Basement Fires

By Brian Butler

Basements and cellars are the most dangerous fire location inside of a structure. With limited access, egress, advancement, and lack of ventilation options, be prepared to take a hit at the top of the stairs. 

Fires in subdivisions have killed more firemen than all upper floor fires have. Descending down a chimney of intense heat and hot gases from above to fight a below grade fire is no easy task. There are several dangers the company officer will have to address before advancing on a fire in a subdivision (or checking the fire to protect egress of occupants). 

Concerns for first due engine crews are intense heat, limited visibility, floor collapse, stair burn through, entanglement, limited ventilation, secondary means of egress and the occurrence of a hostile fire event, especially in areas with taxpayers, lightweight construction, and long reflex (response) times.

Basement or Cellar:
If more than half of the floor height is above ground (or the curb), it's a basement, if less than half is above ground, it's a cellar. Some garden apartments and brownstones will have their first floor slightly below grade; it's a living space so count it as a story. 

Photos above by CDC NIOSH

Size Up: When arriving to a basement fire it's important to identify key size up indicators that will be of concern in the first several minutes of operation. Identifying life hazards, lightweight truss, balloon frame construction, structures built on a slope or hillside, combustible exterior siding, bars on windows, renovated buildings, and flame impingement on service lines are just several concerns that will influence your initial strategy and tactics. Response time, trapped occupants, and manpower will also factor into your tactical decisions. Knowing the reported fire location given by dispatch, weather conditions and time of day before you even leave the station puts you ahead of the game. Confirming location and extent upon arrival will help determine rescue options, best route to access the fire, ventilation options, and line selection. 

On approach, look for exterior cutout doors, or Bilco doors as an option for secondary egress, fire attack, or ventilation. Take a quick look inside the basement window while stretching the line. For trapped occupants on upper floors, have a charged line for protection of the escape route (interior stairs), and start ground ladder placement for VES. 

Exterior Fire Spread: Vented basement fires will have to be stopped from spreading up the exterior siding. Fires that are not venting will still spread up the interior wall void spaces, especially in balloon construction. Stop any vertical exterior fire spread by quickly applying water from exterior and opening up the siding.

Construction: Not all basements are the same. Basements in urban areas with ordinary construction will differ from those in rural and suburban areas with wood frame construction. An urban basement may have low ceilings, hoarding conditions, illegal boarding with partitions, oil burner, oil tank, exposed utilities, open stairs, and unprotected 2x10 dimensional lumber. The suburban basement may have a large open space with 10' ceilings with an engineered lightweight truss I-beam floor above, protected by drywall and used as an entertainment room, or an apartment with a rear cutout or bilco entrance door. A row of taxpayers may have common basements with trap door access in the rear of the first floor commercial business with exterior access through sidewalk cellar doors.

During size up try to determine the construction and occupancy type, which can help determine the floor support system, access/egress points, and the contents burning below. If a 360° isn't possible, do a 270° and assign another company (or BC) to check the rear, especially if you have a row of attached homes. If it's a wood-frame balloon constructed home with fire, we already know to quickly get crews to the upper floors and cockloft to stop the vertical fire spread. If floor supports are engineered I-beams, fire will quickly burn through the web member and weaken the connection points. Steel C-joist concerns are deformation and connection failure. 

Location and Extent: Determining if it's in the basement can be difficult if you arrive to smoke showing on all floors with no visible fire. Check the basement windows, gather information from the residents, use a TIC on the first floor (perimeter/registers) or perform a 360° size up. Upon entering the front door to make your way to the interior basement stairs, high intense heat is an obvious sign you have fire below. If you have heavy fire venting out of the basement windows on arrival, consider a coordinated transitional attack (team work). When stretching in through the front door, check the stability of the floor on the way to the interior basement stairs. 


For an interior attack with heavy fire in the basement, consider having a fireman take out (and clear) a basement window if present, and dump a 2.5 gallon water can at the basement ceiling while crews are preparing their stretch down the interior basement stairs (remember to control the door until the line is charged and ready to advance). It only takes a few seconds to clear a window and about 45 seconds to empty a water can, which can absorb up to 23,000 BTU's depending on basement temperatures. WARNING: Consider wind conditions when applying this tactic. A strong wind in direction of window will intensify the fire, don't break the window.

Line Selection and Placement: For basement fires, the first attack line should be a smooth bore nozzle. With a limited ventilation fire in a container below, steam concerns, and more GPM's, it's the obvious choice. The attack and backup line should be charged BEFORE entering the basement. The fog nozzle (or breakaway) as the second line is not always a bad choice, as it helps with hydraulic ventilation to clear smoke/steam out of the basement and improve visibility after a quick knockdown. The second line must stay charged on the first floor ready to go in case the attack line has a problem. Firemen have been trapped, injured and killed in basement fires by hoselines being burned through on the floor above.
Determine the best entry point to attack the fire. If there's an outside entrance, stretch through there if it's the best option. Most of the time in urban residential structures, especially row homes, it's the front door to the interior basement stairs. Make sure to check which direction the door opens before you charge your line. If it opens towards you, it may be difficult getting past the door with the line and in position to descend the stairs. If it opens away from you, the products will hit you quickly, but at least the line won't be pinched under the door. Door control must be maintained until the line is ready. If the door has burned through, preventing the vertical fire spread becomes priority. 


