Accoya Wood Information Guide V3.9
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accoya ®
Wood Information Guide V3.9
1
CON T E N TS
1 INTRODUCTION
1
2
Introduction
Accoya wood
2
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: sales@accsysplc.com
Accoya
AccoyaWood
® ®
Wood
Information
Information
Guide
Guide
| |V3.9
V3.9|| 2020 2
CON T E N TS
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 K EY P ROP ERTIES & BENEFITS
Non-metals 30 credentials have been extensively
8 Weathering 33
researched and repeatedly
demonstrated. Accoya wood has H I G H LY H I G H LY IDEAL FOR E XCE L L E N T
9 Coatings 41 properties that exceed those of S TA B L E DUR ABLE COAT I N G M ACH I N A B I L I T Y
10 Fire behaviour 48 the world’s best woods yet it is
manufactured by modifying wood
11 Contact 51 sourced from well-managed
NON B A R E F OOT S T RU C T U R A L LY S US TA I N A B LY
sustainable forests through TOX I C F R I E N D LY CE R T I F I E D SO U RCE D
acetylation without the
introduction of toxins.
LOW
Accoya performance testing LOW CO 2 I N S EC T 10 0 %
E N V I RO N M E N TA L
is reviewed in detail in the E M I SS I O N S R E S I S TA N T R EC YCL A B L E
I M PAC T
Performance Testing Summary
Brochure.
Accoya® Wood Information Guide | V3.9 | 2020 3
CON T E N TS
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
other materials 27 Wet to Oven Dry Radial 0.7%
stocking distributors can be
Tangential 1.5%
Metals 28 found at:
Non-metals 30 www.accoya.com/where-to-buy Equilibrium moisture 65% RH, 20°C (70oF) 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
*What is Class 1 Durability? Wood resistance to rot and decay is measured on a scale of 1 to 5 with 1 being
please see the Accoya Performance
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
CON T E N TS
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
content 15 by the German Institute for Building Parallel to grain ft,0,k 10 13
Technology (DIBt) for load bearing
5 Processing 17 Perpendicular ft,90,k 0,5 0,5
structural applications. This DIBt
approval qualifies the strength class of Compression
6 Gluing 23
A1 and A2 solid Accoya timber, based Parallel to grain fc,0,k 17 20
7 Contact with
other materials 27 on the European strength class system
of C classes (EN338). Perpendicular fc,90,k 2,2 2,4
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 E0,mean 8 10
9 Coatings 41 adjacent table). The approval applies
to Accoya wood in the widths 100mm 5% MOE parallel E0,05 5,4 6,7
10 Fire behaviour 48
to 250mm with a thickness of 25mm Mean MOE perpendicular E90, mean 0,27 0,33
11 Contact 51 to 100mm, and can be used both flat
and upright. C22 and C16 strength Mean shear modulus Gmean 0,5 0,63
classes are common for structural
Density [kg/m3]
timbers produced from spruce and pine
in the UK and Mainland Europe. Density 0k 310 340
Mean density Pmean 370 410
cont on page 6...
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
CON T E N TS
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 Although levels are controlled,
appropriate and may be used. height modification factors (EN
4 Wood moisture Accoya wood may be fastened freshly cut or planed Accoya wood
1995-1-1).
content 15 to a timber sub-frame with nails, may have a slight vinegar-like odour.
clamps, wood screws, dowels and Accoya wood in B grade is not Some of the residual acetic acid
5 Processing 17
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,
edge/end clearance (EN 1995-1- the DIBt work programme or the Accoya wood will therefore have
7 Contact with
other materials 27 1, table 8.2) should be in line with certification. a pH in the range of 4 – 5.5. At these
wood with a density between 420 levels a wide range of coatings,
Metals 28
and 500kg/m³. 2.5 Residual acid glues, fixings and other products can
Non-metals 30
be used with Accoya. Please see the
Many durable wood species applicable sections for each in this
8 Weathering 33 2.4 Property characteristic 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 can create compatibility issues
stiffness and density. The values
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 Q UA L I T Y CO N T RO L SA MPL I N G
• Average residual acetyl
timber species. Average mechanical Note: Accoya carries out destructive testing
compounds content of samples
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
CON T E N TS
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
Metals
Non-metals
28
30
even when wet. Pure science
protection and sustained strength improved performance in multiple
tests and in numerous regions
against various fungal, termite
From non durable woods to Accoya ®
through acetylation
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 inertHydroxyls 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 deliver ACE T YLATION P RO C ESS
susceptible to attack by biological organisms.
