Fire resistance of a house built of CLT panels was tested in Väike-Maarja

Scientists of Tallinn University of Technology in co-operation with Estonian Academy of Security Sciences, RISE (Swedish research institutes), Swedish Wood, State Real Estate Company and German specialists tested fire resistance of a building built of cross-laminated timber panels on training field of Academy of Security Sciences on November 1st.

During the test that was carried out for the first time in Estonia, a two storey building was set on fire under controlled conditions. The building’s load-bearing construction was made of cross-laminated timber. The scientists tested the resistance of the building’ s construction to fire and impact of different building and facade materials used in the house to developments of fire.

Fireproof windows stopped the fire from spreading. Photo: TTÜ

The main goal of the test was to investigate fire resistance of CLT buildings and find a safe solution for usage of CLT’ s in large volume buildings higher than 2 storeys. The test was built up without sprinklers and wooden surfaces were partly displayed inside. Yet the amount of exposed wooden surfaces was the biggest used in similar tests so far in the world. The aim of the test was to find a balance between massive wooden surfaces displayed on the inside and developments of fire in such a manner that when the burning interior decor (cupboards, chairs, tables) has burnt, the fire would just succumb by itself, similarly to a stone building.  

For testing, a test house sized 3,5 m x 4,5 m and height of 6m was built from Peetri Puit OÜ (Arcwood) materials to the training grounds. In order to analyze the test, data was collected from nearly 100 measuring points that for example showed temperature in different layers of the construction and heights of the room, weight of the test body, movement of air flow, etc. Passages had been made of building’ s constructions and during the test, their behaviour was observed in conditions of fire. In addition to inside spaces, the developments of fire were also observed on the facade which was insulated differently on different sides. On one side stone wool was used and on the other side PIR-insulation. Both walls were covered with airy facade covering – wood and cement plates. Both floors of the building had in different walls 2 Aru Grupp windows (total of 4 windows), which in case of upper floor were fireproof and were supposed to stop the fire from spreading to rooms of other floors through the facade. 

Associate professor Alar Just (Tallinn University of Technology) who was responsible for test measuring evaluates the test as successful by all means and believes that all necessary data was received during the fire to make a detailed analysis. “Based on preliminary analysis it can be said that the upper floor of the house remained untouched by the fire due to fireproof windows and cement board facade covering. That is a good sign,” commented Just.

Just would also like to thank all co-operation partners who helped with a nearly 100 000 euro test. “A good co-operation and organization and a large number of partners indicate that fire safety of wooden buildings is an actual and necessary topic. With that test, we can show people that wooden houses are capable to resist fire and bust the myth that they are more fire-hazardous than stone houses.” 

Fire resistance test of a house built of CLT panels in Väike-Maarja. Photo: TTÜ

Project supporters:  Peetri Puit (Arcwood), Gyproc, Paroc, EnerEst, Aru Grupp AS, Raitwood, Ehitusplaat OÜ, Tefire, Genoke.

Introductory video footage with the test can be re-watched at ERR and more thorough overview at ETV „Ringvaade“ (02.11.2017).