Taxpayers— An Overview
Taxpayers, often associated with rapid fire spread and heavy fire losses, have several unique fire problems that firefighters should be aware of. As with all fires, pre-planning is of utmost importance.
The term taxpayer was coined in the early 1900s to describe a building consisting of a number of stores that were erected quickly and cheaply to occupy property and to provide a source of income to pay taxes on otherwise vacant land. This practice continues today with some changes in the construction materials and with a greater increase in building areas.
The taxpayer classification should not apply only to our usual conception of these buildings, namely, a building one story high of ordinary construction (brick or masonry exterior walls with wooden beams, floors, roofs and partitions) and containing stores. Instead, let us broaden this classification to include other buildings of the same construction but housing such occupancies as factories, shopping centers, warehouses, garages, bowling alleys, catering establishments, theaters, skating rinks, meeting halls, etc.
Characteristics to consider
Second stories may be found covering either the entire area or a portion of these structures. This area can be occupied as offices, meeting and dance halls, factories, storage areas, apartments and, in some cases, additional commercial shops. Mezzanines are built into some of these areas with weak structural members and decreased heights in the upper and lower levels.
Cellar areas, too, can be full, partial or non-existent. The division of the cellar may not be identical to the first floor store division. One store in the building can occupy a major portion of the cellar, extending under other stores, with smaller or no space at all allocated to the remaining stores. The division walls are usually of weak construction with little fire-retarding properties.
Exterior or division walls are constructed of brick (some only two courses of brick wide) or concrete block. They are load-bearing walls that support the girders and joists at their extremities. The walls have very little lateral strength, and their stability depends on the load of girders and roof assembly being concentrated in a downward, vertical direction.
Parapet walls are the wall sections that extend above the roof level. They are free standing and have no sheer strength. Front parapet walls in these structures span large openings (display windows and entrance doors). Their weight is supported by steel I-beams or angles (lintels). The lateral support for these walls is provided at their ends where they tie into the exterior sidewalls. Often, the roof girders are butted and tied into the front parapet wall lintels.
Partition walls, which separate the building into smaller areas, are usually wood studs covered with lath and plaster or Sheetrock. In some buildings these partitions are support for the roof beams. Should a fire destroy or weaken these walls, the roof will collapse.
These walls are fire stopped, to some degree, at the floor and ceiling by wood sills and plates. In most cases, these walls do not extend above the ceiling level, which creates the large open area (cockloft) above all the occupancies within the enclosure walls. This permits the fire to spread horizontally and rapidly and drop down into adjoining stores. On occasion, these walls may be of masonry, extending through the cockloft and above the roof. The presence and location of partition walls must be reported by members of the roof team to the officer in charge.
Girders, mostly steel I-beams, generally run the length (front to rear) of the building to support the floor and roof beams (joists). In the older buildings, the girders are spaced 20 to 25 feet apart, but in modern construction where bar joists (roll-bar, parallel chord truss) are used, their spacing is greatly increased. The girders’ purpose is to provide open space within the loadbearing walls of the building. Where large open floor spaces are required, heavy steel I-beams are used with no supporting columns. Where open space is not a factor, lighter I-beams or wooden beams that use columns of cast iron or steel (lally columns) are spaced along the length of the girder for support.
Girders which protrude above the roof level, or roofs being built in step fashion because of the elevation of the ground may give the false impression of firewalls dividing the building. The covering over the protruding girders and the sidewalls where roof heights change will be wood sheathing that permits the fire to extend readily to another area.
Photo by Bob Pressler
Floor and roof beams (joists) are of wood or steel bar joists (parallel chord trusses). They rest on the exterior or division walls or girders within the building. When wooden joists are used, they span a distance of 20 to 25 feet; however, bar joists, depending on their size, can span much greater distances. Wood joists, when supported by I-beams, can rest on the lower or top flange.
Lateral stability for wood joists is achieved by bridging, placing cats (braces) between the beams and the floor boards, or by securing plywood to the beam. Bar joists have their upper chords resting on and welded to the top of the steel girder or built into the bearing walls.
Other appurtenances on roofs such as dust collecting or material storage hoppers, air conditioning units, ventilators, signs, increase the weight that the roof joists will have to support.
Skylights and roof openings that have been removed or that are covered over may have supports of much weaker construction than the remainder of the roof.
