Silent Floors, Silent Killers?

Over the past two decades, the fire service has had to deal with the increased use of lightweight structural components. Much of our concern over that time has dealt with small dimensional truss floors and roofs. But with the building boom that has been seen throughout much of the country over the past several years, small dimensional lumber concerns must now also include other types of engineered lumber. A major concern on which we must now focus is wooden I-joists (photo 1).


(1) The wooden I-joist consists of an upper flange, a center web section, and a lower flange.
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Wooden I-joists have been called by several terms in the wood product industry and in the fire service, including wooden I-beams, composite wooden joists, plywood I-beams, TJI®s, and silent floor joists. From the fire service point of view, these joists historically have presented a history of collapse hazards when exposed to fire. The collapses appear to be sudden, with little or no warning. So the question must be asked: Will these silent floor joists, when under attack by fire, be silent killers of firefighters?

I-JOIST CONSTRUCTION

The wooden I-joist is made up of upper and lower horizontal components called the upper and lower flanges and a vertical section called “a web,” which is between the flanges. These three components are considered engineered products. Flanges may range in size from 1 5/16 to 1 1/2 inches thick and from 1 1/2 inches to 3 1/2 inches wide. They are made from laminated veneer lumber or laminated structural lumber.

The web is typically made using oriented strand board (OSB) and is either 3/8 inch or 7/16 inch thick, based on residential installation. OSB is a structural panel made with layers of thin, rectangular strands of wood produced by a cutting machine called a strander. The wood strands are mixed with adhesives and then glued under heat and pressure to the desired panel thickness. Strands in the exposed layers of the panel are formed at right angles to those in the core layer, stiffening and strengthening the panel.1 This panel can be produced in sheets, as plywood, and can be used as structural sheathing. For this article, we are looking at its use as the I-joist web.

The top and bottom edges of the web are cut to match a corresponding groove cut into the top and bottom flanges. The web is then glued, inserted into the flange, and pressed together to assemble the wooden I-joist.2

The depth of the I-joist can vary as well, usually from 9 1/2 to 16 inches in most residential installations, although a depth of up to 48 inches is possible for commercial construction. Note that when I-joists were initially introduced, plywood webs and sawn lumber flanges were used; hence, they may be found in some older installations. Additionally, some manufacturers still offer a mix of sawn lumber flanges with OSB webs (photo 2).


(2) The wooden I-joist consists of an upper flange, a center web section, and a lower flange.
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Wooden I-joists are used because they can support the same load as dimensional lumber, can be used over long spans within the structure, and are lightweight. They usually are uniformly manufactured, which means that the vast majority are accepted at the construction site and not rejected. They do not warp or shrink, thus eliminating the floor squeaking that occurs when dimensional lumber shrinks or warps. The joists are usually stamped by the manufacturer with a production date and time, which is visible if a walk-through inspection of the property is conducted before the gypsum board is installed (photo 3).


(3) Manufacturer’s information, including size of I-joist and date of manufacture, will be stamped on the I-joist.
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Wooden I-joist performance standards are contained in American Society for Testing and Materials (ASTM) D 5055, Standard Specification for Establishing and Monitoring Structural Capacities of Prefabricated Wood I-Joists.

USAGE

These engineered I-joists are widely used in wood-frame and mixed wood-frame construction: residential and commercial occupancies, new construction, and rehabilitation projects on existing buildings in which floors and roofs are being added or replaced. One of the greatest concentrations of I-joists is found in residential housing, including multiple dwellings, townhouses, and single-family homes.

But their presence can be found in a myriad of commercial properties and buildings of ordinary construction as well. Wooden I-joists may not be found throughout the entire project; what you see in one area may not represent what can be found in other portions of a building. For example, it may be apparent from the street that sawn dimensional lumber is being used for the roof structure. However, a closer inspection might reveal that the I-joists are being used in the floor construction of the same building. I-joists may have been used in the roof, but the floors may differ in construction (photos 4-8).


