Fire sprinkler systems for indoor aquatic facilities and swimming pools in Washington State
IBC occupancy classification for natatoriums and aquatic centers, corrosion-resistant head requirements under NFPA 13 Section 6.2.7, pool chemical storage Group H analysis (sodium hypochlorite, chlorine gas, calcium hypochlorite), HVAC obstruction coordination, and the Washington DOH public pool permit critical path for Pierce County projects.
Indoor aquatic facilities: a specialized fire protection category
Indoor aquatic facilities occupy a category that most fire sprinkler contractors encounter infrequently — but when they do, the permit package is more complex than the building's occupancy classification initially suggests. The combination of a corrosive pool environment, high-hazard chemical storage, complex HVAC obstruction patterns, and a parallel regulatory track through the Washington Department of Health creates a permit process with more moving parts than a standard Group A-3 project.
This article covers the fire protection design and permit requirements for indoor aquatic facilities in Washington State, including community recreation centers, competitive swim facilities, hotel and resort natatoriums, swim school instruction facilities, and private swim and athletic clubs.
IBC occupancy classification
Indoor aquatic facilities typically involve multiple IBC occupancy classifications depending on the program:
Group A-3 (Assembly — Amusement and Recreation): The standard classification for the pool hall and recreational swimming area — the natatorium enclosure containing the pool basin, pool deck, and areas used by swimmers. IBC Section 309.1 defines Group A-3 as assembly uses intended for recreation and amusement. Community recreation pools, lap pools, instructional pools, and leisure pools are all Group A-3. IBC Section 903.2.1.3 triggers fire sprinklers when the fire area exceeds 12,000 square feet, when the space is on a floor other than the level of exit discharge, or when the space is below any floor of Group B or M occupancy. Most commercial indoor pools well exceed the 12,000 square foot trigger in the natatorium space alone.
Group A-4 (Assembly — Indoor Sporting Events): When permanent or fixed spectator seating — bleachers, grandstands, or fixed bench seating — is present for competitive swim events, the spectator zone classifies as Group A-4. IBC Section 903.2.1.4 triggers sprinklers under the same threshold conditions as Group A-3. If the spectator seating area is separated from the pool deck by a fire-resistance-rated barrier, each area may be analyzed as a separate fire area; without a rated barrier, the aggregate fire area combines both zones.
Group B (Business): Swim school instruction facilities where the primary use is classroom-scale swim instruction — a single teaching pool with instructor and students, without general public access — may classify as Group B if the occupant load remains below the assembly threshold and the facility is structured as an educational use rather than a public recreation use. AHJ interpretation varies; confirm with the fire authority at the pre-application conference before relying on Group B classification for a swim school.
Group S-1 (Storage — Moderate Hazard): Pool mechanical equipment rooms that store pool chemicals below the Group H MAQ threshold — or equipment rooms that contain filtration, pump, and chemical injection equipment with moderate combustible loading — classify as Group S-1.
Group H (High Hazard): Pool chemical storage commonly triggers Group H classification when quantities are analyzed against the IBC MAQ table. This is the most frequently missed classification issue in aquatic facility projects. See the pool chemical storage section below.
NFPA 13 hazard classification by zone
Pool facilities span a wide range of combustible loading conditions across their program spaces:
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| Zone | NFPA 13 Hazard Classification |
|---|---|
| Natatorium pool hall (deck and spectator area) | Ordinary Hazard Group 1 (OH1) — pool deck is wet and inherently low combustible loading; light furnishings in spectator areas |
| Lobby, reception, administrative offices | OH1 |
| Changing rooms and locker rooms with wood lockers | OH1 to OH2 depending on locker material and volume |
| Fitness and dry-land training areas adjacent to pool | OH2 |
| Pool mechanical equipment room (pumps, filters, controls) | OH1 to OH2 |
| Pool chemical storage room, below Group H MAQ | OH2 minimum; confirm with AHJ |
| Pool chemical storage room, above Group H MAQ | Extra Hazard — confirm design density with AHJ; separate Group H permit |
The pool basin itself — open water surface — does not require sprinkler coverage under NFPA 13. No combustibles exist at the water surface. Sprinklers serve the natatorium enclosure, pool deck, and all adjacent program spaces.
Corrosion-resistant head requirement
The most common NFPA 25 deficiency in existing natatoriums is corroded sprinkler heads. Addressing it correctly on new installations is straightforward; correcting it on an existing installation requires head-by-head replacement.
