For many years, changes in building construction and materials have played a major role in firefighting operations. The fire service has had to endure many dangerous building construction features such as the lightweight truss, burglar bars, and laminated I-beams, just to name a few. These features have contributed to many firefighter entrapments, injuries, and even deaths while battling a fire inside a structure. Now, there is another building material that could pose a life safety hazard to firefighters operating on the fireground. It is National Gypsum’s Hi-Impact wallboard.
WHAT IS HI-IMPACT WALLBOARD?
Hi-Impact wallboard is 5/8-inch drywall with a Lexan backing. Four thicknesses of Lexan are available: 10 mil, 20 mil, 30 mil, and 80 mil. The thicker the Lexan backing, the stronger the wallboard. The wallboard with the 10-mil Lexan has an impact resistance of 264 ft.-lbs. and can easily be penetrated by any hand tool. But, when you get to the 80-mil Lexan , the impact resistance rating goes up to approximately 2,200 ft.-lbs., which makes it much more difficult to penetrate. It is designed to resist abrasion, impact, and penetration, to provide higher strength and security. This product may be found in schools, hospitals, mental health care facilities, prisons, commercial occupancies, and residential apartment buildings. A distributor of the wallboard explained that homeowners were using the material to create “safe rooms” or “panic rooms” in single-family dwellings. The wallboard is installed with ordinary drywall screws; the manufacturer recommends the use of metal wall studs. But, if Joe Homeowner wants to use the wallboard to add a “safe room” or is tired of repairing holes in his walls from his children’s toys, he probably will be using wooden studs.
TEST RESULTS
Below are the results of two tests members of the Roberts Park (IL) Fire District conducted on this product.
Test #1-Breach Test
The purpose of this test was to determine the effectiveness of basic firefighting hand tools when attempting to breach a wall constructed with Hi-Impact wallboard. The objective was to create a hole large enough for a firefighter to fit through. The wallboard used had 80-mil Lexan backing. Five hand tools a firefighter most likely would have with him during firefighting operations were used: an 8-lb. maul, a 12-lb. sledgehammer, an 8-lb. pickhead ax, a halligan bar, and an 8-lb. flathead ax. The wall was constructed of wooden studs on 16-inch centers; the wallboard was attached by ordinary drywall screws. The firefighter was in a kneeling position, to simulate staying low in fire conditions. The firefighter was to strike the wall until a hole large enough to accommodate a firefighter in full turnout gear with SCBA was created or it was evident that a hole could not be created.
 (1) The test wall was constructed using wooden studs on 16-inch centers. The Hi-Impact wallboard was attached with ordinary drywall screws. (Photos by author.) |
The results of this test were quite alarming. All of the striking tools used proved ineffective in breaching the Hi-Impact wallboard. The firefighter struck the wallboard at least 14 times with each striking tool, only to leave dents in the Lexan . The cutting tool (the pickhead ax), on the other hand, proved to be the most effective when breaching the wallboard. Most of the cutting tools penetrated the Lexan in fewer than 10 swings, but additional swings were required to make the hole big enough to accommodate a firefighter. The pickhead ax (blade) and the pick end of the halligan bar were most effective. The pickhead ax penetrated the wall on the sixth swing; however, it took a total of 38 swings to make the hole large enough. The halligan bar performed the best, penetrating the wall on the fourth swing and making the hole large enough on the 30th swing. The Lexan part of the wallboard did not break easily after being struck, but it cracked enough to make it pliable so that it bent while the firefighter crawled through the hole.
 (2) This photo was taken from inside the wall. This hole was created by the pickhead ax. Note the sharp and jagged edges that can rip or cut personal protective equipment |
One thing to consider while crawling through the wall is that the Lexan has a tendency to get caught on personal protective equipment and will possibly cut or rip the personal protective equipment with its sharp and jagged edges. Another very important consideration is the time it takes to create a hole large enough to accommodate a firefighter. Keep in mind that the pickhead ax and halligan bar each took at least 30 swings to accomplish the task. How much time does it take to swing a halligan bar 30 times? If fire conditions are deteriorating, the firefighter is at an increased risk if he has to breach Hi-Impact wallboard to escape injury. Also, this test was performed with the Hi-Impact wallboard on only one side of the stud. Chances are that if this product is encountered, it would be installed on both sides of the studs, therefore at least doubling the time and effort needed to breach the wall in an emergency.