(4) The roof of this building is made with dimensional lumber, but wooden I-joists were used in the first and second floors.
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(5) Rear view of the same building, taken earlier. Note cut pieces of I-joists in lower right corner of the photo.
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(6) These newly constructed homes use wooden I-joists in the basement and on the first and second levels.
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(7) These newly constructed homes use wooden I-joists in the basement and on the first and second levels.
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(8) In this multiple dwelling, all the floors and the roof contain wooden I-joists.
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Portions of commercial buildings may have trussed overhangs and wooden I-joists over the majority of the roof (photo 9). Additions to existing structures may contain I-joists while the original section may have been built using dimensional lumber (photos 10, 11). Preplan orientation walk-throughs should be a common practice so members can become familiar with construction practices, especially when wood-I-joists and trusses can be seen stacked up on the job site. Wooden I-joists should be used only where they can be protected from the weather, in dry use applications.


(9) In this restaurant, the overhang is trussed, and wooden I-joists make up the main roof structure.
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(10) This existing house was rehabilitated; I-joists can now be found throughout.
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(11) This existing house was rehabilitated; I-joists can now be found throughout.
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OPENINGS

Although openings may be made in the web (not the flanges) for the passing through of utilities, they should be done in accordance with the manufacturer’s installation guide. Some webs may have perforated knockouts already indicated for such use. Some manufacturers produce I-joists with large holes (up to 20 inches) already in the joist and engineered to meet certain projects.

The building inspector should be informed of notched or damaged flanges or what appears to be overly large or odd-shaped holes punched through the web for utility runs. The manufacturer may need its engineer to evaluate such damage and require certain repairs to be made to ensure the joist’s stability (photos 12-14). The manufacturer’s recommendations, including its specified penetration charts showing how the I-joists can be cut, must be followed. These charts are different for end-supported, intermediate-supported, and cantilever-supported joists, so that the contractor, hopefully, follows the correct guide. Information in the charts will also vary according to the joist model and depth. The space required between the holes may also vary, depending on whether the opening is square or round.


(12) Large, irregular holes should be brought to the attention of a construction official.
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(13) Cuts and notches in flanges (circled) violate the manufacturer’s installation guidelines. The bottom wooden I-joist has three notches in the upper flange.
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(14) This flange and web were cut to allow room for a roof rafter. The same condition occurred on the opposite side of the house.
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Allowable hole charts contain too much information to be covered here, but several guidelines should be followed and how well they were adhered to should be a key consideration during walk-through site inspections. They include the following: A minimum of 1/8 inch of web should be left at the top and bottom of each opening; no holes should be closer than 12 inches to any end, middle, or cantilevered support; cantilevered reinforcements should not have holes cut through them; and flanges should not be notched or cut (photo 15).


(15) Wooden I-joists may be extended to construct balconies or terraces.
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Some joists may allow for a simple span (no center support) of five feet or longer and one maximum-size round hole at the center of the I-joist as long as there are no other holes in the joist. For example, a residential I-joist with a 16-inch depth may be allowed one maximum opening of 13 inches as long as the joists are uniformly loaded and meet the standards of the installation guide.3 Others may have been engineered with larger openings already in them. Determine whether the joists were delivered with holes already engineered in them or if such openings were made on-site. Question the contractor, talk to the building inspector, and look over installation guides (usually available from the manufacturer’s Web site), to obtain information about these products.

SPANS AND SUPPORTS

Because of the wooden I-joists’ ability to span long distances, many times a single joist will extend from bearing wall to bearing wall. There will be times, however, when longer area distances will call for an intermediate support, typically a steel I-beam or an engineered laminated wood beam, which in turn will be placed atop supporting columns.

