BY JAY LOWRY
Manufactured housing poses grave threats to firefighters who do not respect it. The fire service has known for years that the fire death rate in this type of housing is twice that in regular site-built homes. The eighth edition of Fire in the United States, published by the U.S. Fire Administration, said this concerning mobile homes:
Mobile homes are a special category of one- and two-family dwellings. While only a small fraction of the U.S. population lives in mobile homes, they have had a severe problem in terms of fire fatalities in the past-double the fatality rate per fire compared to other homes. This caused the U.S. Department of Housing and Urban Development in 1976 to establish strict standards for improving the fire safety of such homes (often now called “manufactured housing”). The HUD standard clearly made an impact. However, the mobile home fire problem is still significant.”1
 (1) Wood hides the trailer hitch from view. (Photos by Abigail S. Lowry.) |
Firefighters should put the mobile home high on their list of extremely hazardous occupancies in which to conduct fire operations. We have to look at the mobile home with the same wariness we look at lightweight wood truss construction. The inherent instability of the structure, along with the rapid involvement that occurs when one is burning, makes this a formidable foe.
THE MANUFACTURED HOME OR MOBILE HOME
Mobile homes are commonly referred to as “trailers.” Although this is the popular term, it is incorrect. Officially, trailer fires occurred before the 1976 Housing and Urban Development code, or HUD code, was adopted. The code demanded new standards for these structures, renamed “manufactured homes.” Despite the code’s changes in the design and construction of these structures, they still present many hazards for firefighters. The code is inadequate. Manufactured homes are not held to the same code review and update process as site-built homes.
 (2) This fire was knocked down quickly but the damage is apparent. |
In 1980, Congress, at the behest of the manufactured housing industry, changed the category of housing from “manufactured homes” to “manufactured housing.” This structure is referred to as a mobile home in this article.
A simple definition of a manufactured home is any structure constructed in a manufacturing plant and transport-able in one or more sections.2 The manufactured home is mounted on a chassis. It is designed as a dwelling, although in many areas it is used for other purposes. The mobile home can be set up with or without a foundation.
WHERE ARE THESE STRUCTURES?
According to the Manufactured Housing Institute, some 19 million people live in more than eight million of these homes nationwide. In 1999, it was estimated that mobile homes accounted for nearly 21 percent of all newly constructed single-family dwellings. That is a significant number. It is estimated that more than 550,000 new structures come off the assembly line each year. They are located in every region of the country. Florida has a significant number of these structures because of the number of retirees in that state. The average price of a mobile home is far less than that of a site-built home, making it attractive to buyers in virtually every state. Zoning regulations usually restrict the placement of mobile homes, generally outside the city in a rural setting. Although they are located in and around urban areas, mobile homes are commonly seen throughout rural America. Regardless of their location, they can be the site of potentially devastating fires. If you believe that your community is free of manufactured housing, check around for job-site trailers. A portable office used by construction companies working on projects is found in many communities. When the job at that site is completed, the “office” is hitched to a truck and moved to the next site. This is a very economical way to do business. Some of the smaller offices have a single egress and exceptionally small windows. The danger is readily apparent.
CONSTRUCTION
The mobile home is built in an assembly plant. Units can be turned out in as little as five days. The frame is constructed of lightweight steel framing. When heated, lightweight steel framing can warp and bend, causing a catastrophic collapse. Francis L. Brannigan notes in Building Construction for the Fire Service, Third Edition, that steel will “expand from 0.06 percent to 0.07 percent in length for each 100°F rise in temperature.”3 This expansion poses problems for steel beams of significant size. The effects on the lightweight frame of a mobile home can be much more devastating in a much shorter period of time. The floor is often wood covered with tile or carpeting. The wood flooring may have been constructed of wood chips, a far cheaper process. During a fire, these boards can disintegrate from the heat conditions, causing dangerous openings in the floor. The unsuspecting firefighter could fall to the ground or may become hung up in the structure’s frame, unable to maneuver himself out of harm’s way. In these types of structures, a quick resolution is needed.
The side walls are installed first; the ceiling is squared and fastened to the side walls. Do not mistake the walls of mobile homes for the walls of a business or other structure. You can breach the mobile home walls easier to gain access to victims (as we will see later). The siding is usually installed next; it is applied to the exterior of the structure walls. This siding is often metal or aluminum-a particular favorite in the 1970s. A mobile home owner may attach wood to the exterior in place of vinyl or metal. In such cases, you may be deceived and believe that the structure is a regular site-built house. This siding can contribute to fire spread from an adjacent mobile home in a mobile home park. It is important to stop lateral spread of the fire to save neighbors’ homes.
The flooring in mobile homes may be angled or sloped as a result of the structure’s settling in one or more spots. Keep in mind that these structures arrive at the site in separate pieces and are joined together.
