MEGAMALLS: A FIRE PROTECTION AND SUPPRESSION CHALLENGE
The megamall is a fast-spreading construction phenomenon underway in many places across the United States. It offers consumers virtually every conceivable convenience imaginable It’s a place where they can spend the day and “shop till they drop.” Here, the “bigger is better” theory prevails. But as convenient and wonderful as these megamalls may be for shoppers, they’re anything but that for the fire department. The demands placed on fire protection and suppression services are as awesome as the structure itself, and the fire department must be fully prepared to meet such challenges.
THE SAWGRASS MILLS MALL
Sawgrass Mills, located in Sunrise. Florida, is a 2.2-million-square-foot shopping and entertainment complex that includes nine anchor stores and about 250 specialty stores and eateries in the mail’s four core areas. It is the largest stogie-story building in the southeastern United States, spanning one mile in length. From a developer’s standpoint, its location is ideal: Sunrise, with a population of more than 69,000 people, is Florida’s secondfastest growing city, and Broward County is the state’s second-fastest growing county’. Daily mall attendance is estimated at 80,000 to 100,000 occupants on weekends and holidays. Estimated annual occupant flow is projected at 20 million shoppers and visitors. (By comparison, Walt Disney World in Orlando, Florida has an annual attendance of 30 million people.)
Because of the immense size of the structure, the developer sought fire protection trade-offs through the Broward County Board of Rules and Appeals. After a series of lengthy hearings and meetings, several ad-hoc subcommittees of the Board of Rules and Appeals ruled on fire protection conditions. The Sunrise Fire-Rescue Department was actively involved in the proceedings. Significant alternatives to the South Florida Building Code’s traditional fire protection requirements were granted. For instance, in lieu of fireproofing for the steel members, a highly reliable, active automatic suppression system was installed to protect the steel. The mall stores and restaurants are divided by one-hour fire-rated tenant separation walls, These walls must be at least 12 feet high; however, they are not required to extend beyond that height. Depending on tenant space design, some separation walls run to the 12-foot level and some to a drop ceiling. There are no floor-to-ceiling fire-rated tenant separation walls. A unique active. electrical/mechanical smoke removal system was designed to control and limit smoke to the area of fire origin; in fact, its effectiveness relies on sufficient vertical and horizontal openings in the tenant spaces. Building design also incorporates a passive smoke control feature system.
Sunrise Fire-Rescue has spent a great deal of time on this large-scaleproject. The cite hired a fire protection engineer as a consultant and a full-time fire plans examiner to monitor the Sawgrass Mills project and other related facilities. Revenues generated for fire department activities relative to Sawgrass Mills have been in excess of S2 million. This includes money for plans checking, automatic sprinkler testing, permits, restaurant chemical system permits, fire impact fees, and fire inspection fees. The mall will contribute S2 million annually to the property tax rolls of the city.
During construction, the Fire LifeSafety Division conducted routine onsite walk-throughs; it participated in numerous acceptance tests of the fire pumps, water mains, hydrants, and site-change orders. Project managers, prime contractors and subcontractors, building officials, and fire officials held weekly meetings at the Building Department.
The project required specialized training for the inspection and acceptance of smoke removal systems. It takes a minimum of 16 personnel — including fire, electrical, mechanical, and structural inspectors—to conduct an area acceptance test for the systems. All anchor stores and core areas were tested; 14 individual tests were required in all.
IMPORTANT FEATURES
Construction/layout. Sawgrass Mills is a Type II (noncombustible, nonrated) structure. It is constructed of exposed steel structural members and has a metal-deck roof. Its exterior walls are of a composite, Gunite-type fireproofing material blown onto a synthetic wire-like grid. The use of wood is limited to storefront facade headers and decorative trim, and the building is windowless.
The core area’s four “boxcars” (the four major sections of the mall proper, so named because the rectangularshaped core areas are staggered like a derailed train) comprise one million square feet. The nine attached anchor stores comprise 1.2 million square feet.
