Can mechanical grooved couplings be used in a low pressure CO2 system?

Using mechanical grooved couplings in a low pressure CO2 system is permitted if these couplings are specifically listed for carbon dioxide service. This is particularly crucial because CO2 imposes unique material and compatibility requirements compared to other fluids due to its physical characteristics, such as temperature and pressure conditions, as well as the potential for corrosion or material breakdown.

When couplings are appropriately listed for CO2, it ensures that they have been tested and validated to handle the specific properties of carbon dioxide, providing a level of safety and reliability required in such applications. This minimizes the risk of leaks or failures that could arise from using couplings not designed for CO2, thereby ensuring compliance with safety regulations and standards in the industry.

Other options suggest prohibitions or conditional uses without the necessary qualifications, which do not align with standards that allow the use of suitably rated materials and fittings in low-pressure CO2 systems.