Advancing hoselines can be extremely difficult. Remember that water adds to the load being supported by the lightweight frame. The structure’s body may also be supported by outriggers, steel framing members-not directly under the frame-that support the structure’s weight. We see this in newer homes; front pieces extend from the normal linear body. The collapse of one or more of these outriggers is equivalent to the collapse of a column. That portion of the supported structure will collapse, putting additional stress on the rest of the structure.
 (4-5)Note the close proximity of other mobile homes. To the right of the rear structure in photo 4 is the same setup, so that you have four mobile homes to a driveway. |
Another concern is the space beneath the mobile home. It is often covered with “skirting,” a latticework or thin metal sheet that surrounds the lower portion of the home.
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Fires can start under the skirting. In many instances, flammable liquids are stored there. Firefighters should not go underneath a mobile home with a hoseline trying to knock down visible fire. It is unwise to crawl under a burning mobile home no matter how good the idea may seem at the time. If combustibles or flammables are present, the fire can worsen rapidly while the firefighter is under there.
The roof may be made of metal with wooden boards under it. It may contain shingles if the structure is modern. The roof may also be constructed of aluminum. The aluminum roof can be a double-edged sword. Aluminum melts rapidly and can ventilate the fire, which can be a plus. However, since aluminum melts rapidly under intense heat, do not go on the roof of a mobile home. There is little value in doing so anyway because of the structure’s size.
 (6) Here, the main driveway leading in is quite wide. In the evening, however, cars may be parked on both sides, making positioning a ladder truck, not to mention engine companies, difficult. |
Note: Some mobile homeowners “brick in” or apply a single layer of brick to the exterior of the mobile home. No changes are made to upgrade the structural components. It may appear that you have responded to a site-built home. The practice of adding brick is becoming more popular. The best way to identify these structures is to be familiar with your response area.
In addition to the construction hazards, the small spaces in mobile homes can also be detrimental to firefighters. Space is at a premium. Mobile home appliances are much smaller than those used in site-built homes. Evolutions such as search and rescue, fire suppression, and ventilation are affected by the lack of space. During search and rescue, the firefighter may be able to find a victim, but getting that victim back down the hallway to an egress door or to a window could be difficult, if not impossible. Two firefighters cannot work side by side. Removing the victim can be dangerous. Once the searching firefighter has located the victim, problems may arise. The firefighter may find irregular size doors or windows, especially on models built before 1976. Anyone who has advanced a charged hoseline knows that the tighter the space, the less cooperative the hoseline is. What we consider tight turns in ordinary construction can be child’s play when compared with turns from a hallway into a bedroom in a mobile home. The personal protective equipment, including SCBA, takes a lot of maneuvering room in the largest of structures. The mobile home exacerbates this already difficult situation. Firefighters can become trapped in between doorframes and walls. If the fire is in a one-egress home, the actions firefighters can perform are severely limited. Stretching a hoseline to knock down the fire or hold it in check is critical.
Time is also on the side of the fire. Search and rescue must be performed quickly and, if possible, with the protection of a hoseline. Breaching walls may be the most expedient way to gain entry or take out a victim or firefighter.
HEATING AND ELECTRICITY
In mobile homes built before 1976, heating and cooking equipment are in close proximity to sleeping areas. This poses dangers to occupants and firefighters. The closer the source of the fire is to the sleeping area, the shorter the time the searching firefighter has to effect rescue. Site-built homes have numerous areas in which to place utilities, and they usually don’t close the only escape route for occupants, as happens many times in mobile homes. Space heaters may pose a threat in modern mobile homes as well. So much of the structure is made of combustible, lightweight materials that a fire can grow at a quicker pace than a fire in a dwelling. Heating in modern mobile homes is generally electrical or gas. In older homes, propane is the common source of fuel. The heating equipment is usually just off the hallway leading to the sleeping area. Keep this in mind when looking for victims. As stated before, the source of the fire can be just inches from the bedrooms. According to a bulletin published by the Centers for Disease Control/National Institute of Occupational Safety and Health, fires caused by heating units and electrical fires are the primary causes of fires in mobile homes. Keep this in mind when responding to a fire in a mobile home. Utilities should be secured immediately.
PROPANE
Propane is a liquefied petroleum gas and aromatic hydrocarbon that may be used as a gaseous fuel. Propane’s best-known hydrocarbon neighbors are methane (natural gas) and butane (disposable cigarette lighters). Propane vapor is heavier than air. A leaking propane tank can allow vapors to settle underneath the home, creating an explosive atmosphere. Liquid propane will vaporize at any temperature above !44°F. A gallon of liquid propane weighs 4.24 pounds and contains 91,650 Btus. Propane, and all other hydrocarbon-based fuels, must be kept away from open flame and ignition sources. It is, therefore, vital to treat propane with the utmost respect. Propane fires, or fires that directly affect propane tanks, require immediate attention. The fire department will have to consider how it is going to protect the mobile home from the propane tank or vice versa.
Fire departments should always follow these guidelines when propane is involved:
- Follow the OSHA regulations 29 CFR 1910.120 (q)-Emergency response to hazardous substance releases. These regulations should be incorporated in your standard operating procedures (SOPs), which should be strictly enforced.
