Fire behaviour of facades in multi-storey wood-framed houses

Tuula Hakkarainen, Tuuli Oksanen, Esko Mikkola

Research output: Book/ReportReportProfessional

6 Citations (Scopus)

Abstract

The fire behaviour of wooden facades in multi-storey houses has been studied in a Nordic research project on the fire safety of wood (Brandsäkra Trähus). The results of the research have been used in pilot projects for multi-storey wood-framed houses and utilised in the reform of the structural fire safety regulations of the Finnish building code. Two different fire scenarios were studied: a relatively small ignition source outside the building and a flashover of a compartment fire. These test arrangements correspond to possible fire scenarios in sprinklered and unsprinklered houses, respectively. Fire tests of wooden facades with different materials, surface treatments and structures were performed on intermediate and large scales. In the case of an external fire, the most efficient way to prevent the propagation of flames to the next storey of the facade was structural modification of the facade profile, i.e. cantilevers and oriels. Special attention must be paid to the sufficient width and length of the protrusion, and the non-combustibility of its lower surface. In the tests of fire retardant (FR) treated specimens, the flame spread was considerably delayed or even stopped depending on the FR treatment used. However, the long-term stability of FR treatment is generally undefined. When the facade was exposed to the flashover flames of a compartment fire, the fire spread could not be prevented by a 400 mm wide cantilever or special ventilation structures of wooden eaves. On the basis of the test results, the use of wood in the facades of multi-storey houses with unsprinklered apartments should be limited to 20 - 50 % of the total surface area depending on the location of the wood material. In sprinklered houses, however, wood can be used more extensively. Simple criteria based on heat flux levels to the windows of a facade and falling pieces have been proposed for sprinklered and unsprinklered buildings. According to these criteria, the fire safety of wood products to be used in facades of multi-storey wood-framed houses can be estimated.
Original languageEnglish
Place of PublicationEspoo
PublisherVTT Technical Research Centre of Finland
Number of pages58
ISBN (Print)951-38-5098-6
Publication statusPublished - 1997
MoE publication typeD4 Published development or research report or study

Publication series

NameVTT Tiedotteita - Meddelanden - Research Notes
PublisherVTT
Volume1823
ISSN (Print)1235-0605
ISSN (Electronic)1455-0865

Fingerprint

Facades
Wood
Fires
Flame retardants
Flashover
Wood products
Surface structure
Ventilation
Ignition
Surface treatment
Heat flux

Keywords

  • facades
  • external walls
  • wooden structures
  • fire safety
  • sprinklers
  • fire protection
  • fire tests
  • apartment buildings
  • ignition
  • fire spread

Cite this

Hakkarainen, T., Oksanen, T., & Mikkola, E. (1997). Fire behaviour of facades in multi-storey wood-framed houses. Espoo: VTT Technical Research Centre of Finland. VTT Tiedotteita - Meddelanden - Research Notes, No. 1823
Hakkarainen, Tuula ; Oksanen, Tuuli ; Mikkola, Esko. / Fire behaviour of facades in multi-storey wood-framed houses. Espoo : VTT Technical Research Centre of Finland, 1997. 58 p. (VTT Tiedotteita - Meddelanden - Research Notes; No. 1823).
@book{36eec44e09254bde95564914527dd20b,
title = "Fire behaviour of facades in multi-storey wood-framed houses",
abstract = "The fire behaviour of wooden facades in multi-storey houses has been studied in a Nordic research project on the fire safety of wood (Brands{\"a}kra Tr{\"a}hus). The results of the research have been used in pilot projects for multi-storey wood-framed houses and utilised in the reform of the structural fire safety regulations of the Finnish building code. Two different fire scenarios were studied: a relatively small ignition source outside the building and a flashover of a compartment fire. These test arrangements correspond to possible fire scenarios in sprinklered and unsprinklered houses, respectively. Fire tests of wooden facades with different materials, surface treatments and structures were performed on intermediate and large scales. In the case of an external fire, the most efficient way to prevent the propagation of flames to the next storey of the facade was structural modification of the facade profile, i.e. cantilevers and oriels. Special attention must be paid to the sufficient width and length of the protrusion, and the non-combustibility of its lower surface. In the tests of fire retardant (FR) treated specimens, the flame spread was considerably delayed or even stopped depending on the FR treatment used. However, the long-term stability of FR treatment is generally undefined. When the facade was exposed to the flashover flames of a compartment fire, the fire spread could not be prevented by a 400 mm wide cantilever or special ventilation structures of wooden eaves. On the basis of the test results, the use of wood in the facades of multi-storey houses with unsprinklered apartments should be limited to 20 - 50 {\%} of the total surface area depending on the location of the wood material. In sprinklered houses, however, wood can be used more extensively. Simple criteria based on heat flux levels to the windows of a facade and falling pieces have been proposed for sprinklered and unsprinklered buildings. According to these criteria, the fire safety of wood products to be used in facades of multi-storey wood-framed houses can be estimated.",
keywords = "facades, external walls, wooden structures, fire safety, sprinklers, fire protection, fire tests, apartment buildings, ignition, fire spread",
author = "Tuula Hakkarainen and Tuuli Oksanen and Esko Mikkola",
year = "1997",
language = "English",
isbn = "951-38-5098-6",
series = "VTT Tiedotteita - Meddelanden - Research Notes",
publisher = "VTT Technical Research Centre of Finland",
address = "Finland",

}

Hakkarainen, T, Oksanen, T & Mikkola, E 1997, Fire behaviour of facades in multi-storey wood-framed houses. VTT Tiedotteita - Meddelanden - Research Notes, no. 1823, VTT Technical Research Centre of Finland, Espoo.