Why natatoriums are corrosive: Pool water chlorination generates free chlorine in the water and chloramines (monochloramine, dichloramine, nitrogen trichloride) as chlorine reacts with nitrogen compounds from swimmer perspiration, urine, and body oils. Chloramines off-gas from the water surface into the natatorium air. Combined chlorine (chloramine) concentrations above 0.5 ppm in the air create a corrosive environment that progressively attacks unprotected metals — including the solder, sealant, and metal components of standard sprinkler heads.
NFPA 13 Section 6.2.7 requirement: NFPA 13 requires listed corrosion-resistant sprinkler heads in environments classified as corrosive. Indoor pool enclosures universally meet the corrosive classification. Listed corrosion-resistant heads include brass heads with listed corrosion-resistant coatings and listed stainless steel heads. The listing is head-specific — not all brass heads are listed for corrosive environments, and not all stainless steel heads are listed for natatorium applications. Specify the exact listed model on the sprinkler design drawings; do not rely on a generic "corrosion-resistant" specification without confirming the listing.
Above-ceiling application: The corrosive atmosphere migrates through ceiling penetrations and perforations into the above-ceiling space. Practice varies on whether designers specify corrosion-resistant heads in the above-ceiling space above a natatorium; at minimum, the ceiling penetrations and heads within the pool hall boundary below the ceiling should be corrosion-resistant. Discuss the above-ceiling treatment with the AHJ at pre-application.
NFPA 25 operational implication: NFPA 25 requires replacement of corroded heads at each inspection cycle. Facilities that install standard heads in a natatorium will face recurring replacement costs as corrosion progresses. Listed corrosion-resistant heads are more expensive per head but eliminate the replacement cycle. Document the head type and listing on the as-built drawings so future NFPA 25 inspectors can confirm correct replacement heads are used.
Pool chemical storage — the hidden Group H trigger
Chemical storage is the fire code issue most frequently missed or underestimated on aquatic facility projects. Most pool operators do not think of their chemical room as a hazardous materials storage area — but from the IBC's perspective, several common pool chemicals trigger Group H classification at quantities well below what typical aquatic facilities use.
Sodium hypochlorite (liquid bleach, 10–12.5% NaOCl)
Sodium hypochlorite is the most common chlorination method for commercial pools in Washington. It is classified as a Class IIIA oxidizer under NFPA 430 (Code for the Storage of Liquid and Solid Oxidizers).
- IBC MAQ: IBC Table 307.1(2) limits Class IIIA oxidizer storage to 500 gallons per control area in a sprinklered building (250 gallons in a non-sprinklered building). Above this limit, the storage area classifies as Group H-3.
- Typical pool quantities: Commercial pools often store sodium hypochlorite in 250-gallon to 2,000-gallon bulk tanks, or receive regular truck deliveries to on-site tanks. Any installation exceeding 500 gallons per control area requires Group H-3 classification for the storage room.
- Group H-3 implications: The storage room requires 1-hour fire-resistance-rated separation from the remainder of the building, a dedicated exhaust ventilation system, and NFPA 13 sprinkler coverage designed to the hazard density. The storage room may be constructed as a detached hazardous material storage building to avoid the separation requirement in the main pool building.
Gaseous chlorine (Cl₂ gas cylinders)
Gas chlorine is still used in older commercial pool installations, particularly municipal facilities with legacy systems. Gas chlorine cylinders are being phased out in favor of sodium hypochlorite but remain in service.
- Classification: Chlorine gas is classified as a toxic compressed gas under NFPA 55 (Compressed Gases and Cryogenic Fluids Code). It is also a strong oxidizer.
- IBC MAQ: IBC Table 307.1(1) limits toxic gas storage to 1 pound per control area. A standard 100-pound gas chlorine cylinder contains 100× the Group H-2 MAQ. A 150-pound cylinder contains 150× the MAQ.
- Group H-2 classification: Any facility using gas chlorine cylinders — even a single 100-lb cylinder — will trigger Group H-2 classification for the chlorine room. This is one of the most severe Group H triggers in the IBC, and it surprises pool operators who have been using gas chlorine without incident for decades.
- NFPA 55 requirements: Chlorine gas detection systems, emergency shutoff, and coordination with the local fire authority on emergency response planning are typically required by NFPA 55 and the IFC for toxic gas storage above MAQ.
