Evolving elevator hoistway codes and industry product development provide architects with new design options.
While dramatic shots of fire and flames make for attention-grabbing stories on the nightly news, the spread of smoke and toxic gases throughout the interior of a building poses an even greater danger for occupants and first responders. This is particularly true for high-rise structures that 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. The result is smoke inhalation and death for those trapped on seemingly untouched or ‘safe’ floors above a fire.
To address smoke migration, the International Building Code (IBC), beginning in 2000, required elevator lobbies to be constructed as smoke enclosures so as 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.
“While elevator lobbies have made a tremendous impact on occupant safety, they also come with significant design and facility-planning drawbacks,” stated David Dawdy, director of fire and life safety new-product development at CornellCookson LLC, Mountain Top, PA. “Not only do they reduce valuable leasable space in commercial buildings, they produce significant limitations for architects and designers as they are incongruent to today’s world of open-concept design.”
In the face of growing pressure to provide the A&D community with alternatives to elevator lobbies, in 2003 the IBC approved the use of coiling fabric or film closures for hoistway openings meeting Underwriters Laboratories (UL) 1784, Smoke and Draft Control Door Assemblies requirements. 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 as a result of these innovations,” explained Dawdy. “At the same time, standards from the National Fire Protection Association (NFPA), Quincy, MA, continue to evolve to include new opportunities with regard to smoke and fire infiltration in commercial buildings.”
These closure systems help eliminate the IBC elevator lobby requirement (IBC 3006) and allow forward-thinking designers to create unique building layouts without having to design around lobbies on each floor or bank of elevators. “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 building occupants,” added Dawdy.
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 functional requirements of the system compared to traditional fire doors, and limited access to the training necessary to acquire this knowledge.
The first major development in this product’s acceptance came several years ago when the IBC approved the use of coiling fabric or film closures for hoistway openings. As a result, using these products in lieu of constructing elevator lobbies has become popular in the design community.
“Newer sliding-type fire doors complying with smoke and draft requirements are frequently allowed as an alternative to building lobbies,” said Dawdy. “In some applications, accordion-type doors are employed to seal banks of hoistways. Rolling steel fire doors are specifically not allowed. However, they may be used in lobby designs that also include listed swing doors, providing personal egress,” he added.
Modern elevator hoistway closures range from semitransparent film-type to woven, coated fiberglass materials. The design intent is to seal hoistway openings to prevent smoke migration during a fire, allow for through-passage of car occupants, and reseal the opening if accessed during an alarm.
Different Elevators, Standards
Public passenger elevators are installed to serve all floors of a building or may have separate banks targeting exclusive floors, which requires multiple lobbies to protect the hoistway from the migration of smoke and other combustion products.
“Public elevators are a good target for hoistway closures since they eliminate the construction of elevator lobbies throughout the building,” explained Dawdy. “This is a significant savings for residential and commercial buildings that have elevators targeting exclusive floors.
When public elevators need to be used for emergency evacuation, hoistway smoke closures are still appropriate, based on 2015 IBC Section 713.14.1, “Elevator, Dumbwaiter and Other Hoistways,” which states “Enclosed elevator lobbies are not required where additional doors are provided at the hoistway opening…when tested in accordance with UL 1784 without an artificial bottom seal.”
There are some IBC codes and sections architects and designers must be aware of, including Section 403.6.2, “Occupant Evacuation Elevators” that states, “Where installed in accordance with Section 3008, passenger elevators for general public use shall be permitted to be used for occupant self-evacuation. Where elevators are to be used for occupant self-evacuation during fires, all passenger elevators for general public use shall comply with Section 3008 (10 sections).”
“Since these types of elevators are intended to be occupant operated during evacuation periods, they must be in a ‘hardened’ shaft with a one-hour fire-resistance rating up to four stories and two-hour rating above four stories,” explained Dawdy. “Additionally, occupant evacuation elevators require lobbies at all floors except the level of discharge, meaning there is no code provision for hoistway closures,” he added.
Unlike public passenger and occupant evacuation elevators, fire-service access elevators (FSAEs) provide a capable and durable hoistway with the ability to operate for extended periods during a fire to aid fire fighters and emergency responders. FSAEs must serve all floors.
In buildings with an occupied floor more than 120 ft. above the lowest level of fire department vehicle access, no fewer than two FSAEs—or all elevators, whichever is less—shall be provided in accordance with Section 3007, “Fire Service Access Elevators.” Each FSAE shall also have a capacity of not less than 3,500 lb. and shall comply with Section 3002.4 [Elevator car to accommodate ambulance stretcher]. Similar to evacuation elevators, FSAEs must be in a ‘hardened’ shaft with a one-hour fire-resistance rating to four stories and two-hour rating above four stories.
FSAEs are also required to have an elevator lobby from the second floor up as long as the floor of discharge is sprinklered. Therefore, hoistway seals are not required in 2015 IBC 709.4.2, “Smoke-barrier Walls Enclosing Areas of Refuge or Elevator Lobbies,” within FSAE lobbies.
Recent changes in fire and building codes are a direct result of the door industry looking to help solve the fire problem in high-rise buildings by employing innovative products at elevator openings. The resulting win-win for designers and building owners is more cost-effective choices in the use of space once reserved for elevator lobbies.