Regulations on the calibration of instruments in chemical plants
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I would like to ask the experts: are there any regulations regarding when instruments in factories, such as pressure transmitters, thermometers, level gauges, and pressure gauges, need to be calibrated? All I know is about the mandatory inspections; for example, pressure gauges require inspection every six months, while combustible gas detectors need to be inspected once a year. What about the other transmitters, thermometers, and so on? How are those handled?
For instruments, **there are corresponding verification procedures and calibration standards, which generally specify a verification/calibration cycle, such as JJG882-2004 \"Verification Procedures for Pressure Transmitters\" and so on........
The procedures you mentioned only explain how to conduct the testing, without specifying the corresponding frequency
It was just said tentatively, not more than a year. If it needs to be inspected, should it be sent for external inspection or conducted as a self-inspection?
This is my personal understanding: verification and calibration are two distinct concepts. Verification is carried out by **relevant authorities, who issue a legally valid certificate of compliance upon successful completion; whereas calibration is merely a method used for maintenance and repair, and no certificate is issued in such cases. Instrument calibration is classified into three grades: A, B, and C. Grade A instruments require mandatory calibration; they include those that are extremely important, as well as instruments used for detecting toxic, flammable, and explosive substances. Grade B instruments are of moderate importance and can be subject to periodic calibration or random inspections. Grade C instruments generally only need to be calibrated once. Instruments subject to mandatory Class A inspection need no further explanation – they must be taken for inspection on schedule; otherwise, liability for any accidents that occur will lie with the owner. Class B instruments are subject to periodic calibration, and must be sent for inspection upon expiration, usually every about one year. Class C instruments generally come with a calibration certificate upon leaving the factory and do not require further calibration. As for how to classify them, relevant **standards** need to be consulted. After separating category A, the relatively important instruments among the remaining ones are classified as category B, while the rest are classified as category C. Typically, this classification is like a pyramid, with the fewest Class A instruments, followed by Class B, and the most being Class C.
For mandatory inspections, the cycle is fixed; for weekly inspections, the cycle can be set by oneself
This post was last edited by xxkhc on 2018-3-9 at 13:25. Take a close look at all the calibration procedures – each one includes a clause regarding the \"calibration cycle\". The verification cycle can be referred to as the calibration cycle; nowadays, the term “verification” is also being replaced by “calibration”.