- Practical recommendation: If a project is converting from gas chlorine to sodium hypochlorite as part of renovation, the Group H-2 classification is eliminated by the conversion. The construction budget for chemical storage room upgrades and the ongoing safety liability of gas chlorine storage should be weighed against the conversion cost.
Calcium hypochlorite (Ca(OCl)₂, granular pool shock)
Granular calcium hypochlorite is marketed as a pool shock product and is sometimes used instead of liquid sodium hypochlorite. It is more hazardous from an IBC standpoint than liquid sodium hypochlorite.
- Classification: Calcium hypochlorite is a Class 3 oxidizer under NFPA 430 — a higher hazard tier than sodium hypochlorite.
- IBC MAQ: IBC Table 307.1(2) limits Class 3 oxidizer storage to only 10 pounds per control area in a sprinklered building. This is a very low threshold.
- Practical impact: A single 50-pound bucket of granular pool shock exceeds the Class 3 oxidizer MAQ by 5× in a sprinklered building. Many pool operators store several buckets of granular shock for manual treatment and emergency super-chlorination, without realizing that the aggregate quantity triggers Group H classification.
- AHJ position: Confirm the AHJ's position on calcium hypochlorite MAQ at pre-application. Some jurisdictions treat pool shock storage in a dedicated ventilated cabinet differently from bulk storage in an equipment room; others apply the MAQ strictly.
Muriatic acid (hydrochloric acid, pH reducer)
Muriatic acid (hydrochloric acid, typically 31% HCl) is used to lower pool water pH.
- Classification: Classified as a corrosive liquid, Group H-4 trigger under IBC.
- IBC MAQ: Class IIIB corrosive (HCl at 31%) — MAQ for indoor sprinklered storage is 1,000 gallons per control area. Most commercial pool installations stay below this MAQ with pH control quantities.
- Note: The MAQ is higher than sodium hypochlorite, but muriatic acid and sodium hypochlorite cannot be stored in the same room — they react to generate chlorine gas when mixed, which is a significant safety hazard. Separate storage rooms or separated storage cabinets with appropriate containment are required when both chemicals are present at the facility.
Chemical storage planning checklist
At the pre-application conference, bring a complete chemical inventory including:
- Chemical name and concentration
- Maximum quantity stored at any one time (gallons for liquids, pounds for solids, pounds for gases)
- Storage location and configuration (tank, totes, drums, bags, cylinders)
- Secondary containment capacity
This inventory drives the IBC MAQ analysis, Group H determination, and the sprinkler hazard design for the chemical storage area. Architects and GCs who skip this step consistently encounter plan review corrections that require structural changes to achieve the required fire-resistance-rated separations.
HVAC coordination in natatorium enclosures
Natatorium HVAC systems are significantly more complex than standard commercial building HVAC, and this complexity affects the sprinkler design in two ways: obstruction and condensation.
Obstruction: Natatorium HVAC typically delivers large volumes of low-velocity air targeted at the pool water surface and the occupant breathing zone above the pool deck. This requires large-diameter supply air duct soffits and return air louver banks positioned near the ceiling perimeter and above the pool deck. These soffits are often 24 inches to 36 inches deep and run the length of the pool hall — creating substantial obstructions to ceiling-mounted sprinkler head coverage under NFPA 13 Section 8.5. The sprinkler contractor must receive the natatorium HVAC ductwork drawings — including duct cross-section dimensions and elevations — before the sprinkler design is finalized. Submit the coordinated design with obstruction analysis to the AHJ.
Dehumidification equipment: Natatoriums use aggressive dehumidification (desiccant wheels, refrigerant systems, or both) with large above-ceiling air handling units. AHU placement above the natatorium ceiling creates large equipment footprints that must be factored into the sprinkler design.
Condensation protection: In the above-ceiling space above a natatorium, warm humid air from the pool hall mixes with the cooler above-ceiling environment, creating conditions where condensation can form on cold metal surfaces — including steel sprinkler pipe. Steel pipe in this environment requires evaluation for external corrosion protection; some designers specify CPVC or corrosion-resistant coatings for the above-ceiling pipe in natatorium applications. Confirm the material specification with the sprinkler contractor and AHJ.
Freeze protection for above-ceiling piping
The occupied pool hall is heated and does not create freeze exposure for sprinkler pipe in the habitable space. The above-ceiling space is a different matter.
