BY GREGORY HAVEL
OLDER BUILDINGS CAN POSE HAZARDS TO FIREfighters because their behavior is unpredictable under fire conditions.
Many buildings were erected before building codes or consensus standards for construction, including those in historical preservation districts (photo 1). Some buildings have been remodeled by the owner without benefit of engineering, plan review, building permits, or code compliance (photo 2); some have “deferred maintenance” issues-we used to call these “neglected.” These include buildings whose maintenance and remodeling have been limited to keeping up appearances, without any attention to hidden deterioration of the structure.
 (1) This block of buildings includes ordinary and wood-frame construction of two and three stories, with cellars. Some cellars extend under the sidewalk. (Photos by author.) |
These types of buildings can be as hazardous to firefighters as modern buildings constructed of trusses and lightweight materials. Fires in them can spread in unexpected ways if we are not familiar with how they were built or rebuilt. In fires, these buildings are likely to collapse earlier than we might anticipate.
In older buildings, as in any building, certain elements are critical to structural stability under fire conditions:
- The age and integrity of the structural components.
- The condition of connections between structural components.
- Void spaces within the building, and the extent to which they are interconnected and combustible.
- The age and integrity of building systems, including plumbing; electrical; and heating, ventilating, and air-conditioning.
- Changes in occupancy, use of space, live loads, and fire loads of the structure.
Building codes and consensus standards establish minimum standards for construction. If these standards are met or exceeded, the building’s behavior under normal conditions is predictable. Under fire conditions, the building’s behavior is usually more predictable than it would be if it were not code compliant. Today’s building codes and consensus standards are based on decades of experience with structures built before codes or standards were developed for those types of structures. Many code requirements are the result of bad experiences like structural collapse and fires with injuries, fatalities, or near-misses.
OLDER BUILDINGS USUALLY ARE BUILT THE SAME WAY
Before building codes or consensus standards were developed, buildings of similar materials were constructed in similar fashion because of customary practice and a standard of craftsmanship that often was unwritten. Variations in construction methods were related to geographic location and availability of materials, the age of the structure, and the training the builder received as an apprentice.
The most common types of construction found in older buildings are ordinary (bearing and exterior walls of brick, stone, or other masonry-bearing exterior walls with wood joists, floors, roof decks, and partitions, photo 3), heavy timber (brick or stone exterior and bearing walls with heavy timber beams, columns, joists, floors, and roof decks, all exposed to eliminate void spaces in which fire could travel), and wood frame. Three common types of wood frame are post and beam connected with mortise-and-tenon joints (photo 4), balloon-frame (studdings for bearing walls are continuous from the foundation to the plate supporting the roof rafters), and platform frame (studs bear on each floor’s joists and deck and carry the next floor’s joists on the top plate).1,2
Materials
One of the most common features of older buildings is that the masonry, including the foundation, was constructed with sand-lime mortar. This type of mortar does not bond as well to brick or stone as today’s Portland-cement mortar. It absorbs moisture and loses its strength in damp locations and can be washed out of the wall by repeated wetting from leaking pipes, missing downspouts, or a hose stream (photo 5). These buildings must often be restored using sand-lime mortar for historical accuracy and appearance.3 This potential problem can be found in buildings of ordinary, heavy timber, and wood-frame construction. In the latter, one wythe of masonry is a veneer over the wood frame.
 (5) The sand-lime mortar has been washed out of this fieldstone foundation by years of exposure to rain and snow. |
Masonry materials are not uniform. The front or street side of a building was likely to be constructed with care for its appearance, often of quality brick or cut stone. The other sides might be exposed only in an alley or might be an unexposed bearing wall adjacent to another building. In these locations, appearance was not as important, and the wall could be constructed of whatever materials were available and inexpensive: brick, tile, terra cotta, or fieldstone (photo 6).