Joist hangers are nailed into wood placed on the web section of the steel I-beam or directly into the laminated wood beam. One end of the wooden I-joist is then placed in the joist hanger with the opposite end resting on the outside wall, interior bearing wall, or additional rated support, depending on the length to be covered (photo 16).


(16) Joist hangers connect the wooden I-joist to the steel beam. The PVC and copper pipes appear to have been placed too close to the end of the joist and should be checked by a proper authority.
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Other installation practices may have the wooden I-joist travel over the steel I-beam, fastened to wood placed on top of the steel. I-joists need to be held vertically in place when supported by a beam. When the joist is held vertically, the full strength of the I-joist is developed. The I-joist web is not designed to transfer extreme concentrated loads and may buckle or split if not supported correctly in the vertical position. One way of achieving the correct support is to use joist hangers. The other is to increase the stiffening of the web near the ends or intermediate support points of the I-joists by using blocking. (2, 5) Usually these “web stiffeners” are 2 × 4 lumber or additional cut pieces of OSB web cut to fit between the flanges of the joists, carrying a load and fastened to the web, or with 2 × 4 sawn lumber nailed to the flanges and adjacent to the web on both sides of the joist (photo 17). This second method, called “squash blocking,” may be found anywhere along the length of the I-joist when there is a load-bearing wall above.


(17) Here, 2 × 4 cut lumber is fastened to the face of each web as a stiffener. Note that the section of OSB placed perpendicular to the long joists has been cut to allow for electrical work.
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Lateral support at the end of each bay is needed to secure the in-place I-joists. A connection to a braced end wall is one way to do this. Additional cut sections of I-joists may be secured between the longer I-joists at right angles to assist in lateral support. On many occasions, I have had contractors tell me that these smaller cut pieces between the joists are “firestopping,” even though the product is installed with clearly visible gaps that could not meet the definition of proper firestopping. Sheathing or decking nailed to the first four feet of the joists can also be used as bracing. A minimum of 1- × 4-inch planking should be nailed from a braced wall or sheathed area to each joist. Until this is accomplished, buckling or rollover of the I-joists is possible under minimal loading, including workers walking on the joists. (3, 5)

The question of firestopping comes into play when sprinkler system installations are required and there is a question of sprinkler head obstruction. In National Fire Protection Association (NFPA) 13, Standard for the Installation of Sprinkler Systems, section 8.6.4.1.2 (4) [which applies to “open” I-joists, such as those found in basements without a drop ceiling] reads, “Installed with the deflectors within the horizontal planes 1 inch to 6 inches below the composite wood joists to a maximum distance of 22 inches below the ceiling/roof deck only where joist channels are fire-stopped to the full depth of the joists with material equivalent to the web construction so that individual channel areas do not exceed 300 ft. (27.9 m).” Simply cutting smaller sections of I-joists and placing them between the ends of the longer composite joists and not filling the gaps between these pieces with rated fire caulking should not be considered adequate to stop the spread of fire (photo 18). Some contractors may use 1/2-inch plywood cut into strips equal in size to the depth of the web and fastened across the face of the shorter piece of I-joist to enclose these gaps.


(18) Short pieces of I-joist placed perpendicular to the longer joists are often called fire stops by contractors, even though gaps between the pieces are visible and usually remain.
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Consider that several references to wooden I-joists and obstructed combustible construction can be found throughout NFPA 13 and that sprinkler head placement regulations will change depending on the sprinkler type. Firestopping requirements may change as well. Extended coverage and early suppression-fast response sprinkler heads-are not allowed by the standard to be installed under combustible obstructed construction. A quick guide on this subject, Sprinkler Deflector Positions Under Obstructed Construction, can be downloaded from the United States Fire Administration/National Fire Academy Web site.4 Also note that section 8.14.1.4 of NFPA 13 states that enclosed composite wood joist channels need to have sprinkler protection when the joist channel contains a heat-producing device and concealed spaces of no more than 160 square feet (when ceilings are attached to the I-joists).

