ASSESSMENT AND SELECTION OF MATERIALS FOR
MELBOURNE CITY COUNCIL HOUSE 2
Dominique Hes, Andrew Walker Morrison and Margaret Bates (RMIT University)
ABSTRACT
This paper highlights the role of material selection in the
development and contribution toward environmental excellence in
the building project Council House 2 (CH2). The paper focuses on
the assessment of material and the strategies used by the design
team in CH2to ensure the best environmental result. The paper
then goes on to explore in a case study the application of these
strategies in the selection and specification of concrete on CH2.
The purpose of the paper is to explore the difficulties and rewards
of careful research of manufacturers' claims and the relative
benefits of different materials. The paper concludes that the
process of material selection adopted on this project has increased
the education of architects and manufacturers alike as well as
being environmentally beneficial.
Keywords: material selection, concrete, specification, embodied
energy.
INTRODUCTION
Buildings account for one-sixth of the world's fresh water
withdrawals, one-quarter of its wood harvest, and two-fifths
of its material and energy flows .. . Building and construction
activities worldwide consume 3 billion tons of raw materials
each year or 40 percent of total global use. (Roodman and
Lenssen , 1995)
As buildings become more energy efficient and other impacts
become offset through improvements in design and application, the
role and impact of materials becomes more important particularly
over the life of a building. This paper looks at the role of materials
selection and the current methods of assessing the environmental
impacts of materials. The progression of materials through the CH2
design phase is looked at to show the ways in which the issues
and challenges of materials selection can play out in reality and be
resolved (to some extent). Concrete is then used as an example in
the case study to look at the decision making process used in the
CH2project; the influences on decisions and the outcomes.
It has been generally held that operational energy requirements
are by far the greatest environmental impact over a project's life,
with operational energy overtaking the energy it takes to make a
standard commercial building in as little as five to ten years. But
as Roodman and Lenssen (1995) indicate, the reality is that such
figures do not tell the whole story. Particularly as buildings become
more operationally efficient the relative environmental impact of
building materials will be greater again. However, materials have
impacts other than only energy. These include:
• Habitat degradation arising from logging, mining , transport,
waste dumping and pollution from various stages of extraction ,
production and disposal.
• Erosion of natural capital through (short) one-life use of most
materials.
• Greenhouse gas emissions from transportation, production,
installation and demolition/disposal.
• The construction industry constitutes a large percentage of total
economic activity in most countries. Therefore there is non
construction impacts in other areas of the economy driven by the
practices used in the construction industry, for example waste.
As a result CH2sought to establish new benchmarks in the
selection and use of 'sustainable' building materials in its
construction .
Most of the in-depth research on materials has been done on
individual materials - e.g. steel , timber. Published studies looking
at the contribution of all materials tend to focus on embodied
energy. Embodied energy (EE) looks at the total non-renewable
energy used to create a product or material from cradle to cradle,
the Australian Greenhouse Office (AGO, 1999, p.98) define it
as: 'the energy required directly and indirectly to manufacture a
product.' Within this there can be considerable range. One study
found that EE per m2of floor area of buildings can be between
4-12 GJ/m2 - representing less than 5% of the total energy
consumption of the building investigated (Cole 1998; Cole and
Kernan 1996). Another study shows 7 GJ/m2(Scheuer et aI. , 2003)
for a six storey university building with a life span of 75 years (2.2%
of life cycle primary energy consumption), while in Japan looking at
a 40 year life span the materials and construction component was
8.95 GJ/m2 - 15% of total energy (Suzuki and Oka, 1998). Large
though these numbers are, they all represent a small percentage
of the total energy consumed by the building over its life. The
exact percentage of capital and churn EE relative to operational
energy has been disputed and therefore it is possible that EE could
vary between 4 and 40 years of operational energy. More research
is needed in this area.
The Organisation for Economic Co-operation and Development
(OECD) reported in 2002 and 2003 that buildings consume 30%
of available raw materials, 42% of energy, generate 40% of our
emissions to air and 40% of waste to landfill (OECD, 2002; 2003).
In Australia , the built environment also accounts for around 12%
of our consumption of potable water (ABS, 2000). Further, the
materials in buildings can significantly affect human health. The
indoor air level of many pollutants, the OECD reported , may be
2.5 to 100 times higher than outdoor levels. The indoor air level of
pollutants is primarily emissions from the fitout materials and some
building materials.
The focus for material selection should be on the choice of
materials, using the traditional design paradigm of reduce - reuse
- recycle, aiming for healthy indoor air, resource conservation
and the minimization of waste and emissions. These will be
briefly discussed after a general introduction to the complexity of
assessing material environmental performance.
