Anodised Aluminium
Whitepaper
Seven outstanding features of anodising and how
they relate to modern building design
This document has been prepared by Australian Aluminium Finishing Pty Ltd (AAF)
for distribution through Cirrus Media. For further information refer to back page.
www.aafonline.com.au
Colours and finishes are critical
components of architect’s
designs. Decades after
construction the finishes of
building components should
ideally be just as pure as when
the projects were completed.
Ann C. Sullivan
Architect, journalist & technology editor
for Architecture Magazine, USA
2
Cover image: National Bank, Docklands. Evershield “Diamond Light” Louvre blades
Introduction
Aluminium alloy is a highly versatile material that has allowed
architects and building designers to usher ideas into the physical
world. From curtain walls to shop fronts, sun louvres to decorative
featured-if your project is architectural, odds are that aluminium
features in one form or another.
Aluminium weighs 60 percent less than steel and required
considerable less maintenance2. It also won’t degrade on external
walls like timber does3.
Aluminium naturally forms a thin and relatively soft oxide layer
on its outer surface, however there is one special process
that enhances alloy whilst still preserving its natural beautiful
appearance. This process is called anodising.
Since it saw common use in construction, Anodising has been
considered best practice for finishing architectural aluminium4
and is specified for its robust, weather resistant composition that
protects the very base of the metal.
In anodising, the process conditions are controlled so that the
surface is grown and transformed. Ultimately, this process
creates products whose finish has amazing and unique properties
combined with extraordinary durability.
3
* White Paper on Anodising (http://www.aafonline.com.au/content/download/14530/253552/file/White-Paper-Anodising.pdf)
** KMH Environmental Impact Comparison (http://www.aafonline.com.au/content/download/5528/85066/file/KMH-Environmental-ReportAnodising-Vs-PowderCoating.pdf)
The Proof is in
the Building
Sydney’s AMP Centre (1962)
Located at Sydney’s Circular Quay, it’s hard to miss the dramatic metallic
curtain walling of the iconic AMP Building.
At 26 stories it was Australia’s first skyscraper. When Peddle Thorp &
Walker (PTW) designed the tower back on the 1960’s, a key provision was to
incorporate technological strategies that were to guide industry standard for
the next half of the 20th century. And they delivered1.
One enduring element that contributed to the building’s status as an industry
yardstick is its anodised aluminium framing1A – an element that has remained
largely untouched since completion.
AMP 1962
4
AMP 2015
7 Wonders of High
Grade Anodising*
5
E
Environment & Sustainability
N
Natural Beauty
D
Durability
L
Lustres & Colours
E
Edge-Cover
S
Seaside Applications
S
Security. Warranty & Accreditation
Independent sustainability analysis confirms the significant advantages of anodising in the
environment. Powder coatings principally embody large petro-chemical based products and
polymers**
Anodising is the transformation of the aluminium itself into a natural metallic finish.
In modern building design anodising complements and blends with other natural
building materials.
In everyday use we touch anodised products such as iPhones and kitchenware. With hardness
comes durability, and Evershield High Grade anodising rates 9 on MOHS scale of hardness,
comparable to rubys/corundum. Iconic anodised Australian buildings, now exceeded 50 years and
still in great condition.
AAF’s Evershield new colour range includes “Illustro” finishes. A unique mid-range
lustre providing a silky feel, touch and look. Anodising bright finishes provide exceptional
gloss readings.
In the paint/powder industry “edge pull” refers to pulling back from edges leaving lower
film builds creating weak points. Anodising’s immersion process is deal for perforations,
punching or indeed any aluminium extrusion.
High grade anodising is incomparable when it comes to durability in seaside locations.
AAF Evershield “Coastal” provides added protection, with proven durability and suitability
for architectural seaside locations.
All anodising is not the same. Specifying AAF EverShield High Grade Anodising is
supported by Third Party Accreditation and the AAF warranty programme.
* White Paper on Anodising (http://www.aafonline.com.au/content/download/14530/253552/file/White-Paper-Anodising.pdf)
** KMH Environmental Impact Comparison (http://www.aafonline.com.au/content/download/5528/85066/file/KMH-Environmental-ReportAnodising-Vs-PowderCoating.pdf)
Environment and
Sustainability
A recent example of the use of anodising in
modern building design is the 6 Green Star
building at 8 Chifley Square in Sydney.
One key feature included an integrated
externally shaded façade. Solar shading
anodised by AAF Evershield High Grade
Anodising.
6
Anodising contains no petro-chemically
based products. In powder coating
there “is a large energy embodiment in
the chemicals and polymers used”
(KMH report)
Our future depends on us all acting in a
sustainable way and thinking creatively about
how we impact our environment and our
communities. High grade anodising meets those
requirements and exceeds all other comparable
forms of aluminium finishing.
A 2010 Environmental Impact Assessment
prepared by KMH Sustainable Infrastructure5
provides an independent Environmental Impact
Comparison between anodising and powder
coatings based on a 100 year lifecycle analysis
(LCA). Results showed that anodising has
almost half the required energy component
compared to polyester powder coating and
performs better both in terms of energy used
(kWh) and greenhouse gas emissions (CO2-e).
Why does anodising outperform it’s
alternatives?
For starters, paints and powders are petrochemical based organic finishes. These are
generally more susceptible to the effects of UV
light and weather over time. Even high grade
polyesters will eventually be impacted by colourfade, loss of gloss and chalking which all can
limit the finish service life. Anodising, on the
other hand, just like its base alloy, is 100% and
indefinitely recyclable. The finish is integral to
the alloy, a much harder finish and cannot
peel off.
