Scientists at the materials science research institute Empa (Dübendorf, Switzerland) teamed up with the insulation materials manufacturer isofloc AG (Bütschwil, Switzerland) to develop a nontoxic, fireproof insulation for use in prefabricated wooden elements and multistory timber houses.
Made primarily from recycled paper, this insulation takes the shape of a cube made from grey flakes in its hardened state. These paper fibers are firm enough to offer long-term protection against fire for load-bearing elements, yet also pliable enough to be machine blown into a construction cavity until the space is filled. Once these fibers fill the cavity, however, they harden much like a hand-fitted insulating panel would.
According to Jon-Anton Schmidt, isofloc AG’s head of application technology, the blow-in nature of the insulation affords significant advantages. “Fitting the insulating material in loose form saves an enormous amount of time. With the additional advantage of dimensional stability and the associated effectiveness for fire safety, we can achieve protection that is on a par with glued mineral wool mats,” Schmidt said.
In spring 2017, Empa scientists Franziska Grüneberger and Thomas Geiger began working with Willi Senn, isofloc’s development engineer to find a binding agent for isofloc’s cellulose fibers. The team had two prerequisites for its binding agent: it had to be nontoxic enough to be comfortably handled by humans, and it had to be affordable and abundant enough to make it a cost-effective option. After a series of trials combining insulating fibers with different additives, they ultimately found the ideal material in the form of a substance from the food industry. Not only was this additive harmless to humans, animals, and the environment, it displayed a reliable bond between the cellulose flake structure.
To determine whether this fireproof insulation would work on a large scale, an upscaling test was performed. First, the flakes with the binding agent were blown into several wooden frames while flakes without the agent were fitted into an identical cavity. Then the frames were exposed to high-temperature flames for an hour. As a result, the additive-infused insulation was able to protect the wooden frame from fire while the insulation without the additive was not able to adhere well enough to the wood to protect it.
Currently, isofloc technicians and engineers are developing new blow-in machines capable of installing the fireproof insulation on a repeatable and controlled basis, as well as making sure that the insulation’s binding agent is dosed at manageable levels. Once those tasks have been completed, isoflec expects to release both the insulation and the corresponding blow-in machines by or around 2020.
Source: Empa, www.empa.ch