ADHESIVES

The last significant component of the I-joist is the adhesive used to hold components together. In the wooden I-joist, the flange and the web are glued components. The adhesives used in I-joist construction are synthetic and classified by the wood products industry as adhesives for structural products (as opposed to adhesives for interior, nonstructural products). Adhesives in this classification include phenol formaldehyde, resorcinol, phenol resorcinol, polymeric MDI, polyurethane polymer, and several others. Such adhesives are used in wood products that need structural strength immediately after their composition, and they are at risk for exposure to moisture.5

During the manufacturing process of the wooden I-joist, several types of adhesives may be used. The OSB web portion may include a phenolic or polymeric MDI adhesive, or both. The web may be glued to the flange with resorcinol or polymeric isocyanate adhesives. The laminated veneer lumber flange may be bonded with phenolic adhesives used in a hot press. Finger-jointed connections on flanges may be assembled using phenol resorcinol formaldehyde or melamine adhesives. (5, 4)

Although the wooden I-joist only recently has been given an increased role in modern construction projects, it has been available for more than 35 years. Although mainly associated with floor structures, it can also be used in roof assemblies. The majority of wood I-joist roof assemblies are flat, but these joists have been used in peaked roofs as well. Walk-through inspections during construction will allow you to detect these assembly concerns (photo 19).


(19) This one-story commercial structure uses a wooden I-joist (right side of photo) and truss mixed peak roof assembly.
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I-JOISTS AND FIRE

Our main concern is how wooden I-joists react under fire conditions. Test burns and real-world history have shown there should be a significant concern about operating in buildings with wooden I-joists. The lumber industry will say that as a protected assembly, following ASTM E-119, Standard Test Methods for Fire Tests of Building Construction and Materials, the wooden I-joists should pose no significant threat. But real-life lessons have shown that fires start in and can spread into the “protected” assembly. Additionally, in many residences and commercial structures being constructed, the first-floor joists in the basement are not being covered with gypsum board.

FIRE TESTS

In 1986, the Illinois Fire Service Institute at the University of Illinois tested five types of floor systems to determine their structural stability. Included in this testing were wooden I-beams set at 24 inches on center. Of all the floor systems, the wooden I-beams failed first at 4 minutes and 40 seconds. In their report, the authors write:

At 4 minutes and 40 seconds, the wooden I-beam platform failed completely. There was no sagging or warning noises to indicate a structural problem. The system carried the load level until failure. The failure of a wooden I-beam to sag prevents firefighters from determining if the building is in structural trouble … A wooden I-beam with a 3/8” web is not safe if the gypsum protection is penetrated.6

In May 1981, the Los Angeles City (CA) Fire Department tested several nonprotected assemblies, including wooden I-joists with 3/8-inch webs. The fuel load consisted of paint thinner and pallets; no live load was imposed. The test time began at the ignition of the fuel; the time limit was six minutes. The wooden I-joists covered a span of 12 feet, were spaced at 32 inches on center, and were sheathed with 1/2-inch CDX plywood. The report states the assembly failed in 1 minute and 20 seconds.7

With test results that showed a failure time faster than that of trusses, wooden I-joists need to be taken as a serious threat to firefighters when involved in a fire. In Building Construction for the Fire Service, the late Francis Brannigan notes two case studies in which wooden I-beams were involved in early collapses during structure fires.8

Because of the great increase in the use of wooden I-joists in new construction in my area over the past several years, I decided to conduct my own nonscientific test burns. In the first burn, two four-foot sections of I-joists supported on both ends and with a piece of gypsum board nailed on top were set on fire. The fuel load consisted of cut-up pieces of wooden pallets. Sudden failure of one I-joist occurred approximately 13 minutes after ignition, but this was only 7 minutes and 11 seconds after the flames impinged on the flange of the joist.

