1. Used for safety protectionpressure gaugeMandatory verification is required. Including the following 7 categories:

1) Measurement of boiler main cylinder and feedwater pressure parts;

2) Measurement of pressure in the air chamber and main pipe of a fixed air compressor;

3) Measurement of oil pressure for generators, gas turbines, and locomotives;

4) Measurement of pressure in medical high-pressure sterilizers and pressure cookers;

5) Measurement of pressure with alarm device;

6) Measurement of pressure in sealed pressurized containers;

7) Measurement of pressure in harmful, toxic, and highly corrosive media. (such as spring tube pressure gauge, electric remote transmission and electric contact pressure gauge).

2. Wind pressure gauges used for safety protection require mandatory calibration. Namely: measurement of wind pressure and speed in tunnels in mines. (such as mining wind pressure gauge, mining wind speed gauge).

3. Oxygen meters used for safety protection require mandatory calibration. Including the following two categories:

1) Measurement of oxygen monitoring pressure during the process of filling oxygen cylinders;

2) Measurement of oxygen pressure that is explosive and affects safety during the manufacturing process.

4. Oxygen meters used for medical and health purposes require mandatory calibration. The measurement of oxygen pressure on the float type oxygen inhaler and oxygen supply device used for hospital oxygen delivery.