Shenzhen Zhongnuo Testing Technology Co., Ltd. specializes in the calibration, verification, and measurement services for equipment such as gas alarms, combustible gas detectors, and toxic gas analyzers in various locations. We hold the necessary qualifications to serve nationwide, providing solutions to electrical safety and explosion-proof fire prevention issues for our clients, and contributing to safe production.
Regular Inspection Content for Gas Alarm Units
Installation spacing of inspection (probe) points
2. Installation Height of the Detector
3. Indicated Error (Concentration)
4. Repeatability (Concentration)
5. Alarm Error (Concentration)
6. Response Time (Seconds)

Routine Inspection Items for Environmental Gas Detection and Alarm Equipment in Workplaces:
1. Alarm sound and light (if applicable)
2. Low response value
3. Indication Error (for Gas Detectors/Gas Detector Alarms)
4. Instrument Drift (in Portable Instruments)
5. Alarm Error (for Gas Detection Alarms/Gas Alarm Devices)
6. Pump-actuated instrument gas collection distance and flow rate (for pump-actuated instruments)
7. Power Supply (for battery-powered instruments)
8. Response Time
9. Status Indicator (with Wireless Communication Function)

What are the contents of the report for the calibration of combustible 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.
① Title, such as "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 indication of each page and page number;
Please provide the name and address of the shipping entity.
⑥ Describe the target school clearly and explicitly.
Calibration date and receipt date;
⑧ Technical specifications for calibration basis, including names and codes;
Description of the traceability and validity 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 of the issuer of the calibration certificate or 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, to be determined by the submitting unit based on actual usage. During the secondary calibration process, if there are any doubts about the instrument's test data, or if the main components of the instrument are replaced, as well as after repairs, a recalibration is required.

Key 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 the alarm components should also be equipped with a manual self-check function.
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: The standard specifies specific alarm value settings for different gases.
For example, the oxygen deficiency alarm setting is 19.5% VOL, and the oxygen-rich alarm setting 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 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 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, with established calibration procedures and corresponding interfaces to ensure the accuracy of its measurement results.
6. Explosion-proof Performance: Instruments used in explosive environments must possess explosion-proof capabilities in accordance with relevant regulations and obtain an explosion-proof certificate.
7. Audio-Visual Alarm Devices: The audio-visual alarm devices of the alarm should meet specific visibility and sound pressure level requirements 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 a ventilation system, etc.
9. Power Requirements: Specific requirements for power supply voltage, continuous operating time, etc., are set for battery-powered and non-battery-powered instruments.
10. Other Performance Requirements: Includes specifications for bearing, 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 resistance, and functionality.
Shenzhen ZhongNuo Testing Technology Co., Ltd. is a third-party service provider specializing in electrical safety, electrical explosion-proofing, gas alarms, and toxic and harmful gas detectors for regular inspections, metrological measurements, and calibration. We hold the necessary qualifications to address fire and explosion prevention issues for our clients.