AEC definitions
A riser diagram is a schematic that shows a system running vertically through a building, floor by floor. It is not drawn to scale. Plumbing, electrical distribution, and fire protection use riser diagrams to show how stacks and feeders connect.
Definition
Where a floor plan shows a pipe or a conduit at one level, the riser shows that element continuing up the building and what it connects to at each floor. Sizes are noted, not scaled. A plumbing riser shows stacks, vents, and branches. An electrical riser shows service, switchgear, and feeders to panels. A fire-protection riser shows the standpipe or sprinkler riser, valves, and floor control assemblies. The diagram does not replace the plans that locate the shaft.
In depth
The floors are stacked so a reader can follow a 4 inch stack from the underground to the vent through roof. The distance between floors on the sheet is graphic. The building section has the real floor-to-floor height.
Sizes, fixture units, and feeder designations are written. If a size is missing at a floor, do not infer it from the line weight.
Waste and vent are often separate risers from domestic water and storm. Each should be labeled. A combined drawing that does not say which line is which produces a shop drawing that guesses.
Horizontal branches on the floor plans have to match the connections the riser claims. A riser that shows a restroom group the plan deleted is a coordination error.
It shows the service point, the main gear, and feeders up to distribution panels and down to the floors. Panel names on the riser must match the panel schedule. A feeder called out here and missing from the one-line, or the reverse, is a conflict.
Some offices call this sheet a riser and others call a similar sheet a one-line. Read the title and the line convention. A one-line uses a single line for a three-phase circuit. A riser emphasizes the vertical path. A set can contain both.
Standpipe and sprinkler risers show control valves, flow switches, test drains, and floor control assemblies. The fire official and the plans examiner both read them. A missing valve that the standard requires will be a comment or a failed inspection.
The riser does not show head layout. The floor plans do. Both have to tell the same story about which floors are sprinkled and where the floor control valve sits.
A riser can show six stacks. The architectural shaft and the structural openings have to be large enough, with the rated walls the code requires. That check is drawing coordination, and it happens on the plans, not on the schematic.
Sleeves and rated penetrations are specified and detailed separately. The riser identifies that a pipe passes a floor. The detail shows the firestopping.
Examples
The plumbing riser shows a 4 inch waste stack serving the typical restroom on levels 2 through 6, with a vent through the roof. The plan on each of those levels shows that restroom.
The electrical riser names panel LP-2A fed from distribution panel DP-2. The panel schedule cover says the same name.
The sprinkler riser shows a floor control assembly at each level. The RCP shows the valve access panel at that shaft.
FAQ
Unlock the value of your institutional knowledge—organized, connected, and grounded in your team's critical workflows with Nomic.