As also highlighted by the KMH report, “the
lower energy consumption in recycling,
chemicals and gas for anodising corresponds
to lower GHG emission …”5
7
A building by Mirvac/Rogers Stirk & Partners and Lippmann Partnership.
Natural Beauty
Anodising is the transformation of the metal itself, creating
a remarkable natural finish that outlasts almost any finish
available. Paints and Powders are petro chemical based
products applied onto the base aluminium. Anodising, due
to this natural metal composition, creates an unsurpassed
metallic finish that is available in various lustres and
colours. Anodising complements and blends with other
natural building materials such as timber, bricks, concrete
& steel. Anodising is natural and enhances other finishes.
Dragonscale by Lockers is carefully formed to
provide a three-dimensional, textural element
to an installation, without the use of traditional
perforating or expanding techniques. The
anodising process provides full edge cover
and outstanding durability of the natural
metallic finish.
The anodised façade on the new 2014 stand
at the Sydney Cricket Ground complements
the original brick heritage-listed Clock Tower.
Finish AAF Evershield high grade anodising,
colour Jamaican Chocolate. Façade cladding
& screens by the Townsend Group.
8
Durability
The anodising immersion process is a transformation of
the surface of the original metal into an incredibly hard
and metallic finish. In an everyday sense, we are touching
and/or using anodised products. Other examples include
scientific instruments, protecting satelites from the harsh
enviroment of space plus a full range of building products.
It is extremely hard, durable, and easy to clean and
maintain. For example, AAF Evershield High Grade
architectural anodising rates 9 on the MOHS scale of
hardness, equal to Rubys (corundum) and just below a
diamond.
In an everyday sense, we touch
anodised products on iPhones, tablets,
kitchenware etc. It is extremely hard,
durable, and easy to clean & maintain.
After 35 years the Centre Point Tower
in Sydney is another example of the
extraordinary durability of high grade
anodising. Maintaining its brilliant gold colour
and lustre, it still stands proud and reflective
Extensive anodising by AAF and others within
Federation Square blends with many other
finishes on this iconic Melbourne building
9
There are now many examples, such as the AMP Circular
Quay, Sydney, of the durability of high grade anodising in
Australian landmark buildings. Now over 50 years old, and
still in good condition.
Lustres, Colours and
Consistency
Today there are new colouring technologies to create
colour derivations of existing technology. Additionally,
there is a variety of lustres available including, matt/ satin,
bright and new mid-range lustres.
In 2015 AAF is launching a new mid-range anodising
lustre. With a new soft and silky feel it offers a new
dimension in appearance and reflectivity. Powder coatings
offer a great variety of colours, but anodising companies
such as AAF, now also offers an impressive range of
colours and lustres. The AAF Evershield Cosmic range of
colours has recently introduced new shades of grey and
stainless steel metallic appearances.
New technology, through the use of spectrophotometry,
is now used by some anodisers to measure and manage
colours between loads, improving the consistency of
finishes. For cladded facade projects where colour
consistency is key, it is also important to liaise with the
anodiser prior to metal procurement so they can also
advise on improving final consistency via management of
consistently supplied alloy products.
When combined with many new colours and lustres, anodising
choices available today have expanded significantly.
Colour Consistency
Colour matching techniques have improved
significantly. Under strict specification
requirements photospectometer testing
was used on 7,000 anodised panels for the
podium level of the Shanghai Mori Tower,
the highest structure in China. Contractor
Permasteelisa, and anodised by AAF in their
Sydney plant.
10
Example of some of AAF Evershield
warranty grade colours:
Matt
Platinum (E87CM)
Stella Grey (E78NM)
Star Dust (E70NM)
Apollo Grey (E66NM)
Sea Breeze (E67TM)
Portland Stone (E60TM)
Amber Gold (E42TM)
Jamaican Chocolate (E35TM)
Burnt Sienna (E29TM)
Ebony (E26TM)
Summer Maize (E82GM)
Sovereign Gold (E78GM)
Palladium Coin (E87CL)
Aztec Silver (E68NL)
Monaco Stone (E64TL)
Medallion Bronze (E45TL)
Bronze Monument (E30TL)
Gun Barrel (E26TL)
Gold Odyssey (E78GL)
Smokey Quartz (E60TG)
Smooth Onyx (E25TG)
Illustro
Bright
Diamond Light (E87CG)
11
Burnished Gold (E80GG)
Edge-Cover
What is edge pull?
Powder and paints are primarily applied through spray
systems. A coating applied to a sharp edge will pull back
from the edge, leaving the edge with a lower film build6.
This is known as “edge pull” and creates weak points
which are more susceptible to edge corrosion.
Anodising’s winning edge cover
avoids the weak points that
arise on paint/powder coating
finishes.
How does anodising solve the problem?
The anodising process overcomes this issue in two ways.
Firstly, the etching process is comparatively much more
vigorous so has the effect of smoothing sharp edges.
Secondly, the anodic film then evenly grows the protective
oxide layer around all surfaces, including edges and
avoiding weak points around sharp edges.
Why is it important?
The anodising process provides a significant advantage
in the durability of finishing any aluminum with sharper
edges, from perforations, punching, louvres or screen
edges or any aluminium extrusions generally.
Anodising
Powder Coating
Edge Pull
12
Anodonic Layer
Powder Coating
Aluminium
Aluminium
The Five Dock, Sydney, Audi “Terminal” constructed in 2008 was the
world’s first in this design. The long term durability of the edge surfaces
is paramount to maintain the brilliance and metallic lustre of the façade.
Anodised in AAF Evershield “Diamond Light”. (Disclaimer: Not all Audi
terminals are anodised by AAF).
The immersion anodising and
etching process provides
extraordinary edge coverage.
