What is the required minimum water pressure maintained in a wet pipe system?

In a wet pipe fire sprinkler system, the required minimum water pressure that must be maintained at the highest sprinkler head is typically at least 20 psi. This pressure ensures that when a sprinkler head activates, there is sufficient water flow to effectively suppress a fire. Maintaining this pressure is critical because it accounts for potential pressure loss due to elevation changes and friction within the piping system.

The 20 psi minimum is an industry standard that provides an adequate pressure margin for the system to operate effectively and allows for the proper distribution of water to dampen flames and control fire spread. This specification is particularly important in ensuring that all heads can function properly, especially in buildings with multiple levels where the highest heads may require additional pressure to deliver the necessary water flow to effectively combat fire hazards.

This requirement reflects good engineering practices aimed at ensuring the reliability and effectiveness of the sprinkler system in a fire emergency.