Shenzhen ZhongNuo Testing Technology Co., Ltd. specializes in the calibration, certification, and measurement services for gas alarms, flammable gas detectors, and toxic gas monitors for various locations, offering solutions to electrical safety and explosion-proof fire prevention issues across the country, contributing to safe production.
Regulatory content for periodic calibration of gas detectors
Installation spacing of inspection points
2. Installation Height of the Detector
3. Indication Error (Concentration)
4. Repeatability (Concentration)
5. Alarm Error (Concentration)
6. Response Time (Seconds)

Calibration Method
Appearance and structure
Inspect and feel according to the requirements of 4.1
Logos and Branding
Inspection to be conducted in accordance with 4.2 requirements.
Power-on inspection
Inspect visually and by touch in accordance with the requirements of 4.3 to check the 5.3.4 alarm function and alarm action values.
Introduce a standard gas substance with a concentration exceeding the alarm set point, causing the instrument to trigger an alarm. Observe whether the instrument's sound and light alarm functions normally and record the instrument's reading when the alarm is triggered. 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 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 the alarm components also requiring a manual self-check function.
2. Specified Effective Detection Distance: The effective detection distance of non-contact gas detectors shall not be less than 20 m.
3. Alarm Value Setting: For different gases, the standard specifies specific alarm value settings.
For example, the oxygen deficiency alarm setpoint is 19.5% VOL, and the high-oxygen alarm setpoint is 23.5% VOL (refer to GB 8958-2006 "Operation Procedures for Oxygen Deficiency Hazardous Operations" and GB 30871-2022 "Special Operation Regulations for Hazardous Chemical Enterprises").
The first-level combustible gas alarm setpoint does not exceed 25% LEL, and the second-level alarm setpoint does not exceed 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 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 be equipped with calibration programs and corresponding interfaces 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 audio-visual alarm device of the alarm should meet 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 or initiating an 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: Includes specifications for direction, response time, full-scale indication error, high-speed airflow, long-term stability, insulation voltage resistance, temperature, constant humidity and heat, electromagnetic interference resistance, steam interference resistance, vibration and drop, and functional aspects.

What information is included in the calibration report for a combustible gas detector?
The verification results should be reflected in the verification certificate or report, and the verification proof or report must include the following information.
① Calibration Certificate or Calibration Report
② Laboratory Name and Address;
③ Calibration Location (if not calibrated in the laboratory)
④ Certificate or report (e.g., with serial number), indicating each page and the total number of pages;
Please provide the company name and address for shipment.
⑥ Describe and clearly identify the school target.
Calibration date and receipt date;
⑧ Technical specifications for calibration foundation, including names and codes;
Description of traceability and validity of the measurement standards used for calibration.
⑩ Description of Calibration Environment
11. Calibration Results and Measurement Uncertainty Statement
12. Signature, title, or equivalent emblem of the issuer of the calibration certificate or calibration report, and the issuance date;
13. Calibration results are only applicable to the calibration object.
14. No part of the certificate or report may be copied without written consent from the laboratory.
Re-review interval
The recalibration period for instruments is typically one year, determined by the submitting unit based on actual usage. During the re-certification 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 required after repair.
Shenzhen Zhongnuo Testing Technology Co., Ltd. is a third-party institution specializing in electrical safety, electrical explosion-proofing, gas detectors, and toxic gas alarm instruments, providing regular inspections, metrological measurements, and calibration services. We hold the necessary qualifications to assist customers in addressing fire and explosion prevention issues.