The Problem With Big
As storage occupancies get bigger, they create new challenges for the fire service. Now experts are rethinking how to protect those buildings in the event of fire - and how to minimize firefighter risk.
NFPA Journal®, March/April 2009
By Lisa Nadile
At 10:30 p.m. on December 11, 2007, fire alarms sounded at Tupperware Brands Corp.’s manufacturing and distribution center in Hemingway, South Carolina. The Hemingway Volunteer Fire Department soon arrived, followed quickly by the Williamsburg County Fire Department. Firefighters checked the all-metal warehouse to see if all occupants were evacuated and began aggressive firefighting operations, attempting an interior attack until their air supplies were exhausted. They also used a thermal imaging camera to locate hot spots on the roof, where they then cut a pair of vent holes. Despite the water and the activated sprinkler system inside, and the assistance of fire departments from 13 surrounding cities and towns, the fire burned through the night.
The next morning, smoke continued to drift from the building, and crews continued to spray water through the roof vents. It was a large building—165,000 ft2 (15,329 m2), filled with plasticware for preparing, serving, and storing food—that met state and local code requirements, including those of NFPA 13, Installation of Sprinkler Systems. The design of the 20-year-old building included a sprinkler system chosen to protect the warehouse’s specific type of racks, storage containers, and inventory. The sprinkler system was sound, and there was a 3.7-million-gallon (14-million-liter) pond adjacent to the building that the fire department could use.
Firefighters, though, were growing increasingly concerned. The building’s interior layout, the density of the stored goods, and the difficulty pinpointing the exact location of the fire all contributed to a mounting sense of frustration.
"I knew it would be a nightmare to fight a fire there," says Chief Timmy Godwin of the Williamsburg County Fire Department, who had visited the site previously. "They had rows and rows of plastic containers in there, four long and narrow walkways through the building, and the fire was about 15 to 20 feet [4.6 to 6 meters] up where we couldn’t get to."
At around 3:00 p.m. on December 12, almost 17 hours after the first alarm, crews temporarily deactivated the sprinkler system for 20 minutes to better locate the fire, and tore loose a section of the building’s metal skin to get water on it. Within a half-hour of the shutdown of the sprinklers and the influx of ventilation, though, the fire spread out of control. The firefighting operation then switched to defensive tactics. Flame and smoke soon consumed the building, which was a total loss.
"Once that plastic started melting and burning, there wasn’t anything you could do," says Godwin.
Jane Bindas, Tupperware’s director of risk management, says the company was "deeply affected" and "very surprised" by the total loss of a fully protected facility. "Immediately, the executives questioned whether the sprinkler systems worked, and they had," she says. "They had to learn the difference between a sprinkler system designed to control a fire and final extinguishment."
That’s just one of the considerations for builders and owners of modern storage occupancies. As owners seek to make the most of their storage footprint, they construct buildings that are bigger and higher than ever before, many covering hundreds of thousands of square feet under one roof, which itself can be well over 100 feet (30 meters) high. But experts also caution that encompassing greater volumes of rack storage space means creating greater fire risk, and they urge all stakeholders, including the fire service, to review NFPA 1620, Recommended Practice for Pre-Incident Planning. Soon to be upgraded to a standard in its 2010 edition, this document contains minimum requirements for the pre-incident planning process, including plan development and data collection, physical and site considerations, occupant considerations, water supplies and fire protection systems, special hazards, emergency operations, and pre-incident plan testing and maintenance. With this plan, building owners may help prevent situations in which the fire service is forced to take desperate action in the event of fire, such as turning off a sprinkler system.
Designers, owners, and the fire service are reexamining how to protect such structures and how to fight fires in them when they occur. "The solution is to develop a fire protection system that takes into account [today’s changes in warehouse design]," says James Golinveaux, senior vice-president of New Technology, Codes, and Standards for Tyco Fire Protection. Those changes include rethinking the idea of sending firefighters into large storage occupancies to combat a fire, especially one located high above the building’s floor. "I don’t think a fire department is going to get on lifts inside a warehouse to go up 40 feet [12 meters] to put out a fire, let alone 80 to 100 feet [24 to 30 meters]," says Golinveaux—meaning that the building’s sprinkler system, designed for containment, may not be enough to extinguish the fire on its own, as was the case in South Carolina.
That’s why NFPA staff and committee members, along with insurance carriers, the fire service, suppression and rack product manufacturers, building owners, and the Fire Protection Research Foundation, have begun discussing new approaches to fire protection in large storage occupancies. In January, representatives of these groups met in the Boston area to discuss a proposal submitted to the Research Foundation to study the issue of manual fire service extinguishment for large in-rack storage warehouses. The proposal was submitted by Zurich Services Corp., an international insurance-based financial services company with U.S. headquarters in Schaumburg, Illinois.
"We know there is not one solution," says Jeffrey Shearman, a business director for Zurich. "It’s going to be a mix of technology, possibly code changes, and some things we haven’t remotely thought of at this point."
