accoya® Wood Information Guide V3.9
1 CONTENTS 1 INTRODUCTION
1 Introduction 2
2 Accoya wood About this guide properties 3
3 Transport and storage 13
4 Wood moisture Welcome to the Accoya Wood Information Guide. This document content 15 has been written for professionals wishing to use Accoya wood to 5 Processing 17 create beautiful, reliable and highly durable end products and has 6 Gluing 23 been compiled to offer best practices and recommendations for
7 Contact with the handling and use of Accoya wood. other materials 27
Metals 28 The guide is composed from current Non-metals 30 good practice, without aiming to 8 Weathering 33 be exhaustive and is produced as part of the supporting information 9 Coatings 41 portfolio to the “Accoya wood – 10 Fire behaviour 48 Certificate of Warranty”.
11 Contact 51 In addition, Accsys runs an approved Manufacturer Training Programme and we would This is version 3.9 of the Accoya encourage all manufacturers Wood Information Guide. To planning to use Accoya to confirm this is the most up to participate in this training date version and check for other programme. potentially useful information please check our website: Should you require any further www.accoya.com information or guidance, please contact your local sales representative or send an email to: [email protected]
AccoyaAccoya® Wood® Wood Information Information Guide Guide | |V3.9 V3.9 || 2020 2
CONTENTS 2 Accoya wood properties
1 Introduction 2 Accoya wood has been produced commercially since 2007, 2 Accoya wood initially in small volumes, then growing as manufacturers properties 3 and architects gained an appreciation for its characteristics. 3 Transport and storage 13 Adoption has accelerated to the extent that almost 4 Wood moisture 350,000m3 has been used around the world for a range of content 15 exterior applications. Accoya represents a major development 5 Processing 17 in wood technology that has made the consistent supply 6 Gluing 23 of durable, dimensionally stable and reliable wood from 7 Contact with a sustainable source possible. other materials 27
Metals 28 Accoya wood’s performance KEY PROPERTIES & BENEFITS Non-metals 30 credentials have been extensively researched and repeatedly 8 Weathering 33 demonstrated. Accoya wood has HIGHLY HIGHLY IDE AL FOR EXCELLENT 9 Coatings 41 properties that exceed those of STABLE DURABLE COATING MACHINABILITY 10 Fire behaviour 48 the world’s best woods yet it is manufactured by modifying wood 11 Contact 51 sourced from well-managed NON BAREFOOT STRUCTUR ALLY SUSTAINABLY sustainable forests through TOXIC FRIENDLY CERTIFIED SOURCED acetylation without the introduction of toxins.
LOW Accoya performance testing LOW CO INSECT 100% 2 ENVIRONMENTAL EMISSIONS RESISTANT RECYCLABLE is reviewed in detail in the IMPACT Performance Testing Summary Brochure.
Accoya® Wood Information Guide | V3.9 | 2020 3 CONTENTS 2 Accoya wood properties technical data
1 Introduction 2 2.1 Appearance Property Test method Value 2 Accoya wood Accoya wood is supplied as rough properties 3 Durability EN 113 (EN84), ENV 807 and EN 252 Class 1* sawn and finger jointed in various AS5604 Class 1 3 Transport and storage 13 sizes and grades. Density 65% RH, 20°C (70oF) 515 ± 80 kg/m³ 4 Wood moisture Detailed information on available 32 lb /ft3 ± 5 lb /ft3 content 15 dimensions is available at: Shrinkage (avg) ISO 4469 5 Processing 17 www.accoya.com Wet to 65% RH, 20°C Radial 0.4% 6 Gluing 23 Details of end product Tangential 0.8% 7 Contact with manufacturers and Accoya Wet to Oven Dry Radial 0.7% other materials 27 stocking distributors can be Tangential 1.5% Metals 28 found at: o Non-metals 30 www.accoya.com/where-to-buy Equilibrium moisture 65% RH, 20°C (70 F) 3 – 5% content 8 Weathering 33 2.2 Material properties Thermal conductivity EN 12667 0.12 W/m K 9 Coatings 41 This table shows the average ASTM C-177 0.10 W/m K
10 Fire behaviour 48 properties of Accoya wood made Janka hardness ASTM D143 Side 4,100 N from radiata pine and has been End 6,600 N 11 Contact 51 compiled using data from official test Brinell hardness EN 1534 2.4 kgf/mm2 reports from independent institutes 24.0 N/mm2 in Europe, USA, Australia and New Zealand. For further information on a wider range of testing information please see the Accoya Performance *What is Class 1 Durability? Wood resistance to rot and decay is measured on a scale of 1 to 5 with 1 being the most durable. Provisional durability class can be determined in a 16 week petri dish test (EN113). Official Testing Summary brochure, durability class can only be determined from long term, real life durability testing (EN252). Results show many available at: www.accoya.com wood types can under perform in EN252. Accoya achieves durability class 1 in both EN113 and EN252. As there is no durability class system in the USA, Accoya has been tested alongside other durable woods including FEQ Burmese teak, sapele mahogany and western red cedar. This five year ground contact test in accordance with AWPA E9 standards was run by an independent lab at their Gainesville Florida test site. Accoya outperformed all tested durable woods. Please see the Accoya Performance Testing Summary brochure available at www.accoya.com for more details.
Accoya® Wood Information Guide | V3.9 | 2020 4 CONTENTS 2 Accoya wood properties technical data
1 Introduction 2 2.3 Mechanical properties Characteristic values for strength class: Property strength [N/mm2] 2 Accoya wood The Accoya acetylation process C16 (A2 Grade) C22 (A1 grade) properties 3 improves hardness and compression Bending fm,k 16 22 3 Transport and storage 13 strength significantly. Accoya is Tension approved for a general building use 4 Wood moisture Parallel to grain f 10 13 content 15 by the German Institute for Building t,0,k Technology (DIBt) for load bearing Perpendicular f 0,5 0,5 5 Processing 17 structural applications. This DIBt t,90,k 6 Gluing 23 approval qualifies the strength class of Compression A1 and A2 solid Accoya timber, based Parallel to grain f 17 20 7 Contact with c,0,k other materials 27 on the European strength class system Perpendicular f 2,2 2,4 of C classes (EN338). c,90,k Metals 28
Shear fv,k 1,8 2,4 Non-metals 30 Accoya A1 quality is classified as C22 strength grade and Accoya Stiffness [kN/mm2] 8 Weathering 33 A2 quality is classified as C16 (see Mean MOE parallel E 8 10 9 Coatings 41 adjacent table). The approval applies 0,mean to Accoya wood in the widths 100mm 5% MOE parallel E 5,4 6,7 10 Fire behaviour 48 0,05 to 250mm with a thickness of 25mm Mean MOE perpendicular E 0,27 0,33 11 Contact 51 to 100mm, and can be used both flat 90, mean Mean shear modulus G 0,5 0,63 and upright. C22 and C16 strength mean classes are common for structural Density [kg/m3] timbers produced from spruce and pine Density 0 310 340 in the UK and Mainland Europe. k
Mean density P 370 410 cont on page 6... mean
NB: Characteristic values are used in structural grade classification and stated as the average result minus two standard deviation.
Accoya® Wood Information Guide | V3.9 | 2020 5 CONTENTS 2 Accoya wood properties technical data
1 Introduction 2 The standard wood design safety To achieve design values, the • Maximum residual acetyl 2 Accoya wood factors (kdef, kmod) as given in characteristic values are divided compounds content of individual properties 3 EN 1995-1 were determined in by a material factor and multiplied samples ≤ 1.8% the DIBt test programme to be by climate, load duration and beam 3 Transport and storage 13 appropriate and may be used. height modification factors (EN Although levels are controlled, freshly cut or planed Accoya wood 4 Wood moisture Accoya wood may be fastened 1995-1-1). content 15 to a timber sub-frame with nails, may have a slight vinegar-like odour. Some of the residual acetic acid 5 Processing 17 clamps, wood screws, dowels and Accoya wood in B grade is not bolts. For non pre-drilled holes, the strength graded in any way and will dissolve in water absorbed by 6 Gluing 23 minimum spacing distance and is not included in the scope of Accoya wood. In wet circumstances, the Accoya wood will therefore have 7 Contact with edge/end clearance (EN 1995-1- the DIBt work programme or other materials 27 1, table 8.2) should be in line with certification. a pH in the range of 4 – 5.5. At these levels a wide range of coatings, Metals 28 wood with a density between 420 glues, fixings and other products can Non-metals 30 and 500kg/m³. 2.5 Residual acid be used with Accoya. Please see the Many durable wood species 8 Weathering 33 2.4 Property characteristic applicable sections for each in this naturally contain a quantity of guide. 9 Coatings 41 values for strength class acid. Accoya wood contains a small 10 Fire behaviour 48 The strength class determining amount of residual acetic acid from properties of timber are strength, the acetylation process. Since acids 11 Contact 51 stiffness and density. The values can create compatibility issues mentioned in EN 338 are so- with coatings, glues and fixtures, called characteristic values of the the acetic acid content is measured material properties. For safety as part of the quality control reasons, these are threshold values procedures of Accoya wood and ® that at least 95% of the pieces within our KOMO approved Quality of timber will meet. Hence these System. Individual batches are only characteristic values are lower than released for sale if the residual acetic the average mechanical property acid level is within specification: values commonly reported for QUALITY CONTROL SAMPLING • Average residual acetyl timber species. Average mechanical compounds content of samples Note: Accoya carries out destructive testing property values should not be used on the core of the wood from every batch. ≤ 1.0% (mass/mass oven dry for structural calculations. wood)
Accoya® Wood Information Guide | V3.9 | 2020 6 CONTENTS 2 Accoya wood properties technical data
1 Introduction 2 2.6 Acetylation and All audits involve factory visits and destructive testing by the 2 Accoya wood Durability properties 3 certification body. Thus consistent Accoya wood is modified uniformly quality and performance in 3 Transport and storage 13 through the cross section, not just accordance with set standards 4 Wood moisture at the surface. The entire cell wall is assured. Accoya wood always content 15 structure is altered to the effect meets the requirements of Durability 5 Processing 17 that it repels moisture, greatly Class 1 for Use Classes 1-4 in reducing the capacity for bound accordance with EN 350-1 & EN 6 Gluing 23 water and therefore swelling and 335-1. See 2.8 for more information. 7 Contact with shrinkage. This bulking up of the other materials 27 structure in turn gives it excellent Accoya wood has evidenced improved performance in multiple Metals 28 protection and sustained strength even when wet. Puretests s andc in iencenumerous regions Non-metals 30 rom non dura e ood against to Accoya various® t rou fungal, acety ation termite 8 Weathering 33 The wood structure is modified and other insect species in many through the process to give it its locations around the world. 9 Coatings 41 Hydroxyl groups unique stable, durable and inert ydroxyls are hydrophilic attract water , Non durable Distillation of 10 Fire behaviour 48 properties with high thermal causing cellulose to swell and shrink when wood species by-products subsequently dried and become more insulation that all helps to deliversusceptible to attack by biological organisms ACETYLATION PROCESS 11 Contact 51 Acetylation long term performance. Accoya Water returned to Acetyl groups ground water system wood performs in the harshest Woodof cellulose contains a small environments and even lends itselfnumber of naturally occurring acetyl groups which are hydrophobic repel Water Acetic anhydride and acetic acid reused to being coated black. water). There are an insufficient number of acetyls in natural wood to provide durable, stable performance Naturally Modification quality of each batch occurring acetyl produced is validated to the Acetylation Free hydroxyls Acetylated wood eaction of wood with acetic anhydride core of the wood by a range of concentrated acetic acid at high temperature Cellulose to precisely increase the level of moisture sophisticated and proven tests that Acetic anhydride resistant acetyl groups take place in Accsys’ laboratories. This quality control approach is Acetyl group independently audited on a regular basis by organisations from USA, France and the Netherlands.