Wood truss roof construction in occupancies such as supermarkets, bowling alleys, garages, auto repair shops, factories, etc., where large unobstructed areas are needed with no columns or division walls, is utilized. These trusses consist of top and bottom chords, with webbing and gusset plates tying them together. The strength of a truss depends on each element of the truss holding the parts together. The failure of one part may cause the collapse of a large section of the roof or the entire roof.
Each type of truss is recognizable from the exterior of the building: the pitched truss with the high peak and pitched sides; the bow string truss by the humped shape of the roof; and the parallel chord truss by the flat roof with the edges slanted inward above the exterior walls. (See FIRE ENGINEERING, Jan. 1984, p. 19.)
Fire departments that have trussed roof buildings in their localities should know their locations, endeavor to hold periodic drills at these sites and have pre-fire plans formulated for possible emergencies in such buildings.
A pitched or inverted roof is a roof with its supports above the heavy joists that are at the ceiling level. The supports for this roof are 2 X 4-inch beams with 2 X 4-inch braces resting on the ceiling joists and covered over with boards or plywood. This makes for a weak roof that can fail before the ceiling joists on which it is supported.
Signs, marquees, and canopies on the front of stores or occupancies will be a potential collapse hazard if a fire occurs. due to the shear stress on the bearing or parapet wall.
Fire spread in taxpayers
The reasons for the rapid spread of fire and subsequent heavy losses in taxpayers should be looked into.
First, let us consider the construction features of such buildings, the structural materials used, their flammability and strength, and the arrangement of these structural components within the building.
Most taxpayers utilize wooden interior materials in their construction. Wooden beams, girders, columns, roofs and studding are covered with wooden siding or shingles. These in turn may be covered with stucco, metal or composition siding.
In addition to this non-fireproof construction, the following factors must be considered:
- The open areas of such structures that are much larger than those found in residences and office buildings.
- The irregular layout of some of these buildings, especially in the cellar and second floor areas that usually do not conform to the first floor layout.
- Areas that extend behind other areas in an “L”-shaped fashion.
- Unprotected vertical openings such as stairs, elevators, escalators, conveyors, chutes, etc.
- Large, unprotected openings in fire separations made for the movement of stock or the enlargement of an area.
- Additions to existing structures may find that the beams in the addition are not laid in the same direction as those of the original building. Additions are characterized by stepped-up roof areas around the original perimeter.
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- The many hidden channels for the spread of fire, such as:
- Common cocklofts over several stores or occupancies. This is the area that is formed between the underside of the roof sheathing and the top of the ceiling below when the roof is pitched to provide for roof drainage. The depth of this cockloft area is usually great at the front of the building and decreases toward the rear of the building.
- Bays between ceiling beams (joists) formed when tin or other material is secured directly to the beams or to furring strips (wooden strips used to build out the existing members) attached perpendicular to the beams.
- Hanging or dropped ceilings are the areas between ceilings and the area between the bays of the original ceiling. Air-handling ducts, air-handling machinery, water and steam piping, electrical wiring, and recessed lighting fixtures are often installed in the false ceilings. These ceilings are suspended by light wood strips, steel wires or bars that cannot sustain much weight above that of the materials they are supporting. Any additional weight or weakening of the supports can cause large sections of these ceilings to fall.
If the original ceilings are not removed when the dropped ceilings are installed, this forms two or more additional voids for fire spread.
- Pipe recesses, cable runs, dumbwaiters, vent and light shafts.
- Air-handling ducts through which fire and heat can travel to remote areas.
- Non-existing or very poor firestopping features within the exterior walls and the holes made in such stops.
- The interior walls butting the exterior walls are usually secured to furring strips attached to the exterior wall. This creates spaces between the inside face of the exterior wall and the interior wall through which fire can spread.
- The three methods of heat transfer must also be considered:
Conduction of heat through walls or floors, metal beams, and columns, pipes and cables all may heat adjoining areas.
Convections of heat, whereby the heated air is transmitted to adjoining areas through ducts, stairs, shafts, voids and other openings.
Radiation of heat through space will heat materials, causing them to ignite and spread the fire rapidly.
Usually, these three heat transfer methods will occur simultaneously.
- Fire can spread to exposures by means of flying brands, embers and radiated heat. Depending on conditions, such as large, self-vented fires, it may be best to initially concentrate firefighting efforts on exposure protection rather than on fire extinguishment in the original fire building.
Photo by Bob Pressle
- Other factors that must be considered:
- Life hazard not only in normal business hours, but especially those structures that have apartments or other areas that may be inhabited at all hours of the day.
