
Key insights into fire risk and curtain wall firestopping in high-rise buildings

The critical importance of fire containment in high-rise buildings
Fire safety is non-negotiable for high-rise buildings. Indeed, it is central to the International Conference on Fire Safety’s definition of such buildings: “Any structure where the height can have a serious impact on evacuation” [1].
Height, a high concentration of people and the limited capacity of elevators and stairwells combine to make it challenging to evacuate all occupants quickly if fire strikes. Because fire spreads vertically, a blaze may potentially reach large numbers of people who are far from the ground.
Traditional fire-fighting methods may often be powerless to help. Fire department ladders and hoses may not reach the source of a fire at higher levels. This makes effective fire, smoke and toxic gas protection and containment critically important: high-rise buildings need to cope with much longer fire exposure times. In particular, a strict compartmentation plan is crucial to create escape routes, help save lives, limit damage and comply with legal requirements.
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Curtain wall design should limit fire and smoke spread via interior joints
The narrow gap between the floor slab and a building’s façade is bigger than it looks!
Take a 30 x 30 m building with the usual 5 to 10 cm void. That may seem like a tiny footprint, but it adds up to 12 m2 of open space for gas, smoke and flames to rise from floor to floor. The more floors a building has, the more critical this void becomes – it may allow fire to engulf the entire structure. After many fires that have taken hold via the voids between a fire-rated floor and non-fire rated curtain wall, architects and engineers now recognize how critical perimeter fire barriers are to high-rise building’s safety plan.
Consequently, on each floor, the void at the intersection of the exterior curtain wall assemblies and the floor assembly has to be sealed with an approved system. This needs to prevent the interior spread of fire for a time period of not less than the fire-rating of the floor assembly.
More effective, more reliable and code-compliant solutions for edge-of-slab applications
As well as helping to prevent the spread of fire, curtain wall joints need to meet a variety of further requirements. These include good movement and seismic capabilities, particularly because high-rise buildings are subject to more movement conditions than low-rise structures. Other considerations include acoustic performance, air and water resistance, thermal insulation, and Green Building goals. With these industry trends in mind, we have developed innovative firestop solutions that not only help to protect lives, but may solve other engineering, specification and installation challenges as well. Versatile spray sealants are at the forefront of this new generation.
Our high-end solution: the fast-curing Hilti Firestop Silicon Sealant
CFS-SIL Hilti Firestop Silicone Sealant is a fast-curing and highly elastic firestop sealant for curtain wall or edge-of-slab applications. This silicone-based spray is water-resistant, so –when it comes to firestop – your productivity is not weather-dependent.
The movement capabilities of CFS-SIL meet leading industry standards, and its water-resistance helps to reduce moisture damage to the joint. After curing, the sealant can easily be painted.
Stay on the safe side and contact us today!
Source:
[1] Saatcioglu, Murat. ‘High-Rise Buildings in Natural Disaster’, Encyclopedia of Natural Hazards. Link: https://doi.org/10.1007/978-1-4020-4399-4_168