Shenzhen ZhongNuo Inspection & Technology Co., Ltd. specializes in the calibration, certification, and metrological services for gas alarms, combustible gas detectors, toxic and harmful gas detectors, and other equipment in various locations. We offer services nationwide, addressing various electrical safety and explosion-proof fire prevention issues for our clients, and contributing to safe production.
Appearance and structure
The instrument should not have any appearance damage that affects its normal operation. The surface of newly manufactured instruments should be smooth and glossy, with a uniform paint and plating layer, free of peeling and rusting.
The instrument's connections are reliable, and all dials or buttons should operate and control normally.
Logos and branding
Instrument name, model, manufacturer's name, manufacturing date, serial number, explosion-proof marking and number, as well as the manufacturing measurement instrument license marking and number for domestic instruments should be clear.

What are the contents of 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.
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., numbered), with page numbers and total page count indicated on each page
5. Shipper's name and address;
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 of the issuer of the calibration certificate or calibration report, position or equivalent symbol, and the date of issuance.
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
Instrument recalibration is typically every 1 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, as well as after repairs, a recalibration is required.

Gas Standard Material
We use gas standard substances of the same type as the gas measured by the instrument, such as methane or ethane, or gas standards can also use isopropanol, etc. If the instrument does not specify the type of gas being measured, the concentration of the gas at the set point (60% of the full scale) is approximately the concentration of the standard substance. The uncertainty of the expanded gas standard substance is not significant (%). The flow indication error of the repetitive dilution device should not be greater than 0.1% for gases with high concentration. The concentration unit of the gas standard substance should be converted to match the unit of the inspected instrument during use, and the discrepancy should not exceed 0.1%.

The calibration cycle for flammable gas detectors is typically once a year.
In accordance with the standard JJG 693-2011 "Flammable Gas Detectors," the calibration cycle for flammable gas alarms typically does not exceed 1 year. This means that, under normal circumstances, a comprehensive calibration and testing of the flammable gas alarms should be conducted annually to ensure their performance meets the relevant requirements.
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 for regular calibration, measurement, and certification services. We hold the necessary qualifications to help clients address fire and explosion prevention issues.