A second test burn consisted of four OSB wooden I-joists 10 feet long and 9 1/2 inches deep. The joists were supported on both ends and spanned an opening of 103 inches. The joists were covered with 5/8-inch CDX plywood and fastened using a compressed-gas nail gun; there were no openings in any of the webs. A licensed professional engineer rated the assembly as having the ability to carry 720 pounds. A load of only 171 pounds, consisting of concrete block, was placed on top and spread out over the center bay. Again, a fire load consisting of pieces of wood pallets only was ignited under the assembly. A partial collapse occurred in 7 minutes and 15 seconds after ignition. At the 9-minute mark, a second collapse occurred; and all four web members had burned through (photos 20-23).


(20) In this test burn, a fire was ignited under the I-joist second from right. The swirling of fire within the center bay is evident.
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(21) Fire has burned through the web of both center I-joists, spreading the fire into adjoining bays.
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(22) This collapse occurred 7 minutes and 15 seconds after ignition.
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(23) The destruction of the web is clearly evident as the fire burns through.
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So what seems to happen to these I-joists during these fires? In the several burns in which I have been involved, similar flame patterns seem to develop. First, the fire begins to ignite the flange, and flame quickly moves up across the face of the web center. The fuel load in the web seemed to allow the fire to burn faster and sustain the fire growth. As the fire moves up across the web and the top flange, it contacts the decking at the top of the enclosure. This action allows the fire to continue along under the decking until it meets with and pushes down along the face of the adjacent I-joist. Many times, a pronounced swirling of the flame is seen as it rapidly fills up the bay area between the joists. The fire will burn through the web center, allowing fire to pass into the next bay on each side. As the fire burns across the front of and through the length of the web, it destroys the structural integrity of the joist, even though the flanges may still appear to be intact. Shortly thereafter, with the destruction of the web between them, the flanges collapse with little or no sagging or other warning.

A December 4, 2006, notice by the International Association of Fire Chiefs warned that I-joist composite floor systems involved in fires across the country have led to several injuries to firefighters and a possible line-of-duty death. It also included the following advice:

Extreme caution should be exercised in any situation where entry is made above a basement fire. Conventional methods such as sounding ahead with a tool and checking for sponginess may not provide sufficient warning of a weakened floor. Using a thermal imaging camera is recommended to sweep the floor for hot areas before entering and to help avoid areas that appear to be hotter than the surrounding flooring. Be aware that thick carpets or tile floors may compound the risk by making it even more difficult to detect hot spots.9

But what does the engineered lumber industry say about these products when they are exposed to fire? Two publications that address this are the Wood I-Joists Resource Guide and the >Adhesives Used in Engineered Wood Product Resource Guide. These guides were developed through an agreement between the United States Fire Administration and the American Forest and Paper Association. Regarding the ignition of glues, the Adhesives Guide states:

The ignition point of phenolic and PMDI adhesives used to manufacture engineered wood products is actually higher than that of the wood they bond. Wood generally ignites between 375 and 450 degrees Centigrade, depending on thermal exposure. The autoignition temperature for phenol formaldehyde is between 476 and 614 degrees Centigrade. When burned, the glues char in similar fashion to wood; in other words, the glues will not weaken, produce substantially higher flame spread rates, or enhance combustion. (5, 6)

But to the firefighter, does it really matter if the wood or the adhesive ignites first, especially if the ignition temperature difference may be as little as 26°C? As to the fact that burning adhesives don’t produce “substantially” higher flame-spread rates, it must be concluded that somewhat higher flame-spread rates were found. This guide also states

Engineered wood products and solid wood burn similarly in a fire. As with solid wood, the size and mass of an engineered wood product has an effect on fire endurance performance. (5, 8)

This statement supports the fact that two-inch nominal sawn lumber will endure longer than the 3/8-inch or 7/16-inch-thick web of a wooden I-joist.