- Train first responders to be aware of the hazards associated with propane tank fires, including a boiling-liquid, expanding-vapor explosion (BLEVE).
- Evacuate nearby residences since mobile homes are in close proximity of each other.
- Protect the tank by doing one of the following:
•Cool containers by flooding them with large quantities of water until well after the fire is extinguished.
•Place a hose stream on the tank to help cool the contents and avoid a BLEVE, which can occur with the smallest of tanks and can prove deadly. Keep in mind that should a BLEVE occur, sections of the tank could fly in any direction.
EXPOSURES
In a mobile home park, the greatest danger is exposures. Because of their size, mobile homes are densely packed into a relatively small amount of space. A fire occurring in one mobile home can quickly spread to another.
Arriving firefighters must make an aggressive attack on the involved structure while ladder company members enter exposures to remove drapes and other combustibles from the windows. This will help to prevent the fire’s spreading, but the type of construction comes into play here as well. Often, other homes “light up” as quickly as units arrive. Stretch hoselines to protect those exposures. We know the importance of protecting exposures; however, a mobile home fire may swiftly spread to two, four, or eight structures before you can alter the balance of the fight. Some departments use aerial trucks to provide this exposure protection. This is a good idea, but keep in mind that the limited space may not allow for ladder operations. Mobile home parks are not known for wide driveways.
The quick use of a master stream and large handlines can prevent or diminish the exposure problem. It may be necessary to concentrate on defending a particular line-in other words, choose a spot, and concentrate your efforts on not allowing the fire to pass that point. Sometimes, high winds or the advanced stage of the fire will make this decision for you.
FIRE
With the above in mind, you must still seek out those whose lives are in danger. You may have to go in harm’s way. Some of the difficulties in performing search and rescue were pointed out earlier. The burning mobile home is a less-than-stable platform, making search and possible rescue of occupants even more dangerous. In older trailers with single egress and small windows, you are somewhat limited in exploring the home. This is not always the case in site-built homes, and the differences can be staggering. However, the structural weakness of a mobile home can provide a way in, if you locate a victim from the exterior, or a way out, if rapid egress is warranted. Ensure that all utilities are secured as quickly as possible. Breach the exterior wall, and gain access to the victim. The exterior walls are flimsy compared with those of most site-built homes. Remember that if a life is in the structure, you must use any method to rescue the occupant or, in a tragic circumstance, a firefighter. Property damage is not a concern when a life is at stake. Furthermore, the majority of mobile home fires end up destroying the mobile home anyway. Breaching walls is especially effective in mobile homes.
The narrow halls complicate search. In many models of mobile homes, you can feel both sides of the structure as you search. This saves time. Always keep in contact with the wall in your search pattern. Use a halligan or a hook to help extend your reach.
If the first-due engine pulls up and the mobile home is burning from end to end, your strategy has been decided for you. You have to knock down the fire to move in. If the home is in a mobile home park, again, protecting exposures is vital. Radiant heat can ignite the homes nearby. Stretch your attack lines accordingly. Remember that you will need plenty of water. Ventilation will already have been accomplished for you if the structure is totally involved. Rural departments are familiar with this scene.
If the first-due engine and ladder find a fire condition in the mobile home, stretch the first hoseline. Subsequent lines will be too little, too late, if enough water is not given to the first line as quickly as possible. As Battalion Chief John Norman has reinforced over the years in Fire Officer’s Handbook of Tactics,4 extinguishment of the fire is the quickest way to make the conditions improve. While extinguishment may have to wait if rescues are necessary, it is better to put the water on the fire as quickly as possible. This is at the heart of aggressive interior structural firefighting. Operating off the booster tank while acquiring a water supply is helpful. Water will be delivered to the attack line quickly, and you can hold the fire so a primary search can be done. It is imperative to gain access and get the hoseline on the fire as quickly as possible.
The mobile home, because of its construction defects, requires fast water. You must get inside and knock down the fire, preventing its spread. Traditional tactics such as vent-enter-search, used at single-family dwelling fires, are not applicable here. Get the line in, and knock down the fire.
References
- Fire in the United States, Eighth Edition, U.S. Fire Administration.
- Mobile Home Fire Safety Fact sheet AE26, adapted by William J. Becker and Heather Pirozzoli, Engineering Department, Florida Cooperative Extension Service, CDC/NIOSH, http://www.cdc.gov/niosh/nasd/ docs/as07900.html.
- Brannigan, Frank L. Building Construction for the Fire Service, Third Edition. (National Fire Protection Association, 1992).
- Norman, John. Fire Officer’s Handbook of Tactics, Second Edition. (Fire Engineering, 1998).
Additional Reference
Phoenix Fire Department, http://www.ci.phoenix.az.us/ FIRE/mobilhom.html.
JAY LOWRY is a former firefighter and senior fire marshal for Charleston, South Carolina. He has served on various NFPA Committees and has been published in fire service journals. He is a certified firefighter, fire inspector, and fire marshal.