Fire behaviour of facades in multi-storey wood-framed houses. / Hakkarainen, Tuula; Oksanen, Tuuli; Mikkola, Esko.

Espoo : VTT Technical Research Centre of Finland, 1997. 58 p. (VTT Tiedotteita - Meddelanden - Research Notes; No. 1823).

Research output: Book/ReportReportProfessional

TY - BOOK

T1 - Fire behaviour of facades in multi-storey wood-framed houses

AU - Hakkarainen, Tuula

AU - Oksanen, Tuuli

AU - Mikkola, Esko

PY - 1997

Y1 - 1997

N2 - The fire behaviour of wooden facades in multi-storey houses has been studied in a Nordic research project on the fire safety of wood (Brandsäkra Trähus). The results of the research have been used in pilot projects for multi-storey wood-framed houses and utilised in the reform of the structural fire safety regulations of the Finnish building code. Two different fire scenarios were studied: a relatively small ignition source outside the building and a flashover of a compartment fire. These test arrangements correspond to possible fire scenarios in sprinklered and unsprinklered houses, respectively. Fire tests of wooden facades with different materials, surface treatments and structures were performed on intermediate and large scales. In the case of an external fire, the most efficient way to prevent the propagation of flames to the next storey of the facade was structural modification of the facade profile, i.e. cantilevers and oriels. Special attention must be paid to the sufficient width and length of the protrusion, and the non-combustibility of its lower surface. In the tests of fire retardant (FR) treated specimens, the flame spread was considerably delayed or even stopped depending on the FR treatment used. However, the long-term stability of FR treatment is generally undefined. When the facade was exposed to the flashover flames of a compartment fire, the fire spread could not be prevented by a 400 mm wide cantilever or special ventilation structures of wooden eaves. On the basis of the test results, the use of wood in the facades of multi-storey houses with unsprinklered apartments should be limited to 20 - 50 % of the total surface area depending on the location of the wood material. In sprinklered houses, however, wood can be used more extensively. Simple criteria based on heat flux levels to the windows of a facade and falling pieces have been proposed for sprinklered and unsprinklered buildings. According to these criteria, the fire safety of wood products to be used in facades of multi-storey wood-framed houses can be estimated.

AB - The fire behaviour of wooden facades in multi-storey houses has been studied in a Nordic research project on the fire safety of wood (Brandsäkra Trähus). The results of the research have been used in pilot projects for multi-storey wood-framed houses and utilised in the reform of the structural fire safety regulations of the Finnish building code. Two different fire scenarios were studied: a relatively small ignition source outside the building and a flashover of a compartment fire. These test arrangements correspond to possible fire scenarios in sprinklered and unsprinklered houses, respectively. Fire tests of wooden facades with different materials, surface treatments and structures were performed on intermediate and large scales. In the case of an external fire, the most efficient way to prevent the propagation of flames to the next storey of the facade was structural modification of the facade profile, i.e. cantilevers and oriels. Special attention must be paid to the sufficient width and length of the protrusion, and the non-combustibility of its lower surface. In the tests of fire retardant (FR) treated specimens, the flame spread was considerably delayed or even stopped depending on the FR treatment used. However, the long-term stability of FR treatment is generally undefined. When the facade was exposed to the flashover flames of a compartment fire, the fire spread could not be prevented by a 400 mm wide cantilever or special ventilation structures of wooden eaves. On the basis of the test results, the use of wood in the facades of multi-storey houses with unsprinklered apartments should be limited to 20 - 50 % of the total surface area depending on the location of the wood material. In sprinklered houses, however, wood can be used more extensively. Simple criteria based on heat flux levels to the windows of a facade and falling pieces have been proposed for sprinklered and unsprinklered buildings. According to these criteria, the fire safety of wood products to be used in facades of multi-storey wood-framed houses can be estimated.

KW - facades

KW - external walls

KW - wooden structures

KW - fire safety

KW - sprinklers

KW - fire protection

KW - fire tests

KW - apartment buildings

KW - ignition

KW - fire spread

M3 - Report

SN - 951-38-5098-6

T3 - VTT Tiedotteita - Meddelanden - Research Notes

BT - Fire behaviour of facades in multi-storey wood-framed houses

PB - VTT Technical Research Centre of Finland

CY - Espoo

ER -

Hakkarainen T, Oksanen T, Mikkola E. Fire behaviour of facades in multi-storey wood-framed houses. Espoo: VTT Technical Research Centre of Finland, 1997. 58 p. (VTT Tiedotteita - Meddelanden - Research Notes; No. 1823).