{"id":2423,"date":"2019-02-13T18:12:56","date_gmt":"2019-02-13T18:12:56","guid":{"rendered":"https:\/\/www.sim.sbio.vt.edu\/?p=2423"},"modified":"2019-02-13T18:12:56","modified_gmt":"2019-02-13T18:12:56","slug":"is-the-cross-laminated-timber-clt-market-an-option-for-the-hardwood-industry","status":"publish","type":"post","link":"https:\/\/sim.sbio.vt.edu\/?p=2423","title":{"rendered":"Is the Cross-laminated timber (CLT) market an option for the hardwood industry?"},"content":{"rendered":"\n



<\/strong><\/p>\n\n\n\n

\"\"
Three ply cross-laminated timber (CLT) made of Yellow Poplar<\/figcaption><\/figure>\n\n\n\n

By Henry Quesada<\/em><\/p>\n\n\n\n

*Articled published in the Virginia Loggers Association Newsletter in August 2018.<\/em><\/strong><\/p>\n\n\n\n

Cross laminated timber (CLT) has been in the market\nsince 2000 when it was launched in Austria by a company called KHL. A CLT panel\nis composed of 3, 5, or 7 layers of lumber. Each layer is glued perpendicularly\nto each other. Today almost 100% of the CLT panels being produced are made from\nsoftwood species and it is estimated that the current CLT production in Europe\nis around 1 million cubic meters. <\/p>\n\n\n\n

In the United States, production of CLT started about\n5 years ago. There are currently three companies producing CLT panels in the\nUSA: DR Johnson (OR), Smartlam (MT) and Sterling (IL). DR Johnson uses Douglas\nFir (DF) as the main raw material while Smartlam uses Spruce-Pine-Fir (SPF) and\nSterling uses Southern Yellow Pine (SYP). It has been announced that over the\nnext two years the following 4 CLT production facilities will start production:\nKaterra in Washington, a second plant by Smartlam in Maine, LignaCLT Maine, and\nInternational Beams in Alabama. All of the upcoming facilities will be using\nsoftwoods as raw material.<\/p>\n\n\n\n

All of the US CLT current and planned producers (except\nSterling Lumber) are in compliant with the CLT standard, PRG-320. Sterling\nLumber produces CLT matts for energy projects (non-structural application) so\nthere is no need to follow the CLT standard. <\/p>\n\n\n\n

The CLT standard, ANSI\/APA PRG-320, does not admit\nhardwood lumber yet; a major hurdle for hardwood lumber to become an accepted\nCLT raw material. Any softwood species as described in the ALCS under PS 20\nwith specific gravity higher than 0.35 should be an acceptable raw material for\nCLT, according to ANSI\/APA PRG-320. In most of the cases, hardwood species have\nhigher specific gravity than softwood, so this should not be a problem. In\naddition, lumber for CLT should be dried to a moisture content (MC) of 12%+-3%.\nThis is also not an issue for hardwood lumber as most of it is dried to 8% MC. <\/p>\n\n\n\n

A key requirement for lumber going into CLT is that\nthe minimum thickness in the PRG-320 is 5\/8. As we know, most of hardwood\nlumber is produced in 4\/4 thickness. In addition, the board width should exceed\nits thickness by 1.5 times (in the major strength direction of the CLT panel)\nand by 3.5 times in minor strength direction of the panel. Currently, most\nhardwood mills produce random widths that definitely need to be sorted out to\ncomply with this requirement. <\/p>\n\n\n\n

Glue-line performance should be considered too. Hardwood\nlumber has a more complicated cellular structure than softwood lumber that\ncould present challenges with adhesion. For example, some hardwoods are stiffer\nthan softwoods and this might require additional pressure or pressing time.\nAlso, chemicals in the hardwood lumber could also prevent an optimal glue-line\nin- between the panels.<\/p>\n\n\n\n