- The time of the fire. Most large losses occur during night hours when discovery of the fire is usually delayed. The amount and location of the fire is a major factor in deciding whether the initial attack will be interior or exterior. Remember, the effect of fire on the structural members of such buildings will greatly increase the collapse potential.
- Fire protection or fire detection/alarm systems in the majority of these buildings is virtually non-existent. Some buildings may have systems that are either defective or not in operation.
- Venting and access problems, especially to the cellar and rear areas.
- Poor water supply facilities.
- The large amount and flammability of the stock or working materials and the way in which these materials are stored and handled (high piling, inadequate aisle space, blocking of exits, etc.).
- Accumulations of rubbish and waste materials in some occupancies.
The hazards of newer building construction
With the advent of steel roll-bar joists (parallel chord trusses) and heavy steel girders, the open areas within these structures have been greatly increased with fewer supporting columns.
Structural parts of these newer buildings will not burn, but if they are not fire protected, heat generation in their vicinity will cause them to lose their strength. (Steel loses its strength at about 1,000°F.) Depending on thickness, length, load carried and the fire’s intensity, the newer building can collapse rapidly—in some cases, as fast as five minutes.
Large, open-space construction provides for greater concentrations of combustible stock and materials; and in the event of a fire, the increased draft conditions permit the fire to spread even more rapidly.
Sprinkler systems, if properly designed, installed and maintained, should be able to control and possibly extinguish a fire in these structures. Alterations (such as moving partitions in the building or changing the nature of and the manner of handling and storing stock) for which the sprinkler system was not engineered, may negate the effectiveness of such a system.
Pre-plan and size up
Fires in taxpayers are always a problem and present a challenge to all our firefighting forces. Taxpayer fires require an intelligent and aggressive strategy for control, with greatemphasis on life safety, both for the occupants and the firefighters.
The importance of pre-planning cannot be neglected and should be employed by all fire departments. Knowledge of the building layout, the construction and operations being conducted therein, and the nature and amount of stock on the premises will be invaluable information in the event of an emergency.
Because of the taxpayer’s features, the four major fire control operations (locating, confining, extinguishing, and examining/overhauling) will be more difficult and prolonged. Thus, serious consideration must be given to the availability of adequate equipment and manpower.
In addition to considering the time of day, the season, and the potential life hazard, let us look at the other important points of size up:
- The building’s features:
- Height causes problems of fire spread and access to the upper areas for entry, evacuation, need for and placement of ladders, etc.
- Area, if large, presents the possibility of rapid fire spread and the creation of a large fire requiring heavy caliber exterior streams and the stretching of many long handlines. Some areas of the structure’may be beyond the penetration of effective fire streams.
- Construction in many cases will determine the probability of a collapse, the addition of fuel to the fire, and the many areas through which fire will spread.
- Occupancy can be the indication of the anticipated hazards, the type and amount of fire and its spread, and the need for special extinguishing equipment and methods.
- The fire situation:
- The location of the fire will determine its accessability for extinguishment and its effect on the structural members.
- The extent and duration of the fire will determine the need for an interior or exterior attack depending on the amount of fire and the structural stability of the building. The amount of manpower and equipment that will be needed for the operation must also be considered.
- The exposures could present a life or fire hazard and will require protection. In some cases, this factor may have to be given first consideration.
- Apparatus, manpower and equipment that will be immediately available should be known and a judgment made whether this will be adequate to control the situation. If there is any doubt, additional alarms or mutual aid should be requested early. Keep in mind the time necessary for this additional response to become useful at the scene.
- The location of auxiliary fire protection equipment on the premises (such as sprinkler and standpipe systems) should be known. Protection should be afforded openings in fire barriers.
- Water supply availability, the source, location and adequacy.
- Weather can have an effect on firefighter stamina and on the fire. This may have a bearing on the strategy employed (roof venting after a snow storm, for example).
- Special matters such as:
- Problems with access to the interior or exterior sections of the premises.
- Exposures with a large concentration of human occupancy, such as schools, hospitals, office buildings, housing developments, etc.
- The terrain of the site and the surrounding areas.
- The business, type of operation, the storage and handling of stock within the structure.
- The location of hazardous areas in and around the establishment, as well as the location of material storage areas.
With the consideration of the above points, a very good idea of the situation you are confronted with will be obtained. Upon arriving at an incident, every firefighter should survey the exterior of the building and the surrounding area on the side to which he has responded or from which he will operate, noting the following:
- The fire condition—the location of the fire, its severity; if the fire structure has vented itself, where, and how severe a problem it is.