13
Sea-Side
Applications
High grade anodising is incomparable when it comes to
durability in seaside locations7. The higher salt (chloride)
content in the sea-side air can significantly impact the
durability for many finish options, whether for aluminium or
other metals.
High grade anodising is long known for its excellent
protection of aluminium in coastal locations. AAF also
offer an Evershield COASTAL warranty grade anodising
which is engineered to provide even greater protection of
architectural aluminium components in seaside locations.
Newport Beach House: Everhield® Burnt Sienna
14
Award Winning Boheme, Bondi Beach, anodised in AAF
Evershield Coastal Grade, colour “Platinum”. Winner of
the Fenestration Australia 2013 Award for the best use of
anodising.
Security – not all
anodising is the same
Accreditation
Third Party Accreditation has become an essential part of
the Australian building industry8. The Australasian Institute
if Surface Finishing recently outlined and launched a Third
Party Accreditation program for anodisers. Companies such
as AAF have joined the inaugural programme to reinforce
support for consistent anodised quality in the industry.
Anodising extensive warranties
Due to extraordinary durability of high grade anodising,
extensive warranty periods are available. Refer to the AAF
website for details on AAF Evershield warranty Grade
anodising.9
www.aafonline.com.au
25 Year
Performance Warranty
In summary –
anodising is the real deal
The real case for Anodising is its natural metallic lustre finish. Anodising increases the thickness of
the natural oxide layer on the surface of metal parts rather than adding a layer of paint or powder. Its
immersion process ensures all the surfaces are equally coated all the way to (and including) the edge
which is especially important for louvres, solar shading, perforations and extrusion, and is something
powder coating’s ‘edge pull’ cannot achieve.
The final result is a real metallic finish that is highly sustainable, looks great and will genuinely change
with light and weather conditions depending on reflectivity and season.
15
References
1
Rathi, Prof. M.K. & Patil, A.K., “Use of Aluminum in Building construction”, Civil Engineering Portal, 2013
http://www.engineeringcivil.com/use-of-aluminium-in-building-construction.html
1A Australian institute of Architects, “The AMP Building Sydney Cove”, 2013
http://dynamic.architecture.com.au/awards_search?option=showaward&entryno=2012022993
2
Vectran Fiber, “Tensile Properties”, 2010
http://www.vectranfiber.com/BrochureProductInformation/TensileProperties.aspx
3
Costmodelling Limited, “Typical Life Expectancy of Building Components”
http://www.costmodelling.com/downloads/BuildingComponentLifeExpectancy.pdf
4
Service One Inc, “ Maintenance and Restoration of Architectural Aluminum”
http://www.denkalift.com/documents/SOI_Technical_Paper_on_Architecural_Aluminum.pdf
5
KMH Sustainable Infrastructure, “ Environmental Impact Comparison of Fluoropolymer Powder Coating,
Polyester Powder Coating and Anodising Procedure”, 2010
http://www.aafonline.com.au/content/download/5528/85066/version/1/file/KMH+Environmental+Report+
Anodising+vs+Powder+Coating.pdf
6
Dulux Powder Coating, “Hot Dip Galvanising”, September 2009
http://www.duluxprotectivecoatings.com.au/technotespdf/1.2.5%20HDG%20-%20Painting%20Considerations.pdf
7
Gonzalez, J.A. et al, “The Behavior of Anodized Aluminum in Sea and Brackish Water”, 1994
8
AI Group, “Non-conforming product research project”, 2013
http://www.aigroup.com.au/portal/site/aig/standards/nonconformingproductresearch/
9
AAF, “Standards, compliance certification and traceability”
http://www.aafonline.com.au/specifiers_warranty/terminology_explained
This document has been prepared by Australian Aluminium
Finishing Pty Ltd (AAF) for distribution through Cirrus Media.
With four anodising plants located in Sydney, Melbourne
and Brisbane, AAF is the largest anodiser in Australia.
Evershield® high grade anodising is AAF’s warranty
grade process.
Powder coating: AAF also operates powder coating facilities
in each of the same locations which are licensed and audited
to the international Qualicoat Standard. There are many
features and benefits of powder coating which are well
promoted by powder manufacturers. This paper is to explain
some of the unique features of anodising.
www.aafonline.com.au
AUSTRALIAN ANODISING
ASSOCIATION
Environmental Impact Comparison
of Fluoropolymer Powder Coating,
Polyester Powder Coating and
Anodising processes
Prepared for: Australian Anodising Association
Prepared by: KMH Sustainable Infrastructure
Report Number: KMH 4010213 Rev 0
Date: XX November 2010
PROJECT NUMBER: KMH 4010213
DOCUMENT NUMBER: KMH 4010213 REPORT 101123
REV
0
DESCRIPTION
Report
PREPARED
BY
REVIEWED
BY
APPROVED
BY
DATE
SN
TT
GL
23/11/2010
LIMITATIONS STATEMENT
This report has been prepared in accordance with the scope of services agreed upon by the above
named client and KMH Sustainable Infrastructure. To the best of KMH’s knowledge, the information
presented herein represents the above named client’s intentions at the time of printing the report. In
preparing this report, KMH has relied upon data, surveys, analyses, plans and other information
provided by the above named client and other individuals and organisations. Except as otherwise
stated in this report, KMH has not verified the accuracy or completeness of such data, surveys,
analyses, plans and other information. The information presented herein is copyright KMH.
KMH 4010213 Report 101123
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TABLE OF CONTENTS
1.
2.
2.1.
2.2.
2.3.
2.4.
2.5.
2.6.
2.7.
3.