 (6) A view of the alley side of the corner building in photo 1. This wall is a mixture of fieldstone and brick with sand-lime mortar. |
Another feature of older buildings is that the wood used for columns, beams, joists, and rafters may be deteriorated because of rot, insect damage, or age. In some of these buildings, columns and beams are simply logs (with or without bark) and were squared by ax or had flat spots cut to support floor joists or other beams. When a log is sawn into timbers and lumber, internal defects and weaknesses are exposed, offering the opportunity to use substandard lumber in less critical places. When a log is used “as is” for a structural support, any defects are concealed, and cracking and splitting as it dries are uncontrolled (photo 7).
In addition to age and natural defects, wood deteriorates from cyclical changes in temperature and humidity, which can cause cracking and splitting; from being too damp as a result of leaks or poor ventilation, which can allow molds and fungi to grow and feed on the wood; and from insects burrowing into or feeding on the wood (photo 8).
A natural feature of sawn timbers and lumber in older buildings is that it is rough-sawn, full-dimension lumber. These timbers were used as they came from the sawmill, without planing, since they would be concealed and appearance didn’t matter (photo 9). Lumber with a rough surface may ignite more easily in a fire because it has a greater surface area than if it had been planed smooth, and its roughness and splinters provide areas of greater surface-to-mass ratio that absorb heat more quickly.
Some older buildings were constructed or renovated using cast-iron columns and wrought-iron beams. Cast iron has good compressive strength, but it has little tensile strength and it can crack or shatter on impact. Cast iron can crack if it is unevenly cooled after heating, as by a hose stream in a fire.
Other aging buildings have steel columns and beams that were added during renovation. This material has both compressive and tensile strength but elongates greatly when heated and can fail at a relatively low temperature. Both iron and steel rust on exposure to air; this oxidation happens more quickly when exposed to moist air and rapidly in wet locations, to the point of failure.
Connections
As previously mentioned, the most common connection for masonry materials is mortar. When wood beams and joists were set into pockets in a masonry wall, they were often mortared in place to keep them plumb and level. Because the beams were rough-sawn, the mortar bonded to them as well as to the masonry.
Connections in some older wood-frame buildings also are made of wood, using mortise-and-tenon joints, dowels, or pegs (photo 4). These connections can deteriorate in the same way that wood framing deteriorates.
Iron, wrought iron, cast iron, and steel also are used as connections in older buildings. The most common cause of deterioration and weakening of these connections is rust, usually because of a damp location. These materials have been used in nails, screws, bolts, connection plates and straps, rivets, and tie rods used to reinforce and stabilize a building (photo 10). Some connections may be shared by two buildings, as in two buildings with a common bearing wall with joists from both buildings in the same pockets in the masonry wall.
Void Spaces
Almost every building has concealed void spaces. These include chases in masonry and other types of walls to conceal pipes and other utilities (the only concealed space likely to be found in unmodified heavy timber construction); the space not occupied by joists between a floor deck and the ceiling below (photo 11); the space not occupied by stud between the exposed wall surfaces in adjacent rooms (photos 3 and 9); crawl spaces; attics and cocklofts (between the top floor ceiling and the roof); and enclosures constructed to hide pipes, ducts, and structural supports (photo 12).
 (12) This void space will enclose a steel column and pipes. |
Fire and smoke can travel through these spaces, especially if they are not fire-stopped (to prevent vertical fire spread) or draft-stopped (to prevent horizontal fire spread). Fire spreading through these spaces is of special concern if these voids connect common cocklofts or attics with basements or cellars that are common to more than one building (or that have been made so). Even if the building has an automatic sprinkler system, many of these void spaces will not be protected.
Building Systems
Every building has systems for the convenience and comfort of its occupants. These include the following:
- Heating, ventilating, and air-conditioning (HVAC) system pipes, ducts, vents, and machinery.
- Plumbing pipes, vents, fixtures, and other equipment.
- Electrical conduits, wires, cables, lighting fixtures, switchgear, and connection points for use of electricity.
- Automatic sprinkler and standpipe system pipes, valves, and other equipment.
- Fire protection and security alarm system conduits, wires, cables, and network equipment.
- Communications and data cables, connections, and network equipment.
