What does 'Flow Pressure' refer to in plumbing systems?

Flow pressure specifically refers to the pressure in the plumbing system when water is actively flowing, which is typically measured with a faucet or fixture fully open. This is critical to ensure that there is adequate pressure available at the fixtures during operation, meaning the system can deliver water effectively during peak usage situations.

Understanding this concept is essential for plumbing design and analysis, as it helps to identify the water supply's capacity to meet demand. Proper flow pressure ensures that when any water-using fixture is activated, it will receive a sufficient and consistent supply of water without significant drops in pressure, which could lead to inadequate flow rates and unsatisfactory performance.

Other answers might refer to different contexts or states of pressure within the plumbing system but do not accurately define flow pressure as it is understood within plumbing practice.