INTRODUCTION ...................................................................................................................... 4
LIFE CYCLE ANALYSIS........................................................................................................... 4
Primary Production of Virgin Aluminium ................................................................................... 4
Surface Coating Energy Consumption ..................................................................................... 4
Surface Coating Profile ............................................................................................................. 5
Aluminium Recycling Energy Consumption.............................................................................. 5
Surface Coating Life Expectancy ............................................................................................. 5
Emission Factors ...................................................................................................................... 6
Alternative Energy Emission Factors ........................................................................................ 6
SUMMARY AND CONCLUSION ............................................................................................ 12
TABLES
Table 1 Anodising energy consumption and GHG footprint ........................................................... 7
Table 2 Fluoropolymer Powder Coating energy consumption and GHG footprint ......................... 8
Table 3 Polyester Powder Coating energy consumption and GHG footprint ................................. 9
Table 4 Energy used for production of 1 tonne of surface coated aluminium .............................. 10
Table 5 GHG footprint for production of 1 tonne of surface coated aluminium (100 year life cycle)
(tCO2-e per tonne of Al produced) ................................................................................................. 11
FIGURES
Figure 1 Energy use (100 year life cycle) for production of 1 tonne of surface coated aluminium
....................................................................................................................................................... 10
Figure 2 GHG footprint for 100 year life cycle production of 1 tonne of surface coated aluminium
....................................................................................................................................................... 11
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1. INTRODUCTION
KMH Sustainable Infrastructure has been engaged to provide an Environmental Impact
Assessment on the Anodising and Polyester Powder Coating processes. The Australian Institute
of Surface Finishers (AISF) seek a review of the full life-cycle energy and environmental data
available for Anodising, Fluoropolymer Powder Coating and Polyester Powder Coating. Much of
the data has been developed from local industry information including association members. This
data has been used to calculate energy consumptions for the various steps in the production of
coated aluminium products, all on the basis of kilowatt-hours per tonne of aluminium product
(kWh/tonne of Al), and the associated greenhouse gas (GHG) emissions in carbon dioxide
equivalents per tonne of aluminium produced (CO2-e/tonne of Al).
The whole product life-cycle assessment has been completed in accordance with the Australian
Competition and Consumer Commission‟s (ACCC) Green marketing and the Trade Practices Act
1
and includes the manufacturing, recycling, destruction and disposal process. This document
specifically recommends the use of whole product life-cycle as one of a number of principles to
be followed when making claims about a particular product.
2. LIFE CYCLE ANALYSIS
The product Life Cycle Assessment (LCA) methodology uses actual figures, such as those for
energy consumption, emissions to the environment and materials used for both the Anodising,
Fluoropolymer Powder Coating and Polyester Powder Coating processes and for aluminium
section primary production and recycle processes. This data is separated into stages of the lifecycle and all other factors considered are outlined in this review.
2.1. Primary Production of Virgin Aluminium
The life cycle of 1 tonne of surface coated aluminium begins with the primary production of virgin
aluminium, a highly energy intensive process involving mining, shipping, refining and smelting,
with major electric and fuel consumptions, as well as the considerable embodied energy in the
chemicals used. This is followed by reheating and forming, including casting, forging, extrusion
and rolling processes, to produce the sections and other products required. The surface coating
process involves the use of chemicals, electricity, fuel and gas heating energy.
Electricity and gas consumption in terms of energy per tonne of aluminium production and GHG
emissions per tonne of aluminium for both manufacturing processes are displayed in Table 1 for
the Anodising process, Table 2 for the Fluoropolymer Powder Coating and Table 3 for the
Polyester Powder Coating process. The process steps, including the manufacture of chemicals
consumed, are separated into corresponding electricity, fuel and gas consumption figures per
tonne of aluminium. Because Anodised, Fluoropolymer Powder Coated and Polyester Powder
Coated products all involve the same primary production these energy figures have been omitted
from the comparison.
2.2. Surface Coating Energy Consumption
KMH has obtained site specific energy and production data for the past 12 months from a total of
three Anodising, Fluoropolymer Powder Coating and Polyester Powder Coating manufacturing
process sites along the eastern seaboard of Australia, including a site visit in Victoria. Additional
data has also been obtained from the Australian Aluminium Finishing (AAF) members. An
average based on throughput (kWh/tonne of Al) of the three sites in Australia has been used to
calculate Electricity and Gas consumption per tonne of Aluminium product. Production and
performance data for the three processes was used to calculate energy consumption (kWh) and
2
2
GHG emissions. Based on average production a figure of 2.3 – 2.4kg/m or 0.426m /kg has been
used.
1
Australian Competition and Consumer Commission (ACCC) 2008, Green marketing and the Trade Practices Act,
http://www.accc.gov.au/content/item.phtml?itemId=815763&nodeId=69646a6d15e7958a41b40ab5848c6968&fn=Green%
20marketing%20and%20the%20Trade%20Practices%20Act.pdf
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2.3. Surface Coating Profile
Coating depth or „thickness‟ is the principal energy affecting variable in the actual Anodising,
Fluoropolymer Powder Coating and Polyester Powder Coating processes. Anodising coating
thickness generally varies from 5 to 25 micron depending on the duty, and 20 micron has been
assumed for the present exercise, this has been suggested as best representing the most
frequently used product in Australia.
Fluoropolymer Powder Coating thickness generally varies from 2 to 50 micron depending on the
duty, and 50 microns has been assumed as a comparable coating for the present exercise, again
representing the most „popular‟ product.
Polyester Powder Coating finish thickness to a large extent determines the useful life of the
coating and following the Australian Standard 3715 (2002) for architectural applications a 60
micron coating has been employed for the present exercise.
2.4. Aluminium Recycling Energy Consumption
After the surface coating reaches the end of its functioning life, the aluminium can be recycled.