11 Contact 51
long term performance. Accoya Acetylation
Water returned to
Acetyl groups
wood performs in the harshestWood of cellulose contains a small
ground water system
environments and even lends itselfnumber of naturally occurring acetyl
groups which are hydrophobic (repel Acetic anhydride and
Water
to being coated black. water). There are an insufficient
acetic acid reused
number of acetyls in natural wood to
provide durable, stable performance
Modification quality of each batch Naturally
occurring acetyl
produced is validated to the Acetylation Free hydroxyls Acetylated wood
Reaction of wood with acetic anhydride
core of the wood by a range of (concentrated acetic acid) at high temperature Cellulose
sophisticated and proven tests tothat
precisely increase the level of moisture
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
CON T E N TS
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
4 Wood moisture 50 years above ground, 25 years timber and wood-based products.
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 cont on page 9...
6 Gluing 23 section on www.accoya.com
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
Northern Europe for more than a 1 No contact with the ground, Permanently dry Permanently dry < 20%
Non-metals 30
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
CON T E N TS
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
CON T E N TS
2 Accoya wood properties
technical data
1 Introduction 2 2.9 Dimensional stability MOVEMENT LEVELS FROM GREEN TO OVE N D RY CO N D I T I O N
2 Accoya wood comparison Typical characteristic values Wetting Warranty
properties 3 Species
Radial Tangential Maximum5
Accoya wood exhibits superior
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
other materials 27 remains stable during processing.
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 10CON T E N TS
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 (Acetylated radiata pine)
movement from green (soaked) to
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
dimensional stability often allows Ipe 0.38 / 9.6 0.46 / 11.6 -
5 Processing 17
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
not closing up when soaked Siberian larch 0.23 / 5.8 0.51 / 13.1 -
9 Coatings 41
in winter months. Teak (Burmese FEQ) 0.14 / 3.6 0.33 / 8.4 -
10 Fire behaviour 48
It is however still necessary Thermally modified ash 0.13 / 3.3 0.23 / 5.8 -
11 Contact 51
to take into account the expected
Western red cedar 0.14 / 3.5 0.29 / 7.3 -
expansion in installing
Accoya products.
Tangential or flat sawn
Quarter or radial sawn
Accoya® Wood Information Guide | V3.9 | 2020 11CON T E N TS
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 materials depends on factors such
dimensionally stable but this does dependent on the particular
4 Wood moisture not mean it is completely inert. as degree of weathering, surface coating system and the cleaning
content 15 Changes in humidity can cause profiling, coating, wetness of the maintenance.
slight changes in its dimensions and boards and maintenance – i.e. the
5 Processing 17
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
In extreme conditions the movement vary greatly across the world (even compared to grooved surfaces,
7 Contact with
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 flooring surfaces. for Accoya wood when tested by
considerations for common wood
8 Weathering 33
these methods are comparable to
products should be more than
The most common slip resistance unmodified wood species with the
9 Coatings 41
sufficient for Accoya wood.
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 lubricant and/or biofilm).
shape tolerance for delivered
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 12CON T E N TS
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 contentCON T E N TS
3 TRANSPORT AND STORAGE
1 Introduction 2 3.3 Storage As with other wood species, with each board is printed at one
2 Accoya wood storage at the building site should end of the board’s sawn surface.
Accoya wood that needs further be a minimum of 10cm above
properties 3
processing, gluing or coating concrete flooring and 30cm above Batch number should be recorded
3 Transport and storage 13 should be carefully stored as part of a manufacturer’s
(unpaved) ground. Additional
4 Wood moisture
(preferably horizontally), in closed 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. ventilation underneath the sheets is verify the product’s authenticity.
5 Processing 17
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 other should have the bearers sustainable wood certification such
8 Weathering 33
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
10 Fire behaviour 48
straightness and shape of parts 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
keep tight schedules between time It is important to inform the
of 3. Again, bundles on top of
of machining and assembly. Direct owner and third parties performing
each other should have the
exposure to water and changing installation that Accoya has been
bearers aligned.
climate (temperature and relative used in the manufacture of the
humidity) should still be avoided. (end) product. Sections of this
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 14CON T E N TS
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, the cell walls and is bound. More
9 Coatings 41 product quality can be harmed by
wood moisture content, as excessive moisture gain through
free water during manufacture;
10 Fire behaviour 48 expressed in this guide, is the mass soaking quickly fills the cell wall
it is therefore essential that the
of the water contained in wood, absorption limit and is deposited in
11 Contact 51 moisture content of the wood
expressed as a percentage of the the cell wall cavity (fibre lumen) as
is determined prior to further
mass of absolutely dry wood. free water.