- Trash chutes, collection areas, and incinerators.
- Mail collection systems and pneumatic systems for business and banking papers.
A malfunction of any part of one of these systems will cause inconvenience and discomfort for building occupants or, in the worst-case scenario, a fire or other serious damage to the building and its contents. Potential ignition sources include substandard or deteriorated wiring; deteriorated gas piping; improperly constructed or deteriorated chimneys, flues, and vents; and poorly maintained or malfunctioning HVAC equipment.
BE AWARE OF CHANGES IN USE AND REMODELING
Over time, the way any building is used will change. Many of the buildings in our historical preservation districts and some of our older residences were built before electricity, indoor plumbing, automatic fire sprinklers, and central heating were available. Adding these systems for the comfort, convenience, and productivity of building occupants required modifications to the buildings, including openings through ceiling and floor assemblies and walls (including those with fire ratings), addition of partitions and other enclosures to conceal the added equipment, removal of other partitions, and adding both live and dead loads that the building may not have been designed to support (photo 13).
 (13) This roof, which is sagging, was not designed for the load of two air-conditioning units that were added decades later. |
These modifications may have resulted in the addition of void spaces, the interconnection of void spaces by removal of fire stops and installation of pipes and ducts in openings larger than they need to be (photo 14), and changes in some of the building loads from distributed loads carried by bearing walls to point loads carried by columns (photo 15).
 (14) These pipes pass through a two-hour-rated wall. This defect was found and corrected during a recent renovation project. |
As each of the systems listed above became available, the building was adapted to accommodate them as well as to the changes in the way the building was being used. Since these systems did not become available at the same time, each building may have been remodeled several times over its life, often with materials and methods different than those used when it was originally built. This periodic remodeling results in removal of natural barriers to fire spread, such as firestops in cocklofts and in walls at each floor, walls that divide basements and cellars, and removal of stairway enclosures. Remodeling also results in components that are added to compensate for known weaknesses of the building or to compensate for loads that are added. These components include tie rods (with or without “stars”), turn buckles, extra columns, and metal plates fastened to cracked timbers (photos 10, 15, and 16).
Suspended ceilings (photo 11) often have been added at different times for the sake of appearance, acoustics, and energy savings. It is not unusual for an old building to have two or three suspended ceilings in addition to its original ceiling. Each of these creates an additional void space that often is connected to others and that can provide another passage for the spread of smoke and fire.
The owner or a handyman often undertakes repairs and remodeling without building permits, engineering design, formal plan review, or concern for building-code compliance. This type of work usually is done at the lowest possible cost and can include unconventional and improvised materials and construction methods (photo 17).
 (17) In this storage addition to a barn, discarded utility poles were used for columns and beams, and the lumber was salvaged from demolished buildings. |
Not all buildings are well-maintained-not even new and modern ones. Frequently, the only maintenance done is for the sake of appearance. Routine maintenance and upkeep are deferred to save money. If the roof or a pipe leaks and damages the interior paint and plaster, the leak will be repaired and the plaster will be fixed and repainted, with no consideration or attention given to the moisture’s effect on the masonry, steel, or wood structure that supports the building. The effects of the moisture over time, and of repeated leaks, will cause deterioration of the masonry, steel, or wood and weaken the structure. A building’s exterior can be neglected to the extent that it is less expensive for the owner to cover the neglect with a new face than it is to repair the old one. Adding a new face to a building can create additional void spaces that are frequently connected to other voids in the existing building.
Sometimes a building will be neglected to the point that it costs the owner less to demolish the old building and build a new one than it will cost to repair the old building. Either choice costs more in the long run than it would have cost to maintain the building and prevent it from deteriorating.
COUNTDOWN TO DISASTER
Repeated remodeling, adding and changing building systems, adding and connecting void spaces, adding loads, and low-budget building maintenance can result in a building with many defects. None of these defects may be serious enough by themselves to compromise the stability of the structure; but together, they set up the building for failure and collapse if conditions are unusual, as in a fire. An example follows.