This involves cleaning, melting, casting and then the forming processes. The recycled aluminium
can then be re-coated through a repeat of the surface coating process.
Surface coated aluminium is fully recyclable along with its aluminium substrate without any loss
of its metal qualities.
Recycling surface coated aluminium involves melting the scrap metal down. This process
requires about five (5%) percent of the energy used to produce aluminium from ore. Recycling of
aluminium emits approximately four (4%) percent of the CO2-e as for primary production of
2
aluminium.
However, a significant part (up to 15% of the input material) is lost as dross (ash-like oxide). The
dross can undergo a further process to extract aluminium. This complexity has not been included
in the present considerations, it is highly energy intensive.
2.5. Surface Coating Life Expectancy
The estimated end of life for Anodised, Fluoropolymer Powder Coating and Polyester Powder
Coated aluminium has been taken as 50, 40 and 25 years respectively. Anodised and
Fluoropolymer Powder Coating years of serviceability have been provided based on reasonable
evidence in industry.
The Japanese Society of Steel Construction Authority (2002) claim that the anti-corrosive effect
3
of a heavy duty Fluoropolymer Powder Coating in general environment lasts up to 50 years . A
severe environment (very salty and severely polluted by exhaust gases or factory smog) is up to
30 years. The average of the two environments (40 years) has been assumed for this exercise
and has been confirmed by the industry experience in Australia.
Architectural Polyester Powder Coating has a life expectancy standard of maximum 10%
4
reduction in erosion resistance properties over 5 years . The end of life for Polyester Powder
Coated aluminium is assumed to be when 50% loss in erosion resistance properties has
occurred. This is deemed to be a sufficient loss of thickness that factors such as dulled
appearance, protective function and potential for corrosion cause the product quality to be
sufficiently diminished that it is ready for replacement. Therefore, a 25 year life has been
2
Subodh K.Das, Secat, Inc., 2007, „Aluminium Recycling and Processing for Energy Conservation and Sustainability‟,
Chapter 9, Emerging Trends in Aluminium Recycling.
3
Lumiflon catalogue „Fluoropolymer for coating‟,
http://www.alpolic-usa.com/media/download_gallery/Lumiflon_Catalogue.pdf
4
Taken from AAMA coating performance standard AAMA 2604-05.
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estimated for Polyester Powder Coated aluminium based on the life expectancy standard of 10%
in erosion resistance properties every 5 years.
A 100 year life cycle has been chosen to represent a reasonable life cycle assessment. For a
100 year life cycle, the Anodised aluminium will be recycled once and go though the anodising
process twice. Fluoropolymer Powder Coating will be recycled two (2) times and coated three (3)
times. Polyester Powder Coated aluminium over a 100 year life cycle will be recycled a total of
three (3) times and coated four (4) times.
Totals in Table 1, Table 2 and Table 3 can be used to look at alternative life cycle years. These
totals are annual amounts that can be multiplied by the number of coatings and recycles that will
occur in the investigated life cycle period.
2.6. Emission Factors
The emission factors for electricity, gas and diesel oil (fuel) consumed in the LCA come from the
Department of Climate Change workbook National Greenhouse Accounts (NGA) Factors (June
5
2009) . Due to variability in emission factors between Australian States and Territories, New
South Wales (NSW) and Australian Capital Territory (ACT) have been used to estimate a point of
reference of emissions to the environment. Any use of the present study results needs
qualification with respect to the energy emission factors employed in the study. It is likely that the
variations from state to state will affect the results to a large degree, but it is certain that any
comparisons of emission factors will still favour Anodising as the more energy efficient
alternative.
For electricity consumption, the full fuel cycle emission factors were utilised. These consist of
Scope 2 (Indirect) (0.89 kgCO2-e/kWh) and Scope 3 (0.18 kgCO2-e/kWh) emission factors for
consumption of purchased electricity from the grid.
The full fuel emission factors for natural gas distributed in a pipeline include both Scope 2
(indirect) (51.33 kgCO2-e/GJ) and Scope 3 (16.4 kgCO2-e/GJ). For NGA calculations, a “small
user” has been assumed and is defined as one with an annual gas consumption of less than
100,000 GJ.
The Diesel oil full fuel emission factors for the “fuel” used in the production and chemical process
include both Scope 1 (direct) (69.5 kgCO2-e/GJ) and Scope 3 (5.3 kgCO2-e/GJ).
In Australia, electricity from the grid in NSW and ACT has the second highest emission factor (full
fuel cycle) 1.07 kgCO2-e/kWh after Victoria 1.35 kgCO2-e/kWh. Tasmania is the lowest at 0.24
kgCO2-e/kWh with Northern Territory the next lowest at 0.79 kgCO2-e/kWh.
Scope 3 emission factors (small user) for Natural gas from NSW and ACT are the highest in
Australia at 16.4 kgCO2-e/GJ. South Australia is 13.9 kgCO2-e/GJ and all other States and
Territories are less than 5 kgCO2-e/GJ.
2.7. Alternative Energy Emission Factors
Energy efficiency measures and alternative forms of energy can have a strong impact on
improving the environmental impact of all three investigated processes. Energy efficiency can
also potentially reduce overall costs. The reduction in energy consumption throughout the lifecycle will directly reduce the amount of GHG emissions produced. Alternative forms of energy
with a lower emission factor may also reduce the environmental impact. The energy content
factor (GJ/kL) of the alternative fuel and its source of origin is used to determine the feasibility of
reducing emissions with regards to the volume of fuel combusted and energy used for
transporting or supplying the fuel.
