A tape for construction membranes when every second counts

Author: Lena Barner-Rasmussen

A tape for construction membranes when every second counts

When dealing with fire safety, the devil can live in the details. One such detail is the tape with which you seal construction membranes to together. Walki can now offer a fire-safe option.

When a fire in a building is ignited, every second counts to save lives. With flame-retardant materials you can slow down – and even hinder all together – a fire from causing large-scale damage both to the building, and of course more importantly to people.

Walki brought a unique vapour barrier to the market a few years ago, the Wall Tight FR G A2, to be used in walls and ceilings as a construction membrane to enhance heat radiation and prevent air and moisture transfer. Made of a combination of aluminium and glass fibre, the membrane ensures that the vapor barrier has a good fire resistance and complies with the industry standard Euroclass A2-s1, d0. In other words: it is non-combustible and does not develop smoke or flaming droplets.

Finding a fire-safe adhesive

The Walki®Wall Tight FR G A2 membrane is sold with a width of either 1.2 or 1.5 metres. To get a barrier for walls and ceilings, that naturally are much wider than that, you use different kinds of tapes and adhesives to combine the membranes for large surfaces.

"To get a tight wall or ceiling, ensuring that there is no air nor moisture going through, you need to somehow overlap the membranes with an adhesive", explains Pierrick Girard, Business Line Manager, Construction Membranes at Walki.

But there is one glitch: up until now, that adhesive have been compromising fire safety.
"The main material used so far has been plain aluminium tapes but they are generally too fragile and do not comply with any reaction to fire standard", explains Ann-Mari Ukkonen, TSD Manager, Construction Membranes at Walki.

So the questions arose: can the tape be made less combustible? Several customers posed the question, and Walki's innovation team got on it.
"The task was to lower the combined fire class for both the membrane and the tape, while not compromising the tape's properties of being water vapour diffusion tight. The tape also needs to be easy to install and develop similar features as the membrane ", says Ukkonen.

By using flame-retardant adhesive on the back of Walki Wall FR G A2 membrane, Walki developed a tape with a reaction to fire Euroclass B-s2, d0. If you use a maximum of 10% of the tape, called WALKI® Wall Tight FR B 215 Tape, for each Wall Tight FR G A2 165 membrane, the combined solution will render a reaction to fire Euroclass A2-s1, d0.

"So now we have a very strong flame-retardant tape based on the membrane itself, and the combination of Wall Tight FR G A2 and the tape complies with Euroclass A2-s1, d0, which says it is non-combustible. In addition, being based on same material, heat radiation is also kept on the full wall surface without discontinuities", says Girard.

Thanks to its non-combustible nature, the Walki Wall Tight FR G A2 membrane and the WALKI® Wall Tight FR B 215 Tape are ideal in buildings such as schools, hospitals, shopping centres and high-rise buildings, where evacuation may take time and every second the fire is slowed down is crucial.

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