With the growth of lightweight construction, fire departments are seeing differences in fire behavior and they are stepping up their planning and education.
What this means for firefighters is they need to cut response times and change tactics. The average “escape” time in lightweight construction is about four minutes. In older construction it was about 20 minutes.
The difference in burn times has to do with how the buildings are constructed and the materials used in modern construction. Because commercial buildings have sprinkler or alarm systems, the lightweight construction buildings that require more prevention and early detection are residential homes.
Until this year, MD required all modular homes be equipped with sprinkler systems which could add up to $10,000 or more to the cost of a new home but did not require site builders to install them. Now that all new site built homes are also to be equipped with sprinklers, new home starts have dropped drastically in the state. Welcome to our world site builders!
At the present time, only CA and MD require them in every new home, When other states jump onto the sprinkler bandwagon you can bet that the NAHB will take up arms to defend their precious site builder members. Because modular are such a small contributor to the total new home market in each state, code regulators will probably single us out for the first ones to be required to add fire suppression systems. Sad but true.
It’s not that (lightweight construction is junk, it’s very effective for our day and age, It just poses new challenges.
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Lightweight construction began to appear 25 years ago and is widely used by residential site builders to cut costs. It burns quicker and fails faster than older construction, and can collapse without warning.
When fire makes contact with the structural components of lightweight flooring, the floor will collapse in four minutes or less.
Floor joists used today are thinner than materials used in older flooring. When the glue in these components heats, they begin to fall apart. Older flooring has full dimension, thick beams that burn less rapidly.
The roofs in lightweight construction also become quickly unstable in a fire. Furthermore, the glue that holds the manufactured beams together will melt with exposure to heat,. More than 60 percent of roof structures in the U.S. are constructed with lightweight wood truss construction techniques
Another contributor to the spreading of fire is the open-concept idea in modern construction. While a wall or closed door can slow a fire, giving more time for escape, larger homes and ones with wide-open spaces are at risk. Drywall will deter a fire’s path, but many unfinished basements have exposed beams.
Lightweight construction is here to stay, and for firefighters, it’s just a matter of being aware that it is different than older construction. Its benefits are that it has structural integrity, costs less and is faster to build.