Accoya® Wood Information Guide | V3.9 | 2020 7 CONTENTS 2 Accoya wood properties technical data
1 Introduction 2 2.7 Classification of natural established for that region. Testing 2.8 Durability use classes on the US Pacific coast is ongoing 2 Accoya wood wood durability to wood- The EN 335 gives general definitions properties 3 with no attack after 4 years. destroying fungi of use classes for different service 3 Transport and storage 13 Accoya wood is warranted for situations and is relevant to solid Accoya wood is resistant to salt 50 years above ground, 25 years timber and wood-based products. 4 Wood moisture and can be used around saltwater content 15 in ground contact and freshwater Accoya wood is suitable for use (for instance as marina decking immersion. A copy of the warranty classes 1-4 defined in this standard. 5 Processing 17 and boardwalks). Accoya is used is available in the warranties in permanent salt water immersion 6 Gluing 23 section on www.accoya.com cont on page 9... but is not warranted for resistance 7 Contact with against attack from marine other materials 27 organisms. However, Accoya wood Use class Conditions of use Wetting Wood moisture content Metals 28 has been tested in the waters of 1 No contact with the ground, Permanently dry Permanently dry < 20% Non-metals 30 Northern Europe for more than a sheltered and dry decade without attack and a 10 8 Weathering 33 year service life position has been 2 No contact with the ground, sheltered Occasionally exposed to Incidental short term wood 9 Coatings 41 with little chance of becoming wet moisture MC >20%
10 Fire behaviour 48 Durability class Description 3 No contact with the ground, not Regularly exposed to Regular, short-term sheltered in all weather conditions moisture exposure >20% 11 Contact 51 1 Very Durable 4 In contact with the ground Permanently exposed or in Permanent exposure to 2 Durable contact with fresh water water with wood MC >20%
3 Moderately Durable 5 In contact with salt or salt water Permanently exposed to Permanent exposure >20% splash zones¹ brackish water to salt water 4 Slightly Durable ¹ The Accoya warranty covers use in salt water splash zones, for instance Marina decking. Accoya is suitable in full salt water 5 Not Durable immersion though the warranty does not cover attack by marine organisms.
Accoya® Wood Information Guide | V3.9 | 2020 8 CONTENTS 2 Accoya wood properties technical data
1 Introduction 2 The AWPA standard U-1 describes 2 Accoya wood use category designations and properties 3 typical applications. Accoya wood is suitable for Use Classes UC1 – 3 Transport and storage 13 UC4A in this standard. 4 Wood moisture content 15 Use category Service conditions Use environment Typical application 5 Processing 17 UC1 Interior, Interior construction Above Ground, Dry Continuously protected from weather or Interior construction and furnishings 6 Gluing 23 Dry other sources of moisture
7 Contact with UC2 Interior, Interior construction Above Ground, Damp Protected from weather, but may be Interior construction, sill plates other materials 27 Damp subject to sources of moisture Metals 28 UC3A Above Ground, Exterior construction Above Ground, Coated & rapid Exposed to all weather cycles, including Coated millwork, siding, trim Non-metals 30 Protected water runoff intermittent wetting
8 Weathering 33 UC3B Above Ground, Exterior construction Above Ground, Uncoated or poor Exposed to all weather cycles including Decking, railings, joists and beams Exposed water run-off. Excludes above ground applications with intermittent wetting but with suffcient air for decks and freshwater docks, fence 9 Coatings 41 ground contact type hazards. circulation so wood can readily dry pickets, uncoated millwork 10 Fire behaviour 48 UC4A Ground Contact, Ground Contact or Fresh Water Non-critical components Exposed to all weather cycles, including Sawn fence, deck and guardrail 11 Contact 51 General use (Includes above ground applications with ground contact prolonged wetting posts, joists and beams for decks and type hazards or that are critical or hard to replace) freshwater docks
Accoya® Wood Information Guide | V3.9 | 2020 9 CONTENTS 2 Accoya wood properties technical data
1 Introduction 2 2.9 Dimensional stability MOVEMENT LEVELS FROM GREEN TO OVEN DRY CONDITION 2 Accoya wood comparison Typical characteristic values Wetting Warranty properties 3 Species 5 Accoya wood exhibits superior Radial Tangential Maximum 3 Transport and storage 13 dimensional stability compared to Accoya 0.8% 1.6% 2.5% 4 Wood moisture other naturally durable species, in (Acetylated radiata pine)4 content 15 both radial as well as tangential Douglas fir¹ 4.8% 7.6% - 5 Processing 17 direction (table adjacent). Ipe1 6.6% 8.0% - 6 Gluing 23 This provides short and long term benefit. In the short term, Accoya Kebony3 1.4% 2.5% - 7 Contact with remains stable during processing. other materials 27 Meranti¹ 3.0% 6.6% - In the medium term, joinery remains Metals 28 stable and resists movement when Merbau¹ 2.7% 4.6% - Non-metals 30 environmental conditions fluctuate Radiata pine4 3.4% 7.9% - 8 Weathering 33 after installation. Sapele¹ 4.6% 7.4% - 9 Coatings 41 Further on in service, deck boards remain flat, stable around fixings Siberian larch2 4.0% 9.0% - 10 Fire behaviour 48 and with practically no splinters. Teak (Burmese FEQ)¹ 2.5% 5.8% - 11 Contact 51 Cladding boards and louvres retain their flush and smooth lines and Thermally modified ash3 2.3% 4.0% - coated products benefit from the Western red cedar1 2.4% 5.0% - board stability placing less stress on the coating and leading to ¹ Wood Handbook, USDA Forest Products Laboratory. Green to Oven Dry measurements requiring earlier maintenance. ² Rosenfeld Kidson – Species Fact Sheet Larix sibirica 3 Internal testing Accsys 4 Dimensional stability of Accoya wood under different moisture conditions, SHR Report 6.322 5 Accoya wood - Certificate of Warranty
Accoya® Wood Information Guide | V3.9 | 2020 10 CONTENTS 2 Accoya wood properties technical data
1 Introduction 2 2.10 Expansion and Species Characteristic values Wetting Warranty 2 Accoya wood Contraction Radial sawn (inch/mm) Tangential sawn (inch/mm) Maximum (inch/mm) properties 3 The adjacent table shows average Accoya 0.04 / 1.0 0.09 / 2.2 0.14 / 3.6 3 Transport and storage 13 movement from green (soaked) to (Acetylated radiata pine) 4 Wood moisture oven dry boards of 5 3/4” or 145mm Douglas fir 0.27 / 7.0 0.43 / 11.0 - content 15 width. Accoya wood’s enhanced Ipe 0.38 / 9.6 0.46 / 11.6 - 5 Processing 17 dimensional stability often allows for: Kebony 0.08 / 2.0 0.14 / 3.6 - 6 Gluing 23 • Greater widths on cladding Meranti 0.17 / 4.4 0.38 / 9.6 - 7 Contact with other materials 27 without excessive cupping Merbau 0.15 / 3.9 0.26 / 6.7 - Metals 28 • Narrower gaps between Radiata pine 0.19 / 4.9 0.45 / 11.5 - Non-metals 30 deck boards Sapele 0.25 / 6.4 0.42 / 10.7 - 8 Weathering 33 • Gaps between deck boards Siberian larch 0.23 / 5.8 0.51 / 13.1 - 9 Coatings 41 not closing up when soaked in winter months. Teak (Burmese FEQ) 0.14 / 3.6 0.33 / 8.4 - 10 Fire behaviour 48 It is however still necessary 11 Contact 51 Thermally modified ash 0.13 / 3.3 0.23 / 5.8 - to take into account the expected expansion in installing Western red cedar 0.14 / 3.5 0.29 / 7.3 - Accoya products.
Tangential or flat sawn
Quarter or radial sawn
Accoya® Wood Information Guide | V3.9 | 2020 11 CONTENTS 2 Accoya wood properties technical data
1 Introduction 2 2.11 Design and allowance 2.12 Slip resistance • If decking boards are coated, stains are more suitable in 2 Accoya wood for expansion The slip resistance of all wooden properties 3 terms of slip resistance than Accoya wood is extremely (decking) boards and many other oils, although that is heavily 3 Transport and storage 13 dimensionally stable but this does materials depends on factors such dependent on the particular as degree of weathering, surface 4 Wood moisture not mean it is completely inert. coating system and the cleaning content 15 Changes in humidity can cause profiling, coating, wetness of the maintenance. boards and maintenance – i.e. the 5 Processing 17 slight changes in its dimensions and these should be taken into account presence of a biofilm of bacteria, • Smooth surfaces have a higher 6 Gluing 23 for product design and installation. fungi and algae. Test methods coefficient of sliding friction vary greatly across the world (even compared to grooved surfaces, 7 Contact with In extreme conditions the movement other materials 27 tolerances in section 2.10 should throughout Europe) and only a few and are therefore less slippery. be allowed. Installation guides countries have official requirements Metals 28 Generally speaking, the results that cover dimensional stability covering the slip resistance of Non-metals 30 for Accoya wood when tested by considerations for common wood flooring surfaces. these methods are comparable to 8 Weathering 33 products should be more than The most common slip resistance unmodified wood species with the sufficient for Accoya wood. 9 Coatings 41 measures express results on new same surface specifics (including 10 Fire behaviour 48 The Accoya Lumber Grade Guide boards in wet and dry condition: dimensions, profile details, surface lists the maximum allowable finish and the presence of a 11 Contact 51 • Most dry timber decking boards shape tolerance for delivered lubricant and/or biofilm). can be considered as sufficiently sawn Accoya planks. Accoya’s slip resistant. dimensional stability does ensure it can resist distortion in all but • When wet, the slip resistance the most severe applications. of decking boards is decreased Traditional approaches such by approximately 35% as engineered component in comparison with dry development may not be required circumstances and are therefore but will improve performance in considered more slippery. particularly severe applications Designing for easy water run- such as oversize doors coated off and ventilation beneath the black. For more specific information boards are therefore important. on dimensional stability values and A shaded location will also affect distortion risk, please contact your the time for the boards to dry out. local Accsys sales representative. Accoya® Wood Information Guide | V3.9 | 2020 12 CONTENTS 3 TRANSPORT AND STORAGE
1 Introduction 2 3.1 Accoya wood packages 3.2 Transport 2 Accoya wood All Accoya wood undergoes In order to prevent damage, properties 3 inspection before leaving the products made of Accoya should 3 Transport and storage 13 plant. Accoya wood is strapped be carefully transported. Protection 4 Wood moisture with banding straps into standard of joints, frame corners, projecting content 15 labelled packages, each with a profiles (cills) and hardware is unique number. The packages are especially important. To prevent 5 Processing 17 covered with paper wrapping for water uptake during transport, 6 Gluing 23 dust protection – the wrapping storage and at the building site, is not water resistant. Accsys it is strongly recommended that 7 Contact with other materials 27 supplies Accoya wood in rough Accoya and Accoya products are sawn dimensions in dry condition stored under cover or covered Metals 28 and ready for use (wood moisture in suitable, breathable and Non-metals 30 content <4% on average). weatherproof material. 3.1 PACKAGING 8 Weathering 33 The recipient at the delivery 9 Coatings 41 address must ensure that Accoya 10 Fire behaviour 48 wood packages are unloaded carefully and any damage is 11 Contact 51 recorded at point of unloading.