5
Department of Climate Change 2009, National Greenhouse Accounts (NGA) Factors,
http://www.climatechange.gov.au/~/media/publications/greenhouse-gas/national-greenhouse-factors-june-2009-pdf.ashx
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Table 1 Anodising energy consumption and GHG footprint
Aluminium Primary Manufacture (Anodising)
Total Mining, refining, smelting and transport (Elec.)
Total Mining, refining, smelting and transport (Fuel)
Casting processes (Electricity)
Casting processes (Fuel)
Forging/rolling/extrusion (Electricity)
Forging/rolling/extrusion (Fuel)
Conventional machining (Electricity)
Conventional machining (Fuel)
TOTAL
Anodising Chemicals
NaOH (Electricity)
NaOH (Fuel)
HNO3 (Electricity)
HNO3 (Fuel)
H3PO4 (Electricity)
H3PO4 (Fuel)
H2SO4 (Electricity)
H2SO4 (Fuel)
Nickel Acetate Seal: Sealing (hot or cold) (including
mining and refining) (Electricity)
Nickel Acetate Seal: Sealing (hot or cold) (including
mining and refining) (Fuel)
TOTAL
Recycle: Melting (energy used to recycle aluminium at
the end of life (50 years) is 5% of the energy used to
produce aluminium from ore and only 4% as much CO 2e as primary production)
Anodising Process: Electricity and Gas
Electricity
Gas
TOTAL
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Energy Consumption
(kWh/kg of Al)
43.6 - 50.3
11.1
0.4 - 0.5
0.2
0.6 - 0.9
0.3
0.9 - 1.1
0.5
Average Energy
Consumption (kWh
per tonne of Al)
46,944
11,111
431
222
778
333
1,042
528
61,389
GHG emission
Annual GHG
factor (kgCO2- footprint (TCO2-e
e/kWh)
per tonne of Al)
1.07
0.27
1.07
0.27
1.07
0.27
1.07
0.27
50.23
2.99
0.46
0.06
0.83
0.09
1.11
0.14
55.9
GHG emission
Annual GHG
factor (kgCO2- footprint (TCO2-e
e/kWh)
per tonne of Al)
Energy Consumption
(kWh/kg)
Annual Energy
Consumption (kWh
per tonne of Al)
2.1 - 2.9
1.5
-0.09
0
0.6 to - 0.7
1.1
-0.27 to - 0.33
0
237
85
-14
0
-15
26
-130
0
1.07
0.27
1.07
0.27
1.07
0.27
1.07
0.27
0.0027
0.0004
0.0001
0
0.0007
0.0003
0.0003
0
2.8 - 5.6
2
1.07
0.0045
8.3
3
0.27
0.0022
194
0.011
3,069
2.237
Energy usage per
tonne production
(kWh/tonne of Al)
1529.7
1910.9
3,440.6
Annual GHG
GHG emission
emissions (TCO2factor (kgCO2e per tonne of
e/kWh)
Al)
1.64
1.07
0.47
0.24
2.10
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Table 2 Fluoropolymer Powder Coating energy consumption and GHG footprint
Aluminium Primary Manufacture
(Fluoropolymer Powder Coating)
Total Mining, refining, smelting and transport (Elec.)
Total Mining, refining, smelting and transport (Gas)
Casting processes (Electricity)
Casting processes (Gas)
Forging/rolling/extrusion (Electricity)
Forging/rolling/extrusion (Gas)
Conventional machining (Electricity)
Conventional machining (Gas)
TOTAL
Fluoropolymer Powder Coating Chemicals
Average Energy
Energy Consumption
Consumption (kWh
(kWh/kg of Al)
per tonne of Al)
43.6 - 50.3
11.1
0.4 - 0.5
0.2
0.6 - 0.9
0.3
0.9 - 1.1
0.5
46,944
11,111
431
222
778
333
1,042
528
61,389
Annual Energy
Energy Consumption
Consumption (kWh
(kWh/kg)
per tonne of Al)
GHG emission
Annual GHG
factor (kgCO2- footprint (TCO2-e
e/kWh)
per tonne of Al)
1.07
0.27
1.07
0.27
1.07
0.27
1.07
0.27
50.23
2.99
0.46
0.06
0.83
0.09
1.11
0.14
55.9
GHG emission
Annual GHG
factor (kgCO2- footprint (TCO2-e
e/kWh)
per tonne of Al)
Pre-treatment: Pre-cleaner - HF (including mining and
refining of fluorspar and heating of kilns) (Electricity)
2.8 - 5.6
49.6
1.07
0.0045
Pre-treatment: Pre-cleaner - HF (including mining and
refining of fluorspar and heating of kilns) (Fuel)
8.3
99.3
0.27
0.0022
-0.28 to -0.33
0
2.8 - 5.6
8.3
3.9 - 5.6
10.0
19.4 - 20.8
9.7
22.2 - 26.1
11.1
-2.4
0.0
2.0
4.0
10.4
22.1
78.1
37.7
93.7
43.1
438
1.07
0.27
1.07
0.27
1.07
0.27
1.07
0.27
1.07
0.27
0.0003
0
0.0045
0.0022
0.0051
0.0027
0.0215
0.0026
0.0259
0.0030
0.07
Pre-treatment: Pre-cleaner - H2SO4 (Electricity)
Pre-treatment: Pre-cleaner - H2SO4 (Fuel)
Pre-treatment - HF (Electricity)
Pre-treatment - HF (Fuel)
Pre-treatment - H2CrO4 (Electricity)
Pre-treatment - H2CrO4 (Fuel)
Powder – Polymer (30%-60%) (Electricity)
Powder – Polymer (30%-60%) (Fuel)
Powder – Pigment (30%-60%) (Electricity)
Powder – Pigment (30%-60%) (Fuel)
TOTAL
Recycle: Melting (energy used to recycle aluminium at
the end of life (40 years) is 5% of the energy used to
produce aluminium from ore and only 4% as much CO2e as primary production)
3,069
Fluoropolymer Powder Coating Process:
Electricity and Gas
Energy usage per
tonne production
(kWh/tonne of Al)
Electricity
Gas
TOTAL
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247.9
3269.2
3,517.1
2.237
Annual GHG
GHG emission
emissions (TCO2factor (kgCO2e per tonne of
e/kWh)
Al)
0.27
1.07
0.80
0.24
1.06
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Table 3 Polyester Powder Coating energy consumption and GHG footprint
Aluminium Primary Manufacture
(Polyester Powder Coating)
Total Mining, refining, smelting and transport (Elec.)
