10.2 Coordination Surveys with Other Trades
Key Takeaways
- Official task 1.5.4 is assist: walk the plenum with HVAC, electrical, plumbing, and fire alarm; mark clashes; measure; photograph; raise an RFI or shop-drawing comment.
- Compare the reflected ceiling plan (RCP) to the sprinkler shop drawing — lights and pendents that share a tile are a clash, not a field surprise.
- Measure duct width: a 54 in duct is 4 ft 6 in, which is over the 4 ft fixed-obstruction threshold that sends sprinklers under the duct (NFPA 13 2022 9.5.5.3 path).
- Clash catalog: lights, diffusers, cable tray, duct mains, access panels, and seismic braces all steal the same ceiling real estate as pipe and heads.
- Do not silently relocate a penetration through a fire-rated wall. That move changes the rated assembly and needs an RFI, listed firestop, and usually the architect/AHJ — not a red marker in the field.
10.2 Coordination Surveys with Other Trades
Quick Answer: NICET Level I task 1.5.4 is assist with coordination surveys. You walk the plenum or ceiling cavity with HVAC, electrical, plumbing, and fire alarm. You hold the reflected ceiling plan (RCP) against the sprinkler shop drawing, mark where lights, diffusers, cable tray, duct mains, access panels, or seismic braces occupy the same space as pipe and sprinklers, measure the conflicts (especially duct width for the 4 ft under-obstruction rule), photograph them, and send an RFI or shop-drawing comment. You do not silently relocate a fire-rated wall penetration or slide a pendent off-grid to clear a 2×4 fixture.
A coordination survey is not a water-supply test, not a hazard-classification meeting, and not a quantity takeoff. Those tasks have their own chapters. This walk exists because the sprinkler layout was drawn on architectural backgrounds that did not yet show the final duct mains, cable tray, or light package — or because those trades moved after the first sprinkler pass. Level I's job is to feed facts to the person who owns the layout, not to reinvent the hydraulic calculation in the ceiling.
Who is in the plenum, and which sheets you carry
Bring three paper (or tablet) layers, plus a tape and a camera:
- Architectural RCP — lights, diffusers, soffits, access panels, ceiling type, and often fire-alarm devices that punch the same tile.
- Sprinkler shop drawing — mains, branches, sprinkler locations, hanger points, and any already-shown under-duct heads.
- Other-trade shops if they exist — HVAC duct, hydronic and domestic plumbing, cable tray, and fire-alarm device layout.
Then walk with the people who own those sheets. HVAC will tell you which duct is a 54 in supply main versus a 12 in runout. Electrical will tell you which 2×4 is a fixture that cannot move versus a spare tile. Plumbing will flag a domestic main that wants the same joist bay. Fire alarm will flag notification appliances and detectors that the RCP shows in the same ceiling module as a pendent. If a trade is missing, the survey still happens — you measure what is already installed or already hung in the air, and you write that the missing shop was not on site.
| Clash type | What you measure or note | Why it matters to layout |
|---|---|---|
| Recessed lights / 2×4 fixtures | Tile location vs pendent; fixture depth into the plenum | Head and light cannot occupy the same opening; deep cans can also obstruct discharge |
| HVAC diffusers | Centerline vs sprinkler; neck size | Same ceiling hole problem as lights; supply air can also delay a quick-response element if the head sits in the airstream |
| Duct mains | Width, depth, bottom elevation, and how far they run | Width over 4 ft drives sprinklers under the obstruction; depth drives hangers and trap-wrap |
| Cable tray | Width, elevation, and whether it is solid-bottom | Treat as a continuous obstruction when it is wide enough; do not use the tray as a hanger beam |
| Access panels | Size and which equipment they serve | A pendent in the only access panel for a VAV box will be moved — better now than after the ceiling is closed |
| Seismic braces | Brace direction, attachment steel, and zone of influence | A sprinkler hanger and a brace often want the same beam; braces also occupy the plenum crossing the pipe |
| Plumbing mains / storm | OD and elevation | Gravity plumbing rarely yields; sprinkler pipe usually reroutes |
| Fire-alarm devices | Device type and tile | Strobe/speaker plates and detectors fight sprinklers for ceiling real estate |
The obstruction geometry itself — three-times rule, beam rule, deflector-to-deck — is Chapter 9. Coordination's contribution is the field width and elevation that those rules consume. If you guess a duct is "about 3 feet" and it is actually 54 in, the under-duct head that should have been on the shop drawing never gets drawn.
RCP versus shop drawing
The RCP is the architect's view looking up at the finished ceiling. It is the contract picture of lights, diffusers, and soffits. The sprinkler shop drawing is the fire-protection contractor's picture of pipe and sprinklers, usually on a floor-plan background that may not show every light. A coordination survey is the act of putting those two pictures in the same coordinate system.
When they disagree, neither sheet automatically wins. The RCP does not authorize you to delete sprinklers. The shop drawing does not authorize you to relocate lights. The survey record is: tile E-12 on the RCP shows a 2×4 fixture; the shop drawing shows a pendent at that centerline; measured conflict; recommended action (shift the head within spacing rules, shift the fixture, or change to a sidewall / concealed / extended-coverage head if the designer so chooses). Level I writes that record. The designer or supervisor decides the code-compliant move.
