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Forestry & Catapult 26th August 2019 – 5th September 2019 products Mark Hughes Department of Bioporducts and Biosystems Aalto University

GoWood BIOECONOMY GRADUATE RESEARCH SCHOOL Contents

• Wood: the essentials! • The family of wood products • Global production of wood products • Wood value chain • Wood products 3 fun facts about wood!

• Keep wood at less than 20% moisture content and it will not rot! • The density of the wood cell wall is around 1500 kg/m3 independent of species • The basic building block of the wood cell wall is the “microfibril”, a nanoscale fiber composed of , and How long?

If the microfibrils in the piece of wood were added end to end how long would they stretch? 1.To the end of the road? 2.To Stockholm? 3.To the moon? 4.To the sun? 5.Something else? Wood: the essentials! Some key facts about wood: • High specific stiffness and strength • Cellular solid: – Efficient structure (density 150-1200 kgm-3) • Highly anisotropic: – Very different properties parallel and perp. to grain • Defects: – Knots, rot, spiral grain, …… • Hydrophilic: – Leads to biodeterioration, swelling and shrinkage Hierarchy of wood

Tree (100-102 m)

Structural timber (100-101 m)

Anatomy (10-2 m)

Microstructure (10-3 m)

Cell wall (10-6 m) Microfibrils (10-9 m) Molecules (10-10 m) (Source: Society of Wood Science and Technology) http://wattsupwiththat.com/2008/04/08/seeing-the-wood- for-trees/

(Source: Society of Wood Science & Technology) Directionality of wood properties

(Source: http://www.flute-a-bec.com/indexgb.html) The family of wood products LOG Wood products

• Sawnwood: Wood-based composites: • Glue laminated timber (glulam) • Cross-laminate timber (CLT) “” products • Laminated veneer (LVL – Kerto®) • • Oriented strand board (OSB) • Particleboard (chipboard) • Medium density fibreboard (MDF) Wood-based panels • Softboard/ • … • …

 Fibre reinforced composites  Modified wood Why wood-based composites?

• The properties of wood are directionally dependent • There is large variability in wood properties due to its structure and to “defects” • Swells and shrinks: dimensionally unstable • Subject to biological decay: it rots • It burns! • Only available in a limited range of shapes and sizes!! • For this reason (and others), in addition to sawn wood there are a great many wood-based composites, modified wood products and, increasingly, wood-fibre reinforced composites Composites based on wood

Wood can be reduced in : size to:

• Sawn timber, lamellae Glue laminated timber • Veneers Plywood, LVL • Strands, strips, particles OSB, particleboard • Wood fibres , MDF, Wood-polymer composites (WPCs) • Cellulose Cellulosic “Nanocomposites” What else?

• Composites make effective use of raw materials that might otherwise be regarded as “waste” (e.g. wood chips & ) • Composites can also make effective use of recycled or reclaimed materials • Relatively small amounts of fossil-based (usually 8- 10% by dry weight) are used in the manufacture and even these could be replaced by renewable resource-based alternatives (or even eliminated!) The wood value chain

(Source: https://fairventures.org/en/about-us/value-chain/#1449652570809-83559c1a-5cdb) (Source: FAO Yearbook of Forest Products 2017) (Source: FAO Yearbook of Forest Products 2017) Wood products: - Sawn wood - Engineered wood - Wood panels Sawmilling is about converting this……

(Source: commons.wikimedia.org)

21 ………to this

(Source: commons.wikimedia.org)

22 Phew!

(Source: en.wikipedia.org) The sawing process

Shipping Measuring Sorting Storage

Debarking Sawing Sawing Edging

Battening Drying Presorting (Greensorting)

Quality grading Packaging

24 Source: Metsäteollisuus ry [online] [referred 9.4.2005] Available: http://ultra.forestindustries.fi/metsate/Puustajalosteeksi.pdf Edited: Ulla Rintala Harvesting

(Source: vendiawoods-en.blogspot.com)

(Source: www.bullcitymutterings.com800 × 600)

Harvesting in Finland: https://www.youtube.com/watch?v=_bdqLSA1-C8 25 (Source: www.loggingon.net) Roundwood into rectangular boards

• Sawing method Yields (approximately): • Sawing pattern • 45 % sawn goods • “Loss” of • 30 % chips • All about optimization! • 15 % sawdust • 10 % bark Cutting optimisation

