Fire Safety Solutions in Finnish Multi-story Timber-Frame Buildings

Abstract

Since the early 1990s, Finland has been actively engaged in the development of multi-story timber-frame buildings in collaboration with other EU countries. Following a brief trial period for constructing wooden apartments (1995–1997), amendments were made to Finnish fire code in 1997, allowing the utilization of timber in the structural frames and exteriors of buildings up to 4-story. In 2011, further revisions to the fire code enabled the construction of wooden buildings ranging from 5–8-story in height. According to the size specifications outlined in the current Finnish fire regulations as of January 1, 2018 (Ministry of Environment Decree 848/2017), it is feasible to erect residential, office, hotel, and care center with timber frames and facades, extending up to 8-story. Additionally, buildings exceeding 8-story can be achieved with the implementation of a functional fire safety inspection. In Finland, wooden buildings exceeding 2-story must be equipped with an automatic sprinkler system. The load-bearing wooden framework should primarily be safeguarded with A2-s1,d0 class fireproof protective coatings, typically consisting of gypsum boards. Furthermore, thermal insulation must meet at least an A2-s1,d0 fire class rating, typically achieved with mineral wool. Fire barriers should be integrated into the ventilation gap and eaves of wooden facades. While facades may have a wooden appearance (fire class D-s2, d2), it is mandatory for the facade of the ground floor to be constructed using a fire class B-s2,d0 material. As of January 2024, Finland has completed the construction of 175 wooden apartments buildings exceeding 2-story, totaling 5,742 apartments.