TIP: Do not open a line in the window or bilco door while interior crews are advancing down the stairs or inside the basement 

In commercial/taxpayers, it's the interior basement stairs, exterior entrances or the sidewalk doors, which better serve at ventilation points. Be aware of hinged trap doors inside that may be left open. Firemen advancing in low visibility may fall through them into the burning cellar.

REMEMBER: Life safety is the top priority. The initial attack line will first protect the interior stairs for escaping occupants, fire spread and firemen conducting searches above.

For oil burners, bring a dry chem/CO2 extinguisher (Carbon Dioxide) and stretch an 1 3/4 line. For more on oil burners, click here.
Responding to Oil Burner Emergencies  

Photos by NIST

Collapse: The first due company officer and nozzleman will have to check floor stability when crossing over to make the interior basement door, especially if arriving to a free-burning fire below. Firemen can usually tell from the construction of the building whether it's 2x10 or engineered lightweight I-joists, but will be unaware if the property has been renovated. A floor support system in an unprotected I-beam lightweight or hybrid truss system can fail in as little as 5-7 minutes when exposed to fire. There's really no way to be 100% sure if it's safe to operate on the floor above the fire. TICs and sounding the floor is not reliable, but if the floor feels spongy or there's fire coming out of the baseboards, floor vents, registers/returns sagging carpet, these are not good signs! 

During UL tests on basement fires (picture above right) there were no signs prior to collapse. ​ Increased ventilation, fuel load, span, and added load from the weight of firemen in full gear increase chances of collapse. Residential basements underneath kitchens have heavy appliances like stoves, dishwashers, refrigerators above them. Commercial properties may have storage, machinery, supplies above, adding weight to an already weakened floor. (See Buffalo LODD)

Other concerns for collapse are long response times and the contents burning in the basement. Responding to a fully furnished family room basement fire in a rural area that has been burning for 20 minutes before the first company arrives means there's a good chance of floor collapse. Even in the city where several companies arrive on scene within several minutes, firemen may be walking into a basement fire with unprotected floor joists/plywood and low ceilings fueled by mattresses, gas cans, hoarding conditions, and other junk stored in basements. Factor in delayed discovery, and the chances of collapse increase. 

When the decision for an offensive attack has been made, the line charged and ready to advance, sound the steps on the way down. Open stairs with fire below exposing them will weaken stairs causing a collapse when weight is applied (if not already burned through) especially 'cardboard constructed' engineered lightweight I-stairs with 2x4 supports, OSB and gusset plates (pictured above left). Sound the center of the step for stability, descend on the outer stair near the supports.  

Stair Collapse: A major concern for the nozzleman making his way down to the basement. Engineered lightweight "I" stairs will collapse fast when exposed to fire. When lightweight construction is present on arrival, expect these cheap stairs. Check stability of steps and descend at the stringer.

Burn Time: Underwriters Laboratories performed testing on floor collapse during basement fires with different types of flooring systems. Collapse times ranged from 3:38 to 12:45, with dimensional lumber averaging 11:57 and engineered flooring systems averaging around 7:00. With all of these tests, there were no reliable signs of floor collapse. Sounding the floor with a tool or using a TIC is not reliable when checking for floor stability. ('I' beam rapid burn through of web member: pics below) When it comes to floor stability, it isn't about the type of flooring/lumber in a newer home, but how it's supported, whether the supports are protected or unprotected and how long it's been exposed to fire. 

UL Test Video Old vs New Room Furnishing

UL Test Video: Water in Basement Window

Test Video Basement Fires

Photos by CDC NIOSH

What type of floor supports and how long have they been burning? Add the weight of firemen crawling over this already weakened floor on the way to the basement door. 

 Ventilation: It's critical that ventilation during a basement fire be coordinated with fire attack. Subdivisions are difficult to vent because of little or no openings. Basement windows on the front of the structure will suffice and may be visible from the street. Other basement windows, bilco doors and exterior cut out entrance doors can be found during walk-around and used as the attack point or ventilation. 


Although rare, with the right conditions present, breaking basement windows or opening BILCO doors on the windward side while firemen are advancing down interior stairs will create a dangerous flow path. 

Many taxpayers have metal cellar door access on the sidewalk in front of the building, but they may be heavily secured to prevent theft. Do not use the interior basement stairway for a vent point as the fire will be pushed into the rest of the building. Cutting holes in the floor is time consuming for ventilation and may jeopardize cutting structural supports (better for flooding cellars). Using positive pressure ventilation (PPV) will be effective in certain conditions, but it's usually more effective after extinguishment. 

Flow Path

Flow Path:  With an open basement window (or bilco doors) some wind, an open interior basement door and the right fire conditions, a dangerous flow path will be awaiting attack crews at the top of the stairs.