8 The Australian Journal of Construction Economics and Building [VoI5, No2J
General techniques for assessing materials
There are many guidelines and techniques used internationally
to assess materials for their environmental credentials (Berge,
2001 ; Woolley and Kimmins, 2000; Anderson et aI. , 2002; Curwell ,
2002), however there is no specific overall standard. One of the
most rigorous methods is life cycle assessment (LCA), a method
for assessing impacts of a product over its life including all of
its measurable inputs and outputs. However, there are several
problems with LCA. The first is with the reliability and extent of
data collected for the databases on which the assessments are
based. Studies on materials are either relatively accurate and take
a lot of time, resources and are often confidential , or they are more
generic and less accurate. A second and related problem is the
amount of time and the cost of carrying out LCAs which is beyond
most building projects. A third problem is that while LCA is strong
at estimating readily quantifiable materials flows such as in a
manufacturing process, there are important impacts that LCA does
not include, typically biodiversity loss and habitat degradation.
Generally manufacturers are the ones who take on the expense
of an LCA to try to make their product stand out and improve their
production processes.
Because of these complexities projects often turn to simpler
indicators such as embodied energy, material intensity per service
unit (MIPS)' or footprints (total land used to produce a product).
But these indicators tend to consider only one or a limited set of
indicators, such as energy and land used, whilst ignoring possible
other crucial impacts such as toxicity. Embodied energy figures
are also typically based on capital accounts that include all of the
costs associated with a product and allocate an energy conversion
factor. This does not reflect actual energy used to make the
product and is often very large as it can include the relative cost
of financing the transport company carrying the product and so
forth. On the other hand using embodied energy based on national
accounts does simplify the process of collecting the information
because there is financial data readily available on all products and
processes.
Another method of simplifying the LCA type process is through
aggregation tools which are based on LCA but provide results
in simple aggregated scores. Examples of aggregation tools
are the European Ecolndicator used in EcoQuantum (housing
environmental and costing tool), and EcolT (material selection of
industrial design), cost (first and future costs) and BEES which
assesses environmental impacts. The main problem with these
types of tools is that the data behind them is often hidden and
it is difficult to add new data if the product being considered is
not listed. The lack of uptake of these aggregation type tools is
highlighted by the fact that there have been no updates on BEES
since late in 2003. Yet another simplified method to support
decision making on material selection is through labelling. There
is no internationally successful program on construction material
labelling though there have been several attempts. The main
problem with labelling construction materials is the variance of
these materials from location to location. Greater success has
been achieved through specification or material choice support
tools such as EcoSpecifier and the US Environmental Building
News, and guidelines such as the Aurora Material Selection
Guideline and the US Federal Government's environmentally
preferable purchasing (EPP) database. The US Federal
Government defines an environmentally preferable product as:
... goods that have a lesser or reduced effect on human health
and the environment when compared to competing products
that serve the same purpose. Environmentally preferable
attributes include reduced toxicity, the use of recycled materials,
and increased energy efficiency. (US Environmental Protection
Agency, 2004)
Labelling is almost always done by a third party that is independent
from the manufacturers or their professional organisations, often
including some kind of certification. For example the Forest
Stewardship Council certifies the certifiers (SmartWood and
Scientific Certification Systems) that assess whether forestry
companies are using sustainable management practices to harvest
wood. In the USA, GreenGuard certifies products that meet strict
indoor air quality criteria. The Energy Star label is an international
standard which identifies equipment and appliances that meet
or exceed standards for energy efficiency, and now there is the
water 'A-rating' label indicating water efficiency (Global Green, no
date). In Australia there is an overall building rating called Green
Star, created and implemented by the Green Building Council of
Australia. However, the place of materials in the rating system
is integrated into the point system rather than having a separate
section.
CH, SELECTION AND DESIGN STRATEGIES
The brief
Melbourne City Council's Brief for CH 2 stated that:
The building is to be a lighthouse for future City developments;
• It is to provide a comfortable, adaptable and stimulating working
environment for its users, the staff of Melbourne City Council ;
• It is to be seen and understood to respond to its natural as well
as its social environment and to make use of resources bearing
in mind the efficient use of embodied energy both in the choice
of materials and in the process of their use;
• It should maximize the use of ren.ewable energy within the
bounds of present technology by harvesting sunlight, the wind
and rainwater together with the complexities of the Melbourne
climate and by following these principles the building should
reduce CO2 emissions to almost zero;
• It should also provide at least the same area of green cover
as its footprint bearing in mind that this area can be measured
vertically as well as horizontally; and
• Finally as a work of art the building should inspire a new
relationship between the city and nature.
An outcome of this was the development of a 'comprehensive
materials assessment process' that aimed to consider key
environmental aspects of a material but with three overarching
priorities:
• Use and adherence to the principle of lowest life-cycle cost for
the antiCipated 100 year life i.e. maximizing durability, minimizing
replacement, maximizing maintainability
• Minimizing embodied energy
• The use of locally grown, sourced or manufactured products and
materials.