processing such as gluing and
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 contentCON T E N TS
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 which is discussed further in
9 Coatings 41
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 PI N ME T E R
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 16CON T E N TS
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
machines than softwoods such as with higher acid levels (for example
Metals 28
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 17CON T E N TS
5 PROCESSING
1 Introduction 2 5.1 Visual grades factors such as the amount of
2 Accoya wood resin in particular logs and boards.
Accoya wood is a high Individual boards are spaced with
properties 3
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
4 Wood moisture
beauty, versatility and charm of 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 D I SCO LO U RAT I O N : RO U G H BOA R D, A F T E R SU R FAC I N G 3MM
cracks, internal resin pockets and and sticker marks visible on A N D A F T E R SU R FAC I N G 6MM FRO M RO U G H
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
6mm
the Lumber Grading Specifications, the course of days and months
available on www.accoya.com. proportionate to the level of UV
25mm
18mm
exposure. Discolouration can be
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 18CON T E N TS
5 PROCESSING
1 Introduction 2 5.3 Changed properties • Accoya wood has an outer zone marks during processing and to
2 Accoya wood of discolouration which should avoid contact with products that
Due to the acetylation process, be considered in profiling. will contaminate the surface, such
properties 3
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,
4 Wood moisture
importance for machining • 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
8 Weathering 33
session at your workshop. too low capacity and/or a large
• Since the moisture content
of Accoya is generally below section of the wood is profiled
9 Coatings 41 5.4 Sawing, planing in one run. Solutions include
5%, this can make some of the
10 Fire behaviour 48
material a little more brittle than
and profiling increasing the blade rotation
unacetylated wood. velocity (rpm), improving the
11 Contact 51 Accoya wood is easy to cut in any
exhaust/extraction system, using
direction. Skilful sawing will give a
• Density has increased (avg. antifriction lubricants or otherwise
smooth appearance with very few
515 kg/m³) as compared to reducing static energy at the rotary
flaws. Standard techniques such
unacetylated radiata pine. blades.
as using back boards can be used
• Internal stress within the wood when very fine results are desired. Despite Accoya wood’s improved
is reduced by the process. This properties, boards may harbour
Accoya wood is easily planed
eases the process of ‘working’ tension and flaws internally, similar
to a very smooth surface finish.
the timber compared to to other comparable wood species.
Special tools are not required. It
untreated radiata pine and many is important to avoid machining cont on page 20...
other wood types used
for exterior use.
Accoya® Wood Information Guide | V3.9 | 2020 19CON T E N TS
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. • W
hen 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 20CON T E N TS
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 D O O R WE D G ES
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 21CON T E N TS
5 PROCESSING
1 Introduction 2 5.7 Fasteners is recommended. This model components to achieve optimal
2 Accoya wood largely follows the guidelines of product service life. Further it is
Accoya wood can be fixed in the the popular Cradle to CradleTM recommended to design in such
properties 3
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
4 Wood moisture
same general rules regarding 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 possible waste management life of the product.
5 Processing 17
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 dumping is the least. recommended that Accoya wood
7 Contact with
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.
11 Contact 51 end-of-life considerations (incineration)
• Burning The last resort should be
Accoya wood waste can be composting where Accoya wood
• Dumping
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 22CON T E N TS
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 23CON T E N TS
6 gluing
1 Introduction 2 6.1 Changed properties as a catalyst and those consisting • With water based adhesives,
2 Accoya wood of two or more components that possibly increase the clamp time
Comprehensive testing has shown could migrate differently may or press time to allow the water
properties 3
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
4 Wood moisture
that the product’s modified 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 adhesive, especially acid catalysed
8 Weathering 33
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 moisture content of Accoya finished product should be fit
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 24CON T E N TS
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 stability of the Accoya fingers
the frame corner joint connection
Non-metals 30 watertight to avoid possible paint (reducing the self clamping benefit
performance problems and after adhesive application), it
8 Weathering 33
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 25CON T E N TS
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 water-repellent stain finishes 6.7 Best practice • Protecting end grain
7 Contact with
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
require moisture for hardening can essential when used in Glulam
for moisture vertical grain on surfaces to
Non-metals 30 mimimise checking and water
be affected by the particularly low applications, and therefore the management in
8 Weathering 33 moisture content of Accoya. ingress points
Accoya Warranty will only apply glulam beams
9 Coatings 41 to Glulam applications where this includes: • A robust adhesive to
Testing has so far been undertaken
guidance and moisture exclusion prevent delamination and
10 Fire behaviour 48 on Accoya wood by Dynea and
is achieved and maintained. moisture ingress
Henkel, in accordance with EN301
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 26CON T E N TS
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
therefore strongly recommended with a high risk of condensation (for
10 Fire behaviour 48
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 27CON T E N TS
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 are not available, coated fixtures
(brass containing tin) and higher
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 corrosion resistant in direct can be considered for those
5 Processing 17
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 It should be noted that the
5052, 3052 and 1100, since they
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 that can be cited.
acetic acid.
corrosion resistant stainless steel
fasteners known to work well
S TA I N L E S S S T E E L G R A D E S P E C I F I C AT I O N S
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
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