3.4 ACCOYA BUNDLE LABEL INCLUDING DIMENSION, GRADE, LENGTH, QUANTITY AND BATCH NUMBER
Accoya® Wood Information Guide | V3.9 | 2020 13 CONTENTS 3 TRANSPORT AND STORAGE
1 Introduction 2 3.3 Storage As with other wood species, with each board is printed at one storage at the building site should end of the board’s sawn surface. 2 Accoya wood Accoya wood that needs further properties 3 be a minimum of 10cm above processing, gluing or coating concrete flooring and 30cm above Batch number should be recorded 3 Transport and storage 13 should be carefully stored (unpaved) ground. Additional as part of a manufacturer’s (preferably horizontally), in closed 4 Wood moisture protection from rain is strongly production record-keeping per content 15 and well ventilated sheds to recommended but sufficient job. In case of doubt, Accsys will prevent water/moisture uptake. verify the product’s authenticity. 5 Processing 17 ventilation underneath the sheets is Please see section 4 for more required to prevent surface moulds. In addition, Accoya wood can 6 Gluing 23 details on determining whether generally be traced through the Accoya wood has absorbed When storing bundles of (rough) supply channel by its packaging 7 Contact with other materials 27 excess water and for drying Accoya please note bearers need number. It is therefore imperative considerations. to be at least every 1.2m and in to retain all relevant documents. Metals 28 line with stickers in the bundle. This tracking is also needed if Non-metals 30 Accoya wood can be manufactured Any bundles stored on top of each you intend to offer products with into parts, even with long intervals 8 Weathering 33 other should have the bearers sustainable wood certification such before assembly. Unlike many and stickers aligned to ensure the as FSC. The packaging number 9 Coatings 41 wood species, changes in size, transfer of pressure does not cause is to be quoted in the case of any straightness and shape of parts 10 Fire behaviour 48 undue stress on the boards. Storing queries, complaints or warranty due to dimensional stability issues bundles of processed products claims. 11 Contact 51 are minimal, and thus it is typically (e.g. cladding boards) should be possible to pre-manufacture days’ horizontally on bearers at least 3.5 Information transfer worth of assembly versus having to every 800mm, with a minimum It is important to inform the keep tight schedules between time of 3. Again, bundles on top of owner and third parties performing of machining and assembly. Direct each other should have the installation that Accoya has been exposure to water and changing bearers aligned. climate (temperature and relative used in the manufacture of the (end) product. Sections of this humidity) should still be avoided. 3.4 Traceability Note that all freshly machined guide, such as proper storage surfaces have the best surface Accoya wood is primarily at the building site, appropriate energy and give best coating identified by its packaging labels, fasteners and fixtures to use and bonding results. which feature the Accoya logos. for final installation and related Additionally the batch number considerations, should be and grade (A1 and A2) associated communicated.
Accoya® Wood Information Guide | V3.9 | 2020 14 CONTENTS 4 WOOD MOISTURE CONTENT
1 Introduction 2 Wood releases moisture in dry climates and absorbs moisture 2 Accoya wood in humid conditions. The moisture within wood takes two properties 3 forms; “free water”, which is contained in the cell cavities 3 Transport and storage 13 (or lumen), and “bound water”, which is contained in the 4 Wood moisture cell wall matrix. content 15
5 Processing 17 While Accoya wood in any It is therefore also important that in a sustained climate of 95% condition will have minimal buildings that introduce high levels relative humidity/20oC (70oF). 6 Gluing 23 bound water, which is what of water via the building materials As such, overseas shipping 7 Contact with accounts for many of its superior require careful management and regional/seasonal climate other materials 27 properties, it can still contain free to maintain a suitable climatic fluctuations can have an influence Metals 28 water (for example as a result environment and equilibrium. on moisture content. Non-metals 30 of not using effective end grain sealer in window manufacture or 4.1 Definition Typically, moisture gain or loss due 8 Weathering 33 in horizontal application). Final to fluctuating humidity occurs in In line with normal convention, product quality can be harmed by the cell walls and is bound. More 9 Coatings 41 wood moisture content, as free water during manufacture; excessive moisture gain through expressed in this guide, is the mass 10 Fire behaviour 48 it is therefore essential that the soaking quickly fills the cell wall of the water contained in wood, moisture content of the wood absorption limit and is deposited in 11 Contact 51 expressed as a percentage of the is determined prior to further the cell wall cavity (fibre lumen) as mass of absolutely dry wood. processing such as gluing and free water. coating if there is a suspicion that 4.2 Wood moisture content the boards have become wet prior Equilibrium moisture content at fluctuating relative humidity levels to the manufacturing step. Accsys dispatches Accoya wood in dry condition (wood moisture EMC during adsorption and desorption sequence [%]
Cell cavity content <4% on average). 0 25 35 50 65 80 95 containing 30 ‘free water’ This allows Accoya wood to
be processed into products for ® 20 Accoya – adsorption Cell wall application directly after being Accoya® – desorption containing delivered. 10 adiata pine – adsorption ‘bound water’ adiata pine – desorption
Accoya wood moisture content 0 FREE WATER ILLUSTRATION increases to between 7 and 9%
Accoya® Wood Information Guide | V3.9 | 2020 15 CONTENTS 4 WOOD MOISTURE CONTENT
1 Introduction 2 4.3 Measuring for 4.4 Water absorption 2 Accoya wood excess water properties properties 3 The typical wood moisture End grain water absorption of 3 Transport and storage 13 content of Accoya wood cannot Accoya is particularly high due 4 Wood moisture be measured accurately with to the cell structure. Liquid water content 15 standard moisture meters prior to absorption can be deep and 5 Processing 17 processing because its moisture Accoya takes longer to dry out content is below the measuring than many species. If there has 6 Gluing 23 range. However, standard moisture been a risk of sustained wetting 7 Contact with meters may be used to determine prior to product manufacture, other materials 27 whether Accoya wood has an measurements for possible excess Metals 28 excess of “free water”. water should therefore be to the core of boards. Extra care should Non-metals 30 For pin-type (electric) moisture be taken in storage and effectively 8 Weathering 33 meters an Accoya setting is sealing end grain of coated wood, not available. For indicative 9 Coatings 41 which is discussed further in measurements either radiata pine section 9 on coatings. 10 Fire behaviour 48 or another pine setting may be chosen. For capacitive meters a Good design and fit for purpose 11 Contact 51 density setting of around 510 kg/ practices should be adopted in m3 should be used. A measurement Accoya use and application. The showing a moisture content of 8% potential for water ingress should or more may indicate the presence be considered and addressed of “free water” and the wood by employing good design and should be allowed to dry before assembly practices appropriate further processing, gluing to the location of the installation, or coating. such as should be employed when working with any timber. For PIN METER example, avoid water traps such as horizontal surfaces, allow plenty of ventilation for cladding and decking and use a protective coating for external windows and doors.
Accoya® Wood Information Guide | V3.9 | 2020 16 CONTENTS 5 PROCESSING
1 Introduction 2 Processing of Accoya wood does not affect its unique 2 Accoya wood properties, such as durability and dimensional stability, properties 3 as the wood is modified throughout the cross section to 3 Transport and storage 13 a uniform level and these properties are not leachable. 4 Wood moisture content 15
5 Processing 17 Accoya is easy to process and against a wide range of standards can be compared, in general, to a in many regions and have shown 6 Gluing 23 harder softwood species such as no issues. 7 Contact with yellow poplar (tulip wood). Accoya other materials 27 typically runs better through As with other wood species with higher acid levels (for example Metals 28 machines than softwoods such as Douglas fir, cedar and larch and oak and WRC), caution should Non-metals 30 much better than most durable be taken to prevent long term 8 Weathering 33 tropical hardwoods. exposure of wood machinery and exhaust systems to high moisture 9 Coatings 41 Special tools are not required for levels combined with dust and 10 Fire behaviour 48 standard operations such as cross shavings to prevent corrosion. cutting, ripping, planing, routing or Prior to machining the wood, 11 Contact 51 drilling. Depending on the required moisture content should be coating, sanding before finishing checked (section 4). A moisture is often not required, due to the content reading below 8% particularly smooth surfaces indicates suitability for processing. of Accoya after machining and Also note that the tracking number subsequent resistance to grain printed on the Accoya sawn boards raising from moisture pick up. (see section 3.4) should be recorded against the job sheet It should be noted that a light prior to processing. vinegar-like odour may become apparent when Accoya wood is processed. With proper suction / ventilation this can be reduced to a minimum. Health and safety tests have been successfully performed Accoya® Wood Information Guide | V3.9 | 2020 17 CONTENTS 5 PROCESSING
1 Introduction 2 5.1 Visual grades factors such as the amount of resin in particular logs and boards. 2 Accoya wood Accoya wood is a high properties 3 Individual boards are spaced with performance, all-natural solid small battens, typically leaving a 3 Transport and storage 13 wood and as such offers the lighter mark where they meet the beauty, versatility and charm of 4 Wood moisture board – known as sticker marks. content 15 the original wood species. Accoya is available in a range of different The acetylation process can 5 Processing 17 qualities. Consistent with the grade result in discoloration generally 6 Gluing 23 purchased, the timber may show up to 6mm in depth with sticker certain visual defects after being marks up to a similar depth, and 7 Contact with other materials 27 processed, which are not visible due to natural wood variation, on the sawn boards’ surfaces as occasionally deeper. Removal Metals 28 graded. The boards are sold on of this surface discolouration is Non-metals 30 the basis of defects visible on the not required when using opaque 8 Weathering 33 sawn boards. Defects arising after coatings or for parts that will processing might include internal not be visible. Discolouration 9 Coatings 41 DISCOLOURATION: ROUGH BOARD, AFTER SURFACING 3MM cracks, internal resin pockets and and sticker marks visible on AND AFTER SURFACING 6MM FROM ROUGH 10 Fire behaviour 48 movement. For more information surfaced, non coated product on grade names and definitions for applications or translucent stain 11 Contact 51 Accoya radiata pine, please see coated applications will fade over the Lumber Grading Specifications, the course of days and months 6mm available on www.accoya.com. proportionate to the level of UV 25mm exposure. Discolouration can be 18mm
5.2 Discolouration more apparent once the wood is 1mm Accoya boards have a discoloured wet or translucent coated. zone around the perimeter. Wood As an example the drawing to the resins move from the core of the right shows a 18mm thick cladding wood to outer zone during kiln board produced from 25mm drying. These resins are then Accoya by setting the bottom knife solubilised and darkened during to remove 1mm from the back side the acetylation process which and 6mm (plus any over thickness) causes discolouration in this from the top side. outer zone. The level and depth of discolouration depends on Accoya® Wood Information Guide | V3.9 | 2020 18 CONTENTS 5 PROCESSING
1 Introduction 2 5.3 Changed properties • Accoya wood has an outer zone marks during processing and to of discolouration which should avoid contact with products that 2 Accoya wood Due to the acetylation process, properties 3 be considered in profiling. will contaminate the surface, such a number of wood properties Please see section 5.2. as oil, lubricant or rust, particularly 3 Transport and storage 13 have been altered that are of if the wood is to be coated or glued, importance for machining 4 Wood moisture • Please reference section 5.2 as this can affect appearance content 15 of Accoya wood: on discolouration when setting and compatibility. up for profiling to achieve the 5 Processing 17 • The Janka and Brinell hardness best result. Accoya wood has a low wood 6 Gluing 23 increases from the original wood moisture content and shavings used to produce Accoya (refer to For further guidance and detailed are fine and may become 7 Contact with section 2 for ratings). As a guide, information please contact your other materials 27 electrostatically loaded due to Accoya wood is more comparable local Accsys sales representative friction caused from machining. Metals 28 in machining to species like yellow and consider arranging an Accoya This can lead to impressions of Non-metals 30 poplar/tulip wood. Manufacturer Training Programme shavings if the exhaust system has session at your workshop. 8 Weathering 33 • Since the moisture content too low capacity and/or a large section of the wood is profiled 9 Coatings 41 of Accoya is generally below 5.4 Sawing, planing 5%, this can make some of the in one run. Solutions include 10 Fire behaviour 48 and profiling material a little more brittle than increasing the blade rotation velocity (rpm), improving the 11 Contact 51 unacetylated wood. Accoya wood is easy to cut in any exhaust/extraction system, using direction. Skilful sawing will give a antifriction lubricants or otherwise • Density has increased (avg. smooth appearance with very few reducing static energy at the rotary 515 kg/m³) as compared to flaws. Standard techniques such blades. unacetylated radiata pine. as using back boards can be used • Internal stress within the wood when very fine results are desired. Despite Accoya wood’s improved properties, boards may harbour is reduced by the process. This Accoya wood is easily planed tension and flaws internally, similar eases the process of ‘working’ to a very smooth surface finish. to other comparable wood species. the timber compared to Special tools are not required. It untreated radiata pine and many is important to avoid machining other wood types used cont on page 20... for exterior use.
