New boron-free insulation still meets strict fire safety requirements:Nviro challenges misconceptions about paper-based insulation

Nviro, which supplies cellulose-based insulation for the construction industry, is now relaunching its Isocell insulation solution in a boron-free variant that maintains the same fire classification as before. With this new solution, the company also aims to nuance the perception of biogenic insulation materials in construction and shift the discussion from assumptions to documented performance.

Boron salts are among the most commonly used fire retardants in biogenic insulation materials. However, as certain boron compounds are listed on the EU’s REACH list of substances of concern, there has been increasing focus on finding alternative solutions. This has now been achieved, enabling Nviro to launch a new cellulose-based insulation that is free from substances on the REACH list while retaining its fire performance properties.

“Isocell is made from recycled paper that has undergone an impregnation process with fire-retardant agents. Previously, boron salts were part of this process, but new solutions based on modern fire retardants have been developed, offering the same effects as boron salts. This makes our insulation solution even more suitable for certified construction such as DGNB,” explains Per K. Thomsen, Technical Director at Nviro.

According to Nviro, the new boron-free variant of Isocell has been tested in accordance with EU standard methods and achieves a B-s2,d0 fire classification.

“With this new variant, we can offer cellulose insulation without boron salts that still meets the fire safety requirements typically applied in construction. This provides consultants and contractors with a solution where documentation and material choices align well,” says Per K. Thomsen.

Biogenic building materials still face significant barriers
With the boron-free Isocell solution, Nviro aims not only to offer an alternative but also to contribute to a more nuanced discussion about biogenic materials in construction.

“Many biogenic building materials fall outside the pre-accepted solutions of the building regulations, meaning it is up to the developer to document that the materials comply with fire safety requirements—regardless of their fire classification. This is a major barrier to the wider adoption of, for example, cellulose-based insulation—and an unnecessary obstacle for developers who want to use biogenic and circular materials,” says Per K. Thomsen, adding:

“Isocell proves that biogenic materials can easily meet strict fire safety requirements, but these nuances are often missing from the discussion, which tends to be dominated by assumptions that timber buildings are highly flammable. That is something we at Nviro want to change. Our hope is that this will encourage policymakers to listen, so that more biogenic materials are included in pre-accepted solutions—helping to drive demand and support the green transition in construction.”