Large-span natatoriums — particularly those constructed in metal building systems with minimal ceiling insulation — can have above-ceiling temperatures that drop below 40°F during Washington winters when the roof structure is exposed to outdoor temperatures. Natatorium roofs with high thermal mass and good insulation stay warmer; thin metal panel roofs with minimal insulation do not.
Evaluation requirement: The mechanical engineer's thermal analysis of the roof and ceiling assembly should be reviewed to determine whether the above-ceiling space has freeze exposure. If the design minimum temperature in the above-ceiling space cannot be confirmed above 40°F, the designer must address freeze protection for the above-ceiling pipe runs. Options include routing all pipe through heated spaces, adding attic insulation and heat tracing on exposed pipe, or using a dry-pipe or preaction system for the above-ceiling portion of the natatorium.
Pre-application question: Raise the above-ceiling temperature question with the AHJ at pre-application, particularly for metal building natatoriums constructed with minimal ceiling insulation.
Washington DOH public pool permit critical path
Public swimming pools in Washington State are regulated under WAC 246-260 by the Washington State Department of Health (DOH). The DOH public pool permit is a separate regulatory track from the building permit, and both must be resolved before the facility can open.
Scope: WAC 246-260 applies to any pool, spa, hot tub, or similar water feature available for use by the public — including hotel and motel pools, health club pools, municipal recreation pools, and swim school pools. Private pools at single-family residences are exempt; private pools at multifamily residential buildings with more than a certain number of units are covered.
DOH permit requirements: The DOH evaluates the pool design for filtration capacity, turnover rate, water chemistry control, recirculation system, emergency drain, safety features (depth marking, lifeline positioning, diving equipment limitations), and chemical feed system design. The chemical feed system design intersects directly with the IBC chemical storage analysis.
Sequencing: The building permit (including fire sprinkler permit) and the DOH pool permit run concurrently but independently. Certificate of Occupancy closes out the building permit; DOH pool permit final approval is required before the pool can be open to the public. The fire authority's acceptance test for the fire sprinkler system must pass before the CO is issued; the CO must be issued before the facility can open. If the DOH pool permit is on a longer review cycle, the facility may obtain CO and then wait for DOH final approval before opening — but the fire system must be complete and accepted before CO regardless.
Pre-application engagement: Engage the Washington DOH pool program office at the same time as the building department pre-application conference. Some chemical storage configurations that satisfy the IBC's Group H requirements may require additional measures under WAC 246-260 — particularly for chemical injection systems and bulk chemical storage adjacent to the pool mechanical room. Resolving both permit tracks together prevents late-stage plan revisions.
Pierce County AHJ context
Indoor aquatic facilities in Pierce County span city jurisdictions and unincorporated county areas.
City of Tacoma: Tacoma Development Services (building permit and SEPA) and Tacoma Fire Department (fire code, NFPA 13 permit, IFC hazardous materials permits for pool chemical storage). Tacoma Fire has experienced plan reviewers for Group H chemical storage analysis; the pre-application conference should include a chemical inventory and a floor plan showing chemical storage room location and proposed Group H separation. Washington DOH western region office handles WAC 246-260 pool permits for Tacoma facilities.
City of Puyallup: Puyallup Development Services and Puyallup Fire Department. The South Hill residential corridor has active swim school and private aquatic club permit pipeline. Coordinate with Puyallup Fire on chemical storage classification early — the Group H analysis for sodium hypochlorite is sometimes interpreted differently at the local level.
City of Bonney Lake: Bonney Lake Community Development Department and Bonney Lake Fire (East Pierce Fire & Rescue). New aquatic facility TIs in Bonney Lake are often associated with YMCA facilities and residential club amenities in the Sumner-Bonney Lake growth corridor.
Unincorporated Pierce County (South Hill, Frederickson, Spanaway, Graham): Pierce County Development Center (building permit) plus the applicable fire district having jurisdiction. Spanaway area facilities may fall under Pierce County Fire District No. 22 or adjacent districts; confirm AHJ routing before the pre-application conference.
Metropolitan Parks District of Tacoma (Metro Parks): Metro Parks operates several recreational facilities in the Pierce County area including the Sprinker Recreation Center (Spanaway — Pierce County jurisdiction, not Tacoma city limits). Metro Parks capital projects go through Pierce County Development Center for facilities outside Tacoma city limits.