1 MIPS quantify the material intensity of a product or service by adding up the overall material input which humans move or extract to make that product or
provide that service. It puts life cycle thinking at the beginning of the product chain. MIPS is measured in kilogram per unit of service. The material input is
calculated in five categories: abiotic raw materials, biotic raw materialS, water, erosion and air.
The Australian Journal of Construction Economics and Building [VoIS, No 21
The central role of materials from the charrette stage
A comprehensive materials assessment process was first
explicitly addressed from the two week-long design charrette.
The architectural design process typically starts from preliminary
or 'Schematic Design', literally the schema or rough placement
of spaces and shapes, through to design development, where
buildings are typically drawn to scale and resolved in some detail,
to contract documentation, which involves the documentation
of the project in all respects to allow its construction. Materials
selection , even in 'green' projects, is often considered at the
stage of design development - or even contract documentation. A
combination of aesthetic/functional/cost drivers and the designers'
familiarity with broadly available products drives implicit and
explicit decisions: 'I know we can do this in brick, this in steel , this
in timber.' The exact specification is typically resolved near the end
of the projects life in the designers' office.
However this 'business as usual' process can carry a high
cost that can limit ecologically sustainable development (ESD)
to the ecological impacts of individual building materials. For
example it is common industry practice to use plasterboard or
fibre-cement sheet wall lining in most buildings. This practice
allows cables, pipes and services to be routed over the building
structure but hidden by the wall and ceiling finishes. However it
can eliminate opportunities to use the effective thermal mass of
a concrete structure. A completely different design of services
and construction is required for a concrete structure as the finish.
This is not something readily done after schematic design. It also
fails to consider the life-cycle impacts of these lining substrates
and a raft of practices implicit in their use, such as replacement
and repainting of surfaces that are ultimately easily marked and
abraded.
Step 1: Synergy, honesty and simplicity in materials
In the initial charrette the design team put up a proposal for
discussion and constructive criticism that used a concrete structure
and extensive thermal mass and pursued synergy, honesty and
simplicity in materials use.
• Synergy: obtain multiple benefits from a materials use e.g. use
the structure as a thermal mass and durable finished surface.
• Honesty: use materials for their aesthetic and other intrinsic
properties, seek not to clad, coat or hide them.
• Simplicity: simple is better than complex. Monolithic materials
are easier to maintain, repair, and recycle than laminated, glued,
composite products.
This approach, according to Designlnc, strongly influenced from
the outset the design team's philosophy and aesthetic that was
likely to be radically different from many contemporary 'Grade
A' commercial buildings. It would be the genesis of innovative
thinking that resulted in the striking selection of materials and
fin ishes throughout the project.
Step 2: A planned approach to materials research and specification
The consideration of specific materials did not come up in the
initial charrette: only that whatever materials were selected had
to be in keeping with the design philosophy, and adhere to the
requirements of the brief including minimizing embodied energy,
life-cycle costs, and general environmental preferability.
The next question was how to achieve this in practice. In 1999
there were very few tools available to the design team to aid their
research . EcoSpecifier was in its earliest days of development and
had only 80 products listed. There were no other local resources
available. Designlnc was left with only one option - to undertake
the enormous research task of vetting all potential products and
materials that might be used on the project.
A rolling R&D program was designed, commencing in 2000. The
key elements of this program were:
• Establish a methodology for side-by-side comparison of products
through the Environmental Performance Questionnaire (EPQ),
discussed below.
• Establish a peer-review process to ensure transparency and
accountability, and limit liability, through the involvement of the
Commonwealth Scientific and Industrial Research Organisation
(CSIRO).
• Shortlist potential products and issue the questionnaire as a
condition of consideration to suppliers for completion, and to
other suppliers through the course of the project as relevant.
• Establish in-house systems that would enable effective storage,
referencing and use of data through effective storage and inter
personal communication .
• Integrate data into effective decision-making in the project in a
timely manner through coordination and project reviews.
Designlnc used a slightly modified Environment Australia
'Environmental Performance Data Sheet' as their 'Environmental
Performance Questionnaire' or 'EPQ' to generate standardized
responses from suppliers. Questions asked by the EPDS/ EPQ
include:
• The type and relative contributions of different materials in the
product
• The energy required to make the product in its various
manufacturing stages, and the energy source.
• Whether the product contains or during production emits any
of a list of chemicals listed by the Australian National Pollutant
Inventory.
• The projected lifespan and ability to repair the product.
These responses were provisionally reviewed before being
forwarded to the CSIRO for scoring. The CSIRO team was asked
to develop a scoring system and, from the responses to the EPQ,
give each product a final score.
The CSIRO method was as follows:
Step 1 - The material assessment was carried out on (1)
product-manufacturer or product-supplier responses
to a set of questionnaires on product composition and
manufacturing, and (2) considered opinions of CSIRO
experts. Neither of these on its own was considered to be
sufficient to calculate the ratings .