Accoya® Wood Information Guide | V3.9 | 2020 19 CONTENTS 5 PROCESSING
1 Introduction 2 These typical wood guidelines also 2 Accoya wood apply to Accoya wood: properties 3 • Similar to other wood species, 3 Transport and storage 13 re-sawing, ripping or heavily 4 Wood moisture planing Accoya boards can content 15 reveal stresses created during drying and processing. Ripping 5 Processing 17 to create thinner boards is not 6 Gluing 23 recommended with boards having an original thicknesses 7 Contact with other materials 27 of more than 38mm and should be approached cautiously in Metals 28 all instances. Please consult Non-metals 30 your Accsys sales manager for 8 Weathering 33 guidance on specific situations or variations. • When planing Accoya wood • To attain the highest surface 9 Coatings 41 ensure that knives are aligned finish quality on Accoya wood, 10 Fire behaviour 48 • Checks and resin pockets can correctly and are sharp. If it is best you contact your appear, especially after heavy working with multiple species machine and tooling provider for 11 Contact 51 planing or re-sawing. and knives that are rapidly optimum feed and cutter speed dulled, it is advised to machine settings advice. When machining • Although the Accoya wood Accoya wood first before the Accoya wood for the first time process relieves a lot of the other species. it is best to produce some test stresses that can cause runs to establish the appropriate distortion, normal selection • Due to the smooth Accoya parameters for a particular processes still apply for reducing surface after planing all machine and set up. the chances of change beyond cutter marks may be more acceptable limits. Thus, for defined and show through the • The in-feed rollers can be critical parts and for deep coating. Special care is needed aluminium but the out feed milling, wood pieces with and feed speeds should be rollers of equipment should pronounced slope of grain, adjusted accordingly. A feed preferably be rubber to prevent irregular growth rings and speed comparable to durable surface damage. similar issues should be avoided hardwoods is common while or used in more tolerant areas. experience is developed. Accoya® Wood Information Guide | V3.9 | 2020 20 CONTENTS 5 PROCESSING
1 Introduction 2 5.5 Drilling 5.6 Sanding 2 Accoya wood Accoya wood drills in a manner Sanding Accoya wood presents no properties 3 and quality consistent with most challenges. Experience from Accsys 3 Transport and storage 13 softwoods. For deep drilling, care manufacturing customers over the 4 Wood moisture may be needed to remove debris, years has shown that it is often not content 15 given the fine smaller shavings that necessary to sand Accoya wood are produced by Accoya wood. For between coats of water based 5 Processing 17 dowel connections it is important coatings since fibres scarcely 6 Gluing 23 that the diameter of the drill is no ‘bloom’ or roughen the surface after smaller than the diameter of the moisture absorbance. Nevertheless, 7 Contact with other materials 27 plug to prevent splitting. advice should be taken from your coatings partner on good process Metals 28 Best practice for wedges for door detail, as poor practice may result Non-metals 30 construction is to make sure the in reduced surface aesthetics. dimensions of rebate and wedge 8 Weathering 33 are sufficiently large, the wedge is When sanding of the wood 9 Coatings 41 flattened rather than pointed and surface is required, a belt sander 10 Fire behaviour 48 care should be taken in installing: with a 120 grit pad will give good a series of taps will avoid splitting. coating quality results. Orbital palm 11 Contact 51 See section 6.3 for additional sanders may create a “washboard” details. effect as the soft pad will sink in and erode the softer summerwood, leaving the denser winterwood high. Avoid this type of machinery DOOR WEDGES or make sure the sander has a hard and rigid base (no Velcro type fixing of the pad).
Accoya® Wood Information Guide | V3.9 | 2020 21 CONTENTS 5 PROCESSING
1 Introduction 2 5.7 Fasteners is recommended. This model components to achieve optimal largely follows the guidelines of product service life. Further it is 2 Accoya wood Accoya wood can be fixed in the properties 3 the popular Cradle to CradleTM recommended to design in such same way as other commonly (C2C) philosophy to close biological a manner that product or material 3 Transport and storage 13 used softwood species and the and technological cycles as far as re-use is facilitated, as the service same general rules regarding 4 Wood moisture possible and re-use materials. life of Accoya wood might be content 15 pre-drilling, countersinking and The model consists of the following exceeding the (economical) service keeping sufficient distance from 5 Processing 17 possible waste management life of the product. the edges should be applied. Like scenarios in which prevention is 6 Gluing 23 most durable woods, Accoya the most desirable option and If this is not possible, it is contains a small amount of acid. It recommended that Accoya wood 7 Contact with dumping is the least. other materials 27 is therefore strongly recommended is used for energy production that corrosion resistant fixings, • Avoiding waste through incineration. The Metals 28 such as high quality stainless steel, • Designing products that German wood research institute Non-metals 30 are used. For further information integrate waste avoidance and Wilhelm-Klauditz-Institut (wki) 8 Weathering 33 on stainless steel and other metal re-use at the end of their life has confirmed that Accoya wood options, please refer to section 7. • Re-use of the product may be incinerated for energy 9 Coatings 41 • Re-use of the material production in the same manner 10 Fire behaviour 48 5.8 Waste wood and • Use for energy production as untreated wood. (incineration) 11 Contact 51 end-of-life considerations • Burning The last resort should be Accoya wood waste can be • Dumping composting where Accoya wood handled in the same way as can be handled in the same way untreated wood. Accoya wood Since Accoya wood has a long as untreated wood. Please bear is non toxic and does not require service life, it is often the proper in mind that the decomposition any special disposal considerations. selection and maintenance of other process will be longer than for Given its long life, multiple components that now become untreated wood because of applications and non toxicity, the critical success factors. It is Accoya wood’s resistance to Accoya wood is suited for therefore recommended integrating biological degradation. re-use and recycling. Accoya wood’s performance into the overall design strategy of a In the end-of-life phase, the product, and apply an appropriate adoption of the “preferential maintenance interval for coatings sequence for waste management” and other finished product
Accoya® Wood Information Guide | V3.9 | 2020 22 CONTENTS 6 gluing
1 Introduction 2 As with all wood species, the optimal glue choice will depend 2 Accoya wood on the application and the required performance of the glue properties 3 bond. Accoya wood has been tested with various types of 3 Transport and storage 13 adhesives for many applications. 4 Wood moisture content 15 In general, Accoya wood can 5 Processing 17 be glued using most commonly 6 Gluing 23 used wood adhesive systems. Particularly good results are 7 Contact with other materials 27 obtained with polyurethane (PU), Metals 28 emulsion poly isocyanate (EPI), epoxy and phenol resorcinol Non-metals 30 formaldehyde (PRF) adhesives. 8 Weathering 33 The results of gluing with polyvinyl acetate (PVAc) improve with longer 9 Coatings 41 clamp times but it should not be 10 Fire behaviour 48 solely relied on for strong joints. Melamine urea formaldehyde (MUF) 11 Contact 51 should be avoided.
When gluing Accoya wood it is strongly recommended to test first and if needed contact your adhesive supplier(s) as they have in-depth knowledge of the gluing process and their adhesives. Use should always be in line with best practice, design and performance specific demands. Gluing Accoya and products offered by adhesive system partners is part of the Accoya Approved Manufacturer training programme. Accoya® Wood Information Guide | V3.9 | 2020 23 CONTENTS 6 gluing
1 Introduction 2 6.1 Changed properties as a catalyst and those consisting • With water based adhesives, of two or more components that possibly increase the clamp time 2 Accoya wood Comprehensive testing has shown properties 3 could migrate differently may or press time to allow the water that Accoya wood has good gluing have weaker bonds. to be absorbed and the adhesive 3 Transport and storage 13 properties. However, it is imperative to produce adequate green that the product’s modified 4 Wood moisture For further information about the strength to bond the Accoya content 15 properties are taken into account. moisture content of Accoya wood, wood pieces. This is of particular importance please refer to section 4. 5 Processing 17 because common wood adhesives • The applied pressure during 6 Gluing 23 (PVAc, EPI, PU, PRF) either harden Aspects that require extra attention gluing should be adapted to the on contact with moisture or part of for the effective gluing of Accoya strength of Accoya wood, as 7 Contact with wood are detailed hereafter. The other materials 27 the water content of the adhesive should the temperature if heat needs to be absorbed by the wood. presence of a low amount of acetic is applied. Accoya wood should Metals 28 acid in Accoya wood, as with many be treated as moderately hard Non-metals 30 The acetylation process other durable woods, can affect the softwood in this context. substantially reduces the ability of 8 Weathering 33 adhesive, especially acid catalysed the wood to swell. This can impact adhesives and adhesives with a • The curing time and the best 9 Coatings 41 properties such as the ability of large amount of alkaline additives. curing conditions. 10 Fire behaviour 48 joints to ‘self-clamp’. Another effect is that the equilibrium 6.2 Optimising the adhesion • The properties of glued and 11 Contact 51 finished product should be fit moisture content of Accoya process wood is substantially lower than for purpose. untreated wood in the same It is highly recommended that you climatic conditions. While this consult your adhesive supplier in makes Accoya wood dimensionally order to obtain the best results for stable, it can mean that absorption gluing Accoya wood. Points properties of the adhesive into the to consider include: Accoya wood are different due • The quantity of adhesive to to the hydrophobic nature of the be applied should, if possible, wood surface, especially during the be even on both sides in first few minutes after the adhesive accordance with the adhesive is applied to the surface of Accoya manufacturer’s instructions. wood. Adhesives that require water
Accoya® Wood Information Guide | V3.9 | 2020 24 CONTENTS 6 gluing
1 Introduction 2 6.3 Joints 6.4 Finger jointing 2 Accoya wood It is strongly advised that any Good results have been achieved properties 3 end-grain that will be exposed with EPI, PRF and PU. Special care 3 Transport and storage 13 be sufficiently sealed using a is required in producing the fingers. 4 Wood moisture suitable product as recommended Sharp, damage free knives need content 15 by the supplier. This is particularly to be used to ensure high quality critical for joinery. For a long lasting fingers as blunt knives can result 5 Processing 17 result, the importance of a proper in “broken” fingers. 6 Gluing 23 frame corner joint is emphasized. Despite the improved durability Due to the short-term 7 Contact with hydrophobicity of the Accoya other materials 27 and dimensional stability of Accoya wood, it is still important to make wood surface and dimensional Metals 28 the frame corner joint connection stability of the Accoya fingers Non-metals 30 watertight to avoid possible paint (reducing the self clamping benefit after adhesive application), it 8 Weathering 33 performance problems and other damage. might be necessary to increase 9 Coatings 41 pressing time and curing time. 10 Fire behaviour 48 Dowels, biscuits and similar Press pressures should be devices, if not made from Accoya adjusted to softwoods or to the 11 Contact 51 wood, may swell (much) more specific settings recommended than Accoya wood. Plastic dowels by the adhesive supplier. graded to the application may be used as an alternative to wooden 6.5 Laminating pressure because Accoya wood is dowels. For dowel connections it smoother and may expel adhesives Good results can be achieved is important that the diameter of from the gluing surface. Take with PU (both 1 and 2 component the drill is exactly the same as advice from your adhesive supplier types), PRF and EPI. The best the diameter of the plug. This is on best practice for surface results are obtained with structural to prevent splitting of the ends. preparation (roughening) before PU and PRF adhesives and only laminating. Adhesive may also these types should be used in require more time to penetrate the uncoated use or applications which surface of the Accoya wood. will be subject to regular wetting. It is important to work on a flat cont on page 26... surface and not apply excessive Accoya® Wood Information Guide | V3.9 | 2020 25 CONTENTS 6 gluing
1 Introduction 2 Due to the high dimensional Whilst EN14080:2013 suggests 2 Accoya wood stability of Accoya wood, the that the durability of glued properties 3 annual ring orientation and the laminated products shall be taken amount of balancing of layers as the natural durability according 3 Transport and storage 13 is of less importance. to EN 350-2 of the timber from 4 Wood moisture which they are made, and therefore content 15 6.6 Best practice in design DC1 with Accoya, professional 5 Processing 17 of structural laminate bodies such as the Structural Timber Association (STA) in the UK 6 Gluing 23 The physical and chemical changes consider the use of well-maintained associated with acetylation, can 7 Contact with water-repellent stain finishes 6.7 Best practice • Protecting end grain other materials 27 affect the curing process of the glue together with rain screening and line. In particular adhesives which in designing • Orienting lamella to achieve Metals 28 other protection measures as for moisture vertical grain on surfaces to require moisture for hardening can essential when used in Glulam Non-metals 30 mimimise checking and water be affected by the particularly low applications, and therefore the management in ingress points 8 Weathering 33 moisture content of Accoya. Accoya Warranty will only apply glulam beams to Glulam applications where this 9 Coatings 41 Testing has so far been undertaken includes: • A robust adhesive to guidance and moisture exclusion on Accoya wood by Dynea and prevent delamination and 10 Fire behaviour 48 is achieved and maintained. Henkel, in accordance with EN301 moisture ingress 11 Contact 51 and EN 302-1 (PRF adhesives) Please contact your Accsys • Regular inspection for or EN 15425 (PU adhesives), to sales manager for best practice identification and repair confirm that their adhesives are guidelines related to structural of splits or delamination suitable for structural bonding of laminate design and maintenance. Accoya. It may be possible to • A maintained, film use other adhesives, but these forming coating would need to be confirmed by the relevant manufacturers. • Drainage, particularly on horizontal surfaces and ventilation.
