What is the difference between a calibration certificate and a verification report for a combustible gas detection alarm?

Here, it is the Quality and Technical Supervision Bureau that conducts the inspections, and only one inspection report is issued; I’ve never heard of two reports being issued

Safety supervision agencies only recognize calibration certificates, not verification certificates

Calibration has no legal validity and is not recognized by the safety supervision authorities; calibration has legal validity and is recognized by them

For those with **metrological verification regulations, a verification certificate is required; those without such regulations can be calibrated**

Based on my work experience, I understand that this issue is actually related to the difference between verification and calibration. Generally, when there are established verification procedures and the results of instrument verification fall within those limits, the metrology institute issues a verification certificate; instruments that fail verification are not allowed to be used further. However, if the test results show deviations but still meet the user’s requirements, the metrology institute issues a calibration certificate, allowing the user to decide whether to continue using the instrument based on their own needs. In practical operations, it is common for the measurement values of various electronic instruments to be out of range during calibration, but they become within acceptable limits after calibration, and in such cases a calibration certificate may be issued. For example, suppose there is an electronic digital caliper, and the user requires precision at the millimeter level; however, the actual accuracy may reach 0.01 millimeters. According to the standards, a deviation of 0.01 mm means the instrument is not qualified, but for the user, precision within 0.1 mm might already be sufficient for their needs. In such cases, issuing a calibration certificate allows the instrument to be used again. Generally, the metrology institute does not issue two certificates; it is either a verification certificate or a calibration certificate. The specific type of certificate required depends on the regulations set by the safety supervision authorities. However, both calibration certificates and verification certificates have legal validity.

The inspection report is sent to the Quality Supervision Bureau for approval, and then the Work Safety Supervision Bureau verifies it.

Whether calibration certificates and verification certificates have legal validity depends on whether the entity conducting the calibration and verification possesses the necessary legal qualifications.

The inspection report is sent to the Quality Supervision Bureau for approval, and then the Work Safety Supervision Bureau verifies it.

What was said upstairs is mostly correct; the certification document is issued by the Metrology Institute, and it indicates whether the meter meets the standards or not. Calibration certificates are usually issued by the manufacturer of the alarm device; in other words, they are certificates issued after calibration has been carried out by the manufacturer itself. Although factory calibration is not necessarily inferior to that conducted by metrology institutes, due to the different entities responsible for issuing certificates, in many places the work safety supervision agencies only recognize certification documents issued by metrology institutes.