Finally, the firefighters used in this test were fresh. They did not just pull a hoseline to the third floor of an apartment building to attack the fire or perform a primary search before having to breach the wall. Therefore, the time and number of swings rise because of firefighter fatigue resulting from other tasks already performed on the fireground.
 (4) Approximately five minutes after ignition, heavy purple/gray smoke pushed from the test wall. |
The key to dealing with this product is to recognize its existence inside a structure before one of your firefighters discovers it when trying to breach a wall to avoid deteriorating fire conditions or to rescue a civilian.
Test #2-Fire Inside the Wall
For this test, a fire was lit inside the wall. The purpose of this test was to evaluate the behavior of fire and smoke in case of a fire inside a wall constructed with this product. We built a 4-ft. 4-ft. wall with metal stud framing and Hi-Impact wallboard mounted to both sides of the studs and ignited approximately four pieces of white packing paper inside the simulated wall to start the test. The paper simulated any burning materials that could fall inside the wall during a structure fire or an electrical fire inside the wall. The fire was allowed to burn inside the wall for approximately 20 minutes from the point of ignition. At the end of the burning period, the fire was extinguished using a five-gallon pump can through the holes in the metal studs. After the fire was extinguished, one side of the wallboard was removed to evaluate how it reacted to the fire.
 (5) Heavy fire and smoke vent from the test wall about six minutes after ignition. |
Throughout the test, the smoke conditions changed numerous times. Approximately four minutes after the paper was ignited, the smoke color changed from light white to a heavy black/gray color, and the Lexan backing was seen burning. After about one minute, a heavy purple/gray smoke started issuing from the wall. Six minutes after the point of ignition, heavy fire and smoke were showing from the end stud at which the fire was started. Heavy smoke was pushing from every other opening on the test wall. The heavy fire and smoke continued for about a minute; conditions changed to a very heavy push of a bright pink and gray smoke with no fire. Gray smoke started coming out of the openings in the top and side of the wall; as soon as it hit the outside air, it changed to bright pink. During the next few minutes, the conditions would alternate from heavy fire issuing from the end stud to very heavy pink/gray smoke issuing from the same area. The Lexan started “pooling” at the bottom of the wall as it melted down during the test. When the burn time was completed, the fire was extinguished using water from a five-gallon pump can. The water extinguished the fire with no problems.
 (6) One side of the test wall was removed and laid in front. Note the damage to the stud space on the left, where the fire was ignited. |
After extinguishment, one side of the test wall was removed to evaluate the amount of fire spread inside the wall. The fire completely consumed one full bay of the Lexan backing between the stud spaces where the fire was started. The fire then traveled through the pipe chases in the stud to the next bay, consuming the top half of the second stud space. Some of the Lexan that had melted down was starting to ignite the bottom of the wall in the second stud space. The third bay in the wall suffered very minor damage, if any at all.
As the test demonstrated, the Lexan backing of the Hi-Impact wallboard readily contributed to the fire spread within the wall. The Lexan also created a heavy and multiple colored smoke condition.
LESSONS LEARNED
The most important lesson learned was that fire departments need to get out of the station and preplan the buildings in their response areas, including automatic-aid and mutual-aid response areas. If your jurisdiction has any new construction underway, that is the most opportune time to see if Hi-Impact wallboard is being installed. You might not catch it if it is already installed because it looks just like ordinary drywall after it is hung.
The second lesson we learned is if a fire is started inside a wall constructed with Hi-Impact wallboard, it is going to be a labor-intensive and time-consuming operation. Because of the Lexan backing, it is going to be extremely difficult to pull the wall and gain access to the fire. Consideration must be given to start pulling the wall far enough ahead of the advancing fire so it doesn’t get past fire crews before they can get the wallboard down. This will more than likely be a very smoky fire with different color smoke, so SCBA is highly recommended during overhaul operations.
Currently, we are talking to the jurisdictions we serve about different ways for dealing with this product. An option we are looking at is a building marking system that identifies buildings that have Hi-Impact wallboard installed. Another option is to write a city ordinance banning the use of this product within our district. As of now, our fire inspector will notify the personnel if the wallboard is going to be used in our district.
If this product is found in your jurisdiction, make sure all of your personnel and neighboring departments know about its existence and the danger it poses. The time to find out it is in your response area is not while working on the fireground. ■
A copy of the video and complete reports on both tests are available; e-mail ffmurf792@ aol.com or [email protected].
