Shenzhen ZhongNuo Testing Technology Co., Ltd. specializes in the calibration, verification, and measurement services for equipment such as gas alarms, flammable gas detectors, and toxic gas analyzers for various locations. We hold the necessary qualifications to serve nationwide, providing solutions for electrical safety and explosion-proof fire prevention issues, and contributing to safe production.
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 manual self-check capabilities 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 Setting: Specific alarm value settings are stipulated for different gases in accordance with the standard.
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 Regulations for Hypoxia Hazardous Work," 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, and calibration programs and corresponding interfaces should be set up to ensure the accuracy of its measurement results.
6. Explosion-proof Performance: Instruments used in explosive environments must have 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 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 outlined for the supply voltage, continuous operating time, etc., for battery-powered and non-battery-powered instruments.
10. Other Performance Requirements: Including specifications for azimuth, 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.

Gas Detector Alarm Calibration Specification Requirements
Regulation 5.5 of the "Procedures for Verification of Combustible Gas Detectors" (JJG693-2011) stipulates: The verification cycle for combustible gas detection and alarm instruments: generally, the verification cycle of the instrument should not exceed one year. If there is any doubt about the instrument's measurement data, or if the instrument has been replaced with major components or repaired, it should be promptly submitted for verification.
Section 3.5 of the "Regulations for the Use of Combustible Gas Detection and Alarm Systems" (SY6503-2000) stipulates: Combustible gas detection and alarm systems in use shall be calibrated regularly as per regulations.
Occupational Health Service Establishment Code for Toxic Gas Facilities (GBZ/T223-2009) Article 7.2.1 stipulates: Calibration of detection and alarm devices shall be carried out regularly according to the manufacturer's specified time and procedures.
Section 3.4 of the "Regulations for the Use of Combustible Gas Detectors" (SY6503-2000) stipulates: Combustible gas detectors for installation and use shall have measurement instruments manufactured by an institution recognized for their**explosion-proof performance**.

The detection principle of the instruments mainly includes catalytic combustion, infrared absorption, and thermal conductivity types. The sampling methods are diffusion and aspiration. The instruments are primarily composed of detection elements, amplification circuits, alarm systems, and displays, used for monitoring the concentration of combustible gases in the environment.

Standard for inspection and metrological calibration of flammable and toxic gas detectors:
GB/T 50493-2019 "Design Standard for Detection and Alarm of Combustible Gases and Toxic Gases in Petroleum and Chemical Industry"
GB12358-2006 General Technical Requirements for Environmental Gas Detection and Alarm Instruments in Workplace
JJG693-2011 "Regulation for Calibration of Combustible Gas Detectors"
Shenzhen ZhongNuo Testing Technology Co., Ltd. is a third-party institution specializing in electrical safety, electrical explosion prevention, gas alarm systems, and toxic gas detection equipment for regular inspections, metrological services, and calibration. We are licensed to help clients address fire and explosion prevention issues.