27 The sawing pattern Air seasoning Drying defects Strength grading

• Different qualities required for different products and applications • Sorting either visually or automatically • Sorting rules are defined in standards (e.g. C16, C24) Further processing

• Grading • • Finger • Gluing (glue laminated timber – “glulam”) • Others (CLT etc.) Engineered wood and structural panels Engineered wood • Products include: – Glulam (glue laminated timber) – Cross-laminated timber (CLT) – (LVL – Kerto®) – Plywood – Oriented Stand Board (OSB) – Others: • Parallel Strand Lumber (PSL) • Laminated Strand Lumber (LSL) • Oriented Strand Lumber (OSL) Glue laminated timber – glulam • Glulam is made by composing a number of individual wood laminations that have been specifically selected and positioned in the glulam , based on their strength characteristics • The “lams” are bonded together with durable, moisture-resistant adhesives, such as PRF – Phenol Resorcinol , RF – Resorcinol Formaldehyde, MF – Melamine Formaldehyde, MUF/MURF – Melamine Urea Formaldehyde/Melamine Urea Resorcinol Formaldehyde • Glulam is available in depths from 15 to 180 cm (or more) and lengths of up to 30 m • To obtain lams of sufficient lengths, individual stress- graded pieces can be finger jointed to form a continuous length Applications

• Glulam allows much flexibility in design – curved beams of long length • Connections: bolts or

Curved glulam used in sports arena in Joensuu, Eastern Finland. Applications

(Source: MetsäWood) Moisture

(Courtesy: Prof. Stefan Winter, TUM)

(High moisture content; inappropriate use – UF!) Cracking

(Courtesy: Prof. Stefan Winter, TUM)

Curved beams – tension perpendicular to the grain Delamination

(Source: TRAC Structural Ltd) Cross-Laminated Timber - CLT

• CLT or Cross-Laminated Timber • Made from stress graded (C24/C16 ) bonded together with alternate layers laid perpendicular to the adjacent layer • Binderholtz panel production http://www.youtube.com/watch?v=bb- TOnLDmoE&feature=related • http://www.youtube.com/watch?v=rLqiwBL28v4 Applications

• Structural applications • Walls, roofs, floors • Massive timber, so advantages in terms of thermal and sound insulation • Thermal mass and moisture buffering effects Bridport , Hackney, London, UK Multi storey CLT construction Applications

source: Storaenso, http://www.clt.info/ CLT project in Ås, Norway

Veneer manufacture and plywood hp

Slicing

Rotary peeling Staylog (semi-peeling) Source: Puuproffa Ry Puu Pro / [online] [referred 19.10.2011] Available: http://www.puuproffa.fi/arkisto/viilut_ja_viilutus.p Plywood has three main applications

Transport Buildings Concrete forming • boats • trucks • aeroplanes • gas tankers -160 °C Laminated veneer lumber - LVL

LVL forms a group of materials/products known as structural . These include, LVL, parallel strand lumber (PSL), laminated strand lumber (LSL) and oriented strand lumber (OSL)

Laminated Veneer Lumber

• LVL has been available commercially for over 30 years • LVL is made from sheets of veneers usually thicker than plywood (3-4 mm) • The veneers are chamfered (~5 cm) at the edges and combined into a continuous mat. In this way the length of the mat is not limited, unlike in plywood

• The exact positioning of joints and their distribution throughout the LVL cross-section is crucial • LVL is produced and used in a variety of different lengths, thicknesses and widths, but one of the main products are structural beams for LVL beam production

Side view

Hot press Pre-press / cold press Lay-up

12 m

From above

Cutting to beams LVL Products

Beams • All veneers are glued parallel to each other. The billet is cut to beams after gluing • Thickness 27 – 75 mm • Width 200 – 600 mm • Length standard max 12 m (customised up to 24 m)

Beams or boards • Most veneers in parallel direction but a few middle layers perpendicular (but not every second like in plywood) • Thickness 21 – 69 mm • Width 600, 900, 1200, 1600, 2500 mm • Length standard max 12 m (customised up to 24 m) Metropol parasol – Sevilla Other structural composite lumber

• Parallel strand lumber: formed from long veneer strands around 25 mm wide, glued together to form long beams with good structural properties • Laminated strand lumber and oriented strand lumber are formed from stands (see later for description of stranding) that are from 15 cm (OSL) to 30 cm (LSL) in length. PSL: structural applications similar to LVL Oriented Strand Board - OSB