The mall was built without major fire separation walls or draft curtains. The anchors are attached to the core areas and separated from them by two-hour fire-rated walls from floor to ceiling. Some passageways to and from the exterior and the core areas are 400 feet long, 200 feet beyond the normal Life Safety Code travel distance of 200 feet. Open-grate drop security doors for anchor stores and all other access openings span a maximum of 54 feet.
Automatic suppression systems and standpipe system. Sawgrass Mills was divided into more than 90 separate automatic sprinkler zones. This includes full sprinkler protection for entrance/exit corridors and water curtain sprinklers operating at both ends of the corridor; these water curtain systems operate independently of the “normal” systems. Water curtains also have been installed at the doors leading to and from the anchor stores and the core areas. Thirteen 1,000-gpm fire pumps deliver water to the sprinklers and standpipes. The sprinkler/fire pump systems have three independent electrical supply sources, a full dual-path power feed, emergency generator power for the fire pumps, complete electrical supervision of outside screw and yolk (OS & Y) and butterfly valves, and onand off-site monitoring for fire and supervisory personnel (45 security personnel are employed by Sawgrass Mills for 24-hour on-site monitoring). The nine anchor buildings, all exceeding 100,000 square feet, operate with stand-alone automatic sprinkler systems. All systems and supervisory signals for the fire pumps are received at the on-site fire control room and security office. Some anchor companies chose dualreporting capability (both to mall security and to off-site locations).
(Photos by author.)
The conservative, hydraulically designed sprinkler system exceeds NFPA 13 recommendations. This includes higher sprinkler discharge densities and closer sprinkler spacing. Special column fire sprinklers were installed to the high point and midpoint (15-foot level) on all exposed steel columns. Storage of merchandise above 12 feet high is not permissible. Comprehensive tenant improvement handbooks were developed to limit storage and detail building modifications. Sunrise Fire-Rescue approval is required on all changes.
The column protection piping is a separate system—nothing else draws off that piping. This was an essential fire protection feature, since structural stability relies on effective column sprinklers. Preplumbed drops and the configuration of the tenant space sprinkler systems made the tenant setup and remodeling phase much smoother in terms of minimal shutdowns and system interruptions. The sprinkler systems were all computerhydraulic designed and certified by fire protection engineers. Victaulic couplings were used.
Class I standpipe hose cabinets were installed at 250-foot intervals throughout the core area, corridors, and anchor stores. Each standpipe will flow 500 gpm. Because of the distances from street access, the hose cabinets will play an important role in interior firefighting operations.
Smoke removal system and occupant evacuation. Sawgrass Mills is protected with high-powered, negative-pressure electrical/mechanical smoke-venting systems for active smoke protection, and high-pitched ceilings in the mall proper were designed to create a “reservoir” for passive smoke protection. Factory Mutual and the Center for Fire Research were commissioned to conduct computer models to study the smoke development and removal systems in conjunction with occupant evacuation.
A mechanical smoke-venting system under full dual-path electrical power was chosen over gravity or manual systems because it was far more practical, given the steep slope and height of the roof. Large fans, some as large as nine feet in diameter with 32-horsepower motors, were installed in all main core areas at the roof apex and at horizontal roof lines of all anchor stores. Air intake is facilitated by pneumatic horizontal vents. There is a shunt override for manual activation of the smoke removal system.
Effective smoke removal for tenant spaces in the core areas hinges on sufficient horizontal and vertical openings within each space through which smoke generated from a fire will be pulled upward by the fans into the ceiling space and through the fan vents. In this way, spread of heat and products of combustion is expected to be contained in the areas of fire origin. Additional advantages to such a system are rapid venting to aid interior firefighting, reduction of the risk of structural failure, delay in loss of visibility, reduction in ceiling temperatures, and elimination of the need for firefighting forces to manually vent the building.
Smoke detectors in the HVAC return system air ducts are arranged to notify fire control room and on-site supervisory personnel; when activated, the smoke detectors initiate smoke removal systems, activate strobe lights and evacuation alarms, and shut down the HVAC systems.