Worked example — 54 in duct and under-duct heads
You are on a light-hazard office floor, unobstructed ceiling, standard spray pendents. A new HVAC shop shows a 54 in wide supply duct running the corridor. The sprinkler shop currently has a 1½ in branch above the duct centerline with pendents at the ceiling, and no heads under the duct.
- Measure width, not height. Fifty-four inches is 4 ft 6 in. NFPA 13 (2022) 9.5.5.3 (the 2019/2022 path MeyerFire cites, including the 9.5.5.3.1.5 exception for noncombustible obstructions whose bottom is 24 in or less above the floor) requires sprinklers under fixed obstructions more than 4 ft wide. This duct is over that threshold.
- Record bottom-of-duct elevation. If the duct is a high plenum main, under-duct heads are in play. If the bottom is within 24 in of the floor and the obstruction is noncombustible, open 9.5.5.3.1.5 before you add heads — that is the published exception, not a shop waiver.
- Photograph the duct with a tape across the width, and note how far it runs continuously. A 54 in duct that exists for 8 ft still feeds the rule for that stretch.
- Return the note: "54 in duct at gridlines C–D; under-obstruction sprinklers required unless a 9.5.5.3 exception applies; branch above does not protect the floor under the duct." Do not strap the sprinkler main to the duct to "get it out of the way," and do not assume one head at the midpoint of an 80 ft duct run is enough — under-duct spacing still follows Chapter 8/9 rules.
- Feed hanger Chapter 10.1: the branch that used to hang from the deck may now need a trapeze to miss the duct, with rods sized for the sprinkler pipe, not a duct strap.
The 4 ft number is a width trigger. A 3 ft 11 in duct and a 4 ft 1 in duct are different answers. That is why Level I carries a tape, not a visual estimate.
Worked example — light fixture versus pendent on the RCP
Tile 4/B on the RCP is a 2×4 recessed fluorescent (or LED) fixture. The sprinkler shop shows a pendent at the center of that same tile, 7 ft 6 in from the adjacent heads on a 15 ft light-hazard spacing grid.
Walk the ceiling. Confirm the fixture is actually in that tile, not a background that was never updated. Measure the fixture housing into the plenum so you know whether a concealed sprinkler would even fit beside it.
Correct assist: mark the tile on both sheets, photograph the RCP note next to the shop-drawing head, and write the comment. Possible designer outcomes — none of which Level I invents in the field — include sliding the pendent inside the remaining spacing window (still at least 6 ft from the next standard-spray head, still not more than half the allowed spacing from the wall), moving the fixture one tile, or changing sprinkler type. Wrong assists: cutting the pendent 3 ft off-grid toward the corridor because "the light is already ordered," or telling the electrician to delete the fixture. Either silent move can create an obstruction, a spacing miss, or a contract fight that shows up at the ceiling inspection.
What Level I does on the walk — and what Level I does not do
Do:
- Walk the route of every main and branch you can see, including above locked ceilings if you have access.
- Measure duct width and bottom elevation, cable-tray width, and the clear dimension under beams.
- Photograph with a scale in the frame (tape, folder with a title block, or a marked stick).
- Cloud the shop drawing and keep a numbered clash list: clash ID, trade, dimension, sheet reference, recommended next step.
- Raise an RFI when the contract documents conflict, when a rated assembly is involved, or when the layout change would alter coverage.
- Note hanger problems you can see: pipe already strapped to duct, missing hangers on a long 1 in run, rod that looks like ⅜ in under an 8 in main.
Do not:
- Silently relocate a rated-wall penetration. Moving a sleeve 8 in to miss a stud is a change to a fire-resistance-rated assembly. It needs a listed firestop system for the new location, often a new sleeve detail, and usually architect/AHJ involvement. Mark the conflict. Do not core a second hole "for now."
- Approve other trades' shop drawings. That is not task 1.5.4.
- Recalculate density/area or change hazard classification because a duct appeared.
- Hang sprinkler pipe from the duct, tray, or plumbing as a coordination "solution."
- Assume the RCP is wrong because the sprinkler drawing is stamped, or the reverse.
Seismic braces deserve a special look on the same walk. A brace that lands on the only available beam flange can steal the hanger point you counted on in Chapter 10.1. Record the brace, the beam, and the pipe, and let the layout add a trapeze or a relocated hanger that still meets Table 17.4.2.1(a). Access panels deserve the same courtesy: a head in the only removable tile over a fan-coil is a future NFPA 25 fight.
Close the survey the way you would close any Level I correspondence: dated notes, photos tied to gridlines, a clash list, and RFIs for anything that changes coverage, a rated assembly, or another trade's contract scope. That package is the assist. The redesigned shop drawing that follows is the layout technician's next pass — still a simple layout, now with the plenum told the truth.
During a coordination walk, the HVAC shop drawing and a tape measurement both show a 54 in wide supply duct under a sprinkler branch in a high ceiling. No exception for a duct within 24 in of the floor applies. What should the Level I note tell the layout technician?
The RCP shows a 2×4 light fixture in the same ceiling tile where the sprinkler shop drawing shows a pendent. What is the correct Level I assist?
A 2½ in sprinkler main is shown penetrating a 2-hour rated corridor wall. In the field the stud sits on that centerline, and a fitter wants to slide the sleeve 8 in along the wall to miss the stud and firestop later. What should the Level I technician do?
Which set of actions matches NICET Level I task 1.5.4 on a coordination survey?