Step 2 - The comparative ratings of products within each category/
application were used as an initial guide to product
selection to narrow the options for a specific project
application. The ratings were not used as a substitute for
more detailed investigation by the project team and expert
consultants and/or specific testing of product attributes
by experts, which may still be required in some cases in
making a final selection.
10 The Australian Journal of Construction Economics and Building [VoI5, No2J
Step 3 - The ratings were made by expert input and qualitative
information where available within each category/
application for each product property or attribute under a
specific context of use (considered a 'standard' condition).
For different conditions and context of use it was
acknowledged that performance might vary. Thus ratings
were comparable only within categories/applications. The
table was meant as an initial guide for quick comparisons
of product attributes across a range of areas.
Step 4 - The products were not categorised as either bad or good ;
that is, a single composite rating was not given. A range
of important attributes for sustainable performance (i.e.
Evergen- Product Selection Guide
'friendly' to people and environment) were considered.
Project clients and design team were encouraged to
consider the relative importance of each attribute in a
particular project in their comparisons and selections (i.e.
the sense of relative importance of each attribute for each
product category may vary from project to project).
Step 5 - Where appropriate, good performance was identified/
noted. Where the rating for a product attribute was
not satisfactory, the intent was to note it to encourage
improvement in this area.
An example of a product scoring sheet is given in Table 1.
Legend: 4 Superior; 3 Good; 2 Average; 1 Poor; 0 Not acceptable; - Insufficient information
Category!
Application
EPQ
Ref.
No. EE Emb.
water
Wastes &
Recycling
Air, Land
& water
emissions
Attributes
Indoor
Emissions
Other
Env
impact
Service Life
(without
maintenance)
Maintenance
Requirement
$
Range
Aust.
Made
(Y!N)
Comments
Glazing GL.xx.xx 3 1 3 2 3 2 2 4
Table 1: Example score sheet (used with permission from CSIRO)
CHALLENGES IN IMPLEMENTATION
Gathering data
The first challenge was getting manufacturers and suppliers to fill
in the questionnaires. Despite the fact that completion of the EPQ
was a condition of consideration, at 25+ pages, and designed
to assist life-cycle assessments, the questionnaires were highly
technical and beyond the experience of many who received them.
About 50% of suppliers did not respond. Only about 30% of all
EPQs issued or requested were fully completed.
To address this problem later in the project, towards the selection
of fitout materials, Designlnc designed and issued a simplified
three-page EPQ. Up to 80% of suppliers returned the document
completed. Designlnc's Claude Bertoni notes that another factor in
this may be that a) the project was better known and b) that over
the period of design the supply sector in Australia had improved
significantly with regards to ESD2.
While there was a product ESD-claim declaration sign-off as part
of the form, there were concerns about the quality of the data
given, as highlighted by Bertoni: "My major fear has been relying
on a manufacturer's word. I would put at the top of my wish list
independent accreditation of products to give peace of mind .'3
Ultimately it was CSIRO that had to make sense of complete,
partial, or contradictory data and supply project recommendations.
Principal Research Scientist, team leader EVERGEN, CSIRO,
Greg Foliente, comments on how this issue was resolved:
When a manufacturer is not capable of answering those
questions, it shows their environmental credentials. We
shouldn't water it down, because it would break the process.
Secondly, even though some of the questions are not filled in,
we ... are relying on expert opinion. Once we know the raw
materials and what the product is, we can guess what goes in
between. It's inexact, but we know enough about the industry.
Give us a few parameters here and there, and we develop a
feel. Then the experts come in with the rest. As long as we are
consistent, the idea is that they are always rated next to each
other, and as long as you have that, it is okay
... we wanted to preserve the integrity of the RMIT effort.
Also we knew [the EPQ] wouldn't be sufficient anyway So the
idea was to use it as base information. Then we relied on the
expert judgement of people in CS/RO who are familiar with
the issues ... This is an informal process we adopted within the
EVERGEN team. 4
On-site substitution
Substitution during construction of non-specified products is a
problem endemic to the construction industry. Over the years
various contractual clauses have been developed to limit this,
including clauses such as 'Taps to be (x) or similar approved' ,
where approval is by the architect or other person nominated. All
approaches however are far from ideal. The designer's control is
largely eliminated in many contracts where the project is passed
over to the builder. In many other instances sub-contractors will
simply use non-specified materials, hoping to get away with it on
the project.
2 Conversation with Claude Berloni 24/01 /2005.
3lbid.