Accoya® Wood Information Guide | V3.9 | 2020 26 CONTENTS 7 CONTACT WITH OTHER MATERIALS
METALS 1 Introduction 2 All wood contains organic acids, although the quantity 2 Accoya wood varies by species. In moist conditions, these organic acids properties 3 contribute to the corrosion of metal fasteners used in wood. 3 Transport and storage 13 Accoya wood has comparable acid levels to many other 4 Wood moisture durable species such as oak and western red cedar. In wet content 15 circumstances, the Accoya wood will have a pH in the range 5 Processing 17 of 4 – 5.5. For a list of system suppliers in your region, please 6 Gluing 23 visit the More about Accoya / System Suppliers section of our 7 Contact with website www.accoya.com other materials 27
Metals 28 Tests have shown that base metals species such as oak and western Non-metals 30 and galvanized metals that are red cedar should be adopted. 8 Weathering 33 in direct or indirect contact with wood containing acids will corrode Indirect contact issues can occur in 9 Coatings 41 in damp climatic conditions. It is non-ventilated high humidity areas with a high risk of condensation (for 10 Fire behaviour 48 therefore strongly recommended that high quality stainless steel, example lock rebates, swimming 11 Contact 51 corrosion resistant aluminium pool enclosures, bathrooms). High or naval brass products be used quality hardware and/or corrosion in areas exposed to moisture or avoiding techniques described condensation. When stainless further on in this section should steel, corrosion resistant aluminium be considered for these areas. As or naval brass is not available it is with any installation, pit or galvanic important to take precautions using corrosion must also be avoided by lesser grade metals. The metal using fasteners that are compatible and/or the Accoya wood should be with the metals used in hinges, coated or otherwise separated to locks and other hardware. avoid direct contact between the Please consult your fixings supplier wood and these metals. Similar to avoid any issues. good practices that are commonly used in the industry for reference
Accoya® Wood Information Guide | V3.9 | 2020 27 CONTENTS 7 CONTACT WITH OTHER MATERIALS METALS
1 Introduction 2 7.1 Stainless steel 7.2 Naval brass and 7.3 Coated hardware 2 Accoya wood The use of corrosion-resistant aluminium When stainless steel fixtures or properties 3 stainless steel fasteners and Corrosion testing on naval brass other corrosion resistant metals 3 Transport and storage 13 fixtures that conform to EN (brass containing tin) and higher are not available, coated fixtures 4 Wood moisture 10088-1 is recommended, such quality aluminium products show (such as with epoxy, lacquer, content 15 as widely used 1.4301 (A2) or that these metals are highly polyurethane or powder coating) 1.4401 (A4) quality stainless can be considered for those 5 Processing 17 corrosion resistant in direct steel. The A4 quality should be contact with Accoya and may be locations where moisture and 6 Gluing 23 used in particularly challenging considered as well. condensation exposure risk is environments, such as in coastal low (for example the dry side of 7 Contact with other materials 27 regions or near highly polluted For example the following windows and doors). Damage industrial zones. An international aluminium grades performed to the coating during installation Metals 28 comparison of grade specifications well in internal testing: 3003, should be prevented to reduce Non-metals 30 is shown in the table below. 6005, 6060 and 6063. Accsys risk of corrosion. For example, 8 Weathering 33 anticipate the following grades by predrilling for fasteners. These comparisons are will also perform well: 6061, 5154, 9 Coatings 41 approximate only since exact 5052, 3052 and 1100, since they It should be noted that the 10 Fire behaviour 48 properties vary by standard. The are commonly used in industrial performance of coated fixtures list is intended as an example manufacture and transport of varies, and no particular standard 11 Contact 51 of commonly available highly acetic acid. that can be cited. corrosion resistant stainless steel fasteners known to work well STAINLESS STEEL GRADE SPECIFICATIONS with Accoya. Many other grades of stainless steel exist, of which USA UNS Old EN Euronorm Name ISO French Swedish Japanese many are also highly corrosion No British No 3506 AFNOR SS JIS resistant, but it is best to work with BS your supplier to understand the 304 S30400 304S31 58E 1.4301 X5CrNi 18-10 A2 Z 6 CN 18 09 2332 SUS 304
compatibility of these other grades 304L S30403 304S11 - 1.4306 X2CrNi 19-11 - Z 2 CN 18 10 2352 SUS 304L with Accoya wood. 3016 S31600 316S31 58H, 58J 1.4401 X5CrNiMo 17-12-2 A4 Z 6 CND 17.11 2347 SUS 316
316L S31603 316S11 - 1.4404 X2CrNiMo 17-13-2 - Z 2 CND 18.13 2348 SUS 316L
Accoya® Wood Information Guide | V3.9 | 2020 28 CONTENTS 7 CONTACT WITH OTHER MATERIALS METALS
1 Introduction 2 7.4 Other metals direct contact with Accoya wood is such as large size laminated avoided, by: sections through good design 2 Accoya wood Galvanized metals or zinc alloys properties 3 and with effective coatings. Cracks are not corrosion-proof when used • Coating the wood or the metal and fissures should be repaired. 3 Transport and storage 13 with Accoya wood. The surface of component with an effective sealer Regular inspections and proper certain aluminium alloys, copper, 4 Wood moisture to provide a protective barrier. maintenance is recommended content 15 lead and other metals may also to avoid problems occurring. oxidise. Experience to date on • Physically isolating hardware 5 Processing 17 the use of solid brass has been from direct contact such as the • Avoid damage to metal hardware 6 Gluing 23 positive, especially on brass that use of plastic (or stainless steel) during storage and transport is factory clear coated to retain spacers, providing enough space (section 3). 7 Contact with for sufficient water drainage and other materials 27 brightness. Chrome plated steel performed very well in testing but if fresh airflow is allowed for. For additional temporary protection it Metals 28 the protective layer is damaged this is recommended to spray all sides of • The concentration of acetic acid Non-metals 30 product will be susceptible to local the metal hardware before assembly, in confined spaces, such as door 8 Weathering 33 accelerated corrosion. using a water repellent spray (such as lock houses, can rise and increase PTFE or silicon based spray) or rust 9 Coatings 41 7.5 Coated steel fasteners the risk of accelerated corrosion. inhibitor. This is also useful when the Metals in these areas should also 10 Fire behaviour 48 approved for pressure coating layer has been compromised. be sealed (for example with a Take care not to spray onto bare 11 Contact 51 treated lumber vapour-proof epoxy or end grain wood surface as these products sealer) even if there is no direct Although stainless steel decking may influence coating adhesion and/ contact between metal and screws are commonplace and the or maintenance of metal hardware. Accoya wood. best option, proprietary coated Preferably pre-drill for screws and other larger diameter fasteners. When steel fasteners such as the coated • Avoiding condensation of installing smaller pieces of Accoya, the deck screws approved for use moisture on metal components use of staples, such as those made in pressure treated lumber, may will help reduce potential of 18 gauge A2 stainless steel, is be used as a lesser alternative. corrosion issues, for example by recommended to reduce split risk. However, damage of the screw effective ventilation around those coating should be avoided and pre- components, as will avoiding high Further information may be obtained drilling is advised. humidity non-ventilated areas. directly from suppliers of fasteners, hinges and locks. 7.6 Avoiding corrosion • Avoiding moisture build up, specifically in engineered wood Corrosion of lesser grade metals can be substantially reduced when Accoya® Wood Information Guide | V3.9 | 2020 29 CONTENTS 7 CONTACT WITH OTHER MATERIALS Non-metal products
1 Introduction 2 Accoya wood has been tested for compatibility with 2 Accoya wood a wide variety of products commonly used in a wide properties 3 range of applciations and regions. The information 3 Transport and storage 13 below is a summary of these findings, partly based 4 Wood moisture on internal research and partly on extensive testing content 15 by system suppliers experienced with Accoya. 5 Processing 17
6 Gluing 23 7.7 Sealants, gaskets 7.8 Cleaning agents on
7 Contact with and related parts uncoated wood other materials 27 Rare examples are known where Cleaning agents vary tremendously Metals 28 the small amount of residual acetic in chemical composition and use. In Non-metals 30 acid in Accoya wood has influenced general, cleaning agents are quite the curing process or the long-term aggressive chemicals that need to 8 Weathering 33 performance of sealants. be handled carefully. 9 Coatings 41 If not already tested and approved, Firstly, after using a cleaner, 10 Fire behaviour 48 it is strongly recommended that extensive washing with clean 11 Contact 51 the sealant supplier performs a water is strongly recommended. compatibility check. This applies Some of these products contain to glazing sealants (silicon, chemicals that can impact the polyurethane, MS-polymer) as well (long term) performance and/ as to sealants used in double-pane or aesthetics of Accoya wood. glass (e.g. polysulphide, silicone Chemicals which degrade wood in and polyvinyl butyral). When general (such as strong acids and installing unfinished Accoya wood, bases) can also degrade Accoya, adhesion can be improved by these chemicals should be avoided. applying a primer before applying An exposure to products above the sealant. a pH value of 9 can invalidate* any warranty.
