A tall riser sits beside a moving pressure probe in a building section with marked elevations. Set the service pressure, the top-floor elevation and an optional inlet pressure-reducing valve (PRV) with its outlet setpoint, then compare service, regulated and top-floor pressure with the ideal static rise capacity.
• A real-time 3D view with numbered, clickable parts: building section and elevations; static water riser; inlet pressure regulator; moving measurement probe; pressure-head reference. Scene tools include home view, focus-selected-part, auto-rotate, expand and show/hide labels, and drag-to-orbit with pinch-to-zoom. • Experiment controls: service pressure (200–1000 kPa gauge); top-floor elevation (10–80 m); enable inlet pressure-reducing valve; prv outlet setpoint (150–500 kPa), plus a show flow/process markers toggle, pause/resume, single-step buttons (0.1 s and 1 s), a playback-speed selector and a restart experiment action. • Live readouts: effective inlet pressure; elevation head consumed; top-floor available pressure; signed head margin at top; ideal static rise capacity; moving probe reading. A model response curve is drawn beside the 3D view and updates as you change controls. • A Curves & measurements tab with two live charts, the model equations as written in the simulator and snapshot readouts; an Experiments tab with 2 guided presets (insufficient source head; regulation reduces pressure) plus a model-verification bench, timestamped event log and copyable trial report. • A Learn & assess tab with 3 lessons (follow the system; connect the measurements; interpret the model), a 2-question knowledge check with reset, and a written model-scope statement.
In a static column of water, gauge pressure falls by ρg per meter of height, about 9.80665 kPa per meter. The model computes pressure at height z as the base pressure minus that amount, so a 50 m building consumes roughly 490 kPa before any flow friction at all. The moving probe reads the pressure at its current height on the riser.
Ideal static rise capacity is base pressure divided by ρg: the height a source could theoretically support. The signed head margin at the top shows how much pressure is left or, when negative, how far short the source falls.
Enabling the inlet PRV caps the base pressure at its outlet setpoint, which protects lower floors but also leaves less pressure for the top floor. When head is insufficient, available pressure at the top is clipped to zero and the margin goes negative rather than pretending water is delivered.
This is a static gauge-pressure model without flow losses. A single inlet PRV is shown, not a pressure-zone design, and proportions are enlarged for explanation. It is a generic educational model, not a code-compliance or sizing tool.
About 9.80665 kPa per meter of water column, which is 0.098 bar or roughly 1.42 psi per meter.
The source cannot sustain the requested column. The simulator shows the top pressure as zero instead of claiming delivery.
The PRV lowers the pressure at the building inlet to its setpoint. Because elevation loss is unchanged, less pressure remains at the top.
Real buildings often use multiple pressure zones, boosters and intermediate PRVs. This lab shows a single inlet PRV to isolate the static head concept.