4 Interview with Greg Foliente... 9 June 2004.
The Australian Journal of Construction Economics and Building [VoI5, No 21 I 11
Designlnc proposed a strategy to avoid this problem: making good required by the architect due to non-permitted
substitutions.
i. The builder's Environmental Management Plan was to contain
In the end, points (i) and (ii) were included in the contract. Point (iii)
provisions requiring that no substitution was permitted unless
was considered too onerous during contract negotiation and was
the proposed product had undergone independent vetting
not included.
using the EPQ and subsequent vetting, and was shown to be
equivalent to the originally specified product. The architects
The influence of 'Green Star'would have 10 days on receipt of such documentary proof to
permit the substitution. The introduction and launch of Green Star in 2003 marked the
start of a whole new learning curve for the project team. Having
ii. That if the architects rejected the proposed substitution no substantially designed the project, they now had to ensure that
impact on the program would be permitted. The onus was on it would meet the highest levels established by the Australian
the builder to not put up substitutions unnecessarily, and if it Green Building Council's new rating tool. Green Star attributes
was not approved any lost time through delay or scheduling a relatively modest 15% of available credits for the base building
was their responsibility. This created great incentive for the materials, and there is no doubt that tool focused the broad
builder to thoroughly assess all products well ahead of time attention of the project team to meeting the particular relevant
as any problems during the project caused by products they requirements: reducing PVC use, avoiding the use of rainforest
were not familiar with and delayed the project would be on their and old-growth timber; using recycled content in concrete and
head. steel , etc. Table 2 identifies the Green Star credit and the actions
iii. The builder deposits a 2.5% bank guarantee as security against taken to ensure CH2 complied so far as was possible.
Green Star Credit CH2 Response
Up to 2 credits for use of post-consumer recycled Use of 100% post-consumer reinforcement steel from Smorgon Steel. No other
steel recycled steel products could be identified for the project.
Up to 3 credits for use of high-supplementary Development of matrix with up to 60% replacement depending on stress
content (cement replacements) in concrete grading and curing speed constraints. Refer Case Study.
Up to 2 credits for use of sustainable timber Use of plantation timber products. Use of recycled timber for louvres. Use
of FSC-certified timber. Use of responsibly sourced timber with source
documentation for window frames'.
Up to 2 credits for reduced use of PVC Use of HOPE for most water and other pipework. PVC used for stormwater
pipes. PVC used for power, data and communication cables .
• A contentious product that generated significant debate during the project's construction.
Table 2: Green Star - Office Design (v1) and CH2 materials
ESD priorities at CHz interviewed on this issue. They commented that such a target was
useful but they needed to work with manufacturers to ensure theWithin this assessment the following issues were specifically
other requirements such as strength, appearance, etc. were met.looked at, for particular material categories:
They also said that they would achieve the overall target but that
some elements would have more recycled content while othersMinimizing indoor air pollutants by specifying:
would have less depending on their functional requirements .s
- Low VOC paints.
Recycled content of structural steel :
- Low VOC carpets.
The Green Star process highlighted the difficulty of gaining
- Low VOC adhesives and sealants.
information necessary when making key decisions on materials.
- All composite wood product is low emission formaldehyde. To meet the project requirements of one Green Star credit point,
recycled steel had to be sourced . No guarantee from local steelRecycled content of structural concrete:
manufacturers could be given that 30% recycled content could
be achieved . To meet this then the project team needed to look
All efforts were made to maximize the use of recycled content
outside Australia to get the recycled content which allowed the
in the structural concrete elements. Being mainly pre-cast the
achievement of this one star. The steel is being imported from
challenge was to work with the suppliers to achieve the aim of
Thailand.
recycled concrete aggregate and replacement of cement with
industrial waste such as fly ash and slag. The structural engineers,
Nat Bonacci and Roger Sykes from Bonacci Group, were
5 Interview with the structural engineers
12 The Australian Journal of Construction Economics and Building [VoIS, No2J
PVC minimization: CASE STUDY' CONCRETE AT CH2
All effort was made to minimize PVC which has a high off-gassing
component and is not readily recyclable. This has been achieved
for all hydraulics and for the data and power cabling.
Sustainable timber selection:
Over 90% of the timber used on the project will be from recycled
or certified sources. The main issue with achieving this score was
the transparency and validity of certification processes. Some
certification schemes due to the recent introduction to the market
are not as well received or supported by stakeholders as others.
Gas+best efficiency+55% extenders+renewable
electricity
Gas+best efficiency+55% extenders
Replace coal with gas
Pure cement
o
Concrete is a ubiquitous material in construction, offering strength,
versatility, and durability at a relatively cost effective price.
It is also highly energy and greenhouse gas intensive. The
production of one tonne of concrete typically uses cement with
an associated environmental price of one tonne of CO2, Figure
1 illustrates the emissions impacts of a tonne of concrete made
using entirely ordinary Portland cement (OPC) through to various
fuel mixes and substitution of OPC with recycled extenders such
as blast furnace slag and fly-ash.
