1. LVL AS A CONSTRUCTION MATERIAL 1.4.3 Wood species used in LVL LVL is commonly produced from softwood and, in Europe, spruce and pine are typically used. Spruce has the best strength to weight ratio, and its low resin content is also advantageous with respect to the production process. Pine veneer, on the other hand, has higher density, which gives the product slightly higher mechanical properties. Some LVL manufacturers in Europe also use the hardwood species beech and birch. The mechanical properties of hardwood LVL are higher due to the higher density. However, higher density introduces additional machining requirements, such as possible predrilling for screw connections. The surface of hardwood LVL is also more sensitive to mould growth in humid conditions. North American LVL manufacturers use different pine species, Douglas fir, western hemlock, yellow poplar and red maple. In Australia LVL is produced from different pine species and karri (eucalyptus). In Japan, LVL is produced from larch and Japanese cedar (sugi). Other species that have the required mechanical and gluability properties may also be used. 1.4.4 Durable and inert gluing of LVL In structural LVL the veneers are bonded together with weather- and boil-resistant phenol formaldehyde (PF) adhesive, which is cured in the hot pressing process. Curing converts the adhesive to a high temperature resistant inert polymer that does not dissolve or react with other materials in the surrounding environment. LVL also fulfils the most stringent formaldehyde emission requirements, with emissions 3 times lower than the limit value of the E1 classification tested according to standard EN 717-1. The dry solids content of adhesive in LVL is approximately 30 kg/m3, i.e. about 6% by weight. 1.5 SUSTAINABLE BUILDING WITH LVL 1.5.1 Traceable raw material and sustainable sources Sustainable forest management and use of forest products play a key role in the mitigation of global warming and contribute to achieving climate policy objectives. Forest climate mitigation options include reducing greenhouse gas emissions from deforestation and forest degradation, enhancing the carbon sequestration rate in existing and new forests, providing wood residues as a substitute for fossil fuels, and replacing non-renewable and energy-intensive materials with wood products, particularly in the building sector. Due diligence on the origin of wood Due diligence systems differentiate wood and wood products from many other building materials by verifying the origin of the wood raw material. The European Union Timber Regulation (No 995/2010) was enacted to ensure that all wood placed on the European market from internal or external sources is covered by a due diligence system for verifying the legal origin of wood 6. The objective is to prohibit any product that contains wood raw material harvested in violation of national or international laws from entering the EU market. The regulation covers all wood and wood products, such as round wood, solid wood, engineered wood, pulp, paper and board. The EU Timber Regulation covers the entire wood value chain. An ‘operator’ who first places a wood product on the European market is obliged to prove the legality of the wood to a national EU Timber Regulation authority. A Due Diligence system is applied for this purpose, including access to information on wood sources, risk assessment, and mitigation of risks. Chain of Custody systems (e.g. PEFC™ and FSC®) can be third-party certified according to Due Diligence requirements. Promoting sustainable, certified forest management European LVL producers are well positioned in forest certification as European forests owners have been active in applying forest certification schemes (most commonly PEFC™ and FSC®). Forest certification schemes provide third-party verification of sustainable forest management practices and the chain of custody from forest to product. They include requirements for sustained harvesting and forest regeneration practices, biodiversity protection, multiple and recreational uses of forests, social sustainability, training of employees, and occupational safety. In order for a wood product to PEFC™ or FSC® labelled, it must contain at least 70% wood raw material from certified forests. When non-certified wood is used in the production of certified goods, the wood must originate from forests covered by an appropriate due diligence system. LVL Handbook Europe 21
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