Distribution, drainage & backflow — how water is supplied, vented, drained and protected inside a building.
Open fixtures up a riser and see total demand, shared-main loss and the pressure left for each floor change.
Raise the building height and watch elevation head consume pressure while an inlet PRV sets the base pressure.
Let a variable-speed pump hold an elevated outlet at a pressure target and see what happens at maximum speed or during an outage.
Pulse pressure at a P-trap and compare the water seal head with the pressure that tries to push it out.
Send a drainage pulse past a roof vent and see how a constricted vent increases suction and erodes trap-seal margin.
Warm a hot-water loop with a circulator and watch loop temperature approach an equilibrium set by flow and heat loss.
Raise downstream pressure across two spring-loaded checks and jam either one open to test the remaining barrier.
Close a valve fast and compare the unprotected surge with a gas-chamber arrestor estimate.
Cycle a sump pump with a float switch and test power loss, a stuck float, leaking check valve and too much inflow.