Confronting an impossible scenario
In-rack sprinklers have been properly suppressing warehouse fires since the late 1960s, says Golinveaux, a member of NFPA 13’s Discharge Committee. "Our fire protection control schemes are more than adequate," he says. "[But] the technology that we have today is for fire control, and we still need assistance for final extinguishment in most cases." He cites examples of other fires that were too high off the ground for the local fire brigade to finally extinguish. "The buildings were filled with smoke and a lot of water, and the fire department couldn’t find the fire. If the fire department decides to turn off the sprinkler system to locate the fire, system failure or other issues may occur."
The Tupperware building had four multiple-row flow-through racks with 16 sections that were each 38 feet (11 meters) high. It was 172 lanes wide (over 300 feet or 91 meters) and 29 totes (over 88 feet or 27 meters) deep. In addition to ceiling sprinklers, the warehouse was equipped with in-rack sprinklers at tiers four, eight, and twelve. Solid horizontal barriers were located above each tier of in-rack sprinklers.
The fire—the result of an electrical problem, according to Bindas—presented an almost impossible scenario for any fire department to handle, says Curt Varone, NFPA’s director of Public Fire Protection. "These buildings present quite a tactical challenge," says Varone. "If the fire is only 15 feet [5 meters] inside a doorway from the exit, it’s not a problem. But the fire could be 350 feet [107 meters] from the closest doorway, and the layout of these buildings is maze-like. They are very treacherous."
Firefighters battling the Tupperware blaze were frustrated by the density of the occupancy’s arrangement, the horizontal barriers, and the location of fire at the top of a storage rack. "Imagine a firefighter standing in a 4-foot-wide [1-meter-wide] aisle trying to maneuver a hose stream to the top of these racks," Varone says. "They may be shooting almost straight up—they may have been given an impossible tactical task. The risk profile of many of these large storage buildings is such that if everyone is out of the building, we’re not going to introduce a life hazard in the form of live firefighters entering the building."
Rethinking large-space fires
That’s why Tupperware and Zurich are looking at the feasibility of technologies and building designs that would take on the onus of fire extinguishment and provide greater safety for fire departments. Participants at the meeting in January agreed that such an effort will require a lot of cooperation, as well as a careful evaluation of the associated costs. New systems would also have to meet the performance expectations of NFPA standards; if the desired performance goes beyond the standards’ requirements, then the appropriate standards would have to be modified.
"NFPA 13 and related standards would be those under consideration," says Golinveaux. "For NFPA 13, I imagine we’d look at another level of protection for storage with heights above 40 feet [12 meters]—that’s about [the limit] where a local fire department can successfully extinguish a fire from the floor. For NFPA 13E, [Recommended Practice for Fire Department Operations in Properties Protected by Sprinkler and Standpipe Systems], how to best do some preplanning on these systems would be addressed," he says. NFPA 72®, Fire Alarm Code®; NFPA 1, Fire CodeTM; and NFPA 1620, Recommended Practice for Pre-Incident Planning, could also be affected.
"The thought is that, if you have a sensor-rich environment to identify the location of a fire, you could then use an [automated storage and retrieval system] to remove the combustible storage around that area that has been identified as being at an elevated temperature," says Richard Gallagher, a business director for Zurich. "Then potentially you could use that same system, perhaps with some kind of extinguishing mechanism, to go into that area and assist with whatever is left."
While the technology Gallagher describes is available today, there is no panacea for protecting large storage spaces, cautions Wes Baker, senior engineering technical specialist for FM Global in Norwood, Massachusetts.
"There is this concept of trying to design a sprinkler system or some type of fire protection where you no longer rely on the fire department to intervene," Baker says. "That’s going to be a tough concept, because in order to get final extinguishment, you basically have to break up the fire triangle, [meaning] you either have to take away your combustibles, take away the oxygen, or take away your heat source. And that is very difficult to do once a fire has already started." Baker and others stress that testing and research to explore possible improvements is still necessary.
Gallagher, meanwhile, urges building owners to carefully review their current fire protection plans. "They should be very aggressive in maintenance of their storage management equipment," he says. Gallagher also advocates for a heightened level of fire prevention that incorporates traditional loss-prevention practices such as hot work programs, fire protection system impairment programs, and smoking controls.
Close monitoring and management of these changes are also important, he says. "Take a look at the structural or facility changes that are planned, such as changes to the product, capacity, packaging, or storage configuration," Gallagher says. "Other hazards might be more human-related, such as temporary stacking in pallets, temporary aisle storage, and temporarily leaving high-hazard commodities where they don’t belong."
Finally, Shearman says, remember that much of fire prevention comes down to managing, training, and monitoring people. "A lot of fires don’t happen at the top of racks," he says, "but because of human error or arson."
Lisa Nadile is associate editor of NFPA Journal.