1. LVL AS A CONSTRUCTION MATERIAL Figure 1.16. Left: Distribution of wood material in LVL production. 2,5 m3 of logs (over bark) is needed to produce 1m3 of LVL. Right: Weight distribution of wood fibres, glue and moisture in ready LVL product 5 . 1.4.2 Material efficiency The initial driver for the development of LVL has been the high efficiency of wood raw material use. Firstly, the dimensions of the final product are not limited by the dimensions of the raw material – even small-diameter logs can be used to produce long LVL beams. Secondly, the veneer structure of LVL products eliminates the impact of natural defects, such as knots, resulting in a homogeneous material with excellent structural properties. This means that logs that are not good enough for sawing can be suitable raw material for LVL. Thirdly, products can be manufactured to exact dimensions minimizing material waste in cross cutting and sawing, and product features LVL 01, Figure 1.13 0% 10% 20% 30% 40% 50% 60% LVL By-products and losses END PRODUCT, BY-PRODUCTS AND LOSSES: SHARES OF TOTAL LOG VOLUME (%) LVL Bark Green chips Core Dry chips & saw dust Drying shrinkage loss Compression loss LVL WEIGHT DISTRIBUTION Glue 6 % Moisture 10 % Wood fibers 84 % can be varied by adjusting production process parameters. In a modern production process about 2,5 m3 of logs (over bark) are needed to yield 1m3 of ready LVL product, which is efficient compared to other wood products intended for load-bearing structures. In addition, the end product yield of LVL consists almost exclusively of the desired product grades and sizes, unlike sawn timber production, which produces a mixture of heartwood and sideboards. 1 m3 of dried sawn timber needs about 2,0 m3 logs (over bark); the corresponding value for glulam and cross-laminated timber (CLT) is 2,6-2,8m3. Figure 1.15. Structural LVL production volume by market 2011 – 2025 5 . Raute Oyj 4,0 3,5 3,0 2,5 2,0 1,5 1,0 0,5 0,0 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 F2025 STRUCTURAL LVL PRODUCTION BY MARKET Million m3 / year Asia & Oceania Europe North America 20 LVL Handbook Europe
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