In Part 1 one of this article, we focused on the need to have a detailed pre-plan in place for managing operations at industrial facilities equipped with sprinklers, standpipes, and water supplies. These procedures are relatively easy to implement and are generally not controversial.
In Part 2, we will continue this discussion with incident command, ventilation and smoke management, and fire doors. There is a wide variety of opinion on these issues. Part of the reason for this is that these subjects are not understood as well. There is less experience with them, and there is less written about them in the literature. The author encourages the reader to write the editor with different points of view and to create an ongoing dialogue.
Industrial facilities are much larger and more complicated than the typical bread-and-butter residential fire. Significant resources are needed, even in a well-protected facility. The functions described below may be needed.
A full alarm for a rapid intervention team. Research by the Phoenix Fire Department has demonstrated that a single engine or ladder company cannot perform this function in a large facility. This may mean that a reported fire in an industrial facility warrants an automatic second alarm; one for the fire and one to serve as a Rapid Intervention Team.
A water supply officer. As described in Part 1, water supply is a critical function. An ideal person to fill this role would be a fire protection engineer familiar with both industrial water supplies and fireground operations. Such a person may be available as part of a mutual aid group. A battalion chief specially trained in this type of operation would also be a good choice.
If implementing the water supply plan requires additional engine companies to relay water, they should be dispatched on the initial alarm for a confirmed fire. Combining this with the need for a large rapid intervention contingent could require an automatic third alarm for a confirmed fire. This may seem like overkill but if it is needed and not done immediately, you could easily end up with a fifth alarm or greater fire. If this is preplanned, relocation or move up companies can also be preplanned. In a city with closely spaced fire stations, this could result in too many crews arriving nearly simultaneously to allow for effective command and control but most industrial plants are now located in areas where station spacing is far enough apart to avoid this. In fact, station spacing is often so far apart that the automatic second and third alarm, perhaps with an automatic recall of off duty personnel, becomes even more of a necessity. This is not an unheard of concept. In New York City, the response for a 10-76, working high-rise fire involves 5 engines, 5 trucks, 1 rescue company, 1 squad company, 4 battalion chiefs and additional specialized units.1 In many locations, this is the equivalent of an automatic second or third alarm.
The roof should be monitored from an elevated position. This is to ensure that fire has not broken through the roof, that plant personnel are not trapped on the roof, and that the roof is not sagging. At a large facility, it would be very difficult to determine this from the ground. I once observed fire break through the roof of a large tire warehouse and shortly thereafter the warehouse flashed over and the roof collapsed. Fortunately the evacuation alarm was sounded and everyone was evacuated safely. Proper management of the water supply and firewalls then helped prevent fire spread to the rest of the facility, which saved about 90% of the facility value.
Air bottle resupply. Even in properly sprinklered properties, there could be a significant need for air bottles. I responded to a fire in a large warehouse that was controlled by 4 sprinklers and one hose line. Visibility was not a problem. Even so, we had to use police cars to shuttle bottles back to the station to be refilled.
Ventilation and Smoke Management
This subject generates plenty of controversy at two story residential fires, let alone industrial fires. Cases abound where the ventilation tactics selected made the situation worse. No ventilation or delayed ventilation made the situation extremely dangerous for the fire crews. In sprinklered facilities, there is even more controversy. The NFPA Fire Protection Handbook provides an excellent summary. Insurance companies have had differing opinions and international opinion also varies.
It is fairly well established that automatic2 smoke and heat venting should not be provided for facilities equipped with Early Suppression Fast Response (ESFR) sprinklers. This is because an open vent may delay the operation of the sprinklers and the fire could grow too large before the sprinklers operate. The E in ESFR means Early and anything that prevents early operation is detrimental. Many authorities having jurisdiction that normally requires automatic smoke and heat vents recognize this as an exception. If the ESFR sprinklers are operating properly there should be no need for automatic vertical ventilation anyway.
It has been argued that if manual roof ventilation is needed to relieve heat in high ceiling, steel bar joist facilities, the fire is beyond the control of the sprinklers and it is not safe to operate on or under the roof. There is a difference between venting to remove cool smoke and venting to relieve excess heat. The smoke will eventually need to be removed. Vertical ventilation relies on a hot smoke layer to provide buoyancy to drive the smoke through the vent. Experience has shown that smoke cooled by sprinkler discharge water (assuming that the sprinkler design is adequate) may not have enough buoyancy to be vented with natural roof ventilation.