While dangerous flow paths will not be an issue at every fire, it is still necessary to recognize the conditions and understand how they are created.

 ATF Mayday/LODD fire modeling analysis with scene audio, FF Mark Falkenhan, Baltimore County FD


Photos above right by CDC NIOSH

Rapid Intervention Team: RIT priorities at a basement fire will be providing the hose team with an additional means of egress BEFORE they need one. Immediately removing bars from basement windows, AC units in windows and performing a 360° to see if any other escape routes are available should be done right away in case a problem occurs. The attack crew entering through the front door in what appeared to be a 2 story home, may be a 3 story from the rear with a walk in basement entrance. This discovery has to be reported to the IC immediately. 

Be prepared to rescue firemen in the basement if a floor collapses or the stairs burn away, trapping them below. Methods of rescue will depend on their location, entanglement, fire/smoke conditions, air supply etc.. Have a ladder, webbing/rope, cutters and RIT pack ready to go. If possible, use the radio to direct them towards a window, bilco door, or other egress point with poor visibility conditions. (Why lights on helmets/coat help)

Some firemen will have trouble escaping through cellar windows above them wearing the full PPE -SCBA. They will have to remove their helmet and SCBA with facepiece still attached, reduce their profile and be pulled out by members on the outside. Enlarge the hole if possible.

It's IMPORTANT during a MAYDAY that members NOT involved with the rescue USE RADIO DISCIPLINE, unless it's a priority/mayday. Continue assigned suppression, search, ventilation duties, and remain on the proper channel. This is often a problem!

TIP: When arriving to a confirmed working fire in a sub-division, the IC should immediately assign the RIT team officer or another member to have a scissor/collapsible ladder or 14' straight ladder ready to go by the entrance, in case of a floor collapse. A good proactive RIT team at a basement or cellar fire will have a sledge hammer and other tools ready to help increase the size of basement window openings, just in case! 

Entanglement/Entrapment: Advancing hose teams should be careful when venturing deep into a basement fire (and attic) because the potential for entanglement and entrapment are high. Basements and cellars in urban areas will have hoarding conditions, illegal boarding-renovations, partitions, furniture, storage, washers/dryers, clothes lines with wire hangers, bicycles, crates, lawn equipment, drop ceilings, utility wires, entertainment centers, oil tanks and heaters. With little or no visibility, use extreme caution and move slow while advancing. Staying at the base of the stairs is usually a good place to attack and knock down the fire in a residential basement. When conducting the primary search in survivable conditions, be cognizant of all the clutter inside of a basement that can trap and entangle you including crawl spaces, closets, appliances, sleeping areas and common basements. Always look for that window or other escape route while entering the structure, hitting the fire, venting or searching. With low ceilings, bring short hooks/tools- and TED/light.  

TIP: While handlines are operating in the basement, it's important for members working on the floor above to recognize any signs of hose on the floor above being exposed to fire as to prevent line burn through. Flaked out hoselines placed over registers, open basement stairs with fire below and drop fire can damage the initial attack line, placing those men in danger. These incidents have already happened numerous times. 

Good RIT/FAST Training.

Gary Indiana fireman trapped in basement, pulled out through window.

Mayday rescue caught on helmet cam when fireman falls through basement.

Basement Fires 2

Basements/Cellars in Taxpayers & Garden Apartments: Subdivisions in taxpayers and garden apartments will differ from those in a private dwelling. The problem with a fire in the cellar of a taxpayer is the difficulty locating access from the interior, especially when there's poor visibility. Access may be through a hinged trap door in the rear of the structure or an adjoining occupancy. The best way to locate access points is to preplan the taxpayers in your district. Many old style taxpayers were constructed with common basements and have been renovated, partitioned off and used for stock/storage. They could resemble a maze with the only second means of egress being a fortified cellar door. Most newer taxpayers of limited/lightweight construction are built on a slab and do not have a basements. Fire preplans are necessary to identify cellar access. Garden apartments have caged storage areas for tenants and laundry rooms in their basements, which may lead to a crawl space. 

Explosions: A cellar is a confined space. Be aware of the explosion dangers in the subdivision and how to mitigate them. Gasoline and propane tanks, natural gas pipes from hot water heaters and a melted connection at the gas meter can cause explosions while firefighters are operating in the basement. For more on explosions in cellars click here



LODD Basement Fires: Fires in subdivisions have claimed the lives of many firefighters. Below are links to LODD (Line of Duty Death) reports of members from the fire service who were killed in below grade fires in various regions in the U.S. They vary from entrapment during searches or burned through hoselines, disorientation, entanglement in a basement used to grow marijuana, to engineered lightweight constructed floor collapse, flashover, smoke inhalation and stair collapse. 

LODD reports are thorough investigations of actual  incidents where firefighters were killed in the line of duty. Using them for training purposes will be beneficial to those reading them. Make them part of your drill school. 

Franklin NJ

Long Island NY

Philadelphia PA