What is the minimum pipe size in inches required for the water column drain cock or drain valve?

The minimum pipe size required for a water column drain cock or drain valve is 3/4 inch. This specification is based on plumbing codes and standards that ensure adequate drainage capacity without causing excessive pressure loss in the system. The 3/4 inch size strikes a balance between effective drainage and compatibility with typical plumbing systems, preventing clogs while still allowing sufficient flow of water when draining.

Using a pipe size smaller than 3/4 inch could lead to insufficient flow rates and increased risk of blockage, particularly in systems that handle a significant volume of water. Overall, the choice of 3/4 inch ensures that the drainage system remains efficient and meets the requirements for proper installation and operation.