Fire protection

Fire protection with CLTPLUS?
It works.

Timber constructions are still underestimated in terms of fire resistance. Ensuring stability in the event of a fire is not just a question of the material, but also of quality planning and execution.

Perfectly predictable

The moisture content of CLTPLUS of around 12 per cent means that water must first evaporate before the wood starts to burn. This results in a charred surface, but not a loss of structural properties. CLTPLUS is a stable and safe building material with predictable fire behaviour that has been tested for fire resistance by Holzforschung Austria and TU Munich.

Info

  • By forming a pyrolysis layer, the wood protects itself in the event of fire.
  • CLTPLUS can achieve a fire resistance of over 90 minutes with appropriate dimensioning.
  • The fire resistance of CLTPLUS solid wood elements is verified as part of a structural calculation based on the ETA European Technical Assessment ETA-20/0843 and the provisions of EN 1995-1-2.

Fire behaviour D-s2, d0

Blanket

  • β0 = 0.65 mm/ min initial burn-off, without fire protection panelling
  • β1a = 2 – β0 = 1.30 mm / min for the first 25 mm when exceeding an adhesive joint
  • β1b = 0.65 mm / min for the further thickness of a layer

 

Wall

  • β0 = 0.65 mm/ min initial burn-off, without fire protection panelling
  • β1 = 0.86 mm/ min for the first 25 mm when exceeding an adhesive joint and for the further thickness of an inner layer

FIRE BEHAVIOUR

D = Normally flammable

SMOKE DEVELOPMENT

s2 = limited smoke development

BURNING DRIPPING/FALLING OFF

D0 = non-dripping

FAQ
Fire protection

CLTPLUS elements from THEURL are classified as D-s2, d0 and therefore as normally combustible with limited smoke development and non-dripping. The flash point of wooden components is between 270 and 300 °C.

When CLTPLUS is exposed to fire, the stored water molecules begin to vaporise at around 100 °C. At temperatures of 200 to 300 °C, the long-chain molecules in the cell walls are also broken down and reach the surface of the wood in the form of gas, where they react with the oxygen in the air and burn.

Yes, the fire behaviour of wood as a material can be precisely calculated. Wood smokes very little and does not drip when burning. The load-bearing function of timber components is retained for a very long time, even in the event of fire.

The fire resistance
of unclad building elements

Anyone who wants to design and build with unclad CLTPLUS elements and achieve highly effective fire protection can optimise the building material in terms of fire protection by increasing the thickness of the CLTPLUS solid wood panel. Thanks to the complete edge bonding of all layers, an airtight and smoke-tight seal is also achieved by a panel thickness of just 60 millimetres or higher.

The fire resistance
of clad building elements

To further optimise the fire resistance of unclad CLTPLUS elements, special fire protection claddings such as panelling or sheathing are available. This means that the timber components are “encapsulated” with non-combustible building materials. This ensures that load-bearing and bracing walls, ceilings and supports made of wood – although combustible themselves – ultimately have highly fire-retardant properties.

One-sided burn-off rate

The burn-off rate defines the layer thickness per minute with which the wood burns off on the side of a CLT component facing the fire. This rate is measured in millimetres per minute and depends on various factors such as: the type of wood, the wood moisture content and the fire protection measures. For the CLTPLUS elements from THEURL, the fire test at IBS Linz showed that in a fire simulation using flame treatment at a temperature of over 900 °C, the top side only becomes lukewarm after 90 minutes and remains smoke-tight according to the standard fire curve. The test was carried out on a 120 millimetre thick 5-layer CLTPLUS panel.

WE OFFER YOU
FIRE-SAFE SOLUTIONS

From pre-dimensioning aid
to the Wallner Mild and DC-Static
design software

ARE YOU LOOKING FOR US IN STRUCTURAL ANALYSIS SOFTWARE
USED IN TIMBER CONSTRUCTION?

The most important components can be designed quickly and easily. You will also find us and our products listed as a manufacturer in the timber construction design software Wallner Mild and DC-Statik.

CLTPLUS PRE-DIMENSIONING FOR R30, R60 AND R 90
MADE EASY

The design and execution is carried out in accordance with Eurocode 5 (EN 1995-1-1 and EN 1995-1-2), taking into account the national specifications in ÖNORM B 1995-1-1 and ÖNORM B 1995-1-2 as well as the current version of the ETA European Technical Assessment ETA-20/0843.

CROSS LAMINATED TIMBER DIMENSIONING
BAND II

As an innovative structural element, cross laminated timber opens up new possibilities in structural timber construction. This guide is intended to help you to properly utilise and implement the possibilities in planning and execution.

More on the
Topic
Building physics