ID Chemical •
I I
I I
I I
I I
I I
I I
0.2 0.4 0.6 0.8
Energy r
1 1.2 1.4
Tonnes of CO/tonne of cement product
Figure 1: Chemical and energy CO2emissions from cement production under various conditions (Pears, 2000)
As can be seen from Figure 1, greater than 50% reductions
in emissions can be achieved through the use of gas-fired
dry-process cement with the use of recycled extender or
'supplementary' products. The total embodied energy of reinforced
concrete can be further reduced through the use of post-consumer
recycled steel reinforcement from an electric arc furnace (EAF)
process such as used by Smorgon Steel. EAF mills are inherently
up to 70+% more efficient that blast-furnace mills, however they
can only process existing steel ingot or recycled steel.
Concrete, due to its use in significant quantities in many
commercial buildings, can contribute a significant percentage of
the base buildings overall embodied energy. While a detailed LCA
or embodied energy analysis of CH2has not been undertaken, the
2000 Melbourne 'Build LCA' study looked in detail at a range of
buildings including two small offices as well as other building types.
The results for Office 1 (6,500m2) are shown in Figure 2 and the
results for Office 2 (27,350m2) are shown in Figure 3. The results
are shown by material for these buildings.
As can be seen, concrete was found to be the second largest
single energy input into the buildings, at 2.0 and 2.2GJ/m2
respectively. This represents approximately 20% of the total
embodied energy. CH2, at 12,500m2gross floor area, contains
approximately 5,200 tonnes of concrete (not including mass of
steel reinforcement) . On the basis of a business-as-usual worst
case this equates to approximately 5,200 tonnes of CO2 - in
broad numbers equivalent to the emissions of 12,500 family cars
travelling the Australian average of 15,000km each over a year.
The CH2design team was looking to reduce the embodied energy
as much as possible. However the project's stated intention to
achieve six stars under Green Star meant that every credit point
mattered. The team now had an implicit energy 'budget' to attain.
The points related to recycled content in structural concrete are
shown in Table 3.
The Australian Journal ofConstruction Economics and Building [VoIS, No 2] I 13
I[JI T o.al EE "alues I
other items
Direct energy
other
Concrete
steel
o 2 3 4 5 6 7 8 9 10
Embodied Energy GJ/rn2 of' GFA (Raw materials through to construction)
Figure 2: Small Office 1 Embodied Energy (Input/Output type analysis) 6,500m2 GFA (Greening the Building Life Cycle, 2000)
IIII Total EE "alues I
other items
Direct energy
c..
:::>
Cl
<.!l
]! other
II
:;:."
Concrete
steel
o 2 3 4 5 6 7 8 9 10 11 12
Embodied Energy GJlm2 0.- GFA (Raw materials th.-ough to construction)
Figure 3: Small Office 2 Embodied Energy (Input/Output type analysis) 27,350m2GFA (Greening the Building Life Cycle, 2000)
14 The Australian Journal of Construction Economics and Building [VoIS, N02]
TITLE AIM CREDIT CRITERIA SUMMARY CREDITS
AVAILABLE
Recycled Content of To reduce embodied Up to 3 credits are awarded where concrete used in the 3
Structural Concrete energy and resource building construction or refurbishment has a significant
depletion due to use recycled content:
of concrete. . 1 credit is awarded for aggregate replacement in
75% of all concrete by volume as follows: 1 credit =
30% of aggregate is recycled concrete aggregate (or
equivalent) .
. Up to 2 credits for awarded for use of supplementary
cementitious materials in 75% of all concrete by
volume as follows: 1 credit = 30% of cement is
replaced with industrial waste product; 2 credits = 60%
of cement is replaced with industrial waste product
(for precast concrete the % of cement replacement is
reduced to 20% for 1 credit and 40% for 2 credits).
If no new concrete is used in the refurbishment of an
existing building type "n/a" in the credits achieved column.
Table 3: Green Star - Offie Design (v1) Credits regarding Concrete (Green Building Council Australia , 2004)
The challenge for the CH 2 team was that while the pioneer building
60L (60 Leicester Street, Melbourne) had achieved up to 60%
replacement of OPC with supplementaries, this had been achieved
in concrete in a low-rise project. Furthermore the Green Star credit
for pre-cast concrete was a target that was theoretically achievable
- but untested in the field.
CH2 on the other hand presented a number of challenges:
• The building stands 11 storeys high and requires high-strength
floor slabs and columns developing up to 80MPa.
• 32% of the total quantity of concrete used is precast, including
many curved concrete ceiling panels requiring a very high class
of visual finish.
• The project was driven by tight commercial realities, i.e. there
was little provision to delay stripping of concrete to allow the use
of later strength-developing high-extender mixes. This would
also prove a challenge with regard to managing shrinkage and
cracking.
