How High Can You Store Under Ceiling-Only Sprinklers?

Ceiling-only sprinklers can protect rack storage under ceilings as high as 45 ft when the sprinklers are Early Suppression Fast Response (ESFR) heads with a large K-factor and the commodity is Class I to IV or cartoned unexpanded plastics. NFPA 13 (2022) sets ESFR limits by ceiling height, not by storage height. Control Mode Density/Area (CMDA) standard spray sprinklers top out near 25 ft of rack storage, Control Mode Specific Application (CMSA) sprinklers sit in between, and exposed plastics cut every one of those numbers down. Above the limit for the installed sprinkler type, National Fire Protection Association (NFPA) 13 requires in-rack sprinklers or a different ceiling design, and the fire code requires a new high-piled storage review.

The question usually arrives from a tenant, a broker or an owner looking at a lease: the building has sprinklers, the racks are going to 30 ft, does anything need to change? The answer depends on four numbers that are easy to measure and one classification that is not. This article lays out the ceiling-only height limits by sprinkler type under NFPA 13, how storage and ceiling height are measured, what changes the answer, and what a project owes the fire code official once a limit is crossed.

What Are the Ceiling-Only Storage Height Limits by Sprinkler Type?

NFPA 13 does not publish one height limit. The standard gives each protection scheme its own chapter, and each chapter lists the conditions that a ceiling-only design has been tested to protect, by commodity class. The CMDA and CMSA criteria pair a storage height with a ceiling height; the ESFR table is indexed by maximum ceiling height alone. If the building’s storage height, ceiling height and commodity all fall inside an entry, ceiling sprinklers alone are permitted; if any one falls outside, the design has to change.

The table below states the structure of those chapters and the headline numbers. It is a summary of the limits, not a reproduction of the tables, and every row needs to be confirmed against the adopted edition and the sprinkler listing before anything is built.

Two patterns in the table matter more than any single number. First, ESFR puts cartoned unexpanded plastics in the same table row as Class I to IV commodities, which is why most modern distribution buildings are designed for that class. CMSA covers cartoned plastics in separate entries, and some of its values differ from Class I to IV. Second, exposed plastics, and exposed expanded plastics above all, lose ceiling-only coverage quickly (exposed expanded plastic in racks has only the K-25.2 ESFR route in Section 23.4), which is why a change in a customer’s packaging can defeat a sprinkler system that was correct the day it was installed. DGA’s guide to commodity classification under NFPA 13 explains how product, packaging and pallet combine into a class.

The 2022 edition tightened some ESFR entries. For uncartoned unexpanded plastics under a 35 ft roof, the K-14 and K-16.8 entries that the 2019 edition allowed were removed, so the design falls to K-22.4 or K-25.2 at the 40 ft roof criteria. Pennsylvania and the Maryland building code still reference the 2019 edition, so the same building can have a different answer across a state line.

How Are Storage Height, Ceiling Height and Clearance Measured?

Storage height is measured from the floor to the top of the highest stored commodity, including the pallet it sits on and any load that overhangs the top beam. The top of the rack upright does not count; the top of the product does. Ceiling height is measured from the floor to the underside of the roof deck or ceiling, not to the bottom of the joists or the sprinkler deflector. Clearance is the vertical distance from the top of storage to the sprinkler deflector.

NFPA 13 (2022) sets the minimum clearance from the top of storage to the deflector at 18 in. for standard spray sprinklers (Section 20.9.6.1 for storage), 36 in. for CMSA sprinklers (Section 13.2.9) and 36 in. for ESFR sprinklers (Section 14.2.12). The 36 in. figure exists because suppression-mode sprinklers need room to develop their spray pattern before it reaches the top of the array. A tenant who stacks one more pallet on the top beam can violate the clearance rule without coming anywhere near the storage height limit in the table above.

Three storage conditions change the answer even when the heights are fine. Encapsulated commodities, meaning pallet loads wrapped in plastic over the top as well as the sides, shed sprinkler water and carry a higher density in the CMDA criteria of Chapter 21. The CMSA and ESFR tables make no encapsulation distinction. Solid shelves wider than the open-rack limits block water from reaching the levels below and generally force in-rack sprinklers or a specific-application design. Open-top containers on upper levels catch the ceiling water meant for the storage beneath them; DGA’s article on why open-top bins defeat rack sprinklers covers the fix.

Can the Existing Ceiling Sprinklers Protect the New Storage?

The design check runs in a fixed order, and the first three steps need no engineer, only a tape measure and the product list. The decision tree below is the sequence DGA’s engineers follow when a rack fit-out brief comes in. Each “no” has a cost, and the cheapest fixes sit at the top.

What Are the Exceptions and Alternatives When the Limit Is Exceeded?

The first alternative is the one NFPA 13 names: in-rack sprinklers. NFPA 13 (2022) Chapter 25 consolidates every in-rack design, with one or more levels of sprinklers inside the rack and a matched ceiling design, and it covers storage heights that ceiling-only designs cannot. In-rack systems add piping inside the racks, a risk of forklift damage, and a maintenance burden, which is why owners of speculative buildings avoid them, but for exposed expanded plastics they are often the only path outside the K-25.2 ESFR option in Section 23.4.