* This excludes the brief exposure to high alkali coatings up to the
point they cure. Accoya® Wood Information Guide | V3.9 | 2020 30 CONTENTS 7 CONTACT WITH OTHER MATERIALS Non-metal products
1 Introduction 2 7.9 Fire retardants of the repair system with other components. It is strongly advised 2 Accoya wood As with other woods, fire retardant properties 3 to use a repair system that has chemicals will generally have an been tested for paint adhesion, 3 Transport and storage 13 impact on compatibility and/or shrinkage behaviour, practical performance of coatings, adhesives 4 Wood moisture workability and resistance content 15 as well as other products. For more against moisture, UV light information on fire retardants 5 Processing 17 and high temperature. Two please refer to section 10. component systems (e.g. epoxy 6 Gluing 23 Please note that certain fire or polyurethane) are strongly 7 Contact with retardant chemicals products preferred. One component systems other materials 27 might invalidate the Accoya that tend to be hydrophilic or shrink Metals 28 warranty. Please contact your local after drying (creating capillaries) Non-metals 30 Accoya sales manager to discuss should be avoided. compatibility of fire retardant 8 Weathering 33 chemicals with Accoya in respect 7.11 End-grain sealers 9 Coatings 41 to the Accoya warranty. For Accoya wood products that 10 Fire behaviour 48 will be finished with a film-forming 7.10 Wood repair products coating system it is strongly 11 Contact 51 For Accoya wood products that recommended that all exposed will be finished with an opaque end-grain be effectively sealed. It is film-forming coating system it advisable to use a product that has is recommended to repair all been tested for its ability to reduce mechanical damage, checks and liquid water uptake by the wood, unsound knots prior to finishing. adhesion and UV resistance. This is to prevent water ingress Coating manufacturers often which could reduce the service life produce their own end grain of the coating system. sealers. In all cases, the end It is important to adhere to the grain sealer should be approved instructions of the supplier and as compatible by the coating verify any possible interaction manufacturer.
Accoya® Wood Information Guide | V3.9 | 2020 31 CONTENTS 7 CONTACT WITH OTHER MATERIALS Non-metal products
1 Introduction 2 7.12 Pressure treated 2 Accoya wood wood products properties 3 Typical pressure treated lumber 3 Transport and storage 13 (used e.g. as sub-frame battens 4 Wood moisture or decking joists) containing metal content 15 salts such as CCA, ACQ and MCQ 5 Processing 17 can leach copper.
6 Gluing 23 It has been reported, particularly with recently treated and damp 7 Contact with other materials 27 pressure treated lumber have been presented where the copper Metals 28 in the pressure treated lumber Non-metals 30 was wicked into the Accoya 8 Weathering 33 and resulted in green staining on the surface of Accoya wood. 9 Coatings 41 To prevent this staining risk, 10 Fire behaviour 48 isolation techniques such as plastic (or stainless steel) strips 11 Contact 51 or spacers and barrier coatings are recommended. Design of the structure to allow quick drying of the pressure treated wood also reduces this staining risk. Alternatively, Accoya can be considered as a higher performing alternative to pressure treated lumber in these applications and will also eliminate green staining showing through. WICKING OF PRESSURE TREATED SOFTWOOD FRAMING CHEMICALS THROUGH ACCOYA Further information may be obtained directly from suppliers of barrier products. Accoya® Wood Information Guide | V3.9 | 2020 32 CONTENTS 8 weathering UNCOATED ACCOYA WOOD
1 Introduction 2 From a technical performance perspective, in respect 2 Accoya wood of attributes such as durability and dimensional stability, properties 3 there is no need to finish Accoya wood for cladding and 3 Transport and storage 13 decking applications. Joinery applications are more complex 4 Wood moisture so it is recommended that you seek expert advice before content 15 using Accoya for uncoated windows and doors. 5 Processing 17
6 Gluing 23 Like any natural wood species, 8.1 Greying 7 Contact with Accoya wood is susceptible other materials 27 to weathering in outdoor Because Accoya wood has Metals 28 circumstances. All materials a very high resistance against wood destroying fungi, a popular Non-metals 30 exposed to exterior conditions are degraded by a series of chemical, choice is to use it in various 8 Weathering 33 biological and physical processes. applications uncoated. It will 9 Coatings 41 The surface of any wood will be weather naturally to a silvery- blemished by a combination of UV, grey colour, due to physical and 10 Fire behaviour 48 moulds, algae, mildew, yeasts and biological processes that take place 11 Contact 51 pollution. Accoya is no exception within the board surfaces: and the initial light colour of cont on page 34... uncoated Accoya may cause early moulds and blemishes to stand out more than on other wood types, prior to it weathering further to grey. WEATHERED UNCOATED ACCOYA
Accoya® Wood Information Guide | V3.9 | 2020 33 CONTENTS 8 weathering UNCOATED ACCOYA WOOD
1 Introduction 2 • UV light partly degrades the The rate of weathering, eventual colour and level of surface growth 2 Accoya wood surface lignin. As this lignin properties 3 holds the wood cells together, will vary according to the amount this degradation will lead to a of UV, elevation on a building, 3 Transport and storage 13 rougher and more open surface. the surroundings, the installation 4 Wood moisture details (particularly those related content 15 • This opened surface structure will to ventilation) and the surface both cause a change in colour 5 Processing 17 texture of the boards. Accoya wood and also allow surface moulds, will generally grey at a similar rate 6 Gluing 23 yeasts, mosses and algae to as most other wood species, but penetrate and develop faster. 7 Contact with partial shading of a surface will other materials 27 lead to uneven greying and some • These types of growths can visible mould stains, particularly as Metals 28 use many sources of nutrients, the initial Accoya colour is relatively Non-metals 30 including extractives in the light and does not camouflage wood, free sugars, starch, dirt, 8 Weathering 33 these occurrences in early stages of pollution and other available weathering. See examples right. 9 Coatings 41 organic compounds, but do not 10 Fire behaviour 48 degrade the Accoya structure cont on page 35... itself. However, pigment 11 Contact 51 produced by these moulds and yeasts may discolour the surface. WEATHERED UNCOATED ACCOYA
Accoya® Wood Information Guide | V3.9 | 2020 34 CONTENTS 8 weathering UNCOATED ACCOYA WOOD
1 Introduction 2 However, prior to turning grey, 8.2 Appearance uncoated Accoya wood will go 2 Accoya wood A wet and a dry board may vary properties 3 through a phase of bleaching where it turns a lighter shade of in appearance, generally darker 3 Transport and storage 13 its normal colour. Surface growths and less attractive when wet and brighter in dry weather. Due to the 4 Wood moisture are particularly apparent in this content 15 intervening period and can vary installation details, the presence of a shaded area and the natural 5 Processing 17 in level from board to board. This will become less distinguishable differences in the wood between May 2019 6 Gluing 23 after full (even) greying, but in this boards, as for instance density variation or grain orientation, 7 Contact with transition period the Accoya wood other materials 27 surface may look blotchy. some may dry quicker than others. Not only does this reflect on the Metals 28 appearance of a surface while Non-metals 30 drying, it will also have an influence 8 Weathering 33 on the development of moulds, algae and other surface growths. 9 Coatings 41
10 Fire behaviour 48 Jan 2020
11 Contact 51
April 2020
CLADDING PROJECT, NORTH AMERICA
Accoya® Wood Information Guide | V3.9 | 2020 35 CONTENTS 8 weathering UNCOATED ACCOYA WOOD
1 Introduction 2 8.3 Surface growths in wood surfaces by UV light. As this lignin holds the wood cells 2 Accoya wood Acetylation of wood as such – properties 3 together, this degradation will a non toxic process – does not lead to a rougher and more open 3 Transport and storage 13 seem to have an influence on the surface. This may be evident as resistance against surface mould 4 Wood moisture fine fibres on the surface, which content 15 and yeast growth. Independent will eventually erode. review by BM Trada finds that 5 Processing 17 Accoya is similar or less prone to The higher the amount or intensity 6 Gluing 23 mould and yeast growth than un- of UV the surface is subject to, the modified pine. However, in damp faster this process will develop. It 7 Contact with other materials 27 and/or shaded areas there is a should be noted that these fibres high risk that surface growths will are formed on all exposed wood Metals 28 develop on Accoya wood, as species, including Accoya wood, Non-metals 30 they would on other (soft) particularly on flat surfaces like 8 Weathering 33 wood species. decking. A ribbed deck profile will Rough sawn surfaces are more conducive to build-up tend to cause an accumulation of 9 Coatings 41 Levels of mould or yeast developing these fibres, making it all the more on the surface during weathering 10 Fire behaviour 48 noticeable. of the Accoya wood will highly 11 Contact 51 depend on (macro) climatic factors In rare cases, certain harsh climatic such as moisture, temperature conditions may lead to a special and sunlight. Other influences form of surface fibres unrelated are location specific, such as to UV-degradation. Typically, this proximity to vegetation, pollution, involves an apparently extreme dirt accumulation and the naturally amount of surface fibres in spring, occurring differences in the wood. usually after a prolonged snow cover. A lengthy moisture load 8.4 Surface fibres combined with a repeated freeze- Uncoated Accoya wood may show thaw cycle during winter may lead a degree of surface fibres after to a mechanical disintegration of being exposed for some time, due the (uppermost) wood surface. to the natural degradation of lignin cont on page 37...
Accoya® Wood Information Guide | V3.9 | 2020 36 CONTENTS 8 weathering UNCOATED ACCOYA WOOD
1 Introduction 2 The Holzforschung institute of 2 Accoya wood Austria has indicated that Robinia properties 3 and thermally modified woods are particularly badly affected, but also 3 Transport and storage 13 larch, teak and sapele are prone to 4 Wood moisture such behaviour. In all of these cases content 15 the durability of the Accoya wood 5 Processing 17 is not compromised in any way. It is recommendable to periodically 6 Gluing 23 wash any loose fibres off, as they 7 Contact with may flock together and become a other materials 27 spot for organisms to settle, which Metals 28 may lead to disfigurements. Non-metals 30 Inappropriate use of pressure 8 Weathering 33 washers can increase occurrence of surface fibres. Using such cleaning 9 Coatings 41 devices with too high a pressure 10 Fire behaviour 48 will lead to the damage of the 8.4 Naturally occurring surface fibres on decking 8.4 Fibres may get trapped in ribbed surface profiling uppermost surface layer of wood. 11 Contact 51 Accoya wood being softwood in nature, it is therefore important to limit the pressure used.
