Regarding the regular inspection and calibration of instruments

Both instrument verification and calibration must be carried out in accordance with the relevant verification procedures or calibration standards, which specify the verification/calibration intervals; these intervals are generally determined based on those standards. Such as JJG693-2011, the Calibration Specification for Gas Detection and Alarm Devices, etc.

Pressure gauge every six months, alarm every year

Generally, flammable and toxic gas detectors should be inspected once a year, pressure gauges every six months, thermometers, pressure transducers, and weighing devices should be calibrated once a year, while flow meters need to be calibrated every two years.

Ordinary pressure gauges need to be calibrated every six months, vibration-resistant pressure gauges every year, and all other instruments as well every year.

A rigorous approach starts with identifying the relevant standards that define which items need to be tested; it’s not the case that everything needs to be tested. According to the old standard, the \"Provisions on the Inspection of Working Measuring Instruments Subject to Mandatory Inspection in 1991 (Trial)\\", regular inspection was practically required for almost all of them. Fortunately, in November 2019, the State Administration for Market Regulation issued the \"Announcement on the Catalogue of Measuring Instruments Subject to Mandatory Control\", as attached; this document specified that the number of items that required calibration had been significantly reduced. For example, gas detectors are no longer subject to mandatory calibration. As for pressure gauges, the requirement for calibration used to apply to those that came into contact with toxic substances; now it applies only to those used for safety purposes. Since there are no explanations available for this new regulation, we can only interpret it literally. First, we need to determine the purpose of the instrument – if a pressure gauge is used solely for safety purposes, then in my view, only those installed on pressure vessels serve that purpose. As for the pressure gauges at the outlet of pumps, I consider them to be used merely for displaying parameters, and therefore they do not need to be calibrated until they break. After determining the nature of the instrument, we can then determine the appropriate calibration cycle. For example, the calibration cycle for pressure gauges is specified in the standard JJG52-2013 \"Calibration Regulations for Elastic Element-Type General Pressure Gauges, Pressure-Vacuum Gauges, and Vacuum Gauges\", which requires calibration every six months. The calibration cycle for mass flow meters is specified in JJF1708-2018, with a typical cycle length of one year. But what bothers me the most is that in 1988, the Ministry of Chemical Industry issued the \"Regulations on the Classification and Management of Measuring Instruments in the Chemical Industry,\" which required calibration for almost all measuring instruments. No order has ever been issued to repeal this regulation. Some old experts who are nearing retirement like to bring up this standard when conducting inspections; I then explain to them that the Ministry of Chemical Industry abolished this regulation long ago, and it must have been revoked along with the dissolution of the ministry.

After all, there are still no specific operational guidelines; exactly which pressure gauges qualify as those used for safety protection? Is there a clear definition of the scope?

The pressure is manifested in the requirement to send samples to the local quality supervision bureau for inspection every 6 months. Combustible gas probes and transmitters are not mandatory, but testing by a third-party agency is still required. Once a year.

Current pressure gauges offer only four modes to choose from: one for safety protection, one for healthcare, one for environmental monitoring, and one for trade settlement.