by David Dawdy
Fire and life safety is a major concern for high-rise office workers, apartment and condominium dwellers, building owners, and the architectural community around the world. From decades of disaster movies to real-life stories from survivors of tower fires and terrorist attacks, the threat of catastrophe is a sobering reminder fighting high-rise structure fires is a difficult and often perilous task. Recent tragedies like Grenfell Tower in London, England, the 2017 Honolulu high-rise fire and the Torch Tower in Dubai, UAE, punctuate this reality.
While the spread of fire and flames is commonly perceived to be the biggest threat to human safety in these types of situations, smoke and toxic gas often pose an even greater danger for building occupants. High-rise structures typically include multiple stairways and internal elevator shafts. These enclosures and hoistways can act like a chimney or flue in a fire, allowing smoke to infiltrate otherwise safe floors of commercial and residential buildings.
Despite being protected by fire-rated, car-mounted doors, hoistway shaft openings are especially dangerous, allowing hot smoke and products of combustion to infiltrate the area and potentially spreading gases throughout a multifloor building in a matter of minutes. The ability of smoke and hot gases to migrate quickly through unobstructed vertical shafts can result in smoke inhalation and death for those trapped on seemingly untouched or ‘safe’ floors above the fire.
To address smoke migration, the International Building Code (IBC)—beginning in 2000—required elevator lobbies to be constructed as smoke enclosures to encapsulate hoistway openings on every floor of a high-rise building. Swinging doors—at the entrance to an elevator lobby—are activated during a fire event to close and seal the space, thereby minimizing smoke and gas infiltration. Elevator lobbies have made a tremendous impact on occupant safety, but they also come with significant design and facility planning drawbacks.
IBC eventually approved the use of coiling fabric or film closures for hoistway openings meeting Underwriters Laboratories (UL) 1784, Smoke and Draft Control Door Assemblies, requirements in 2003. Manufacturers also began to develop new and exciting alternatives to elevator lobbies at the hoistway opening.
The use of special coiling smoke doors as hoistway enclosures has quietly become mainstream in the design community. Standards from the National Fire Protection Association (NFPA) continue to evolve to include new opportunities with regard to smoke and fire infiltration in commercial buildings.
Whether discussing traditional elevator lobbies or newer products, it is important to understand these developing standards of elevator smoke enclosures and their impact on architects, designers, facility managers, and, ultimately, building occupants.
Option for the design community
IBC 2015, Section 3006.2, “Hoistway Opening Protection Required,” states:
Elevator hoistway door openings shall be protected in accordance with Section 3006.3, where an elevator hoistway connects more than three stories, is required to be enclosed within a shaft enclosure…
Hoistway closures are seen by the overhead door community as specialty products surrounded by a significant degree of mystery, misinformation, and misunderstanding. There are a number of reasons for this, including:
- unfamiliarity with code standards;
- minimal understanding of the system’s functional requirements compared to traditional fire doors; and
- limited access to training necessary to acquire this knowledge of hoistway closures.
In the world of doors, however, specialty is good, and knowledge is even better. Armed with these two essential tools, product manufacturers and door dealers can be more instrumental in fire and life safety awareness, education, and problem solving.
The first major development in this product’s acceptance came several years ago when IBC approved the use of coiling fabric or film closures for hoistway openings (For more information, one can refer to Section 713, “Shaft Enclosures,” of the International Building Code [IBC].). As a result, the employment of these products—for creating additional square footage and more spacious designs in lieu of constructing elevator lobbies—has become popular in the design community.
Elevator lobbies can decrease leasable/usable floor space for building owners and constrain more spacious area designs. In today’s world of open-concept design, elevator lobbies are often incongruent to the overall conceptual vision, according to Gregory Cahanin, fire-protection engineer and code consultant.
Newer sliding-type fire doors complying with smoke and draft requirements are frequently allowed as an alternative to building lobbies. In some applications, accordion-type doors are also employed to seal banks of hoistways. Rolling steel fire doors are specifically not allowed. However, they may be used on lobby designs that also include listed swing doors providing personal egress.
If this sounds confusing, it is. Evolving standards from the International Code Council (ICC) and NFPA mean new alternative products meeting intended performance criteria—which are probably more cost-effective—may become available.
Modern elevator hoistway closures range from semitransparent film-type materials to woven, coated fiberglass products. The design intent is to seal hoistway openings to prevent smoke migration during a fire, allow for through-passage of car occupants, and to reseal the opening if opened during an alarm for access.
