance meets the relevant requirements.

What factors can affect the calibration cycle of a combustible gas detector alarm?
Manufacturer Requirements: Different manufacturers may have varying inspection cycle requirements for flammable gas detectors. Therefore, when purchasing equipment, it's crucial to carefully review the product manual to understand the specific requirements of the manufacturer.
Equipment Operating Environment: The operating environment of the alarm directly affects its inspection cycle. If the equipment is exposed to a high concentration of harmful gases, high humidity, or extreme temperatures (either high or low) for an extended period, the inspection cycle may be shortened accordingly.
‌Equipment Maintenance Status: The condition of equipment maintenance is also a significant factor affecting the inspection cycle. If the equipment faces issues like battery depletion or sensor aging over a long period, the inspection cycle will accordingly be shortened.

Key Technical Requirements for Regular Calibration of Combustible Gas Detectors (Shenzhen ZhongNuo Testing 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 Settings: The standard specifies specific alarm value settings for different gases.
For example, the hypoxia alarm set value is 19.5% VOL, and the hyperoxia alarm set value is 23.5% VOL (refer to GB 8958-2006 "Operation Procedures for Hazardous Work of Hypoxia" and GB 30871-2022 "Special Operation Regulations for Hazardous Chemical Enterprises").
The first-level flammable gas alarm set point is not greater than 25% LEL, and the second-level alarm set point 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 Repeatability: The standard specifies clear requirements for the instrument's indication error, drift, and repeatability. For example, 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: Equipment intended for explosive environments should possess explosion-proof characteristics in compliance with relevant regulations and hold an explosion-proof certificate.
7. Audio-Visual Alarm Device: The audio-visual alarm device 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 the exhaust system, etc.
9. Power Requirements: Specific requirements for power supply voltage, continuous operating time, etc., are set for battery-powered and non-battery-powered instruments.
10. Additional Performance Requirements: Including requirements for bearing, 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 resistance, and functionality.
Shenzhen Zhongnuo Testing Technology Co., Ltd. is a third-party institution specializing in electrical safety, electrical explosion-proofing, gas alarms, and toxic and harmful gas detection instruments for regular calibration, measurement, and verification services. We are qualified to address fire and explosion prevention issues for our clients.