Shenzhen Zhongnuo Inspection Technology Co., Ltd. specializes in the certification, calibration, and metrological services for gas alarms, combustible gas detectors, toxic and harmful gas detectors, and other equipment at various locations. We provide nationwide services with qualifications to address all types of electrical safety and explosion-proof fire prevention issues, facilitating safe production.
GB 12358-2024 "General Technical Requirements for Environmental Gas Detection and Alarm Instruments in Workplaces" is an important standard.
Intended to standardize the performance, functions, and testing methods of environmental gas detection and alarm instruments used in work sites.
The standard was released in 1990 and has undergone several revisions.
The new version is GB 12358—2024, which will be officially implemented on June 1, 2025.
This standard applies to the production and use of detection and alarm instruments for flammable gases, toxic and harmful gases, and oxygen in workplace environments.

What are the contents included in the calibration report for flammable gas detectors?
The verification results should be reflected in the verification certificate or report, and the verification proof or report must include the following information.
Calibration Certificate or Calibration Report
② Laboratory Name and Address;
③ Calibration Location (if not calibrated in the laboratory)
④ Standby Letter of Credit or report (e.g., numbered), with page and total number indicated on each page
Please provide the company name and address for shipping.
⑥ Describe and clearly define the target school;
Calibration date and receipt date;
⑧ Technical specifications for calibration foundation, including names and codes;
Description of the 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 symbol 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.
Two reproofing time intervals
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 repairs.

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

Primary 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, and a manual self-check function should be set for alarm components.
2. Specify Effective Detection Range: The effective detection range of the non-contact gas alarm instrument shall not be less than 20 meters.
3. Alarm Value Setting: Specific alarm value settings are stipulated for different gases in accordance with the standard.
For example, the hypoxia alarm set value is 19.5% VOL, and the oxygen-rich alarm set value is 23.5% VOL (refer to GB 8958-2006 "Operation Procedures for Hypoxia Hazardous Work" and GB 30871-2022 "Special Operation Specifications for Hazardous Chemical Enterprises").
The first-level combustible 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 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 should possess explosion-proof performance in accordance with relevant regulations and obtain an explosion-proof certification.
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 or initiating the exhaust system, etc.
9. Power Requirements: Specific requirements are outlined for the power supply voltage, continuous operating time, etc., for battery-powered and non-battery-powered instruments.
10. Other Performance Requirements: Including requirements for direction, 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 shock, and functional aspects.
Shenzhen ZhongNuo Testing Technology Co., Ltd. is a third-party institution that specializes in electrical safety, electrical explosion-proofing, gas detectors, and toxic and harmful gas alarm instruments for regular verification, measurement, and calibration services. We are qualified to solve fire and explosion prevention issues for our clients.