When Does a Warehouse Need Draft Curtains?

A warehouse needs a draft curtain today mainly where National Fire Protection Association (NFPA) 13 calls for one: on the line where an early suppression fast-response (ESFR) sprinkler area meets an area protected by standard-response sprinklers. NFPA 13 (2022) Section 14.2.5 requires a noncombustible curtain at least 2 ft deep on that boundary, centered over a clear aisle at least 4 ft wide. The International Fire Code (IFC) and International Building Code (IBC) stopped requiring draft curtains with smoke and heat vents in their 2015 editions, so a vent or exhaust requirement no longer brings a curtain with it.

Draft curtains, also called curtain boards, still appear in three other places: as one way to separate two different sprinkler designs under NFPA 13, in a vent design engineered under NFPA 204, and around unenclosed floor openings protected by closely spaced sprinklers. Inside an ESFR area a curtain works against the sprinklers, which is why the model codes moved away from them.

Where Do the Codes Still Require a Draft Curtain?

The table lists each warehouse situation where a current code or standard requires a draft curtain or offers one as an option. The jurisdiction table further down gives the NFPA 13 edition for each state.

The first row drives most warehouse draft curtains built now. ESFR protection is common in new distribution buildings, and the office, packing, battery charging or cold storage area beside it is often protected by standard-response sprinklers, so the boundary between the two needs a curtain unless a wall already sits on that line.

Mixing quick-response and standard-response control mode sprinklers under one open roof is a separate question. NFPA 13 (2022) Chapter 9 expects sprinklers within a compartment to share one response type once quick-response sprinklers are used there, and a draft curtain is not a wall, so the usual answers are one response type or a wall on the boundary.

Why Did the IFC and IBC Stop Requiring Draft Curtains?

Through the 2012 editions, IFC and IBC Section 910 required draft curtains together with smoke and heat vents in large Group F-1 and S-1 buildings and in high-piled storage, with Table 910.3 setting the curtain depth and the area each curtained section could hold. For Group F-1 and S-1 the table called for a curtain at least 0.2 times the ceiling height and never less than 4 ft, enclosing no more than 50,000 sq ft, and the 2012 IFC high-piled storage table (Table 3206.2) carried its own curtain board column. Even then the codes kept curtains out of ESFR areas and placed them only on the line between ESFR and other sprinklers.

Tests by Factory Mutual in 1994 and a 1997 to 1998 study sponsored by the Fire Protection Research Foundation found that draft curtains in sprinklered storage can increase the number of sprinklers that open. The 2015 IFC and IBC then rewrote Section 910 as smoke and heat removal, sized vents from the building volume or floor area, added a mechanical exhaust option and dropped draft curtains.

The 2018, 2021 and 2024 editions kept that approach, with no draft curtain provision in Section 910 and no curtain column or footnote in IFC Table 3206.2. The area bands and the vent or exhaust design for high-piled storage are covered in DGA’s article on when high-piled storage needs smoke and heat removal.

How Is a Draft Curtain Measured and Located?

Draft curtain depth is measured downward from the underside of the roof deck or ceiling to the bottom edge of the curtain, not from the sprinkler deflectors. At an ESFR boundary the minimum is 2 ft under NFPA 13 (2022) Section 14.2.5. Around a floor opening it is 18 in. under Section 9.3.5, and in an NFPA 204 vent design it scales with the ceiling height.

Draft curtain location follows the curtain’s purpose. At the ESFR boundary the curtain sits on the line between the two sprinkler systems, over the center of a clear aisle at least 4 ft wide, so heat from a fire on one side is less likely to open the other system’s sprinklers. Racks, pallets or staged goods in that aisle defeat the separation, so the aisle belongs on the high-piled storage plan and in the floor striping.

The area a draft curtain encloses matters only in a vent design. NFPA 13 sets no area limit on either side of an ESFR boundary curtain, because that curtain keeps heat from fusing the wrong sprinklers rather than holding smoke for vents. NFPA 204 (2021) Chapter 7 does: each curtained area can be no longer or wider than 8 times the ceiling height, with the curtain at least 20 percent of the ceiling height deep.

For a warehouse with a 40 ft ceiling, those NFPA 204 proportions give a curtain at least 8 ft deep and curtained areas no more than 320 ft on a side, or 102,400 sq ft, while the same building’s ESFR boundary curtain needs only 2 ft. A vent design that depends on deep curtains therefore has to be squared with the sprinkler design before either is drawn.

Draft curtain construction is noncombustible at the ESFR boundary, typically sheet metal or gypsum board on a steel frame, and in practice the joints and top edge are closed to the deck so heat cannot pass over the curtain. Around floor openings NFPA 13 also allows limited-combustible material that stays in place during sprinkler operation.

Sprinklers next to a draft curtain follow the rules for their own type. At a floor opening, NFPA 13 (2022) Section 9.3.5 places the closely spaced sprinklers no more than 6 ft apart and 6 to 12 in. from the curtain on the side away from the opening. At an ESFR boundary, the ESFR obstruction rules in NFPA 13 (2022) Chapter 14 treat the curtain like any other element hanging below the deck.

