Fire & Smoke Curtains
UL 10D, BS 8524 & IBC Compliance

What Are Fire and Smoke Curtains?

Fire and smoke curtains are active fire protection barriers that remain concealed in a compact housing during normal building operation and deploy automatically when triggered by the fire alarm system. The curtain fabric — typically a woven fiberglass, ceramic fiber, or stainless-steel mesh material — descends from a roller housed in the ceiling or lintel to create a fire-resistance-rated or smoke-resistant barrier across an opening. UL 10D

Unlike traditional fire barriers (masonry, gypsum board) that are permanently in place, fire curtains provide rated separation on demand — they are invisible during daily use and only activate during a fire event. This makes them the preferred solution for architects and building owners who want open, flowing floor plans without compromising fire compartmentalization.

Fire curtains are tested and listed under UL 10D (Fire Tests of Fire Protective Curtain Assemblies) in North America and BS 8524 in the UK and Europe. The IBC recognizes fire-protective curtain assemblies as opening protectives in fire barriers and fire walls when properly listed and installed. IBC, §707.6

How Fire Curtains Deploy

The deployment sequence is straightforward but must be precisely engineered for life safety:

1. Fire detection. The building fire alarm control panel (FACP) receives an alarm signal from smoke detectors, sprinklers, or manual pull stations in the protected zone.

2. Signal to curtain controller. The FACP sends a signal (typically a relay closure or addressable module command) to the fire curtain’s dedicated controller. Some curtains also have integral smoke detectors as a secondary activation method.

3. Controlled descent. The curtain fabric unrolls from its housing under gravity, controlled by a governor mechanism or electric motor that limits descent speed to approximately 6 inches per second (150 mm/s) or slower. This controlled speed prevents injury to people who may be beneath the curtain during deployment. UL 10D, §18

4. Full closure. The curtain descends to the floor (or to a specified height for smoke-only curtains that create a smoke reservoir). Side guides or channels keep the fabric edges sealed against the wall or column. The bottom edge may include a weighted bar or inflatable seal to maintain contact with the floor.

5. Fail-safe operation. Fire curtains must deploy even during a power failure. Most systems use a battery backup or a gravity-descent mechanism with an electromagnetic brake that releases when power is lost. This fail-safe principle is fundamental — if any component fails, the curtain must still close. BS 8524, §5.3

Fire Curtains vs. Smoke Curtains

The two products serve different functions and are tested to different standards:

Fire-protective curtains are tested per UL 10D (or ASTM E119 as a wall assembly) and provide a fire-resistance rating — typically 1 hour or 2 hours. They block both fire and smoke and can replace traditional fire barriers, fire partitions, or opening protectives in fire-rated walls. Fire curtains use high-temperature fabrics (rated to 1,000 °C or higher) and may include an internal water-cooling system (a perforated pipe that wets the curtain during exposure) to meet the hose-stream test requirement.

Smoke curtains (also called smoke barriers or draft curtains) are tested per UL 10D Category II or per smoke leakage standards (UL 1784 equivalent). They block smoke migration but do not provide a fire-resistance rating. Smoke curtains use lighter fabrics, do not require cooling systems, and are typically used to create smoke reservoirs beneath ceilings, channeling smoke toward exhaust points in atrium smoke management systems. IBC, §909.3

Key Applications

Atriums and multi-story open spaces. Building codes require atrium openings to be separated from adjacent floor areas by fire barriers or by an engineered smoke management system. Fire curtains allow the atrium to remain visually open during normal use while providing rated separation during a fire. They are among the most common fire curtain applications in commercial, hospitality, and institutional buildings. IBC, §404.6

Escalator and stair openings. Vertical openings between floors must be enclosed in rated shaft construction — unless an approved alternative is provided. Fire curtains can enclose escalator wellways, open staircases, and convenience openings, deploying automatically to seal the vertical opening during a fire event.

Open floor plans and large openings. Modern office buildings, retail environments, museums, and airports use fire curtains to separate large open areas that cannot practically be divided by fixed walls. Curtains spanning 30 meters or more are commercially available.

Elevator lobbies. Where the code requires elevator lobby separation, smoke curtains can provide the required smoke barrier without the cost and spatial impact of constructing permanent lobby walls.

Heritage and renovation projects. In existing buildings where adding new fire-rated walls would damage historic fabric or be architecturally unacceptable, fire curtains offer rated separation with minimal visual impact and no permanent structural modification.

Testing & Maintenance

Fire and smoke curtains are mechanical systems with fabric, motors, controllers, and sensors. Unlike a masonry wall that requires no maintenance, curtains require regular testing to confirm they will deploy when needed.

Practical Inspection Tips

Coordinate with alarm testing. The annual fire alarm inspection (NFPA 72) should include testing the curtain activation relay. If the fire alarm test and the curtain test are performed by different contractors on different dates, the integration between them is never actually verified.

Check the housing. The curtain housing is typically recessed in the ceiling. Inspect for construction debris, stored materials, or cabling that could interfere with curtain deployment. In renovation projects, new ductwork or cable trays are sometimes installed directly below curtain housings, physically blocking deployment.

Fabric condition. Inspect the curtain fabric for cuts, tears, abrasion marks, and UV degradation (for curtains near windows or skylights). Even a small tear can compromise the fire or smoke rating. Any fabric damage requires manufacturer-approved repair or replacement.

Egress pass-through. If the curtain includes an egress opening, test it manually. It must open easily under the force limits specified by the applicable egress code (typically 30 lbf for swinging hardware, 15 lbf for sliding). The egress signage must be visible and illuminated.

Power failure test. Annually, simulate a power failure while commanding curtain deployment. The curtain must descend to full closure on battery backup or gravity alone. If the curtain fails to deploy during a power loss, it is not fail-safe and represents a life-safety impairment.

Common Deficiencies

The most frequently identified deficiencies include: curtains that have never been drop-tested since installation, dead backup batteries that prevent fail-safe deployment, fabric damage from construction activities or stored materials, side guide channels blocked by debris or displaced by building movement, fire alarm integration that was connected at commissioning but disabled during subsequent alarm panel reprogramming, and missing or expired annual maintenance by the curtain manufacturer or authorized service agent.

Because fire curtains are a relatively newer technology compared to traditional fire barriers, many building maintenance teams are unfamiliar with the testing requirements. Facility managers should ensure that curtain maintenance is included in the building’s fire protection impairment policy and that only trained, manufacturer-authorized technicians perform service and repairs. NFPA 80, §5.2

References