Total Mining, refining, smelting and transport (Gas)
Casting processes (Electricity)
Casting processes (Gas)
Forging/rolling/extrusion (Electricity)
Forging/rolling/extrusion (Gas)
Conventional machining (Electricity)
Conventional machining (Gas)
TOTAL
Energy Consumption
(kWh/kg of Al)
43.6 - 50.3
11.1
0.4 - 0.5
0.2
0.6 - 0.9
0.3
0.9 - 1.1
0.5
Average Energy
Consumption (kWh
per tonne of Al)
46,944
11,111
431
222
778
333
1,042
528
61,389
GHG emission
Annual GHG
factor (kgCO2- footprint (TCO2-e
e/kWh)
per tonne of Al)
1.07
0.27
1.07
0.27
1.07
0.27
1.07
0.27
50.23
2.99
0.46
0.06
0.83
0.09
1.11
0.14
55.9
GHG emission
Annual GHG
factor (kgCO2- footprint (TCO2-e
e/kWh)
per tonne of Al)
Energy Consumption
(kWh/kg)
Annual Energy
Consumption (kWh
per tonne of Al)
Pre-treatment: Pre-cleaner - HF (including mining and
refining of fluorspar and heating of kilns) (Electricity)
2.8 - 5.6
49.6
1.07
0.0045
Pre-treatment: Pre-cleaner - HF (including mining and
refining of fluorspar and heating of kilns) (Fuel)
8.3
99.3
0.27
0.0022
-0.28 to -0.33
0
2.8 - 5.6
8.3
3.9 - 5.6
10.0
19.4 - 20.8
9.7
-2.4
0.0
2.0
4.0
10.4
22.1
93.7
45.2
1.07
0.27
1.07
0.27
1.07
0.27
1.07
0.27
0.0003
0
0.0045
0.0022
0.0051
0.0027
0.0215
0.0026
22.2 - 26.1
112.4
1.07
0.0259
11.1
51.7
0.27
0.0030
Polyester Powder Coating Chemicals
Pre-treatment: Pre-cleaner - H2SO4 (Electricity)
Pre-treatment: Pre-cleaner - H2SO4 (Fuel)
Pre-treatment - HF (Electricity)
Pre-treatment - HF (Fuel)
Pre-treatment - H2CrO4 (Electricity)
Pre-treatment - H2CrO4 (Fuel)
Powder – Polyester (30%-60%) (Electricity)
Powder – Polyester (30%-60%) (Fuel)
Powder – Pigment (30%-60%)
Bulk TiO2 for white colour (Electricity)
Powder – Pigment (30%-60%)
Bulk TiO2 for white colour (Fuel)
TOTAL
488
0.07
Recycle: Melting (energy used to recycle aluminium at
the end of life (25 years) is 5% of the energy used to
produce aluminium from ore and only 4% as much CO2e as primary production)
3,069
2.237
Polyester Powder Coating Process:
Electricity and Gas
Energy usage per
tonne production
(kWh/tonne of Al)
Electricity
Gas
TOTAL
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2335.1
2,583.1
Annual GHG
GHG emission
emissions (TCO2factor (kgCO2e per tonne of
e/kWh)
Al)
0.27
1.07
0.57
0.24
0.83
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Table 4 and Figure 1 show the life cycle energy consumption per tonne of aluminium production
for the Anodising and Polyester Powder Coating processes. The life cycle is based on 100 years
with Anodising and Polyester Powder Coating life cycles being 50, 40 and 25 years respectively.
The processes are separated into the chemicals, electricity, and gas consumption and recycling
process. The primary production of aluminium is a large amount and is only used for the
calculation of energy and GHG emissions in the recycling process (see Section 2.4 Aluminium
Recycling Energy Consumption).
Table 4 Energy used for production of 1 tonne of surface coated aluminium
(100 year life cycle) (kWh per tonne of Al produced)
Process
Chemicals and
processing
energy
(including Al
original
production and
recycling)
Chemicals and
processing
energy
(including
recycling)
Chemicals
Electricity
Gas
Recycling
Anodising
(50 year life)
71,728
10,339
388
3,059
3,822
3,069
Fluoropolymer
Powder
Coating
(40 year life)
79,392
18,003
1,313
744
9,808
6,139
Polyester
Powder
Coating
(25 year life)
82,882
21,493
1,952
992
9,341
9,208
Energy consumption for production of 1 tonne of surface coated
aluminium (100 year life cycle) (kWh per tonne of Al)
25,000
20,000
kWh per tonne of Al
9,208
15,000
6,139
Recycling
Gas
Electricity
10,000
3,069
Chemicals
9,341
9,808
3,822
5,000
992
3,059
744
388
1,313
1,952
0
Anodising (50 year life)
Fluoropolymer Powder Coating (40 year Polyester Powder Coating (25 year life)
life)
Surface Coating Process
Figure 1 Energy use (100 year life cycle) for production of 1 tonne of surface coated aluminium
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Table 5 and Figure 2 show the GHG footprint, tonnes of CO2-e per tonne of aluminium
production for the Anodising, Fluoropolymer Powder Coating and Polyester Powder Coating
processes. The same life cycle of 100 years has been used to estimate the GHG emissions. The
primary production of aluminium is a high value and only used to calculate the emissions in the
recycling process (see Section 2.1 Recycling).
