Wind gusts of 15 – 20 mph swept over 90 construction workers as they labored diligently on a five-story, wood framed, 396-unit building in historic and diverse Montrose, Texas. The structure was the $50 million upscale Axis apartment complex. At 12:30 p.m., on that quiet March day in 2014, a small fire was reported on the roof of the Axis. Welders working on the roof attempted to put the fire out. But the high winds made it to impossible to control the fire. Soon nearly 200 firefighters and 80 pieces of emergency equipment responded to the five-alarm fire. Regrettably, the fire quickly spread through the wood-framed building. The black smoke blinded the terrified men and women on the job site. The workers were forced to flee the complex. One construction worker was trapped on a third story balcony as the flames whirled around him. Fortunately, he was rescued by ladder just seconds before the flames would have engulfed him. Thankfully, no construction workers or firefighters were hurt. At 2:56 pm, the fire was under control. Tragically, in less than three hours, the luxurious apartment complex was reduced to ashes; just months before it was to open in June.
For years, wood construction has been the standard for both residential and commercial buildings. Wood is a faster, easier, and less expensive construction material than steel and masonry. However, wood-framed, and worse yet, engineered-wood buildings, are inherently more dangerous under fire conditions than those built with steel and masonry. In fact, a study by the National Fire Protection Association documents that engineered- wood burns quicker and fails faster than cut lumber. Steel and masonry are not combustible, so fire spreads slower than either cut or engineered wood built buildings. However, steel can soften and bend, unlike masonry. Another downside to both steel and masonry walls is they lack the thermal performance required by the International Residential Code (IRC) and International Building Code (IBC) and so typically require insulation. Although wood construction is very common, concerns about fire safety are causing designers and architects to often consider alternative materials in wall construction, like masonry, steel, or even better insulated concrete blocks (ICB).
When exposed to fire, insulated concrete blocks (ICB) limit the spread of flames. In addition, ICBs do not burn, bend or soften like steel. Insulated concrete blocks also meet the thermal performance required by the International Residential Code (IRC) and International Building Code (IBC) without additional insulation. In summary ICB’s are capable of achieving fire ratings of up to four hours, prior to any finishes being applied. A four hour rating means a wall’s assemblies will stay intact once exposed to fire for four hours. Compare this to the complete destruction, in less than three hours, of the wood-framed Axis building! The exterior of a building constructed with insulated concrete blocks is identical to a wood-frame building once construction is complete. However, fire behaves differently in ICB than wood frame buildings. Buildings constructed with ICB have fewer empty spaces (cavities between structural members) for fire to spread, and the insulation in ICB’s does not burn. Therefore, fire spreads slower in buildings constructed with ICB than wood.
Bautex Wall System Insulated Concrete Blocks Meet and Exceed Industry’s Standard for Fire Resistance
Exterior and interior walls of residential and commercial buildings can utilize the Bautex Wall System insulated concrete blocks.The Bautex Blocks have an ASTM E119 fire rating of four hours (two times the two-hour requirement), and an ASTM E84 published values for flame speed of zero and smoke development of twenty. Because the Blocks meet the ASTM E84 and NFPA 286 they essentially meet the NFPA 101 code. Bautex Wall System is highly fire resistant. They are also energy efficient, wind and moisture resistant and deliver sound reduction. When it comes to fire resistance, Bautex Blocks provide the maximum safety available in today’s choices of wall assembly materials.
Fire quickly spreads in buildings constructed of wood.The Axis apartment building is a horrible example of how quickly a building constructed with wood can burn to the ground. Utilizing insulated concrete blocks that exceed industry’s standard for fire resistance, like the Bautex Blocks, will create a safer, more fire resistant structure than buildings constructed with wood.
ASTM E119 establishes a wall assembly’s ability to stop a fire from spreading.
The ULC-S101 applies specifically to the testing of material with fire and is unique to walls and ceilings.
ASTM E84 – Surface Burning Characteristics of Building Materials. The purpose of the method is to determine the relative burning behavior of the material by observing its flame spread.
The NFPA 101 is the only document that covers life safety in both new and existing structures with provisions for all types of dwellings, egress requirements, fire protection features, emergency lighting, sprinkler systems, alarms, smoke barriers, and special hazard protection.