The second alternative is to change the storage rather than the sprinklers. Dropping the top beam so the load tops out at 25 ft instead of 30 ft can move a building from “in-rack required” to “ceiling-only permitted” under the same sprinklers. Changing from exposed to cartoned product, or from plastic to wood pallets, can drop the commodity a class. Both are operational commitments that belong in the lease and on the high-piled storage plan, because the fire code official will hold the tenant to them.

The third alternative is a different ceiling sprinkler. Replacing CMSA or older ESFR heads with K-25.2 ESFR sprinklers can extend ceiling-only protection to ceilings up to 45 ft without touching the racks, provided the pipe sizes, the pressure and the water supply can carry the new demand. DGA’s comparison of ESFR and CMSA sprinklers for warehouses covers that trade in detail.

The fourth path is a design outside the NFPA 13 tables. Chapter 24 permits alternative sprinkler system designs based on a sprinkler’s specific listing, and some manufacturers hold listings that go beyond the NFPA 13 tables. FM Global Data Sheet 8-9 publishes its own protection tables by commodity, storage height and ceiling height, which differ from NFPA 13 in places and are often stricter. An FM-insured building has to satisfy both, and the AHJ has to accept the FM design under the alternative-methods provision of the adopted building or fire code.

What Applies Once the Ceiling-Only Limit Is Crossed?

Crossing a height limit triggers four things, and a project usually meets all of them together. First, a new sprinkler design, meaning sealed drawings and hydraulic calculations for the ceiling system, the in-rack system or both, filed under a sprinkler permit. Second, an updated high-piled storage plan: the IFC’s 12 ft and 6 ft triggers and the pile limits in Table 3206.2 are explained in DGA’s article on when IFC Chapter 32 applies to high-piled storage, and once the plan on file no longer matches the racks, the operational permit is no longer valid.

Third, a water supply check. ESFR demands of 1,500 gpm to 2,200 gpm at 50 psi to 75 psi at the top of the riser are common, far above what most municipal mains deliver at the required pressure, so a fire pump, a larger service or a tank often arrives with the new design. Fourth, the insurer’s sign-off, since a carrier that rated the building for 25 ft of Class III will re-underwrite it for 40 ft of plastics.

How Do the Editions Differ Across NY, NJ, PA, MD and DE?

The height limits come from NFPA 13, so they differ across the region only by edition. The 2019 and 2022 editions share the same chapter numbering for storage (Chapters 20 through 25); the 2025 edition that Delaware adopted keeps Chapters 20 through 25 but revises several storage tables, so citations for Delaware projects should be checked against the 2025 text. New York City’s building code references an earlier edition of NFPA 13 as modified by Appendix Q, where the storage chapters carry different numbers again.

Editions as listed in DGA’s Fire Code Cheat Sheet for NY, NJ, PA, MD and DE. Local amendments are not shown.

DGA checks existing sprinkler systems against proposed storage, designs in-rack and ESFR upgrades and prepares high-piled storage plans across New York, New Jersey, Pennsylvania, Maryland and Delaware. Project briefs get confirmation and preliminary code feedback within one business day. See where DGA works →

Worked Example: 25 ft of Cartoned Plastics Under a 32 ft Deck

A tenant proposes double-row racks holding cartoned unexpanded Group A plastics to 25 ft in a warehouse with a 32 ft clear height to the underside of the deck. The clearance is 7 ft, so both the 18 in. and 36 in. rules are satisfied. The storage is over 12 ft, so IFC Chapter 32 applies and the high-piled storage plan has to show the new arrangement. What remains is whether the installed ceiling sprinklers have an entry for 25 ft of cartoned unexpanded plastics under a ceiling that reads as 35 ft in the tables, since common practice is to use the next ceiling height listed rather than interpolate.

The water supply decides the last two rows. Twelve K-16.8 sprinklers at 52 psi flow about 121 gpm each, or about 1,450 gpm, plus 250 gpm of hose allowance for 60 minutes, for a demand near 1,700 gpm at the riser before pipe friction. Twelve K-25.2 sprinklers at 25 psi, the 40 ft ceiling entry, flow about 126 gpm each, or about 1,510 gpm plus hose, near 1,760 gpm. A supply curve from a recent hydrant flow test can be plotted against either demand in DGA’s sprinkler water supply analysis tool; if the curve falls short, a fire pump joins the project.

The lease matters as much as the hydraulics. If the building is marketed as “ESFR” but the heads are K-14 on a 30 ft design, the tenant’s 25 ft of plastics is marginal and 30 ft is out. Owners, tenants and brokers negotiating industrial space in the region can read the sprinkler data plate and the installed K-factor before signing; DGA reviews those on the industrial and high-hazard projects it serves and the finding often changes the deal.

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This article is general information, not a substitute for a project-specific evaluation. Code editions, local amendments, sprinkler listings and insurer requirements change; confirm the adopted edition of NFPA 13 and the authority having jurisdiction for the facility.