Shenzhen ZhongNuo Testing Technology Co., Ltd. specializes in the certification, calibration, and metrological services for gas alarms, flammable gas detectors, toxic and harmful gas detectors, and other equipment at various locations. We hold the necessary qualifications to serve nationwide, addressing electrical safety and explosion-proof fire prevention issues for our clients, and contributing to safe production.
How often should various gas detectors be periodically tested and calibrated?
The recalibration period for instruments is typically one year, determined by the sending unit based on actual usage. During the re-calibration process, if there are any doubts about the instrument's test data, or if the main components of the instrument are replaced, or if recalibration is needed after repairs.

Combustible Gas Detector Alarm Regular Inspection Content and Methods
Annual inspections are conducted on industrial and commercial alarm sensors, primarily checking for the accuracy, repeatability, drift, and response time of the alarms to ensure they meet standards. Additionally, the suitability of the alarm installation location and any interference from other equipment are also assessed.

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 power-on, 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 Settings: Specific alarm value settings are stipulated for different gases in accordance with the standard.
For instance, the oxygen deficiency alarm setting is 19.5% VOL, and the enriched oxygen 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 flammable gas alarm setpoint is not greater than 25% LEL, and the second-level alarm setpoint 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 example, the indication error for flammable 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: Equipment for explosive environments must have explosion-proof performance in accordance 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 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 supply voltage, continuous operating time, and other aspects of both battery-powered and non-battery-powered instruments.
10. Additional Performance Requirements: Includes 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 functionality.

What are the contents of the calibration report for flammable gas detectors?
The verification results should be reflected in the verification certificate or report. 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 Standing proof or report (e.g., with serial number), indicating page numbers on each page.
Please provide the name and address of the shipping entity.
⑥ Describe and clearly identify the target school.
Calibration Date and Receipt Date
⑧ Technical specifications for calibration base, including name and code;
Description of traceability and effectiveness of the measurement standards used in our calibration.
⑩ Description of Calibration Environment
11. Calibration Results and Measurement Uncertainty Statement
12. Signature, title or equivalent symbol, and issuance date of the certifier or issuer of the calibration certificate or calibration report.
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.
Reproofreading interval
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.
Shenzhen Zhongnuo Testing Technology Co., Ltd. is a third-party institution specializing in electrical safety, electrical explosion-proofing, gas alarm systems, and toxic gas detection equipment for regular inspections, metrological services, and calibration. We are qualified to assist clients in solving fire and explosion prevention issues.