Element Mix Comment! Strength Drying Opportunities
designation risk shrinkage for reduction
CH2 was keen to achieve three credits in this area. A strategy
therefore needed to be developed to measure and document
that credits were being met. This strategy, which evolved
through tender and post-tender discussions between the builder,
Melbourne City Council and the architects, took the following form:
i) Develop a complete matrix of concrete elements to be used in
the project which addressed for each element the % of total
concrete, the number of days at which requisite strength would
be developed, and so forth (refer Table 4a and 4b)
ii) Dynamically identify stretch targets and problem areas in the
pre- construction stage
iii) Undertake in-depth builder-architect workshops to establish
what may be possible
iv) Testing, research and development by concrete contractors to
establish parameters
Cenement Aggregate slump plasticer qty supplier
replacement replacement
% %
Table 4a: Summary of input to concrete matrix (for full version see www.ch2.com .au)
Qtym3 % of concrete
on job
I I
TOTALS 7,262 100%
GREEN STAR - OFFICE DESIGN CRITERIA AND COMPLIANCE NOTES
Aggregate repl
62.90%
Needs to be >75%
% of project cenent
repl
37.24%
Neeeds to be >30%
Cement mat repl
86 .15%
Needs to be >75%
% of proj agg repl
54 .96%
Needs to be >30%
Table 4b: Outcome of concrete matrix
The Australian Journal of Construction Economics and Building [VoIS, No 2] I 15
One early outcome of this process was an application by Boral to
the Green Building Council for an exemption to enable washed
aggregate (aggregate washed out of unused concrete returned
from CH2 or other projects) to qualify as 'recycled' aggregate under
the credit. This exemption was granted. Even though the amount of
this aggregate only account for 1-2% of the aggregate used in the
project it proved crucial in assisting the project reach the levels set.
Boral undertook to achieve the targets identified in the matrix
- but this was new territory for the company. Boral had a unique
commercial advantage in the project as three of its city plants had
facilities to crush recycled concrete - critical to the project reaching
recycled aggregate targets. Boral was unwilling to use genuine
post-consumer recycled aggregate (such as that available from
their venture partner Delta or Alex Fraser) in most high-strength
applications due to concerns about the effects of residual cement
on binding strength , shrinkage and other technical performance
characteristics.
The process threw up a number of subtleties that were not
reflected in the Green Star credits. Not least of these were that the
supplementaries locally available in each state in Australia have
quite different performance characteristics.
One very positive outcome of the project was an agreement
reached with Boral to share some aspects of the concrete's
characteristics in the public domain. This data was forwarded to
the Green Building Council to assist with the refinement of the
rating tools.
Construction was not without its challenges:
• Significant cracking was encountered with one major floor
slab. While this was found not to affect structural integrity or
aesthetics (it was hidden under the access floor) it required
further refinement by Boral to address the problem.
• The physical characteristics of the mix resulted in different
flow patterns and mix behaviour in pouring the curved pre
cast concrete panels including scalloping, bubbling and colour
variation - all highly problematic in this high visibility feature.
This was only resolved through significant experimentation and
development, costs for which were born by the client.
Environmental benefits of concrete specification
Detailed analysis of the embodied energy savings achieved at CH2
have not been undertaken. Without this it is difficult to establish the
levels of savings made, particularly as there are indications that in
some instances concrete contractors increased the total quantity
of OPC in the mix to achieve strength and performance, in addition
to requisite levels of supplementaries. However, it is possible that
significant savings have been achieved - in addition to contributing
significantly to the state of knowledge as to what is possible. It is
not unlikely that the project has saved between 20 and 30% of
potential embodied energy (worked out from the concrete schedule
and percentages saved).
ENVIRONMENTAL BENEFITS
There is no doubt that the exhaustive specification process has
reduced the environmental burden associated with the construction
of CH2. The example of concrete alone indicates a significant
greenhouse gas saving. Other key examples of likely benefits
include:
16 The Australian Journal ofConstruction Economics and Building [VoI5, No2J
• Avoided use of rainforest and high-conservation value forests for
much of the timber construction through use of recycled timbers.
• Reduction in embodied energy from use of 100% post-consumer
recycled content steel for reinforcement.
• Design for reduced materials use, flexibility and demountability in
the fitout. As well as savings in capital construction this is likely
to result in compound savings through avoided consumption and
waste during churn.
• Savings for the project-wide emphasis on specification for the
100 year life-cycle costing model, with its emphasis on durability.
Accurate quantification of the environmental savings and avoided
impacts will only be possible when an audit has been undertaken.
This will hopefully be the subject of future research .
Supply chain transformation
CH2 has already had dramatic effects on the broader building
materials supply chain through its iconic status, profile, and
significance as a public sector building breaking new ground
which is likely to a greater or lesser extent to be pursued by other
projects. Examples of this include:
• The development of new products specifically for the project, e.g.
the shower towers, precast and in-situ concrete mixes.
• Placing pressure on a broad web of manufacturers and
suppliers to think about and gather data on the environmental
performance and characteristics of their products.