Under a section titled “General Thermal Degradation Information,” the guide reports that thermal degradation of phenolic adhesives can be divided into three stages.10 But from the firefighting perspective, these defined stages may hold some concerns. For example, the guide states the following:

  1. “In the first stage, up to 300°C (572°F), the polymer remains virtually intact.” This would seem to suggest that some separation of the adhesives begins in the first stage after ignition.
  2. “During the second stage, from 300°C to 600°C (572°F to 1,112°F), decomposition commences and gaseous components are emitted. Random chain breakage begins to occur in both the adhesives and wood.” As the guide previously pointed out, the autoignition temperature for phenol formaldehyde adhesive is between 476°C and 614°C and between 375°C and 450°C for wood. This would mean that “random chain breakage” usually begins when the engineered lumber is exposed to heat and before it actually ignites.
  3. “In the third stage, above 600°C (1,112°F), carbon dioxide, methane, water, benzene toluene, phenol, cresols, and xylenols are liberated.” Most of these same gases are released in the second stage as well. Obviously, the proper use of personal protective equipment, including SCBA, is warranted.

The Wood I-Joist Resource Guide is clearer in its descriptions of fire testing on I-joists:

Full-scale fire tests on I-joists show that the web will typically burn through first, followed by the bottom flange (nearest the fire), and finally the top flange. An I-joist will burn at the same rate as a solid lumber joist but will burn through in a shorter period of time, given the smaller cross-sectional dimensions. (2, 8)

It also reports that “Once the web is consumed, the bottom flange is no longer attached to the joist and falls from the system.” Under the section “Fire Incidents,” the following is written:

As with all types of structural framing exposed to fire, the intensity of the fire load varies from incident to incident, as do the construction details. This results in performance which is unpredictable.

This paragraph is followed by the warning: “Fireground personnel [are] to STAY OUT, STAY OFF, and STAY ALIVE in any structural fire when the fire has reached flashover conditions in any area directly under unprotected floor or roof joists.” (2, 8)

Forintek Canada Corporation, an organization that describes itself as a wood products research institute for the forest industry and governments, also conducted tests on I-joists. These tests also showed that the web burns through first, followed by the lower flange. The report continues

Following the loss of the web and the lower flange, and prior to any failure of the upper flange, the upper flange in combination with the plywood or OSB floor sheathing is fully capable of supporting the entire superimposed load on the assembly, albeit with considerable deflection. In many cases, the fire penetrates the floor sheathing before the upper flange of the I-joist actually fails (breaks). This is because the LVL (laminated veneer lumber) can resist bending stresses without fracturing better than solid lumber.11

But again, these tests raise some questions. What was the superimposed load used for the test, and is it comparable to a hose crew or search team operating above the fire? How long was the fire burning before the web burned through and the lower flange failed? What was the time difference between I-joist failure and sawn joist failure? What does “considerable deflection” of the top flange and decking look like, and could it cause a firefighter to slide into a burned-out opening?

The report states in regard to I-joists: “On average, the maximum deflection in the floors one minute prior to ultimate failure was approximately 320 mm.” For conventional timber joists, the same report says: “On average, the maximum deflection in the floors during the final minute prior to structural failure was approximately 90 mm.”

No one should feel comfortable working above or under any structural component that has had two of its three sections completely destroyed; the fact that the top (fire damaged) flange may remain until the decking burns away is of little comfort, and it may be a key reason that the floor looks or feels good until a significant collapse seems to suddenly occur, giving what is often described as “no warning.”

