Fire Safety – an Added Benefit of Precast Concrete
On Jan. 23, 2014, a fierce fire swept through the Résidence du Havre, in L’Isle-Vert, Quebec, killing 32 of its residents. There were multiple reasons why the fire in this particular senior’s home was so deadly but one thing that was noted by witnesses at the time was the sheer speed with which the fire consumed the wooden structure leaving fire fighters little time to rescue people and no safe route to get to them. A major finding was the lack of sprinklers in the building but several other factors played a role in this horrible fire including the speed of fire travel throughout the building. Due to fires like this people are looking at what other measures would improve fire safety in residences.
Besides sprinklers, designated exists, fire doors and proper building design to enhance building fire safety; construction materials need to be chosen to enhance protective fire safety measures and limit fire spread. Concrete construction materials are resistant to heat transfer and are non-combustible. Concrete construction materials used in stairways and elevator shafts can provide safe exit zones during a fire and allow firefighters to enter the structure to fight fires on multiple levels. Concrete walls can also provide zone separation and can compartmentalize fires and give residents more time to exit the building safely.
Due to the increase in assisted living facilities, senior residences and an aging population that is increasingly living out their senior years in their own homes; fire safety measures built into construction projects have become of increasing interest to building designers and builders. Seniors often have mobility issues and require more time to exit a burning building and the way to provide those precious extra minutes is by creating safer buildings. Concrete construction materials have been around for a long time but designers and builders now have the opportunity to take advantage of the improvements in precast concrete manufacturing technologies to further enhance fire safety in buildings at very economical costs. These newer precast concrete panels have numerous advantages including inherent fire resistance; they retain their structural strength in a fire even under tremendous heat and do not add to the toxic gases associated with fire.
Precast above ground concrete wall panels are built in a factory where all facets of the panel construction can be carefully controlled. Panels are fully cured under climate controlled and quality controlled conditions. The precast panels are dry, and built using a special low water/cement ratio concrete (See CCMC 13628-R). The panels also come with full-length insulation built in to increase energy efficiency. Precast concrete wall panels, like those built by Superior Walls of Beausejour, Manitoba, have high strength, 5000+ psi concrete that is reinforced with steel rebar and polypropylene fibers for added strength and performance.
Basic Fire Safety Protective Measures in Buildings
|Desirable Attribute||Limited heat transfer during a fire to allow occupants time to exit safely||Provide fire fighters with routes to get to the fire zones quickly||Compartmentalize the structure to provide fire suppression zones||Limit combustible materials that can help feed the fire||Limit toxic fumes being released at high temperatures|
|Concrete Attribute||Concrete structures around staircases can be effective in blocking heat transfer during a fire||Concrete foundations and stairs can allow firefighters safer access to the fire – can help support the structural integrity of the building during a fire||Structural walls made of concrete can effectively block rapid fire expansion and travel throughout a building and resisting flashovers||Concrete is not combustible and will not burn even at very hot temperatures and without any other coating or fire suppression measures applied – limiting the fire||Concrete is chemically inert and does not create toxic gases, it doesn’t melt or drip during a fire – totally resistant to water application during fire fighting|
Concrete Fire Safety Attributes:
- Concrete is resistant to fire without any further coatings or protective measures making it a very economical fire safety measure
- Concrete is non-combustible
- Concrete does no melt, drip, release toxic gases
- Concrete structures, in contrast to wood or unprotected metal structures can withstand very high temperatures (Reinforced concrete slab reinforcements only reach their critical temperature of 500 C after 2 hours, at a depth of 3 – 5 cm. A lightweight aggregate concrete can satisfy even greater demands. It constitutes an effective barrier against the spread of fire. https://www.febelcem.be/fileadmin/user_upload/autres-publications/en/docref_feu_en.pdf)
- The lack of heat transfer or thermal inertia of concrete can also delay flash-over
- Makes multi-story buildings safer when concrete is used as the load bearing structural part of the building and foundation
- Structural concrete staircases and compartmentalization of interior spaces with concrete walls and foundations can help limit fire spread and provide extra time for occupants to escape during a fire