KDA503/335 Timber, its origin and characteristics KDA503/335 Timber, its origin and characteristics Content Characteristics of wood and the requirements of application • Definitions and concepts • Key characteristics of wood • Key requirements of acceptance in applications Key concepts in wood properties and applications www.csaw.utas.edu.au Management for sustainability KDA503/335 Timber, its origin and characteristics KDA503/335 Timber, its origin and characteristics Definitions and concepts Definitions and concepts Wood means: • the hard, fibrous substance lying under the bark in a tree or shrub Taken together, the wood has resource characteristics: • These are the physical properties of the material in the log and the log s form • Developed in response to the tree s evolutionary needs Wood and its characteristics www.csaw.utas.edu.au Timber means: • The range of timber and wood products available to meet society’s needs These have product characteristics largely determined by manipulating the resource characteristics during production www.csaw.utas.edu.au Wood and its characteristics KDA503/335 Timber, its origin and characteristics KDA503/335 Timber, its origin and characteristics Definitions and concepts Timber use in Australia Applications means: • Society’s uses for wood and timber For solid wood products, this is predominantly in building Applications generally have performance requirements that are generally set independently of the resource or material characteristics www.csaw.utas.edu.au • Australia’s timber industry sells: – About 75% of production to the residential building sector, mainly for detached house – About further 10% to the non-residential sector • In short, the timber industry make building materials Wood and its characteristics www.csaw.utas.edu.au Wood and its characteristics www.csaw.utas.edu.au 1! KDA503/335 Timber, its origin and characteristics KDA503/335 Timber, its origin and characteristics Key characteristics of wood and timber? Key requirement of acceptance in applications? • • • • • • • natural renewable variable (anisotropic) hygroscopic bio-degradable democratic versatile Wood and its characteristics www.csaw.utas.edu.au KDA503/335 Timber, its origin and characteristics • regulatory compliant performance • market compliant performance • quality (fit-for-purpose) • available • economic Wood and its characteristics www.csaw.utas.edu.au KDA503/335 Timber, its origin and characteristics Natural Key characteristics of wood www.csaw.utas.edu.au existing in or caused by nature; not made or caused by humankind • Timber is a natural product, drawn from the wood in the trunks of trees • Its character is consistent with the species of tree and the form and growth of the wood in it over time Wood and its characteristics www.csaw.utas.edu.au KDA503/335 Timber, its origin and characteristics KDA503/335 Timber, its origin and characteristics Renewable - conditionally Variable / anisotropic having physical properties that have different values when measured in different directions • Timber’s variability doesn’t stop there It also varies with its original location in the tree, and the tree’s age, source, and species not permanently depleted when used • Renewable resources are: – natural forces or – organic - things that can be harvested and regrown • Most renewable building materials are things grown • They require both time and space to renew themselves • They can be used sustainably if the rate of use is less than the rate of renewal • Wood falls into this group Wood and its characteristics Regrowth in a native forest zone of unchanging wood properties zone of wood property change (age of deposited wood – years) Plantation pine www.csaw.utas.edu.au Wood and its characteristics www.csaw.utas.edu.au 2! KDA503/335 Timber, its origin and characteristics KDA503/335 Timber, its origin and characteristics Hygroscopic Biodegradable the ability to loose or gain moisture content with fluctuations in environmental humidity • When harvested, timber holds a significant volume of water • After seasoning, timber absorbs or loses moisture to remain in equilibrium with the surrounding atmosphere • As it absorbs moisture, it expands As it loses moisture, it shrinks capable of being decomposed by bacteria or other living organisms Wood can be consumed by: • fungi (or decay) when its MC is regularly higher than about 20% • insects and termites • marine organisms Lyctid borer attach in sapwood Hardwood drying in racks Wood and its characteristics www.csaw.utas.edu.au Wood and its characteristics KDA503/335 Timber, its origin and characteristics KDA503/335 Timber, its origin and characteristics Democratic Versatile appealing to or adapted for the benefit of people at large • Timber use isn t necessarily limited by skill or equipment • It is relatively easy to make significant and useful items with wood • Increases in skill can lead to significant increases in output Wood and its characteristics www.csaw.utas.edu.au able to adapt or be adapted to many different functions or activities • Wood is available in many forms – Rounds, sawn, glulam, ply, LVL, fiberboard, etc • Each of these forms can be assembled or combined in many ways Hand-made WW2 igloos www.csaw.utas.edu.au KDA503/335 Timber, its origin and characteristics Wood and its characteristics www.csaw.utas.edu.au KDA503/335 Timber, its origin and characteristics Regulatory compliant performance Key requirements of acceptance in applications www.csaw.utas.edu.au performance level dictated by regulation • In Australia, most timber is used in building, and building is regulated by the National Construction Code (NCC) • This establishes the minimum required performance of materials and their arrangement Wood and its characteristics www.csaw.utas.edu.au 3! KDA503/335 Timber, its origin and characteristics KDA503/335 Timber, its origin and characteristics Regulatory compliant performance Market acceptance • Performance level dictated by desire, impression, traditions or market whim • Requirements may not be linked to functionality or ability to supply • Market criteria can be regional and resilient, leading to considerable specification inertia The important aspects for building design are: • Safety; – including structural and fire safety; • Occupant health; • Occupant amenity; and • Sustainability These are all materialindependent www.csaw.utas.edu.au Wood and its characteristics KDA503/335 Timber, its origin and characteristics KDA503/335 Timber, its origin and characteristics Quality (fit-for-purpose) Available appropriate and of a necessary standard for its intended use • Quality requirements may be: Medium Feature Standard: Increased feature providing a surface with distinct natural appeal Low Feature Select: Straight & even grain with uniform texture www.csaw.utas.edu.au able to be used or obtained; at someone's disposal • Items need to be available to be used • Specifiers and users need to: – defined in a BCAreferenced standard – established by market expectation – Know what is available and what it can – Be confident of regular and supported supply • Confidence in quality can be key acceptance requirement Glulam made to AS 1328 Glued-laminated structural timber Wood and its characteristics High Feature: Distinct with a rich, lively & vibrant surface www.csaw.utas.edu.au Timber stock racks Wood and its characteristics KDA503/335 Timber, its origin and characteristics KDA503/335 Timber, its origin and characteristics Economic Summary www.csaw.utas.edu.au • Timber is natural, renewable, variable (anisotropic), hygroscopic, bio-degradable material • It is democratic, versatile in its use and has a high-strength to weight ratio • To be accepted, timber solutions must provide regulatory and market compliant performance • It can (and needs to) provide quality (fit-forpurpose) solutions, available to the building community, and economic when compared to alternative solutions requiring fewer resources or costing less money • Economic construction supplies the desired level of performance at a system cost comparable to or less than alternatives • Specifiers and users need to: – Know that it is economic – Be confident of competitive pricing Class hotel construction Wood and its characteristics www.csaw.utas.edu.au www.csaw.utas.edu.au 4! KDA503/335 Timber, its origin and characteristics Wood and its characteristics www.csaw.utas.edu.au 5! ... about 20% • insects and termites • marine organisms Lyctid borer attach in sapwood Hardwood drying in racks Wood and its characteristics www.csaw.utas.edu.au Wood and its characteristics KDA503/335... the wood in the trunks of trees • Its character is consistent with the species of tree and the form and growth of the wood in it over time Wood and its characteristics www.csaw.utas.edu.au KDA503/335...KDA503/335 Timber, its origin and characteristics KDA503/335 Timber, its origin and characteristics Key characteristics of wood and timber? Key requirement of acceptance in applications?