The Hotel Vendome was built in Boston in 1871, at a time when gas lighting was common and heat was provided by boilers and radiators or space heaters. The building was of ordinary construction, with multiple brick masonry supporting walls about 24 feet apart spanned by wood joists to support floors and roof. Sand-lime mortar was used in the masonry.
In the late 1890s, several supporting walls on the first floor were removed and replaced with wrought-iron beams and cast-iron columns, to make a larger restaurant dining room. These beams carried the weight of the floors and roof. The columns carried this same weight, with a concentrated load at the bearing point of each column that greatly exceeded the capacity of a sound masonry wall built with sand-lime mortar.4
In the 1950s, air-conditioning was added to the Hotel Vendome. Openings were made in walls and floors for installation of the ductwork. One of these openings was made in a masonry bearing wall in the basement below one of the cast-iron columns, at a point where the masonry wall was already overloaded, without a lintel or any other provision for distributing the weight supported by the column.5
On June 17, 1972, there was a fire on the upper floors of the Hotel Vendome, above the restaurant dining room. After the four-alarm fire was controlled, several Boston Fire Department companies were overhauling the burned area, where the fire had traveled through interconnected void spaces. The combined live load of firefighters, equipment, and water, plus the impact load from the overhaul of the fire, caused the failure of the overloaded masonry above the duct opening at the base of the cast iron column, the failure of the column itself, and the collapse of that part of the hotel. Nine firefighters were killed, and eight more were injured.6
The defects that accumulated for more than 100 years at the Hotel Vendome and caused the death of nine firefighters are the same defects that can be found in structures throughout the United States. They are not all present in all structures, but the same construction and remodeling methods and concern for cost savings are nearly universal. Any community with an old or poorly maintained multistory building has the potential for an incident like the Hotel Vendome. Here are some of the ways we can prevent these types of incidents:
- Develop a working relationship with the building inspector, with exchange of information about building permits and plans and changes or defects noted during fire inspections.
- Include fire prevention programs for contractors, architects, and engineers in our public education efforts.
- Educate our fire inspection and other personnel to recognize potential hazards during and after construction and remodeling.
- Arrange tours and inspections of buildings under construction and renovation, to note potential hazards so that these details can be included in our prefire plans for these structures.
- In buildings with known structural defects or hazards, reduce the time allowed for interior search, rescue, and firefighting; include this in your prefire plans.
- Conduct a hazard analysis after control of a fire in one of these buildings, before overhaul and investigation begin, including structural stability, integrity, and defects; note the results after the fire on your prefire plans.
ENDNOTES
1. Essentials of Fire Fighting, 4th Edition; International Fire Service Training Association: Oklahoma State University, Stillwater, OK, 1998, 65-76 and 353.
2. Building Construction Related to the Fire Service, 2nd Edition; International Fire Service Training Association: Oklahoma State University, Stillwater, OK, 1999, 21-30 and 92-93.
3. Building Construction for the Fire Service, 3rd Edition. Francis Brannigan (National Fire Protection Association: Quincy, MA, 1992), 157-158.
4. Francis Brannigan, The Ol’ Professor, “in Memoriam,” Fire Engineering, May 1997, 110.
5. See page 171 of Building Construction for the Fire Service, 3rd Edition, for a diagram of the beams, columns, and duct opening in the masonry wall.
6. Francis Brannigan discusses this incident in detail in his article in Fire Engineering, May 1997. Also visit the Web sites http://www.celebrateboston.com/disasters/disasters.htm and http://www.cityofboston.gov/fire/memorial/vendome_fire.asp
GREGORY HAVEL is a member of the Burlington (WI) Fire Department, a retired deputy chief and training officer, and a 30-year veteran of the fire service. He is a Wisconsin-certified fire instructor II and fire officer II, an adjunct instructor in fire service programs at Gateway Technical College, and safety director for Scherrer Construction Co., Inc. Havel has a bachelor’s degree from St. Norbert College and has 30 years of experience in facilities management and building construction.