Accoya® Wood Information Guide | V3.9 | 2020 37 CONTENTS 8 weathering UNCOATED ACCOYA WOOD
1 Introduction 2 8.5 Other staining cedar, has been observed. This is caused by heat transfer 2 Accoya wood Other occurrences of disfiguring properties 3 from the building to the Accoya stains on Accoya wood have been boards, which will decrease 3 Transport and storage 13 identified as: the average moisture content 4 Wood moisture • Resins; in rare cases individual at the location of the interface. content 15 uncoated boards may exhibit Dryer conditions mean less 5 Processing 17 a reddish brown staining after mould growth, which is why the interfaces are clear whereas 6 Gluing 23 installation. This is the result of natural extractives being the rest of the board surface 7 Contact with transported to the surface or shows mould. Adversely, other materials 27 condensing around (even corrosion inadequate ventilation of the Metals 28 resistant) metal fixings as moisture cavity increases the potential for prolonged wetting of the 8.5 A New Zealand housing project with a very Non-metals 30 in the boards evaporates. These distinct batten (sub-frame) silhouette showing in battens and cladding. This may discolourations will tend to fade the cladding surface 8 Weathering 33 and wash out over time. encourage the growth of surface 9 Coatings 41 mould on the Accoya cladding in • Aggressive cleaning agents can line with the battens, visible as a 10 Fire behaviour 48 cause discolouration and may darker discolouration band. 11 Contact 51 even affect the Accoya wood itself (section 7) if left to soak. • Pressure treated wood used as a sub-frame: these products may • Fasteners; staining around contain metal salts such as CCA, fasteners may occur when non- ACQ and MCQ. Copper leaching corrosion resistant steel is used from this treatment may result (section 7). Also, fasteners may in green staining on the surface transport water to and from the of Accoya wood (see section subframe, which can contain 7.12). To prevent this staining natural extractives. risk, isolation techniques such as plastic (or stainless steel) • Sub-frame silhouette; in some strips or spacers and coatings projects a distinct pattern are recommended. Design of the reflecting the sub-frame behind structure to promote quick drying 8.5 Reddish brown staining Accoya and other types of wood of the pressure treated wood cladding such as western red also reduces this staining risk. Accoya® Wood Information Guide | V3.9 | 2020 38 CONTENTS 8 weathering UNCOATED ACCOYA WOOD
1 Introduction 2 be lifted from the ground, for POOL DECKING OFFICE CLADDING, 8.6 Preventive measures IN OESINGEN, VROOMSHOOP, THE example, by spacer strips. 2 Accoya wood Good design and maintenance is SWITZERLAND NETHERLANDS properties 3 critical in minimising the incidence Polluted surfaces can be cleaned 3 Transport and storage 13 of surface moulds. Surface mould with a nylon brush and clean water 4 Wood moisture development can be reduced by (refresh the water regularly until it content 15 decreasing the level of moisture stays clear); planed surfaces are the wood is subject to, for example easier to clean than sawn surfaces. 5 Processing 17 by creating effective ventilation, Pressure washers can be used 6 Gluing 23 avoiding water traps and shedding but only with a suitable control water naturally. device as a direct high pressure 7 Contact with other materials 27 water spray can damage all Newly installed 2 months of weathering 8.7 Cleaning wood – including Accoya. If using Metals 28 a pressure washer it should be Non-metals 30 Especially exterior horizontal carried out with some experience surfaces will form a biofilm that 8 Weathering 33 and due care. Cleaning coated will hold water and reduce the surfaces with a pressure washer 9 Coatings 41 speed of drying of the board, and should be avoided. a large build-up of such a layer 10 Fire behaviour 48 should be prevented. Without the Persistent stains may be taken care 11 Contact 51 use of preventive measures, regular of by using deck cleaners, which cleaning will be needed to control may also cause the surface of the 10 months of weathering 2 years of weathering the build-up of such a biofilm. wood to bleach to some extent. It is important to adhere to the In normal situations a wooden deck instructions of the supplier. Make should be cleaned once a year, sure to wet the boards thoroughly preferably in spring. More frequent before using such cleaning cleaning may be necessary in case products, and after cleaning to permanently shaded areas can’t be rinse with plenty of clean water. avoided, e.g. on the north side of a house or in the immediate vicinity of bush or tree cover. Flowerpots and plant troughs should always 30 months of weathering 4 years of weathering
Accoya® Wood Information Guide | V3.9 | 2020 39 CONTENTS 8 weathering UNCOATED ACCOYA WOOD
1 Introduction 2
2 Accoya wood properties 3
3 Transport and storage 13
4 Wood moisture content 15
5 Processing 17 May 2019 Newly installed 2 months of weathering 6 Gluing 23
7 Contact with other materials 27 Metals 28 Non-metals 30
8 Weathering 33
9 Coatings 41
10 Fire behaviour 48 Jan 2020 10 months of weathering 2 years of weathering
11 Contact 51
April 2020 30 months of weathering 4 years of weathering
CLADDING PROJECT, NORTH AMERICA POOL DECKING IN OESINGEN, SWITZERLAND OFFICE CLADDING, VROOMSHOOP, THE NETHERLANDS
Accoya® Wood Information Guide | V3.9 | 2020 40 CONTENTS 9 coatings
1 Introduction 2 Despite Accoya wood’s excellent compatibility with a wide 2 Accoya wood range of coating types, it is highly recommended having the properties 3 coating manufacturer involved in the process, as they have 3 Transport and storage 13 in-depth knowledge of their products, suitable application 4 Wood moisture techniques and how to assess the performance of the content 15 finished product. 5 Processing 17
6 Gluing 23 Several leading coating companies 7 Contact with have more than 10 years other materials 27 experience in testing and industrial Metals 28 application of their coatings Non-metals 30 on Accoya. In any case, the manufacturers recommendations 8 Weathering 33 should be followed to attain best 9 Coatings 41 application performance.
10 Fire behaviour 48 Please note that coating 11 Contact 51 formulations vary per manufacturer (and possibly by region) and processes vary depending on the application equipment used and the end product design.
Accoya® Wood Information Guide | V3.9 | 2020 41 CONTENTS 9 coatings
1 Introduction 2 9.1 Preparation Coatings formulated for outdoor • Accoya wood in contact with use that include fungicides water will have a pH in the 2 Accoya wood • Accoya wood should be clean, properties 3 combined with an appropriate range of 4 to 5.5. dry (below 8% mc) and free of maintenance cycle in accordance 3 Transport and storage 13 dust, grease and other pollution. with the manufacturers For processing guidelines, please consult section 5. 4 Wood moisture • Where possible, finish the recommendations, will also content 15 wooden parts on all sides before prolong their overall and 5 Processing 17 mounting or assembling them. cosmetic appearance. 6 Gluing 23 • When using a primer, a high • Always follow the wet/dry film thickness recommendations 7 Contact with quality product that contains other materials 27 resin-bleed blockers and from the coating manufacturer to optimize and preserve the Metals 28 fungicides is recommended. coatings efficacy. Non-metals 30 Resin blocking primers are essential for white paint finishes. 8 Weathering 33 • In certain circumstances Resin blocking primers are (more so with translucent 9 Coatings 41 typically used on hardwood coating systems), suitable species and western red cedar. 10 Fire behaviour 48 and appropriate pre-coating • Accoya wood can absorb a surface preparation can help to 11 Contact 51 high amount of water through achieve a more consistent, clean, the end grain – those should be uniform finish and improve effectively sealed (section 4). the surface film application, appearance and performance. • Due to its superior dimensional Planed surfaces that are left for stability, the integrity of most a period of time before coating film or semi film forming benefit from surface preparation coatings will last considerably (sanding / fladding or textured longer when applied to Accoya brushing) to remove any surface wood compared to other woods. contamination.
Accoya® Wood Information Guide | V3.9 | 2020 42 CONTENTS 9 coatings
1 Introduction 2 9.2 Penetrating oils The wetting of Accoya wood is End-grain should be sealed before different due to the hydrophobic coating with a suitable product so 2 Accoya wood Oils such as tung, linseed, and properties 3 nature of the wood surface in its that the protection of all finished walnut oil, whether pure or oil/ first minutes of exposure. As a sides against water (liquid) uptake 3 Transport and storage 13 varnish mixtures, may be used result of this trait, water-based is approximately equal. with pleasing aesthetic results. 4 Wood moisture stains may not penetrate as deeply content 15 Longevity of such non-film forming or form as thickly on Accoya wood. The rate of drying and/or curing of finishes on Accoya is typically each individual coating layer might 5 Processing 17 no longer than on traditional Non-film forming coatings be different with Accoya wood. 6 Gluing 23 wood types. typically last no longer on Accoya Coating company guidelines for than on other wood types. coating Accoya should be obtained 7 Contact with Please note that oils can be a other materials 27 Testing of a wide range of semi and followed to achieve the food source to fungi and thus film forming coating brands on required performance levels. Metals 28 oils containing a mouldicide are Accoya typically shows longer Non-metals 30 recommended. Accoya wood can maintenance intervals on Accoya. Coating performance on Accoya absorb a great deal of oil. If you 8 Weathering 33 wood in joinery and cladding want to minimize absorption, it Clear or very light pigmented non is improved and maintenance 9 Coatings 41 is recommended that you let the or semi-film forming coatings are intervals are often prolonged. Film 10 Fire behaviour 48 first coat of oil dry before applying not recommended. See section 9.5. forming coatings further extend additional coats. the maintenance intervals due to 11 Contact 51 9.4 Opaque and translucent their high film builds, illustrated 9.3 Non-film forming and coating (film forming) by leading international coating semi-film forming systems companies through numerous case Before a film forming coating is study projects. Do not over apply Accoya wood may be finished applied, it is recommended that the coating wet film thicknesses with semi and non-film forming all mechanical damage or wood as this extends the drying process paint systems such as stains and defects are repaired with a suitable without adding to or enhancing oils. It is recommended for both product. Opaque and translucent performance. cases to apply multiple coats coating systems should be applied and follow maintenance intervals on all sides corresponding to the Clear or very light pigmented non as prescribed by the coating requirements of the end product or semi-film forming coatings are manufacturer. Note that the first and/or paint supplier’s instructions. not recommended. See section 9.5. layer of some oil based products tends to get absorbed by the Accoya wood more quickly. Accoya® Wood Information Guide | V3.9 | 2020 43 CONTENTS 9 coatings
1 Introduction 2 9.5 Best practices (chalk) fillers can cause coating blistering on Accoya and must 2 Accoya wood for joinery properties 3 be avoided. Please consult your Accsys, working with leading coating coatings provider. 3 Transport and storage 13 companies, has gained valuable 4 Wood moisture experience of joinery coating over the • When using an opaque base content 15 years. Although practices may vary coat, preferably an effective and well applied anti-stain blocking 5 Processing 17 from country to country, in line with best joinery practices and coating primer is included and this is 6 Gluing 23 manufacturers advice, it is important critical for white coatings. to note the following guidance when 7 Contact with • Translucent coating systems other materials 27 coating Accoya wood. should contain an effective Metals 28 These guidelines are supplemental mouldicidal component Non-metals 30 to advice from coating to protect the wood from 8 Weathering 33 manufacturers, please consult your unattractive moulds and mildew. coating supplier at all times: As with other wood types 9 Coatings 41 and being a natural material, • A fully factory applied 10 Fire behaviour 48 the porosity of Accoya may joinery coating is strongly vary. Therefore when applying 11 Contact 51 recommended. If site finishing is translucent stains, it is advisable required, then at least a primer to test a sample area first. and mid coat should be applied in the factory and the top coat • Clear or very lightly pigmented must be applied before the coatings are best avoided. They joinery gets wet on site. break down more rapidly in UV exposure and are particularly • Accoya wood must be dry, susceptible to disfiguring stains clean and free from dust when on or behind the coating. As an coated. This is critical when alternative to retain the original brush applying top coats on site. Accoya look, a translucent stain Please see section 4 for moisture with a pigment level similar to testing techniques. the original Accoya wood should be considered. • Opaque coatings with an excess of calcium carbonate cont on page 45... Accoya® Wood Information Guide | V3.9 | 2020 44 CONTENTS 9 coatings
1 Introduction 2 • Sealers must be effectively used • Coatings should be thoroughly Accoya wood contains a small 2 Accoya wood on all end grain throughout cured in a humidity and amount of acetic acid. In some properties 3 the joinery, with a product that temperature controlled circumstances this can disturb is compatible with the paint environment and in line the factory coating processes that 3 Transport and storage 13 system and approved by the with coating manufacturers have re-circulation of the coating 4 Wood moisture coating manufacturer. guidelines. This often involves (as in flow coating). By adding content 15 overnight drying between layers. a buffer in the coating, potential • Dip, flood and flow coat 5 Processing 17 Control is particularly important problems can be prevented. Please application of the first coating in colder months. consult your coating supplier. 6 Gluing 23 layer is widely practiced for all wood joinery and is particularly • Coated joinery should be 7 Contact with other materials 27 effective in forming an all- stored on site as per coating encompassing first coat. Monitor manufacturers guidelines. Metals 28 and control the level of wetting Non-metals 30 of Accoya wood during the • It is strongly recommended to 8 Weathering 33 flow coat, dipping and deluge use corrosion proof hardware application process. Accoya with Accoya joinery. However, 9 Coatings 41 wood tends to be more porous applying three layers of paint 10 Fire behaviour 48 than hardwood and some behind hardware that may be softwoods. Excessive wetting prone to corrosion helps create 11 Contact 51 should be avoided as this can an isolation barrier between it significantly extend drying times. and the wood. It is also good joinery practice to spray inside • Coating manufacturer’s any lock housings and apply end application methods and grain sealer. Please see section guidance should be followed 7 for more details on contact with particular focus on avoiding with metals. aeration in the coating film when spraying, avoiding cold coatings (should typically be above 15°C (60oF) at application), correct film thickness and appropriate drying techniques/conditions.
