Guide
Fire suppression nozzle caps and coverage after hood cleaning
Hood cleaning crews work around the suppression piping all night: they bag nozzles, scrape the plenum, and pull appliances off the line to reach the wall. The morning after, the most common leftovers are simple — a blow-off cap missing or caked in degreaser, a nozzle knocked off its aim point, a fryer pushed back into the wrong slot. None of that shows on the hood cleaning certificate. This page is the opening manager’s check, and the line between what you look at and what the suppression contractor fixes.
What a blow-off cap does
The cap sits over the nozzle tip. When the system discharges, agent pressure pops it off. Between discharges it keeps grease vapor, steam, and cleaning chemical out of the orifice. A plugged orifice means agent does not reach the appliance it was aimed at.
| Cap type (manufacturer literature) | Where used | What to look for |
|---|---|---|
| Rubber cap with retaining strap (Ansul R-102 manual) | Standard nozzles in normal heat | Present, strap attached, not brittle or cracked, snaps back on |
| Metal cap, wire-retained, with O-ring (Ansul R-102 manual; current R-102 nozzles ship with metal caps) | High-heat areas — Ansul cites over about 400 °F, such as broilers | Present, wire attached, cap turns freely on the nozzle |
| Standard vs high-temperature cap (Amerex KP manual) | Amerex standard cap rated to 350 °F; high-temperature cap above that | Right cap for the appliance below it — your contractor decides, you just report missing ones |
| Foil seal caps “if applicable” (Badger Range Guard owner guide) | Range Guard nozzles | Seals in place; no obstructions in front of the nozzle |
The morning-after check (staff, 5 minutes)
- Every nozzle you can see in the plenum and over the line has a cap on it. Count them against yesterday’s photo if you have one
- No caps caked in degreaser or grease. Ansul’s owner guide says check daily for missing or grease-covered caps
- Nozzle bags, tape, or plastic the crew used during cleaning are gone
- Piping not bent, loose, or knocked out of its brackets
- Every appliance is back in the spot it started in, under the nozzle aimed at it (fryer under the fryer nozzle, broiler under the broiler nozzle). See changing your menu or equipment
- Fusible links not wired, tied, or bagged. See fusible links and detection devices
- Releasing unit shows set/cocked, seals intact, manual pull station clear
- Fans run before burners light. See post-clean fan spin test and suppression reset
Anything off: do not try to reseat a nozzle or re-aim it. Badger’s owner guide says that if the monthly check finds a discrepancy, do not run the protected equipment and call the authorized distributor. Write down what you saw and send a photo.
Coverage: why appliance position matters
Pre-engineered systems are listed for a specific nozzle type, height, and aim point over each appliance. Two patterns from manufacturer literature:
| Design | What it means after cleaning |
|---|---|
| Appliance-specific nozzles | Each appliance has its own nozzle. Swap two appliances and both can be unprotected. Amerex says dedicated appliances such as upright broilers need review and possible re-aim after any move. |
| Overlapping / zone coverage (e.g. Amerex Zone Defense) | Eligible appliances may move within the hood’s zone without re-aiming. Dedicated appliances are still the exception. Ask your contractor which design you have. |
The model IFC (2024 §904.14.5.1; 2018 numbering §904.12.5.1) says that when cooking media, appliance position, or appliances change, the existing suppression system has to meet the current commercial-cooking requirements. Ansul’s semiannual maintenance checklist verifies nozzle types, mounting locations, and aim points. If grease or residue is found inside a nozzle, the distribution piping gets inspected and cleaned.
Who does what
| Task | Who | Not |
|---|---|---|
| Protect nozzles during cleaning; remove bags and tape after | Hood cleaning crew | Leaving it for the morning cook |
| Daily / monthly visual: caps on, piping intact, appliances in place | Owner / staff (NFPA 17A monthly owner check, per fire-protection contractors’ code summaries) | Skipping it because the semiannual tag is current |
| Replace missing or damaged caps; re-aim nozzles; review coverage after appliance changes | Authorized suppression distributor / licensed contractor | Hood cleaner pushing a cap back on, or staff with a wrench |
| Semiannual service; cap replacement at service; link replacement | Suppression contractor. IFC: every six months and after activation; fusible links annually (manufacturers often say semiannually) | Hood cleaning invoice line item |
Schedule tip: book the suppression service right after the hood cleaning when you can. Ansul’s owner guide says to have the system inspected immediately after major hood and duct cleaning. See suppression vs hood cleaning.
Who it’s for / not for
- For: Opening managers the morning after a hood cleaning; facilities staff writing a monthly owner check; operators who move appliances around between services
- Not for: Designing nozzle layouts, choosing cap types, or servicing a system. That work requires the manufacturer’s training and, in many states, a license
Sources
- Ansul R-102 Owner’s Guide (PDF, via Greenheck) (monthly inspection; daily check for missing or grease-covered nozzle caps; metal caps turn freely; inspect at six-month intervals and immediately after major hood and duct cleaning; links wired shut during cleaning)
- Ansul R-102 design, installation, and maintenance manual (PDF, via CaptiveAire) (blow-off cap definition; nozzles shipped with metal caps; semiannual maintenance)
- Badger Range Guard owner’s manual (PDF) (owner monthly inspection per NFPA 17A: caps in place, no obstructions; don’t run equipment with discrepancies; advise distributor of appliance changes)
- Amerex KP / Zone Defense manual (PDF) (blow-off cap definition; standard cap to 350 °F vs high-temperature cap; zone of protection; dedicated appliances need review after a move)
- Moreno Valley Fire Department — Fixed extinguishing systems guideline (PDF) (nozzles provided with caps per NFPA 17A 4.3.1.5; acceptance test verifies nozzle type, height, and orientation)
- Orr Protection — Code requirement reference guide (PDF) (secondary: NFPA 17A monthly owner inspection includes nozzle blow-off caps intact)
- 2024 IFC Chapter 9 as adopted by Phoenix (UpCodes) (§904.14.5.1 appliance changes; §904.14.5.2 six-month service; §904.14.5.3 fusible links annually)
Next step
Before the next hood cleaning, take one photo of every nozzle and every appliance position under the hood. The morning after, compare. Missing cap, bent pipe, or appliance in the wrong slot: call the suppression contractor before the first burner lights.