The system is zoned by anchor stores and by the boxcar configuration (in approximately 250,000square-foot core areas). Each of the major sections was live smoke tested before the mall was opened and is tested periodically to ensure optimum working ability-. Smoke removal systems exceed NFPA 204M recommendations.
Voice notification systems, strobe lights, and high dBA evacuation tones were installed to notify occupants in case of an emergency.
FIREFIGHTER TRAINING AND PREPLANS
The Sunrise Fire Training Division continues to prepare for interior fire operations at Sawgrass Mills. Standard engine preconnects will not reach many areas in the corridors and interiors because of the long distance from street access to the stores. One of our major concerns is the ability to cut off a large fire, should it occur, between an anchor store and a core or transition court.
SMOKE REMOVAL SYSTEM CONCEPT FOR SAWGRASS MILLS
We have drilled with large-diameter hose, “hand-jacking” it into the center of the mall’s “Main Street” for placement into portable monitors. This necessitates 400to 500-foot handlays. Purchase of lightweight 1,000-gpm ground monitors is in process. We plan to increase the hose capacity of our existing high-rise packs and add additional hose packs.
Our salvage cover inventory has been increased, along with an industrial-type 20-gallon water vacuum to assist in salvage work for inadvertent sprinkler discharges or water pipe breakages.
Our operational plan has been finalized. Sunrise Fire-Rescue is fully aware of the complexities of the smoke removal systems and firefighting interface action and recognizes the need for specialized firefighter training for this unique environment. We have designated staging areas and continue to conduct mutual-aid drills at the mall. Planning and design for a new five-bay fire station across the access road from the immediate mall area is underway. We have worked in cooperation with the mall management team and security staff to colorcode exterior doors (there are more than 400 doors in the complex), fire pump room locations, and utility rooms for easy identification. A lock box entry key system has been established.
TRADE-OFFS
Fire chiefs, fire protection engineers, and building officials involved with a large-scale project in their communities must ask themselves, What am I giving up to gain this large building? In the case of Sawgrass Mills, the major trade-off considerations were the types of construction, fireproofing of structural members and columns, extended travel distances in exit corridors, and elimination of draft curtains and fire division walls. To offset these considerations, the Broward County Board of Appeals, comprised of building officials throughout the county, required the hydraulically designed sprinkler system to have increased density and required superior, independent column sprinkler protection. The passive design in the building peak’s open area allows for volumetric smoke buildup; the smoke removal system, as tested, works exceptionally well.
The mall’s security television cameras, supervised on scanning monitors in the fire and security office, picked up an unknown trade-off: stock storage greater than 12 feet high, which is forbidden. A tenant who desires to increase storage height must install inrack sprinkler systems. This problem has been rectified but is continually being monitored.
A megamall is a city within itself and will greatly impact any fire agency that inherits the risk. When you think “megamall,” you have to expand your horizons with regard to the fire protection and suppression challenges such a huge structure will impose. The Sunrise Fire-Rescue Department is expanding its organization from 127 to 153 personnel, and it has purchased new apparatus to help meet the challenge. Additional resources will be needed as the response level increases.
Plans already are underway for more extensive services and businesses around Sawgrass Mills. Five additional hotels are planned for 1994 occupancy. The three-and-a-half-mile road encircling the megamall will facilitate seven car dealerships, a 250,000-square-foot strip mall, and 200,000 square feet of office space. Fifty thousand square feet of freestanding retail and service-oriented facilities already is permitted; 750,000 square feet of freestanding retail and service space is planned. The outside entertainment facilities will add a carnival atmosphere and a potential for new types of trauma and accidents.
Megamalls represent “high value risk” properties and require major interface between the fire insurance carriers and the fire-rescue agency. Your ability to interface with these individuals and the many other agencies who will become involved in such a large project will have a significant bearing on the ease or difficulty with which you hurdle the challenges. In the end, your commitment to fire protection will help turn a facility that poses numerous fire control challenges into a place where people can have fun and be safe.*