Six common fire protection mistakes in aquatic facility projects
| Mistake | Consequence | Correct approach |
|---|---|---|
| Installing standard sprinkler heads in the natatorium pool hall | Heads corrode within 3–5 years; NFPA 25 inspection flags corroded heads as deficiencies requiring replacement; ongoing replacement cost | Specify listed corrosion-resistant heads (model number, not generic specification) in pool hall, locker rooms, and any space exposed to chloramine atmosphere |
| Missing the Group H chemical storage trigger for sodium hypochlorite | Plan review correction requires Group H-3 rated separation or relocation of storage to a detached hazardous materials building | Perform IBC MAQ analysis on complete chemical inventory at pre-application; design chemical room with Group H-3 construction if above 500-gallon NaOCl threshold |
| Underestimating the Group H-2 trigger for gas chlorine | Single 100-lb chlorine cylinder exceeds Group H-2 MAQ by 100×; facility cannot pass plan review without Group H-2 construction | Identify at pre-application whether facility uses gas chlorine and analyze against Group H-2 MAQ; evaluate conversion to sodium hypochlorite if Group H-2 construction is not feasible |
| Not coordinating HVAC ductwork with sprinkler design before permit | Natatorium HVAC soffits create large obstructions to sprinkler coverage; obstruction analysis corrections require sprinkler redesign and delayed permit | Submit HVAC ductwork cross-section drawings to sprinkler contractor before sprinkler design is finalized; include obstruction analysis in permit package |
| Forgetting to engage Washington DOH at pre-application | DOH pool permit review flags chemical storage or pool equipment conflicts that require late-stage plan revisions; DOH review cycle on final permit may delay opening even after CO is issued | Engage Washington DOH pool program office concurrently with building department pre-application; resolve chemical storage and pool equipment design conflicts across both permit tracks |
| Not accounting for above-ceiling freeze exposure in metal building natatoriums | Wet-pipe sprinkler pipe in an unheated above-ceiling space freeze-ruptures during first cold winter; flooding damages pool equipment and causes significant repair cost | Evaluate above-ceiling temperature with structural engineer; if freeze exposure exists, specify dry-pipe or preaction system for above-ceiling runs, or add insulation and heat tracing |
Permit sequence for an indoor aquatic facility in Pierce County
- Pre-application conference — IBC occupancy classification for all program spaces; aggregate fire area analysis; complete chemical inventory and IBC MAQ analysis; Group H determination for chemical storage room; Washington DOH pool program pre-application engagement (concurrent)
- HVAC ductwork and structural coordination meeting — confirm natatorium ceiling obstruction analysis before any permit submission
- Building permit application with concurrent NFPA 13 fire sprinkler permit — include chemical storage Group H documentation (or plan showing quantities below MAQ) with the permit package
- IBC Group H permit (if applicable) — reviewed concurrently with building permit; some jurisdictions integrate this into the building permit; others issue a separate hazardous materials permit
- Washington DOH pool permit application — runs concurrently with the building permit process; schedule submission to match the expected building permit timeline
- Plan review — expect comment letters from both the building department and the DOH; chemical storage and HVAC coordination are the most common comment subjects
- Construction — rough-in, pressure test, flush; HVAC ductwork installation coordinated with sprinkler rough-in sequence
- Chemical storage room construction inspection — fire authority confirms Group H separation before chemical storage area is closed in
- NFPA 13 fire sprinkler final acceptance test witnessed by AHJ — confirm corrosion-resistant head installation in pool hall and locker rooms
- IBC Group H final inspection (if applicable) — fire authority and building department confirm chemical storage room construction and operational requirements
- Washington DOH final pool inspection — water quality, safety features, chemical feed systems
- Certificate of Occupancy (after NFPA 13 acceptance and building inspections)
- DOH public pool permit final approval — required before pool is open to the public; may follow CO if DOH review is on a different timeline
FAQ
More questions
- Q.01Does the pool basin itself need sprinkler coverage under NFPA 13?
- No — the open water surface of the pool basin does not require sprinkler coverage under NFPA 13. There are no combustibles at the water surface, and sprinklers would have no effect on a fire in an open pool. NFPA 13 sprinklers serve the natatorium enclosure — the ceiling above the pool hall, the pool deck area, locker rooms, mechanical rooms, storage areas, lobbies, and all other program spaces in the facility. The sprinkler layout is designed around the ceiling plane above the pool and deck, not the pool basin itself. However, the natatorium ceiling is often a high ceiling (20–40 feet or more for competition pools), which affects head selection. Standard quick-response pendant heads are listed to approximately 20 feet; ceilings above 20 feet require extended coverage (EC) heads listed for the actual installation height. Confirm the ceiling height in the pool hall and specify heads with the appropriate listing for that height in the sprinkler design drawings.