- The smoke condition and its color. Is there a possibility of a backdraft?
- The condition of the exterior walls—if they are leaning outward or inward; if any cracks are evident, their location, direction, length and width; if there is any loose or missing masonry—all are indicators of potential collapse.
- The openings in the walls and their coverings will determine the means of access for operations or evacuation if necessary.
- Exterior additions to the building such as fire escapes, ladders, hanging or roof signs, canopies, marquees, awnings, exterior ducts and smoke pipes on the building.
- Look for overhead wires and trees that will affect operations.
This quick survey will also provide the height and width of the structure and in many cases the construction, be it frame, brick, cement block, etc. Knowing the construction may be a clue to the materials used in the structural members and the arrangement of building members.
All this information can be obtained in a very short period and will prove invaluable when making operational judgments and for providing increased personal safety. This information can also be used in determining the possibility of arson.
Because operations at these fires can be extensive and conditions change rapidly, it is very important to maintain centralized control and command of the situation. Therefore, to accomplish our goal of preserving life and property, we may have to divide the entire operation into smaller sectors for better management. The size of the area and the amount of fire will determine the areas of command and the size of the sectors. One firefighter should be designated in charge of each area with the responsibility of relaying information to the officer in command of the operation and issuing and complying with any orders that are given from a command post.
It must be remembered that actions being taken in one section may be having a positive effect on the fire conditions in that sector, but may cause an adverse effect on another section of the problem. Be aware of:
- operation of opposing streams,
- using exterior streams that may endanger any firefighter on either the interior or exterior of the building,
- improper and ill-timed ventilation.
Some of the sectors that the area can be divided into are: interior operations, on several floors if necessary; roof operations; exterior and exposure operations; rear operations. Depending on the initial and developing fire conditions, these areas of command may have to be expanded or subdivided in order to maintain better control and, increase the efficiency of the operation.
It’s evident that communications must be prompt, clear, concise, and as complete as possible. There must be the means of transmitting messages and orders, be it via portable or apparatus radios or voice communications, using runners if necessary. Messages should be brief, but they must state conditions as they exist or change, actions being taken and their effect on the problem. Keep in mind that from one sector a problem may not be evident, but from another sector conditions may indicate a much more serious problem.
Let us now consider some specific fire situations in taxpayer structures:
Cellar fires are very difficult to control and extinguish under any circumstances because:
- access is limited and sometimes hidden,
- ventilation is difficult and a must for efficient entry,
- high bulk storage, irregular aisles and partitions create maze-like conditions,
- fire severity and structural instability due to delay in discovery,
- rapid horizontal spread between joists,
- vertical extension is assured.
It is very important to maintain control of the first floor in cellar fires. This requires the placement of interior handlines on the first floor to stop the fire from spreading upward and also adequate ventilation of this area for the positioning of these lines. Remember to evaluate the stability of the floor and roof before committing any companies to these positions.
Every effort consistent with safety should be made to gain access to the cellar for the operation of lines, whether from the interior or exterior.
At times, two lines operating in unison may be required to advance and extinguish the fire. Also, streams must have sufficient pressure and volume to penetrate the heat barrier of the fire and extinguish it. Handlines may have to be stretched into adjoining cellars and stores as conditions indicate.
If control of the fire cannot be established by operations from one direction, line penetration must be employed in another area if possible. The second line should be connected to the sprinkler Siamese connection if present and supplied with water at an initial pump pressure of approximately 150 psi.
If lines cannot advance into the cellar, holes can be cut in the first floor for the operation of distributors or cellar pipes. If all efforts to gain access to the cellar and maintain control of the first floor have to be abandoned, as a last resort consider flooding the first floor, breaching walls from adjoining stores, and using high-expansion foam.
Ladder companies have many responsibilities at all taxpayer fires. However, at fires in cellar areas, they are additionally charged with:
- forcing entrance to the cellar, other floors and stores as needed,
- providing thorough ventilation to the cellar and first floor by any means available, such as outside and inside cellar doors, keeping in mind that these doors may cover elevators, chutes and conveyors,
- removal of any windows on the first floor and in the cellar where some are in depressed areas covered with gratings,
- cutting holes in the first floor rear windows.