Another view on floor assembly deflections can be found in the “National Engineered Lightweight Construction Fire Research Project Technical Report: Literature Search and Technical Analysis,” which contains an excerpt from the report “Comparative Fire Endurance Tests of Unprotected Engineered Wood Component Assemblies.” In this section the report summary states

The test data indicate that wood I-joists, metal plate connected trusses, and space joist trusses exhibit similar performance characteristics. The deflection for each was small until the temperature reached 1,000°F. Deflection increased dramatically at that point. The deflection was slightly greater for the wood I-joist than for the two types of trusses tested. This would suggest that trusses undergo a more gradual relaxation in load carrying capability as they burn, when compared to I-joists. Failure typically began near the three minute mark and was completed by five minutes in these members.12

The last page of the Wood I-Joist Resource Guide contains the most telling information for the fire service. It lists seven incidents (six in the United States and one in Canada) between February 1995 and December 2003 in which a structural collapse led to a firefighter death and the floor framing consisted of unprotected wooden I-joists.

It is imperative that firefighters understand the dangers associated with wooden I-joists and all engineered lumber products. Although these products have been on the market for some time, their fast-growing use has increased hazards for firefighters that may be as bad or even greater than those posted by lightweight trusses.

A familiarization tour of job sites for newly constructed and rehabilitated structures is a must. If your state or municipality is looking to introduce legislation to label buildings containing trusses, think about including the labeling of buildings containing I-joists as well. Look for information from the industry as well, not only on how the products are used but also on how they react under fire conditions.

Some of this information is presented in terms that may make the joists seem safer than they are. You may read statements like “Adhesives don’t ignite; they ‘pyrolyze,’ and the burned-through area is the pyrolysis zone,” or “Composite wood products do not start to come apart when exposed to heat but suffer ‘random chain breakage.’” Regardless of the terminology used, the end result is the same: a fire-damaged, collapsed, engineered wood product. Make an effort to find out where these products are in your response district; pass this information along; expect to fight a fire in a structure containing wooden I-joists, and train for it. When you encounter these products, change tactics accordingly if necessary. Don’t let the silent floor become the silent killer.

Endnotes

1. Wood-Based Structural-Use Panels Resource Guide, American Forest & Paper Association, 2, 3. Web site: www.woodaware.info/PDFs/Struc_Panels.pdf.

2. Wood I-Joists Resource Guide, American Forest & Paper Association 2. Web site: www.woodaware.info/PDFs/I-joists.pdf.

3. ilevel™ Trus Joist® TJI® Specifier’s Guide TJ-4000, October 2006, 11. Web site: www.ilevel.com/literature/TJ-4000.pdf.

4. United States Fire Administration/National Fire Academy Coffee Break Training, No. 2006-46. November 14, 2006. www.usfa.dhs.gov/downloads/pdf/coffee-break/cb-2006-46.pdf

5. Adhesive Resource Guide, American Forest & Paper Association, 2. Web site: www.woodaware.info/guideadhesives.html

6. Straeske, Jim & Charles Weber, Charles. “Testing Floor Systems,” Fire Command Magazine, June 1988, 47.

7. Mittendorf, John. “Lightweight Construction Tests Open Fire Service Eyes to Special Hazards.” Sponsored by the Los Angeles City (CA) Fire Department. May 1981.

8. Brannigan, Frank, Building Construction for the Fire Service, Third Edition, National Fire Protection Association (1992), 552-553.

9. International Association of Fire Chiefs Web site: www.iafc.org, article 32101.

10. Knop, Andre, and Louis A. Pilato. “Phenolic Resins: Chemistry, Applications, and Performance - Future Directions.” 1985. Springer-Verlag.

11. Richardson, Leslie R. “Failure of Floor Assemblies Constructed With Timber Joists, Wood Trusses, or I-Joists During Fire Resistance Tests.” Forintek Canada Corp.

12. Grundahl, Kirk, P.E. National Engineered Lightweight Construction Fire Research Project, National Fire Protection Research Foundation. (October 1992), 79-80.

JAMES KIRSCH is a 24-year veteran of the fire service and a lieutenant with the Bergenfield (NJ) Fire Department. A former volunteer fire chief, he also serves as a logistics manager with the New Jersey Task Force 1 (NJ-TF1) US&R Team. He has been a classroom instructor for the FDIC and has a master’s degree in public administration.

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