KL-trä är ett relativt nytt konstruktionsmaterial som lämpar sig som stomme i bostadshus, offentliga och industriella byggnader. Eurokod 5 är den europeiska standarden för dimensionering av träkonstruktioner som är obligatorisk att använda i alla länder. Den omfattar både dimensionering i normalfallet och branddimensionering. Nuvarande version för branddimensionering EN 1995-1-2:2004 publicerades 2004 [1]. Den saknar regler för dimensionering av KL-trä. En ny version av Eurokod 5 beräknas komma 2025, den finns idag som utkastet prEN 1995-1-2:2025 [2]. De två versionerna av Eurokod 5 jämförs för KL-trä i denna artikel. Artikeln baseras på ett examensarbete vid Linnéuniversitetet [3]. Endast konstruktioner med synlig träyta har analyserats.

This chapter deals with the fire properties and performance of wood products and structures. It starts with two subchapters on the basic physical and chemical properties under fire conditions including fire-retardant treatments to obtain higher reaction to fire classes. A new European standard to evaluate their long-term fire performance is included. The third subchapter gives an overview of the fire safety design of wood products in buildings. The European system for fire safety of construction products is explained with the two main fire scenarios to be considered: the initial fire where visible wood surfaces may contribute, and the fully developed fire, which is important to limit the fire to the room of origin. Generally speaking, wooden structures can obtain high fire resistance, whereas the surface properties in the initial fire are less favorable. The European reaction to fire class D is fulfilled for most wood products. North American systems are different and their classification of wood products is described briefly. Methods for calculating the fire resistance of wood elements according to Eurocode 5, and US systems, structural detailing, and fire safety at building sites are presented. The chapter ends by explaining the possibilities for using performance-based fire safety design and active fire protection by, for example, sprinklers. 

Building codes around the globe dictate the design and construction of buildings. For most buildings, designers will follow prescriptive code provisions to demonstrate code compliance. However, some buidling codes allow the use of performance-based design to demonstrate code compliance. Performance-based design is usually more complex but allows for greater flexibility in the use of materials and systems. Regardless of the code compliance methods, the combustibility of timber structures and wood products needs to be well understood and properly accounted for in building designs. This paper describes the develpment of a new international guidance document on fire safety in timber building within the Fire Safe Use of Wood (FSUW) network, written by 13 lead authors assisted by more than 20 experts in over a dozen different countries.

A wide variety of active fire protection systems are available to fire safety practitioners. In addition to passive fire protection measures, some level of active fire protection is normally required to meet the expected minimum level of fire safety in modern buildings. Active fire protection can also be used to increase the fire safety in order to achieve a more flexible fire safety design and an acceptable level of fire safety in buildings. There are many types of active fire protection systems, but this chapter deals mainly with automatic fire sprinkler systems, since they are often used to facilitate the use of timber as structure, internal linings and external facades in large or complex buildings. Sprinklers are required in some countries for taller timber buildings, as described in Chapter 4.

This chapter covers control of workmanship, fire safety during construction, responsibilities and enforcement, fire detection and suppression and emergency procedures. Quality and inspection of workmanship are vital for high-quality buildings, whether of timber or other construction materials. Timber buildings require certain precautions due to the risk for greater exposure of combustible materials. Furthermore, not all fire safety measures for the final building will be in place throughout construction; consequently, adequate processes are required to maintain the fire safety of building sites. All construction sites require formalised fire safety management systems, including auditing of contractors and subcontractors.

Wood and wood-based products are extensively used in the building sector due to their interesting combination of properties. Fire safety and fire spread, however, are of utmost concern for the protection of buildings. Therefore, in timber structures, wood must be treated with fire-retardant materials in order to improve its reaction to fire. This article highlights the flame retardancy of novel hybrid organic–inorganic halogen-free coatings applied on plywood substrates. For this purpose, either a huntite-rich mineral (H5) or its modified nano-Mg (OH)2 type form (H5-m), acting as an inorganic (nano) filler, was functionalized with reactive oligomers (ROs) and incorporated into a waterborne polymeric matrix. A water-soluble polymer (P (SSNa-co-GMAx)), combining its hydrophilic nature with functional epoxide groups, was used as the reactive oligomer in order to enhance the compatibility between the filler and the matrix. Among various coating compositions, the system composed of 13% polymeric matrix, 73% H5 and 14% ROs, which provided the best coating quality and flame retardancy, was selected for the coating of plywood on a larger scale in one or two layers. The results indicated that the novel plywood coating systems with the addition of ecological coating formulations (WF-13, WF-14 and WF-15), prepared at two layers, reached Euroclass B according to EN13501-1, which is the best possible for fire systems applied to wood. © 2022 by the authors.