- Q.02Our pool facility stores sodium hypochlorite in a 500-gallon bulk tank in the equipment room. Does this trigger Group H?
- At exactly 500 gallons of sodium hypochlorite (a Class IIIA oxidizer under NFPA 430) in a sprinklered building, you are at the IBC MAQ threshold for that control area. If you store up to 500 gallons in a single control area in a sprinklered building, the equipment room does not trigger Group H-3 classification for the oxidizer alone — though any other chemicals in the room must also be analyzed. If you exceed 500 gallons in the control area, or if you have additional Class IIIA oxidizers that bring the aggregate above 500 gallons, the storage area triggers Group H-3 classification. Group H-3 requires 1-hour fire-resistance-rated separation from the remainder of the building, a dedicated exhaust ventilation system that prevents chemical vapor accumulation, and NFPA 13 sprinkler coverage for the Group H-3 hazard density. The practical solution for facilities using 500–2,000 gallons of sodium hypochlorite is to construct a dedicated chemical storage room with Group H-3 construction — often this is done as a detached storage enclosure adjacent to the pool mechanical room to avoid the rated separation requirements inside the main building. Bring the chemical inventory to the pre-application conference and resolve the Group H determination before the architectural floor plan is finalized.
- Q.03We're adding an indoor lap pool to an existing fitness center that is already sprinklered. What fire protection work is required for the addition?
- The addition triggers a new fire protection review for the area being added, and depending on the construction approach, may trigger work in the existing building as well. For the new natatorium addition: the sprinkler system must be designed per NFPA 13 for the Group A-3 occupancy, corrosion-resistant heads must be specified for the pool hall and locker room spaces, and the HVAC coordination and chemical storage analysis must be completed as described above. The connection between the addition and the existing building affects the scope: if the addition connects to the existing building without a fire-resistance-rated barrier at the connection point, the fire area for IBC sprinkler trigger analysis may combine the existing footprint with the addition, potentially triggering modifications to the existing system. If the addition is separated from the existing building by a fire wall or fire barrier, the addition's sprinkler system can typically be analyzed as a separate fire area. The existing sprinkler system's hydraulic capacity must also be evaluated — if the addition connects to the existing system's water supply and riser, the combined water demand of the addition and the existing system must be confirmed against the available water supply. In many fitness center additions, the most straightforward approach is an independent water supply connection and riser for the aquatic addition, rather than integrating it with the existing system.
- Q.04Why do standard sprinkler heads fail in indoor pool environments, and how long does it typically take?
- Standard residential and commercial sprinkler heads use a combination of materials including solder, brass alloy body components, and heat-sensitive glass bulbs or fusible links. In a natatorium environment, chloramine gas (particularly nitrogen trichloride, the most aggressive chloramine species) is an oxidizing acid that reacts with and progressively degrades unprotected brass alloys, solder connections, and the plated coatings on standard heads. The degradation rate depends on combined chlorine concentration in the natatorium air, temperature, and ventilation effectiveness — but in a pool with elevated combined chlorine (above 0.5 ppm), noticeable corrosion can appear on standard heads within 2–5 years, and by NFPA 25 inspection cycles, corroded heads will be flagged as deficiencies requiring replacement. The failure mode is not sudden activation — a corroded head is more likely to fail to activate when needed (because the fusible element's response characteristics change as corrosion progresses) and to leak at the solder joint before the occupancy temperature activates the head. NFPA 25 Section 5.4.1.1 requires replacement of any head showing signs of corrosion, mechanical damage, or coating that was not factory-applied. Listed corrosion-resistant heads — either heads with a factory-applied listed corrosion-resistant coating or listed stainless steel heads — are designed to resist chloramine attack. The listing is specific to the head model and the corrosive application; confirm that the head model you specify carries a listing for corrosive environments, not just a general 'stainless steel' designation without a specific corrosive-environment listing.
Last reviewed by Michael Berger, Owner · 1st Choice Fire · WA L&I #1STCHCF770OF