The user is required to notify or permit the use of high-pressure gas to the prefectural office.
The “high pressure gas” specified in the High Pressure Gas Safety Act corresponds to a) compressed gas of 1 MPa or more, b) liquefied gas of 0.2 MPa or more. Liquefied carbon dioxide is also applicable (vapor pressure at 20 ° C is 5.6 MPa).

Notification to the prefectural office is required for Type 2 manufacturers. If only CO2 gas for supercritical equipment is used in the office and the processing amount is 300 Nm³ or less in 24-hour conversion, it corresponds to the Type 2 manufacturers. The details vary from case to case, but are roughly as follows.

When exhausting used CO₂ without reusing it

12kg-CO₂/Hr / 44 kg/kmol x 22.4 Nm³/kmol x 24 Hr x 2(pressurization and heating) = 293 Nm³/day < 300 Nm³/day

When recovering used CO₂ and recycling it

 8.1kg-CO₂/Hr / 44 kg/kmol x 22.4 Nm³/kmol x 24 Hr x 3(pressurization, heating and condensation) = 297 Nm³/day < 300 Nm³/day

If you use it at a flow rate higher than the above, apply for permission from the prefectural office because it corresponds to a type 1 manufacturer. You must pass the completion inspection after getting permission. The user needs to prepare the application documents, but the manufacturer usually prepares the documents related to the device.