What is the minimum size of a fixture water supply pipe for a flush valve urinal?

The minimum size of a fixture water supply pipe for a flush valve urinal is 3/4". This size is established to ensure that the urinal receives an adequate flow of water necessary for proper flushing performance. Flush valve urinals typically require a higher volume of water during each flush compared to other types of fixtures, such as those that use tank mechanisms.

Using a 3/4" pipe allows for sufficient water pressure and flow rate to effectively operate the flush valve mechanism. This is important for ensuring proper hygiene and function, as insufficient pipe size could lead to inadequate flushing performance, which can result in standing water and unpleasant odors.

In contrast, smaller pipe sizes such as 1/4" or 1/2" do not provide the necessary volume of water needed during flush cycles and could lead to operational issues, making 3/4" the appropriate minimum size for optimal function.