Kodumaja structures do not burn

The fire resistance properties of a timber-frame residential building are frequently asked about. As wood is a combustible material, it is often (and wrongly) thought that timber-frame houses are easily consumed by fire. Practice and fire resistance tests confirm the opposite. Unlike metal structures, wooden loadbearing structures preserve their integrity for a considerable amount of time even in the case of direct contact with fire. On the contrary, metal structures lose their loadbearing capacity very quickly. This is also a reason why metal structures may be protected from fire by wood.

Fire resistance ratings are given to buildings in accordance with construction regulations of different states, depending on a building's type and the number of storeys. Requirements differ from state to state and it is possible that solutions acceptable in one state would not be given approval in another. For fire sections of the building and various partition walls a minimum fire resistance rating is prescribed. To determine fire resistance of a building sections and partition walls in the case of fire, it is required to make respective calculations or perform tests, or both. However, because calculation methods introduced by the standards often do not enable us to find out the fire resistance rating of different structures, the tests become unavoidable.

Kodumaja has controlled fire resistance of its structures both by calculations and tests. Experts from Estonia, Norway, Finland and Sweden were engaged for this purpose. Kodumaja has established well-working cooperation with the Swedish Research Institute of Wood Technology - SP Trätek and with the Norwegian Institute of Construction Research - SINTEF Byggforsk. European fire rating tests were performed in a testing laboratory which complies with the international standard and has a respective accreditation. All tests have so far confirmed the validity of Kodumaja's calculations of fire resistance ratings. For many types of structures, the results of the tests have actually significantly surpassed the values obtained by calculations. 

Full-scale European fire rating tests of structures

It seems unbelievable for many people that partition walls between apartments in Kodumaja multi-storey apartment houses are able to withstand an intensive fire, when temperatures rise over 900 degrees Celsius, for more than 60 minutes, preventing fire propagation to an adjacent apartment and keeping the loadbearing capacity of walls intact. Such result is definitely not a limit of fire resistance for Kodumaja structures.

Fire resistance analysis of Kodumaja structures was also carried out by the All-Russian Research Institute for Fire Protection (Федеральное Государственное Учреждение «Всероссийский ордена «Знак Почёта» научно-исследовательский институт противопожарной обороны (ФГУ ВНИИПО МЧС России)). The institute is subjected to the Ministry of the Russian Federation for Affairs of Civil Defence, Emergencies and Disaster Relief (Министерство Российской Федерации по делам гражданской обороны, чрезвычайным ситуациям и ликвидации последствий стихийных бедствий).

The analyses confirmed that Kodumaja structures have fire resistance rating 3 and Kodumaja was issued a respective Technical Approval.

In a building of any type, the crucial priority for Kodumaja is to ensure the safety of its occupants. Therefore, during the design of higher multi-storey residential buildings respective fire risk analyses are performed and measures are planned to minimise fire risks to the level required by applicable regulations in the respective markets. Thus, living rooms and evacuation routes in Kodumaja houses that have more than three stories are usually equipped with an automated fire sprinkler systems.

The construction of timber-frame residential buildings has been rapidly developing in the recent years and their popularity has risen dramatically. Many new fire and moisture-resistant materials were introduced.

Alas, not all regulations, standards and computational models have been able to keep pace with such rapid development. Fire safety is not an exception here. Because of this reason, an international project was initiated under the leadership of SP Trätek to develop new methods of fire safety computation and new fire safety regulations for wood houses and structures. The project's results will be published in Brandsäkra trähus 3, a book to be completed by spring 2010.

Owing to Kodumaja's long experience in the development of multi-storey timber-frame buildings and testing of fire resistance of structures, Kodumaja has been involved in this project as a partner.