Manually operated powered roof ventilation fans can be used to exhaust the cool smoke. They have the effect of keeping the smoke isolated to a portion of the building. Of course, this will not work if the fire has damaged the fans or motor wiring. Another option is positive pressure horizontal ventilation to remove the cool smoke. I have seen this work in a 750,000 square foot auto parts warehouse during a fire that was controlled by four sprinklers. Only two standard sized fans were used. This was done after the fire was controlled. This may increase the amount of property exposed to smoke depending on how far it has already spread.
If the fans accelerate the fire, they should be shut down. You can shut a fan down. You can't easily close a hole cut in the roof. Of course, staffed hose lines should remain in place. Management of the sprinkler system was described in part 1. If you protect a tire warehouse, NFPA 230 Annex E is a must read for perspective on ventilation that you have probably never thought of. This material is now in NFPA 13E as well.
Because the relatively cool smoke is less buoyant and is not easily vented through the roof, thermal imaging cameras are a necessity in warehouse and industrial fires. Don't learn how to use them at the fire. Training is absolutely essential. If you have not had training in their use, you will probably be amazed at how much you did not know there was to know. I strongly urge you not to turn off the sprinklers so that the fire will "light-up" so that you can find it. Many facilities have been lost in this way.
Fire doors are an essential part of industrial fire protection. In the event that the sprinklers fail to control the fire, properly designed firewalls with properly protected openings are the last line of defense. Firefighters have a concern that a fire door could close behind them and trap them in the fire area and possibly reduce the flow from their hose line or restrict their ability to advance the line.
If conditions and facility layout allow, consideration should be given to closing the fire doors before the fire spreads to them and attacking the fire from a position that does not require hose lines to be stretched through a fire door. Sometimes fire rated personnel doors are provided next to large fire doors.
I have seen articles that advocate propping a roll down fire door open with a pike pole so that it won't close behind a hose team. If this is done, the pike pole should be removed upon exit if there is time to do so safely. If there is no time to do this in an emergency evacuation, the fire will spread through the door and that part of the facility will be lost as well. This is why it is important to avoid the need to stretch hose lines through the door if possible.
If a fire door does not close because of damaged tracks, it may be possible to use portable monitor nozzles or unstaffed hose lines to keep the fire from spreading through the opening. I know of two cases where this was done with the result of saving major portions of the facility. This should only be attempted if the firewall is designed to remain standing after the collapse of the structure on the fire side of the wall. It's best to avoid the need to do this through proper fire door maintenance. Better yet, avoid this through proper sprinkler design and maintenance.
Something that many firefighters are not aware of is that commodity collapse is relied on for fire control in many situations. The reason piled storage requires less water for fire control than rack storage is that piles are expected to collapse and reduce airflow to the fire. You don't want to be near the pile when it collapses. If cardboard boxes are directly on the flow, as opposed to being elevated on a pallet, the bottom box could weaken from the water on the floor and cause the entire stack to collapse.
Combustible metal deck roofs:
A topic that gets nowhere near enough attention, in spite of the repeated efforts of noted building construction expert Frank Brannigan, is that of combustible metal deck roofs. If a built up roof has too much asphalt on the metal deck (too much means more that 0.12 pounds per square feet) the asphalt will vaporize when the metal deck reached 800? F. This vapor will force its way through seams in the roof and burn under the deck and heat up more of the deck in a self-sustaining reaction. Burning asphalt will fall through the seams and start additional fires.
The proper way to prevent this is through a properly designed sprinkler system that does not allow the roof deck to get hot enough to set up this process. Although it is possible to stop the process by cooling the deck with hose streams from beneath, in an industrial fire, the area could be too large for that by the time the hose streams can be set up. Once that happens, the fire is going to burn to the firewall if there is one. There have been at least four major combustible metal deck roof fires, three of which had losses well in excess of $100 million in today's dollars. Two of those three totally destroyed major industrial facilities and the third did extensive damage to such a facility.
Insurance companies or property loss prevention consulting firms are usually the only entities that scrutinize whether or not a combustible metal roof is present. The building owner should find out from their property loss control consultant what type of roof is present. If the company cannot determine the type of roof present, a core sample may be needed in order to do a laboratory analysis.
Industrial fires are events requiring a highly specialized and well-planned response. They are not like house fires that occur relatively frequently and can be managed by experience. Even in the largest cities, the average firefighter will not have a lot of experience with industrial occupancies and cannot rely on their own experience. It is important to learn from others. Firefighters should know what to expect and should not be surprised by the outcome.
2 Automatic venting means vents that are activated by a fusible link. They open when a link reaches a set temperature. Other forms of automatically operating vents also exist.
John Frank is the Loss Prevention Training Leader for GE Insurance Solutions, Property Insurance & Service Division. He can be reached at (770)569-7082 or at email@example.com