Shenzhen Zhongnuo Inspection 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. With qualifications to serve nationwide, we address a range of electrical safety and explosion-proof fire prevention issues for clients, contributing to safe production.
Calibration Method
Appearance and structure
Inspect visually and by touch according to the requirements of Section 4.1
Logos and Branding
Inspection to be conducted as per requirement 4.2.
Power-on Inspection
Inspect visually and by touch, in accordance with requirements 4.3, to check the 5.3.4 alarm function and alarm action values.
Introduce a standard substance with a gas concentration exceeding the alarm set point, causing the instrument to trigger an alarm. Observe if the instrument's audio-visual alarm functions normally and record the readings at the time of the alarm. Repeat the measurement three times, and the arithmetic mean of the three readings is the instrument's alarm trigger value.

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 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: Specific alarm value settings are stipulated by the standard 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 Work" and GB 30871-2022 "Special Operation Regulations for Hazardous Chemical Enterprises").
The first-level combustible gas alarm setting is not greater than 25% LEL, and the second-level alarm setting 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: Instruments used in explosive environments should possess explosion-proof performance in compliance with relevant regulations and obtain an explosion-proof certification.
7. Audio-Visual Alarm Device: The audio-visual alarm device of the alarm should meet the visibility and sound pressure level requirements under specific conditions to ensure effective alerting of staff during emergencies.
8. Output Control Function: Instruments with output control functionality should be capable of initiating the output control function upon emitting an alarm signal, such as cutting off power or activating the exhaust system, etc.
9. Power Requirements: Specific requirements are outlined for the supply voltage, continuous operating time, etc., for battery-powered and non-battery-powered instruments.
10. Additional Performance Requirements: Including requirements for bearing direction, response time, full-scale indication error, high-speed airflow, long-term stability, insulation voltage resistance, temperature, constant humidity and heat, resistance to electromagnetic interference, resistance to steam interference, vibration and shock, and functional aspects.

The calibration cycle for flammable gas detectors is typically once a year.
In accordance with the standard JJG 693-2011 "Flammable Gas Detector Alarms," the calibration cycle for flammable gas alarms typically does not exceed one year. This means that under normal circumstances, a comprehensive calibration and testing of the flammable gas alarms should be conducted annually to ensure their performance meets the relevant requirements.

How often should various gas detectors be periodically calibrated and tested?
Instrument recalibration is typically every 1 year, determined by the submitting unit based on actual usage. During the secondary calibration process, if there are doubts about the instrument's test data, or if the main components of the instrument are replaced, or if recalibration is needed after repair.
Shenzhen ZhongNuo Testing Technology Co., Ltd. is a third-party institution specializing in electrical safety, electrical explosion-proofing, gas alarm systems, and toxic and harmful gas detection instruments. We offer regular inspections, metrological services, and calibrations. Our资质 ensures we provide solutions for fire and explosion prevention issues to our clients.