Accoya® Wood Information Guide | V3.9 | 2020 45 CONTENTS 9 coatings
1 Introduction 2 9.6 Deck coatings risks of water absorption prior material, the porosity of Accoya to coating and other in field wood may vary. 2 Accoya wood To obtain a “natural appearance” properties 3 complications. of an Accoya wood deck with • Using somewhat thicker and/or 3 Transport and storage 13 reduced potential discolouration • As moulds are capable of multiple coating layers will help 4 Wood moisture issues, a translucent non film- growing on and also through reduce moisture absorption and content 15 forming coating, an oil-based stain coating layers, to reduce risk therefore the risk of mould and/ or some other type of hydrophobic of growth on and beneath the or yeast growth on and through 5 Processing 17 agent is an option. Darker or more coating, at least the first layer coatings. This will also lead to 6 Gluing 23 highly pigmented coatings typically of a stain should contain an a more resilient coating in the have longer maintenance intervals. effective mouldicidal component sense of wear and tear, and may 7 Contact with other materials 27 to help protect the wood lead to a longer life expectancy Note that film-forming systems from possible disfigurement. of the coating. Metals 28 are not recommended for decking Generally, the darker the Non-metals 30 boards because of possible slip risk pigment, the greater the • If so required, slip resistant and a risk of moisture accumulation coatings or applied strips can 8 Weathering 33 maintenance interval. when the coating is compromised be used on Accoya wood in the 9 Coatings 41 by mechanical damage. • Clear or lightly pigmented same way as on other timber 10 Fire behaviour 48 coatings are not recommended decking. • A fully factory applied for Accoya decks. They will 11 Contact 51 coating system is strongly generally provide little protection recommended. Coating should to weathering and greying and be applied on all surfaces, with a can make cleaning of the surface minimum dry film thickness that more difficult if disfigurement corresponds to the requirements occurs beneath them. of the end product and/or paint supplier’s instructions to prevent • Pigmented coating systems will camouflage mould/yeast disfigurement. However, it is advisable to test a sample area first with pigmented stains, because as with other wood types and being a natural
Accoya® Wood Information Guide | V3.9 | 2020 46 CONTENTS 9 coatings
1 Introduction 2 9.7 Service life manufacturer. This includes applying the optimum coating 2 Accoya wood The service life of a decking coating properties 3 film thickness as coating system will depend highly on the quality performance can be affected 3 Transport and storage 13 and thickness of the coating where films are too low or high. 4 Wood moisture layers, the coating colour, regional content 15 differences in UV-intensity, the • Generally speaking, regular average moisture level and the localised remedial work in 5 Processing 17 use intensity. areas with high use intensity 6 Gluing 23 will prolong the interval for Whilst a specific service life of any a complete renovation of 7 Contact with deck coating system can only be other materials 27 the coating. given by the coating manufacturer, Metals 28 generally speaking a maintenance • Regular cleaning (preferably Non-metals 30 interval of more than one year will with a soft brush and clear be rare – in line with other typical 8 Weathering 33 water) will help reduce the risk deck wood species. A seasonal of moulds growing through 9 Coatings 41 maintenance involving a cleaning the coating. 10 Fire behaviour 48 and re-coat is most common and good practice. • The ease of cleaning of non-film 11 Contact 51 forming deck coatings generally • The machining (including planing improves when the coating and/or sanding) of the Accoya is weathered. wood may have an influence on the performance of the • Pressure washing should be coating applied. avoided with coated surfaces as the high pressure water could • For optimum life expectancy damage the coating layer and of any specific system, please decrease the service life. adhere to the maintenance recommendations of the coating
Accoya® Wood Information Guide | V3.9 | 2020 47 CONTENTS 10 fire behaviour
1 Introduction 2 10.1 EU – Product standard EN 14915 excerpt Product detail Mean Board End-use Class Product density ≥ thickness ≥ condition 2 Accoya wood Accoya wood is part of the scope properties 3 max/min of EN14915:2013 + A2:2020 ‘Solid 3 Transport and storage 13 wood panelling and cladding Panelling / Wood pieces with or without 390 kg/m³ 9 / 6mm Without air gap or D-s2, d2 characteristics, evaluation of cladding tongue and groove & with or with closed air gap 4 Wood moisture without profiled surface content 15 conformity and marking’. 390 kg/m³ 12 / 8mm Without air gap or D-s2, d0 5 Processing 17 This harmonised European with closed air gap 6 Gluing 23 standard defines solid wood boards for use in panelling and Panelling / Wood pieces with or without 390 kg/m³ 9 / 6mm With open air gap D-s2, d0 cladding tongue & groove and with or ≤ 20mm behind 7 Contact with cladding and specifies the relevant other materials 27 without profiled surface characteristics and the appropriate Metals 28 test methods to determine these 390 kg/m³ 18 / 12mm Without air gap or D-s2, d0 Non-metals 30 characteristics in both internal and with closed air gap external use, and it provides for 8 Weathering 33 Wood ribbon Wood pieces mounted on a 390 kg/m³ 18mm Surrounded by D-s2, d0 the evaluation of conformity as well elements support frame open 9 Coatings 41 as the requirements for marking air on all sides 10 Fire behaviour 48 these products.
11 Contact 51 One of the properties this standard NB: The above table is based on table 1 of EN14915:2013 + A2:2020. For further details please refer to this standard. deals with is the reaction to fire for cladding applications. This property is one that covers the entire cladding system; including fasteners, detailing, sub-frame and substrate backing the cavity. This means that it is not possible to classify Accoya wood on its own.
cont on page 49...
Accoya® Wood Information Guide | V3.9 | 2020 48 CONTENTS 10 fire behaviour
1 Introduction 2 To avoid testing all possible requirements. Please contact your 2 Accoya wood cladding systems according to EN Accsys sales representative for properties 3 13501-1 (single burning item or fire retardant treatment options SBI test), the EN 14915 standard available in your region. 3 Transport and storage 13 gives guidelines for certain 4 Wood moisture cladding systems that are classified As with other woods, fire retardant content 15 without the need for further testing chemicals used with Accoya generally have an impact on 5 Processing 17 (table on previous page), in which untreated chemically modified compatibility and/or performance 6 Gluing 23 wood is classified as Class D, the of coatings, adhesives and other products. These products should 7 Contact with same class as other softwoods. other materials 27 be tested first to ensure they will If certain local regulations or meet end-product performance Metals 28 building codes call for it, Accoya requirements. Fire retardants Non-metals 30 cladding can meet higher can affect the Accoya decay and 8 Weathering 33 requirements, up to Class B, by dimensional stability warranty giving it a fire retardant treatment. position and Accsys should 9 Coatings 41 This can be done by impregnating be contacted to check queries 10 Fire behaviour 48 fire retardant chemicals. The Wood pertaining to this. Protection Association provides 11 Contact 51 guidance on selection and use of For more information please visit fire retardant treatments. www.thewpa.org.uk/ flame-retardants Since the chemical structure of Accoya is modified, it is possible that the performance of the fire retardant will vary from normal woods. It is therefore important that the fire retardant performance is proven by an independent and accredited body. The Wood Protection Association provides a guidance document on the test
Accoya® Wood Information Guide | V3.9 | 2020 49 CONTENTS 10 fire behaviour
1 Introduction 2 10.2 USA – Flame 10.3 Australia With an average density of 515 kg/m³, Accoya wood (radiata 2 Accoya wood spread test Bush fire risk based zoning is a properties 3 pine) is classified, as other Southwest Research Institute consideration in Australian building softwoods, outside of these lists. 3 Transport and storage 13 (SwRI) performed Flame Spread regulations. They have been adjusted to include requirements 4 Wood moisture Tests and Smoke Developed Tests 10.4 New Zealand content 15 in accordance with the standard on resistance to bush fire for New Zealand uses the same test method for surface burning building constructions on a zonal 5 Processing 17 fire testing principles as Europe characteristics of building materials system from low to high categories, (the so-called room corner test 6 Gluing 23 NFPA 255 (ASTM E84, ANSI, UL described in the standard AS 3959. or SBI), but has different limits 723 & UBC 8-1). 7 Contact with Some species of timber are listed in for the classification: the Time other materials 27 The conclusion of the Flame Appendix E of this standard: To Flashover [s] instead of heat Metals 28 Spread Test results is that Accoya • Bushfire Resistant Timber release and fire growth. Based on Non-metals 30 indicative cone testing, Accoya wood can be classified within the • E1: density 750 kg/m³ or greater range of standard timber species wood is likely to be a group 8 Weathering 33 • E2: density 650 kg/m³ or greater and achieves Class C in this US number 4 material, comparable to 9 Coatings 41 rating system. other softwoods. 10 Fire behaviour 48 ASTM E84 CLASSIFICATION TABLES 11 Contact 51 Flame spread Flame spread Wood / species Flame spread index* Smoke developed index* classification rating or index Accoya** 95 155 Class I (or A) 0 - 25 Douglas fir 70 80 Class II (or B) 26 – 75 Eastern white pine 85 122 Class III (or C) 76 – 200 Lodgepole pine 93 210 * Data source - USDA - United States Dept of Agriculture Wood Handbook. Lower numbers Oak 100 100 equal a lower flame spread or less smoke. Sitka spruce 74 74 ** Note that the classifications presented on this page are valid for untreated Accoya Southern pines 103-195 n/a wood. Higher ratings can be achieved when using fire retardants. Western red cedar 70 213
Accoya® Wood Information Guide | V3.9 | 2020 50 CONTENTS 11 CONTACT
1 Introduction 2
2 Accoya wood Get in touch properties 3 Please email us with enquiries 3 Transport and storage 13 and the responsible sales manager will follow up promptly: 4 Wood moisture content 15 [email protected]
5 Processing 17 United Kingdom and Accsys run an Approved World Wide Enquiries Manufacturer Training Programme 6 Gluing 23 Brettenham House and we would encourage all 7 Contact with 19 Lancaster Place manufacturers planning to use other materials 27 London WC2E 7EN Accoya to contact their distributor Metals 28 +44 (0) 207 421 4300 or Accsys directly to arrange for Non-metals 30 Benelux enquiries this training programme. The Approved Manufacturer status also 8 Weathering 33 Postbus 2147 6802 CC Arnhem brings a number of benefits which 9 Coatings 41 +31 (0) 26 320 1400 support market activity. 10 Fire behaviour 48 North American enquiries 11 Contact 51 5000 Quorum Drive #620 Dallas, Texas 75254 +01 972 233 6565
Accoya is made by Accsys Technologies. Accoya® and the Trimarque Device are registered trademarks owned by Titan Wood Limited, a wholly owned subsidiary of Accsys Technologies PLC, and may not be used or reproduced without written permission. Accoya wood should always be installed and used in accordance with the written instructions and guidelines of Accsys Technologies and/or its agents (available upon request). Accsys Technologies accepts no liability for any defect, damage or loss that may occur where such written instructions and guidelines are not adhered to.
The information contained within this document has not been independently verified, and no warranty (express or implied) or representation is given in respect of the ® same, including without limitation as to its accuracy, completeness or fitness for any purpose. Accsys and its affiliates,Accoya officers,Wood employeesInformation or advisers Guide |expressly V3.9 | disclaim 2020 51 any liability to the fullest extent permitted by law for any loss or damage whatsoever arising in respect of such information or the result of having acted upon it.