In a one-story taxpayer, a store fire may readily involve the cockloft or ceiling area above that store. This will cause the fire to spread to adjoining stores, eventually involving the entire structure unless a proper, rapid, and aggressive attack is made in the original fire area. Remember, a fire in this overhead area will weaken the roof supports, which can lead to a partial or full collapse of the roof and possibly some of the walls.
The first pumper responding to the scene should consider an in-line pumping operation (straight lay will be needed, but in this case lay two supply lines if possible). This will enable the pumper to be positioned in front of the store involved, and the pumper will be supplied with water. The apparatus must be positioned so that it will not be endangered by any fire issuing from the store or any collapse of the front wall. Such positioning of the pumper will provide for short handline stretches
Important factors that must be considered at fires in taxpayers and all other structural fires are:
- The safety of the occupants and firefighters,
The duration, extent and severity of the fire,
- Prompt and extensive vertical ventilation,
- The structural stability of the building and the collapse potential,
- The need for a rapid and aggressive attack on the fire consistent with safety,
- Horizontal ventilation of the rear of the building is a must once lines begin to advance,
- No hesitation in calling for additional help If you are unable to gain control of the fire quickly,
- Communications are vital at any fire operation for the implementation of proper strategies,
- The fire situation can change very rapidly,
- Last but not least, every firefighter at the scene must use his senses of sight, touch, hearing and smell in order to be aware of the conditions in his area of operation. If a firefighter is not thinking and observing, he can become a liability, plus he may endanger the lives of other firefighters or occupants in the building.
Pre-planning is one of our best tools for bettering our capabilities to handle fire or emergency situations. These are only guidelines, and, if followed, do not guarantee a successful firefighting operation because of the many variables in any fire situation. Do not take anything for granted, and be prepared to change your strategies to meet changing conditions.
and the use of a deck pipe if the apparatus is so equipped.
Depending on fire conditions, the first handline with sufficient water and pressure should be stretched into the fire store. A deck pipe also can be used
for this purpose, and the handline then can be taken into an adjoining store to operate into the cockloft or ceiling area if fire is of large enough proportions. For fast water on the fire, the booster tank water on the apparatus can be used. Communicating this tactic to the second arriving pumper is essential if this is not standard operating procedure.
If the building is equipped with a sprinkler system and a Siamese connection, it should be supplied with water. These systems, if operating, help to confine the fire and prevent greater damage. Of course, if the system becomes severely damaged, its water supply should be shut down.
If necessary, a second handline should be stretched into an adjoining store to prevent the spread of the fire, especially in the area above the ceiling. If this line is not needed in this position, it can operate in unison with the first line or it can be the backup line.
Subsequent lines may have to be stretched into adjoining stores as conditions indicate. At times, fire conditions in the cockloft area may dictate the by-passing of an adjoining store or stores and stretching handlines into remote stores to cut off the fire spread in this overused area. Strategy would then dictate working back toward the seat of fire with additional handlines.
If difficulty is encountered in pulling down the ceilings to expose the cockloft, a trench cut should be made on the roof before the head of the fire. This trench should be at least three feet wide and well in advance of the fire to allow for the completion of the trench before the advancing fire makes it impossible to complete the operation. Holes should also be made over any hot spots on the roof.
A handline or lines can be operated through this trench cut into the burning cockloft area. For greater penetration and effectiveness of the stream, the hose should be laid on the roof at right angles to the cut, the nozzle positioned below the roof beams and swept horizontally into the area. If this tactic is going to be used, firefighters in the stores over where the stream is going to be operated should be withdrawn while the stream is in operation. The main objective here is to complete the cut ahead of the fire. Simple ventilation theory will retard horizontal fire spread. The fire must be stopped here—even if handline use is necessary.
At times, an elevated platform stream operated from the street level may be able to penetrate the overhead area from the front of the building and stop the fire spread. Elevated platform streams can also be used to extinguish any fire in a store or group of stores. Removing the signs and the siding over the front of a store may provide an opening for stream operation into the cockloft.
In buildings of more than one story, hoselines will have to be stretched into the upper floors and operated where needed. Exposures that are threatened will have to be considered for water stream protection. If conditions warrant, the initial strategy may have to be a defensive action, protecting the exposures first and when sufficient forces are available, attacking the main body of the fire. Because of the rapid development and changes in the fire situation, be prepared to alter your strategies to ensure the safety of firefighters and to contain the fire.
A fire in the upper floor of a taxpayer will present the same problems as those with a first floor fire. Layout of the second floor will be entirely different from that of the first floor, and the undetected involvement of the cockloft will be an additional problem.