Read the spec first
Start with Division 21. A wet system is in 21 13 13 Wet-Pipe Sprinkler Systems. Many jobs use a performance spec. The contractor then designs the system to the stated criteria. Read the hazard classifications, the pipe types and the head types. Find the water flow test data and its date.
Sheets and schedules that carry the count
- The fire protection sheets, if the set has them. Some show only the riser and the zones.
- The reflected ceiling plans. Ceiling type and height drive the head type.
- The architectural floor plans and the life safety plan. They show room use and rated areas.
- The building sections. They show concealed spaces, attics and canopies.
- The civil utility plan. It shows the fire service line and the hydrants.
- The structural framing plans, for hanger and bracing conditions.
Steps in order
- Confirm who designs the system. Read the criteria.
- Mark each area with its hazard class and ceiling type.
- Count the heads shown, or lay out heads by the spacing rules.
- Find the areas that need a dry system or special heads.
- Measure mains and branch lines by size.
- Count risers, valves, flow switches, tamper switches and test drains.
- Count the fire department connection, the backflow preventer and any fire pump.
- Add hangers, seismic bracing, design, permits and testing.
Count, length, area or volume
- Count: heads by type, valves, switches, risers and connections.
- Length: pipe by size and material.
- Area: floor area by hazard class, for early budgets and for head layout.
- Volume: none.
Conflicts to find, and what to exclude
- The drawings show a head layout. The spec says the layout is the contractor's design.
- The ceiling plan changed in an addendum. The fire protection sheet did not.
- Canopies, attics and loading docks can freeze. The documents show a wet system.
- The flow test is old or missing.
- The fire service line stops at a different point on the civil and fire protection sheets.
State the point where your underground work starts. Exclude fire alarm wiring and pipe painting unless your section includes them. Qualify the fire pump if the flow data is in doubt. State if permit and plan review fees are in your number.
Trade takeoffs · Updated 11 Nov 2026