Shenzhen ZhongNuo Testing Technology Co., Ltd. specializes in the calibration, verification, and metrological services for gas alarms, combustible gas detectors, toxic and harmful gas detectors, and other equipment in various locations. We hold qualifications to serve nationwide, addressing clients' electrical safety and explosion-proof fire prevention issues, and contributing to safe production.
Power-on inspection
The instrument should operate normally after being powered on, with the display sections clear and complete. Check the alarm function and the alarm action values.
Alarm function and alarm action value verification
The instrument's sound and light alarm should be functioning normally. Insulation resistance
Insulation resistance for equipment using AC power should not be less than 20MΩ.

Regular inspection items for environmental gas detection and alarm equipment in work场所:
Alarm sound and light (if applicable)
2. Small response value
3. Indication Error (for Gas Detectors/Gas Detector Alarms)
4. Instrument Drift (in portable instruments)
5. Alarm Error (for Gas Detector/ Gas Alarm)
6. Pump-suction Instrument Gas Sampling Distance and Flow Rate (for Pump-suction Instruments)
7. Power Supply (for battery-operated instruments)
8. Response Time
9. Status Indicator (with Wireless Communication Function)

What factors influence the calibration cycle of combustible gas detectors?
Manufacturer Requirements: Different manufacturers may have varying inspection cycle requirements for their flammable gas detectors. Therefore, when purchasing equipment, 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 frequently exposed to high concentrations of harmful gases, high or low humidity, or extreme temperatures, its 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 Inspection Technology Co., Ltd.)
1. Self-check function upon startup: The instrument should have an automatic self-check function upon startup, and a manual self-check function should be set 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 hypoxia alarm setting is 19.5% VOL, and the hyperoxia 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: Equipment used in explosive environments must have explosion-proof performance in compliance with relevant regulations and obtain an explosion-proof certificate.
7. Audio-Visual Alarm Device: The alarm's audio-visual alarm device must meet visibility and sound pressure level requirements under specific conditions to ensure effective notification to 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 are set for the supply voltage, continuous operating time, etc., for 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.
Shenzhen ZhongNuo Testing Technology Co., Ltd. is an independent third-party institution specializing in electrical safety, electrical explosion prevention, gas detectors, and toxic/hazardous gas alarm instrument calibration, regular inspections, and metrological services, offering solutions to fire and explosion prevention issues for customers.