Table 5 GHG footprint for production of 1 tonne of surface coated aluminium (100 year life cycle)
(tCO2-e per tonne of Al produced)
Process
Chemicals and
processing
energy
(including Al
original
production and
recycling)
Chemicals and
processing
energy
(including
recycling)
Chemicals
Electricity
Gas
Recycling
Anodising
(50 year life)
62.4
6.5
0.02
3.3
0.9
2.2
Fluoropolymer
Powder
Coating
(40 year life)
63.8
7.9
0.22
0.80
2.4
4.5
Polyester
Powder
Coating
(25 year life)
66.3
10.3
0.30
1.06
2.3
6.7
GHG Footprint for production of 1 tonne of surface coated
aluminium (100 year life cycle) (tCO2-e per tonne of Al)
12
10
tCO2-e per tonne of Al
8
6.7
Recycling
6
4.5
Gas
2.2
Electricity
Chemicals
4
0.9
2.3
2.4
2
3.3
0.80
0.02
0
Anodising (50 year life)
1.06
0.22
0.30
Fluoropolymer Powder Coating (40 year
life)
Polyester Powder Coating (25 year life)
Surface Coating Process
Figure 2 GHG footprint for 100 year life cycle production of 1 tonne of surface coated aluminium
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3. SUMMARY AND CONCLUSION
The present study is an energy and carbon footprint comparison aimed at providing the
Association with a more representative answer to a published criticism of Anodising in
comparison with Polyester Powder Coating and subsequently compared to Fluoropolymer
Powder Coating. This study has focused on the energy consumption and related environmental
impact this has on the environment.
From the results of the 100 year Life Cycle Analysis (LCA), Anodising is better both in terms of
energy used (kWh) and greenhouse gas (GHG) emissions (CO 2-e) per tonne of aluminium
product. Over a 100 year life cycle Polyester Powder Coating has almost double the energy
component of the Anodising process and Fluoropolymer Powder Coating has approximately 45%
more total energy component than the Anodising process.
In this LCA, Anodising has been apportioned a longer cycle life (50 years) and is therefore
recycled less and uses less gas fuel and chemicals in the 100 year life cycle compared to the
Fluoropolymer Powder Coating (40 year life) and Polyester Powder Coating (25 year life)
process. However, the Powder Coating processes use significantly less in the way of direct
electricity consumption over the same life cycle, but there is large energy embodiment in the
chemicals and polymers used.
The lower energy consumption in recycling, chemicals and gas for Anodising corresponds to
lower GHG emissions (CO2-e) than Fluoropolymer Powder Coating and Polyester Powder
Coating. However, a major proportion (~50%) of the GHG emissions for the Anodising process is
from the consumption of electricity. Compared with the Polyester Powder Coating process, the
overall GHG emissions for Anodising amount to 38%, or 3.9 tCO2-e less, per tonne of
aluminium. Compared with the Fluoropolymer Powder Coating process, associated GHG
emissions are only 18%, or 1.4 tCO2-e less, per tonne of aluminium.
The surface treatment employed generally depends on the end-use or application. Anodised
products are best suited to storefronts, high-rise and commercial and public buildings, anywhere
a rich metallic appearance and long life is required. The corrosion protection afforded by
Anodising requires tight specification and control to ensure the correct Anodised film thickness is
obtained and that sealing efficiency is high, to maintain corrosion resistance and colour life.
Fluoropolymer Powder Coating is also used on commercial, industrial and residential buildings
due to the high durability, adhesion, colour and gloss retention based on the fluorinated ethylene
vinyl ether (FEVE) and carbon to fluorine atom (C-F) bond energy.
Environmental impact assessments of the coating processes will continue to be an important
factor in the decision making process and there are many more environmental factors than
energy and GHG carbon footprint. Some of the chemicals used require considerable discharge
and emission control. These considerations in order to determine the full environmental impact
warrant further study.
The consumption data was prepared from separate Anodising and Polyester Powder Coating
operations in three states along the eastern seaboard of Australia. The plants offered differing
technologies and products, yielding differing data. Averages of the sites for each of the products
have been used in producing the figures presented in this report.
The range of energy levels across the various sites for the Anodising process are from 3,185
kWh/tonne of aluminium to 3,740 kWh/tonne of aluminium, an average of approximately 3,441
±8%.
The range of energy levels from the Powder Coating process are higher with energy
consumption from 2,127 kWh/tonne of aluminium to 3,137 kWh/tonne of aluminium, an average
of approximately 2,583 ±20%.
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In addition, due to variations in emission factors for power generation across Australian States
and Territories GHG emissions can vary depending on where the energy is sourced. However, it
is certain that any comparisons of emission factors will still favour Anodising as the more energy
efficient alternative. Similar charts could be produced covering the limiting cases.
The 100 year life cycle for surface coated aluminium employed in this LCA seems a reasonable
basis for an end of recycle life, it could be longer, but with recycle losses and wastage this has
been decided upon for present purposes. The longer the LCA period the greater the margin
between the three aluminium surface finishing processes.
Many factors are involved in the overall environmental performance of a surface finishing
process. Besides assessing the scenarios for energy consumption and the associated GHG
emissions, energy efficiency measures and an increased use of renewable forms of energy can
further reduce the CO2-equivalent emissions for all aluminium surface finishing processes, some
may be better than others.
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