Shenzhen ZhongNuo Testing Technology Co., Ltd. specializes in the calibration, verification, and measurement services for gas alarms, flammable gas detectors, toxic and harmful gas detectors, and other equipment in various locations. We hold qualifications to serve nationwide, addressing all sorts of electrical safety and explosion-proof fire prevention issues for our clients, and contributing to safe production.
Regulatory Content and Methods for Regular Flammable Gas Detector Inspections
Annually, we conduct annual inspections on the sensors of commercial and industrial alarm systems, primarily checking for measurement errors, repeatability, drift, and response times to ensure they meet standards. Additionally, we verify the suitability of the alarm system's installation location and whether it is subject to interference from other equipment.

What does a calibration report for a flammable gas detector include?
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 Certificate or report (e.g., numbered), with page numbers indicated on each page
⑤Shipper's name and address
⑥ Describe the target school clearly and specifically.
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.
Description of Calibration Environment
11. Calibration Results and Measurement Uncertainty Statement
12. Signature, title or equivalent mark, and issuance date of the certifier or issuer of the calibration certificate or report.
13. Calibration results are only applicable to the verification object.
14. No part of the certificate or report may be copied without written consent from the laboratory.
Two-proofing time interval
Instrument recalibration is typically every 1 year, determined by the submitting unit based on actual usage. During the re-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 required after repairs.

Method of Verification
Appearance and structure
Inspect and feel according to the requirements of Section 4.1
Logos and Branding
Proceed in accordance with the requirements of Section 4.2 as observed visually.
Power-on inspection
Inspect visually and by touch in accordance with the requirements of 4.3 to check the alarm function and the alarm action values as per 5.3.4.
Introduce a standard gas substance with a concentration greater than the alarm set point, causing the instrument to trigger an alarm. Observe whether the instrument's sound and light alarm function properly 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 Inspection Technology Co., Ltd.)
1. Power-On Self-Check Function: The instrument should have an automatic self-check function upon power-on, 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 m.
3. Alarm Value Setting: Specific alarm value settings are stipulated for different gases according to 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" and GB 30871-2022 "Special Operation Regulations for Chemical Hazardous Enterprises").
The first-level combustible gas alarm setting should not exceed 25% LEL, and the second-level alarm setting should not exceed 50% LEL.
The first and second level alarm settings for toxic and harmful gases are determined based on OEL (Occupational Exposure Limit) or IDLH (Immediately Dangerous to Life and Health).
4. Error and Reproducibility: 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 should possess explosion-proof capabilities in compliance with relevant regulations and obtain an explosion-proof certification.
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 set for the power voltage and continuous operating time for 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, resistance to electromagnetic interference, resistance to steam interference, vibration and shock, and functionality.
Shenzhen ZhongNuo Testing Technology Co., Ltd. is a third-party institution specializing in electrical safety, electrical explosion-proofing, gas alarms, and toxic and harmful gas alarm instruments for regular inspections, metrological measurements, and calibration services. We provide qualifications to help clients address fire and explosion prevention issues.