How Fire Sprinkler Subs Bid and Bill Commercial Work

On most commercial jobs the bid documents give a riser location, hazard classifications and a note that the building is sprinklered to NFPA 13, the installation standard (NFPA); the sprinkler sub does the real layout after award. The federal guide specification for wet-pipe systems shows how much rests on that design: it asks for a fire hydrant flow test "prior to shop drawing submittal in accordance with NFPA 291", and says the hydraulic calculations "must be based on flow test noted in this paragraph" (UFGS 21 13 13). The same section wants the designer certified by NICET as a Level III or Level IV technician (the spec's editor picks which) in the Water-Based Systems Layout subfield. Check your spec for both before bid day.

Because you design it, a GC may later argue that anything the code needed was always in your price. Your defense is the basis of design written into the bid:

Sprinkler work is counted in heads by type (upright, pendent, sidewall, concealed, dry), feet of pipe by diameter and material, fittings, hangers and seismic bracing, valves and risers by each, standpipe outlets by each, and underground by the foot, plus design hours, permit fees and lift rental. The same counts become your add and deduct prices for changes, so keep them with the bid.

List the edges with other trades, because each one tends to exclude the other's half:

The backflow and water service edge is shared with the plumber; see how plumbing subs bid and bill for their side. The pump and switch edges are shared with the electrical sub.

UFGS 21 13 13 is strict about the package: "SD-02, SD-03 and SD-05 must be submitted simultaneously", meaning shop drawings, product data and calculations, and "Partial submittals and submittals not fully complying with NFPA 13 and this specification section must be returned disapproved without review." The product data alone covers pipe, fittings, valves, alarm valves, sprinklers, hangers and supports, alarm and tamper switches, the fire department connection, the backflow preventer and nameplates. Build each submittal the way how to prepare a submittal describes, and send them together.

The engineer's review through the GC is one approval. The other is the fire official's. South Carolina's state fire marshal, for example, says shop drawings for fire protection systems it reviews "shall be approved prior to the start of installation", and that a resubmission must include an itemized response from the professional of record (SC Office of State Fire Marshal). Your jurisdiction's rules differ, but the shape is the same: pipe should not be fabricated or hung until both approvals are back.

A ceiling or duct change after pipe is fabricated is scrap and refabrication. Write it up as a change order request, priced from your per-head and per-foot counts plus the redesign and resubmittal hours.

A sprinkler schedule of values starts with design and permit, because that work is real cost spent before anyone is on site; give it its own lines so it is not read as front-loading. Then follow the trips you make: underground, mains and branch lines by floor, the fire pump, drops and heads after the ceilings, and testing last. A sample for a three-story building:

A fire pump delivered before it is set is stored material, billable only as your subcontract allows; how a sub fills out a pay application covers the stored column and how to calculate retainage covers what is held.

The fictional "Ridgeway Fire Protection" holds the $486,000 subcontract above with 10% retainage. In period 4, level 1 mains and branch lines go from 70% to 100%, level 2 from 10% to 60%, and the fire pump and controller are delivered to the pump room, not yet set.

This period bills $60,400 of work plus $62,000 stored = $122,400. Retainage at 10% is $12,240, so these lines add $110,160 to the payment due. Checks: $54,600 + $23,400 = $78,000; $7,400 + $37,000 = $44,400 = 60% of $74,000; $62,000 + $122,400 = $184,400.

Billing level 1 at 100% assumes its piping has passed its test. The guide spec says piping above ceilings "must be inspected, hydrostatically tested and approved before being concealed", so tie the last percent of each floor to that test, not to the day the last branch line is hung.

Your rough-in finishes early, but your final test is one of the last events on the job, so retainage waits a long time on a small amount of work. Keep the testing and closeout lines priced at what they really cost, and know what the spec asks for before you get there. UFGS 21 13 13 requires aboveground piping hydrostatically tested to NFPA 13 with "no drop in gauge pressure or visible leakage", and its closeout list is specific:

• The NFPA 13 Aboveground Material and Test Certificate and the Underground Material and Test Certificate.
• As-built drawings showing "deviations from both the project drawings and the approved shop drawings", due within two weeks after the final acceptance test.
• Operating and maintenance instructions, and on-site training for the owner.
• Spare sprinklers and wrenches "in accordance with NFPA 13".
• Final lien waiver and the request to get retainage released.

For the whole path from bid to final payment, see the subcontractor's guide and the construction project lifecycle.

When a GC sends a fire protection package through Trade bids in Conflo, you read the scope items and alternates, ask questions (the answers go to every bidder without your name), acknowledge each trade addendum, and submit a base bid with each scope item marked included or excluded, your alternates, and your exclusions and qualifications, which is where your basis of design goes. There is no unit-price field on a bid today, so put your per-head add and deduct prices in your qualifications or your attached proposal PDF.

In Submittals you see only your own company's submittals. Start the shop drawing, product data and calculation submittals yourself, or prepare the ones the GC set up, each with its spec section, type, package and files, and each goes through GC review and then design review. Reviewers answer approved, approved as noted, revise and resubmit, or rejected, with a note on anything but approved. The fire marshal's permit review is not a step in Conflo; attach the approved permit set to the submittal's files so the record holds both.

Conflo does not lay out sprinklers or run hydraulic calculations; you bring those from your design software.

A sprinkler bid is a design you have not done yet, so write down what you assumed: hazard classes, the flow test, the ceiling plans and the system types. Then plan the package and both approvals before you release any pipe to fabrication.

Before your next bid, add the basis-of-design table above to your proposal template.

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1. UFGS 21 13 13, Wet Pipe Sprinkler Systems, Fire Protection (August 2020) — Whole Building Design Guide (USACE, NAVFAC, AFCEC). Read October 22, 2026.
2. NFPA 13, Standard for the Installation of Sprinkler Systems — National Fire Protection Association. Read October 22, 2026.
3. Instructions for Electronic Plan Submission, fire sprinkler systems (version 03/30/2023) — South Carolina Office of State Fire Marshal. Read October 22, 2026.