Machining hardwood lumber is different than softwood\nlumber. Because hardwoods have a different structure, there could be a need for\ndifferent tooling and energy requirements. Some hardwoods present crystals and\nother hard structures that could wear tools faster than softwood lumber. These\nissues ultimately will impact cost and productivity of the planer, finger\njoint, and computer numerical control (CNC) equipment of the CLT production\nline. <\/p>\n\n\n\n

There is also the question about the supply of\nhardwood lumber for CLT. A medium size CLT plant could process about 50,000\ncubic meters per year which translate to roughly 21 million board feet. It is\nestimated that CLT demand in the US would be very similar to Europe or around 1\nmillion cubic meters (424 million bf). The current structure of hardwood\nindustry is fragmented so it would be very difficult for a major CLT plant to\nestablish a steady and consistent supply of hardwood lumber under these market\nconditions.<\/p>\n\n\n\n

Hardwood sawmills that wish to become suppliers of a\nCLT panel plant must adjust their production mix. Virginia Tech researchers conducted\na mill study and determined that Yellow Poplar lumber that is NHLA graded 2\nCommon and lower could be sold as raw material for CLT as long as the specific\nspecies meet the technical requirements in the PRG 320 (specific gravity,\nModulus of Elasticity, etc). Higher grades (1 Common and higher) should\ncontinue to be sold in the appearance market as mills can get more revenue in\nthis market than selling it as CLT raw material. Ultimately, hardwood sawmills\nwould need to train their personnel to grade hardwood lumber under structural\ngrading rules.<\/p>\n\n\n\n

Other issues that should be considered for hardwood\nCLT panels is the weight of panels. It has been estimated that hardwood CLT\npanels could weigh up to 30% more than softwood CLT panels. In terms of\nlogistics and transportation arrangements, this could increase the overall cost\nand time of the projects as additional trips are required to move the completed\nhardwood CLT panels to the construction site. An alternative would be produced\n3 or 5 ply softwood CLT panels and add a layer of hardwoods just to meet the\nweight requirement <\/p>\n\n\n\n

Finally, there is also the question of sustainability.\nIt has been confirmed by the US Forest Service that growth of hardwood forest\ndoubles its harvesting rates. However, it should be considered that growing\nhardwoods might take as much as double the time of growing softwood timber. In\naddition, softwood timber is growing in plantations which increases the\nproductivity of the timber. <\/p>\n\n\n\n

As we just pointed out, it seems that there are\nopportunities for hardwood lumber to participate in the CLT market. However,\nthere are some critical hurdles that need to be resolved before this could\nhappen. At Virginia Tech and other universities, we continue to generate\nresearch in technical, manufacturing, and marketing aspects of the potential\nuse of hardwood lumber in the CLT market. If you have questions, please let us\nknow at your earliest convenience.<\/p>\n","protected":false},"excerpt":{"rendered":"

By Henry Quesada *Articled published in the Virginia Loggers Association Newsletter in August 2018. Cross laminated timber (CLT) has been in the market since 2000 when it was launched in Austria by a company called KHL. A CLT panel is composed of 3, 5, or 7 layers of lumber. Each layer is glued perpendicularly to … Continue reading “Is the Cross-laminated timber (CLT) market an option for the hardwood industry?”<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5,1],"tags":[],"class_list":["post-2423","post","type-post","status-publish","format-standard","hentry","category-product-innovation","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/sim.sbio.vt.edu\/index.php?rest_route=\/wp\/v2\/posts\/2423","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/sim.sbio.vt.edu\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/sim.sbio.vt.edu\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/sim.sbio.vt.edu\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/sim.sbio.vt.edu\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2423"}],"version-history":[{"count":0,"href":"https:\/\/sim.sbio.vt.edu\/index.php?rest_route=\/wp\/v2\/posts\/2423\/revisions"}],"wp:attachment":[{"href":"https:\/\/sim.sbio.vt.edu\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2423"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/sim.sbio.vt.edu\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2423"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/sim.sbio.vt.edu\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2423"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}