Denmark: Now Modular Wooden Buildings of up to 45m as Standard

Up to April 2021, modular timber buildings in Denmark could not have a floor level higher than 12 metres from the ground without special, difficult-to-obtain permits. Now, Build-in-Wood Consortium Partner Scandi Byg achieved a ground-breaking approval: Scandi Byg’s wooden constructions passed the REI 120 fire test, which, in alignment with the Danish "Pre-Accepted Solutions", allows for a building height of up to 45 meters above ground.

A modular housing timber container is placed on a construction site
Assembly of a Modular Timber Building © Scandi Byg
“We are the first on the Danish market to now be able to build prefabricated modular buildings in wood on more than four floors as a fixed standard.”

says CEO of Scandi Byg, Christian Halken. This is an important milestone for timber construction in Denmark. Especially in the densely populated Copenhagen area, more housing space is a vital need. Being able to more than only 4 storeys enables a massive increase of flats provided per square meter of scarce real estate.



What is the REI 120 ?

In Europe, a building components resistance in case of fire is described as REI "xx": The "xx" indicates the number of minutes of resistance. REI stands for R (Loadbearing Capacity) - E (Integrity) - I (Thermal Insulation). That means, a REI 60 wall must keep its loadbearing capacity, integrity and thermal insulation for at least 60 minutes.

Industrial hall with test setting of 1000 degrees hot oven and insulated timber wall for fire resistance test
Left: Insulated timber wall after the fire test, Right: Testing oven, still hot © Scandi Byg

In Denmark, buildings above 12m (to the upper floor level) have to achieve REI 120, so they need to withstand two hours of fire without losing structural stability.

“We now have documentation that our wooden structures are so strong that they can pass a REI 120 test”, says CEO of Scandi Byg, Christian Halken. Scandi Byg's fire test of wooden structures was carried out by the Danish Fire and Safety Engineering Institute in Hvidovre. The load-bearing wooden structures had to withstand fire for at least two hours with more than 1,000°C in the final phase.

The picture above shows the wooden wall element, protected by layers of plasterboard, after the 120 minutes of fire in the standardized oven (still red-hot). The plasterboard cracked into pieces during the test, but managed to fully protect the timber structure for the entire 2 hours of fire.

Check out the blog post on the Scandi Byg website (in Danish) for more information:

👉🏼 https://www.scandibyg.dk/nyheder/scandi-byg-kan-nu-levere-industrielt-fremstillet-modulbyggeri-i-trae-paa-mere-end-fire-etager-som-standard/



Fire Resistance as part of the Build-in-Wood project


The innovation project Build-in-Wood wants to make timber the standard material for the construction of multi-storey buildings. Therefore, component optimization and fire performance tests are an important part of the project. These are conducted and documented by the National Technical University of Athens as part of Work Package 5.

👉🏼 Overview of all workpackages: build-in-wood.eu/work-packages

👉🏼 More details about the project and the Build-in-Wood factsheet (available for download in multiple languages) here: https://www.build-in-wood.eu/project