What This Article Covers -- and Who It Is For
This post explains what NFPA 105, Standard for Smoke Door Assemblies and Other Opening Protectives, requires at smoke-controlled openings -- from leakage limits and labeled hardware to gasketing selection and annual inspection obligations. It is written for facility managers completing compliance reviews, commercial hardware specifiers building door schedules, healthcare construction teams coordinating smoke-barrier corridors, and industrial maintenance staff facing failed inspections. If you have ever wondered why a door that looks fine keeps failing a smoke-control check, the answer is usually in NFPA 105.
What Is NFPA 105?
NFPA 105 is the National Fire Protection Association standard that governs smoke door assemblies and other opening protectives installed in smoke barriers, smoke partitions, and similar smoke-control boundaries. Where NFPA 80 focuses on fire-rated assemblies and flame resistance, NFPA 105 focuses specifically on smoke leakage -- the controlled passage of smoke through a closed door opening under both ambient and elevated temperatures.
The two standards frequently apply to the same door. A corridor door in a hospital, for example, may carry both a fire rating (governed by NFPA 80) and a smoke-leakage requirement (governed by NFPA 105). Specifiers must satisfy both independently.
The Core Performance Requirement: Leakage Rate
NFPA 105 establishes maximum allowable air leakage through a closed assembly. Products tested to UL 1784 -- the standard laboratory method for air leakage of door assemblies -- must demonstrate leakage no greater than 3.0 cfm per square foot at 0.10 inches of water column (approximately 75 Pascals) to be listed as smoke-rated under NFPA 105.
That number matters in the field. A door that meets the fire label but has worn, compressed, or missing perimeter gasketing can blow past the leakage limit and fail an inspection even though the door itself is undamaged.
Hardware That Has to Be Right
Perimeter Gasketing and Door Bottoms
The gap between a door and its frame is where smoke travels. NFPA 105 assemblies depend on continuous, listed perimeter seals -- head, jambs, and bottom -- to hit the leakage limit. The seal material matters: not every weatherstrip product is tested to UL 1784 and listed under NFPA 105.
Products like the Pemko S44 and S88 SiliconSeal adhesive gasketing lines are tested to UL 1784 and meet the NFPA 105-2013 smoke leakage requirements. The S44 and S88 carry BHMA certification to ANSI/BHMA A156.22 (Door Gasketing and Edge Seal Systems) and are available in multiple finishes and bulk lengths -- practical considerations for facilities maintaining dozens or hundreds of smoke-rated doors. For Category B fire door assemblies that need both fire and smoke performance, combination products like the Pemko HSS2000xS88 (Hot Smoke Seal combined with SiliconSeal) address both the edge-seal and smoke-seal requirements in a single installation.
- Self-closing is mandatory. Every NFPA 105 smoke door must be equipped with a self-closing device. The door cannot rely on occupants to close it. Door closers from lines such as Hager, Norton, Corbin Russwin, and PDQ are appropriate; select a unit sized to ensure positive latching without creating an ADA-failing closing force on accessible routes.
- Positive latching is required. The door must latch each time it closes. A closer that swings the door to the frame but does not pull the latch into the strike defeats the assembly.
- Hold-open devices must be listed for smoke-door use. Fusible-link hold-opens are not acceptable on NFPA 105 assemblies because they release on heat, not on smoke detection -- by the time a fusible link opens, smoke has already migrated. Acceptable hold-opens must release via a fire alarm or listed smoke detector signal.
- Exit devices and locksets installed on smoke-rated doors must not compromise the perimeter seal. Trim cutouts, mortise pockets, and bottom-rail hardware should be reviewed against the listed assembly configuration.
Gasketing at the Door Bottom
Automatic door bottoms (ADB) that drop a seal against the threshold or floor when the door closes are a practical solution where a fixed sweep would drag. For smoke-only applications (no fire rating), verify that the ADB and threshold combination is tested for smoke leakage. For openings that carry both fire and smoke ratings, confirm the combination is listed for the full assembly.
Where NFPA 105 Assemblies Show Up in the Field
- Healthcare corridor doors -- smoke barriers separating patient sleeping areas under NFPA 101 Life Safety Code require NFPA 105 compliance; The Joint Commission and CMS surveyors inspect these routinely.
- K-12 and higher education corridors -- corridor separation doors in educational occupancies are increasingly required to meet smoke-partition requirements under the IBC and local amendments.
- Retail and mixed-use occupancies -- tenant separation walls in larger buildings often include smoke partitions.
- Industrial and warehouse occupancies -- smoke-control zones in large-footprint buildings require rated openings at interior boundaries.
Annual Inspection: What Gets Checked
NFPA 105 requires periodic inspection of smoke door assemblies. Inspectors -- whether internal facility staff or a contracted fire-door inspector -- look for the following common failure points:
- Missing, torn, or compressed perimeter gasketing that no longer makes contact around the full frame
- Door bottom or automatic door bottom that no longer drops fully or drags open before the latch engages
- Self-closer that has been disabled, adjusted to minimum force, or replaced with a non-listed unit
- Gaps at the frame-to-wall perimeter (separate from the door-to-frame gap) that allow smoke bypass
- Hold-open devices that are not connected to the fire alarm system
- Labels that are missing, painted over, or illegible
Deficiencies at smoke door assemblies are treated as requiring repair without delay under the applicable codes -- the same standard applied to fire door gap violations under NFPA 80.
Specifying NFPA 105 Compliant Hardware
When building a door schedule that includes smoke-rated assemblies, call out the UL 1784 listing requirement explicitly in the hardware specification for any perimeter seal, door bottom, or threshold. Reference ANSI/BHMA A156.22 for gasketing performance grades. Confirm that the listed closer provides the spring force required to latch the door against the gasketing resistance -- a heavier seal profile needs a stronger closer, which must still comply with ADA opening-force limits on accessible routes.
DoorwaysPlus.com carries gasketing, door bottoms, thresholds, closers, and exit hardware suited to NFPA 105 assemblies across healthcare, education, retail, and industrial applications. If you are building a hardware schedule or sourcing replacements for a failed inspection, the team at DoorwaysPlus can help you match the right listed product to your opening.