• OSB- Oriented Strand Board is an engineered wood product manufactured from strands of wood several centimetres in length and width, but < 1 mm in thickness • Strands are “oriented” in a similar manner to plywood • Bonded with durable waterproof such as phenol formaldehyde (PF) or MDI (methylene diphenyl diisocyanate) • The combination of long, interleaved strands of wood, which are preferentially oriented, give structural properties to the panel Applications • Substitute for plywood: – Good mechanical properties – Low density  good specific mechanical properties – Raw material: good availability; typically lower quality than necessary for plywood; good utilisation of resources • Available in different grades depending on application, e.g. – For dry structural applications, or for dry and humid structural use • Typical applications include: – Construction (components for I beams, sheathing, flooring, internal walls, roof decking) – Interior applications (e.g. shop-fitting) – Industrial applications (agricultural buildings) – Concrete moulding (shuttering) – Oriented strand board (OSB)

(Source: TRADA) Other wood-based panels Particleboard (chipboard)

• Particleboard arose due to scarcity of veneer and the desire to utilise waste materials such as sawdust and planer shavings etc. • Switch to virgin wood for the manufacture of chips so as to give better performance • Switch back to recovered & waste wood with the desire to reduce waste and improve resource efficiency. Now, a significant amount of raw material is waste, or recovered wood • Good, and perhaps only, example of large scale “cascading” Chipboard Applications for particleboard

• Applications: – Examples include: general building work, joinery, upholstered furniture, furniture carcass, veneering, foiling. • Application brochure Medium Density Fibreboard – MDF

• MDF, LDF (Low Density Fibreboard) and HDF (High Density Fibreboard) are dry-formed fibre boards (as distinct from hardboard) • Manufactured from wood fibres that have been produced in a pressurised refining process • Usually bonded with urea formaldehyde (UF) or MDI (methylene diphenyl diisocyanate) resins • Produces a very “fine-scale” and homogeneous product, suitable for a variety of applications • Can be worked, turned and laminated – used for furniture, fittings, partitions, wall-linings, mouldings, flooring and general construction MDF: characteristics

• MDF – Medium Density Fibreboard – Average density: 700 – 800 kgm-3 (typical target 780 kgm-3) – Core density: 600 – 700 kgm-3 – Face density: 1000 – 1100 kgm-3 • Generic term for a range of dry formed fibreboards all produced in a similar way: – HDF: Above 800 kgm-3 – LDF: Below 650 kgm-3 – ULDF: Below 550 kgm-3 • Produced in a range of thicknesses from “thin” (<2 mm) up to 60 mm Medium Density Fibreboard

(Source: Emeri Enterprise Co.,Ltd.) MDF

• First made when fibre produced for wet formed hardboard was processed as particleboard • Good machining and strength properties ensured that MDF rapidly became popular • Technical developments such as “blowline blending” in the 1980’s spurred production • Competition with particleboard manufacture has led to developments in both sectors Outlook: what is the future? Where are the developments in wood products? • To overcome some of wood “deficiencies” – dimensional instability and bio-deterioration – to name but two, there has been much work to develop modified wood • Developing wood products that utilise better its physical (e.g. thermal and moisture buffering capabilities) properties as part of a system • Interface between architecture/design, engineering, design and wood science, in the development of new products and concepts • The role of wood products in climate-change mitigation – balancing the need to protect forests and maximise the positive effects of substituting for non-renewable materials and the carbon storage effect Sneek bridge – the Netherlands: made from modified wood Sneek bridge – element. The bridge is made from Accoya – modified wood Improving energy efficiency with wood

• Hygroscopic (‘hygrothermal mass’) properties of wood can be used to passively lower energy demand through: – Lower direct heating/cooling – Reduced HVAC requirement • Improved indoor air quality • Requires integrated approach encompassing: – Design – Building physics – Materials development Further reading and resources

• General information: – APA: The Engineered Wood Association (http://www.apawood.org/) – Structural Board Association (http://www.osbguide.com/) • Manufacturers: – Kronospan – Egger – Norboard • European Panels Federation (http://www.europeanpanels.eu/) • Wood-based Panels: An introduction for specialists • Wood-based panels international • FAO Yearbook of Forest Products 2017: http://www.fao.org/3/ca5703m/ca5703m.pdf Youtube clips:

Saw mill (short): https://www.youtube.com/watch?v=5at4u6nDZJg mill (long): https://www.youtube.com/watch?v=VxcOz6glk_g