Where Do Draft Curtains Hurt Sprinkler Performance?

Inside a sprinklered storage area, a draft curtain changes where the heat goes, and storage sprinkler criteria assume it does not. The NFPA 13 storage annex (A.12.1.1 in the 2010 edition) notes that the standard’s storage criteria come from fire tests run without roof vents or draft curtains, and NFPA 13 (2022) Section 20.9.5.3 limits automatic roof vents in ESFR buildings to vents with high-temperature, standard-response operating elements.

Three failure patterns show up in testing and in fire losses. A fire that starts under or next to a curtain splits its heat between two sides, so sprinklers open on both sides and the count can exceed the design area. A curtain hung over racks instead of an aisle blocks part of the spray from the sprinklers beside it, and heat held on one side can travel along the curtain and open sprinklers away from the fire, using water the sprinklers over the fire need.

ESFR is the most sensitive case. An ESFR system is designed to suppress the fire with the 12 sprinklers in its design area (NFPA 13 (2022) Chapter 23), and anything that delays the first sprinklers or spreads operation beyond those 12 erodes that margin. DGA’s comparison of ESFR and CMSA sprinklers for warehouses treats a clean ceiling as an ESFR condition for the same reason.

DGA designs warehouse sprinkler systems and sets sprinkler boundaries, draft curtains included, 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 →

What Do FM Global Data Sheets Expect?

FM Global’s guidance, paraphrased, agrees with NFPA 13 on the basic point and is more specific about where curtains belong. FM Global Data Sheet 2-0 on sprinkler installation and Data Sheet 1-10 on the interaction of sprinklers, smoke and heat vents and draft curtains generally advise against draft curtains in sprinklered buildings. The exception is a curtain that separates areas protected by different kinds of ceiling-level storage sprinklers, such as quick-response from standard-response.

The FM Global data sheets set their own curtain depth and aisle criteria, which are paraphrased here and not reproduced. An FM Global insured warehouse is designed to whichever criterion is stricter at each boundary, and checking the data sheet before the curtain is detailed avoids a recommendation after the first insurer visit.

What Exceptions and Alternatives Avoid a Draft Curtain?

Four design choices remove the need for a draft curtain or replace it with something stronger. Each is easiest before the sprinkler layout and the racks are fixed.

One sprinkler type across the ceiling. Extending ESFR protection over the adjacent area, where the ceiling height, obstructions and water supply allow it, removes the boundary that Section 14.2.5 regulates. The reverse also works: protecting the whole building with control mode sprinklers, with in-rack sprinklers where the storage needs them, avoids an ESFR edge; DGA’s article on choosing between ESFR and in-rack sprinklers covers that trade.

A wall instead of a curtain. A full-height wall, fire barrier or fire wall on the boundary line separates the two sprinkler systems more completely than a curtain and also satisfies the adjacent-design rule in NFPA 13 (2022) Section 19.1.2. Walls that already exist, such as the line between the warehouse and the office, are the cheapest place to put a sprinkler boundary.

Extending the more demanding design 15 ft. Where the only rule in play is Section 19.1.2, because two control mode designs meet, the more demanding design can run 15 ft past its edge instead of a curtain. That option does not replace the curtain at an ESFR boundary with standard-response sprinklers, where Section 14.2.5 applies on its own terms.

Vent or exhaust choices that need no curtain. Mechanical exhaust or vents sized to IFC Section 910 need no curtains, and an NFPA 204 design can often be laid out without them. Those choices belong to the vent design covered in the smoke and heat removal article.

What Applies Once a Draft Curtain Is Required?

A required draft curtain becomes part of the sprinkler design and has to appear in three places. The sprinkler shop drawings show the curtain line, its depth, its material and the clear aisle below it, and the hydraulic calculations treat each side under its own design criteria. Where IFC Chapter 32 or NFPA 1 Chapter 34 applies, the high-piled storage plan shows the aisle as a no-storage zone; DGA’s article on when IFC Chapter 32 applies to high-piled storage explains when that plan is required.

A draft curtain also has to survive the life of the building. Roof work, a new conveyor or a re-rack can cut or move the curtain, and pallets stored in the aisle remove the separation without touching it. Each of those changes reopens the sprinkler design and goes back to the engineer of record before work starts.

How Do New York, New Jersey, Pennsylvania, Maryland and Delaware Apply Draft Curtain Rules?

The draft curtain rule travels with the NFPA 13 edition each jurisdiction references, and the IBC and IFC editions in force outside New York City (NYC) carry no curtain requirement in Section 910. The table lists the editions and reviewers as of October 2026.

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

Frequently Asked Questions

This article is general information, not a substitute for a project-specific code analysis. Code editions, local amendments, insurer requirements and reviewer practice change; confirm the adopted code and the authority having jurisdiction for the project.