Contract development
A key area of concern and barrier for many projects breaking new
ground is how to manage risk. There are a number of areas in
which CH2 has re-thought contractual arrangements to allocate,
share or manage new risks with regard to materials. These include:
• Development of the EPQ-approved approach and, potentially, a
specific bank guarantee to minimize risks of undesirable product
substitution on-site.
Illustration of challenges, complexities and barriers
Like any innovation, one of the greatest contributions by CH2 to
ESD will no doubt be identification of challenges, complexities and
barriers ariSing. Some of these are already clear, but others may
well arise in time. They include:
• The challenge of maintaining quality control in areas of new
product development (refer Appendix 1).
• Identifying environmentally preferable products. Regardless
of the complexity of product assessment processes, no team
has access to perfect information. The use of Ecoselect
and subsequent concerns of environment groups illustrated
the challenges of design teams and their consultants being
sustainability experts across a literal planetary range of
products.
• Negotiating solutions to unforeseeable situations arising from
the use of novel materials with contractual parties in the
framework of traditionally adversarial and risk-averse contractual
relationships.
Explicit diffusion, communication and education
Melbourne City Council has embarked on a comprehensive
knowledge diffusion program. Lectures, seminars, conferences,
books, articles in trade press and the broader media have all
contributed to lifting awareness of the project, its ESD ambitions,
and what it set out to achieve. As the project moves to completion
the emphasis will turn to articles in the architectural magazines
that designers and clients read. CH2 will be further researched
and written up in case studies. This broad communication agenda
ensures that many of the lessons and achievements of CH2 will be
taken up by other projects. The benefits will thus multiply.
While the extensive database of 'scored' products remains the
intellectual property of Designlnc, Melbourne City Council is
exploring ways to make at least some of this knowledge available
to a broader audience. In the meantime this knowledge provides
an important resource that will enable the architects to leverage off
the experience of CH2 to pursue eco-preferable products in other
projects, public and private sector, and set a benchmark for other
firms to meet and surpass.
Participation in the development of CH2 has stretched and
educated all involved. One outcome of the project will be a more
educated cadre of architects, engineering and cost-planning
consultants, builders and sub-contractors.
Achievements and challenges
Perhaps as significant as the 'iconic' achievements of CH 2 are
the many small changes in approach , many of which will probably
never be documented. One example of this Bertoni has noticed
have been attitudes to waste on site:
Once you start seriously dealing with ESD design it is not just
quality and aesthetics driven on conventional lines. I don 't
think we have wasted anything, we have repaired it instead.
If a precast slab turns up that is not quite right we don 't
send it back. It represents a significant resource and energy
investment. Instead we ask how we can resolve an apparent
problem.6
This raises some real challenges to the architect or project
supervisor. Building contracts and Australian Standards have
evolved over time to allow tight control over the quality, cost and
extent of projects: but what happens where there is no contractual
experience or Australian Standard? The use of high-supplementary
mix concretes on CH2 is a case in point. The reality, as discussed
in the case study, has been finishes that are not classified under
and do not meet any standard.
How does the architect hold the builder to account? How does the
supervisor prevent a drop in perceived quality? The only answer
to this appears to be more hands-on time , in the concrete yard , in
the joinery shop, as indeed things were 20 years ago. As Bertoni
says; "ESD has generated a new generation of products which are
simply not well understood. There is a learning curve for what they
can and can't do, and the project simply has to allow more time up
front with the builder to make sure things are done right. " 7
CONCLUSION
Green building is at the point in which there is still a lot of learning
for all involved. Each new project contributes to the knowledge of
those working on it as well as bringing benefits to the environment
6 Conversation with Claude Bertoni 24/01 /2005
7 Ibid.
and community. This demonstrates the continued requirements
of education of architects, the construction industry and the
product manufacturing industry. This paper has demonstrated
the challenges and opportunities of integrating environmentally
responsible materials into a building project. Opportunities lie
in selecting materials that have not only a low impact in their
manufacture and use but also within their aesthetics and inherent
qualities (strength , recyclability, etc.) have longevity.
REFERENCES
AGO (1999), Australian Residential Building Sector Greenhouse
Gas Emissions 1990-2010, Australian Greenhouse Office,
Canberra.
Anderson, J., Shiers, D. and Sinclair, M. (2002), The Green Guide
to Housing Specification, 3rd, edition , Blackwell Science, Oxford.
Berge, B. (2001), Ecology of Building Materials,Architectural
Press, Oxford.
Cole, R.J . (1998), 'Energy and Greenhouse Gas Emissions
Associated with the Construction of Alternative Structural Systems',
Building and Environment, vo1.34 , no.3, pp.335-48.
Cole, R.J. and Kernan, P.C. (1996), 'Life-cycle Energy Use in
Office Buildings', Building and Environment, vo1.31 , no.4, pp.307
17.
Curwell , S. (2002), Hazardous Building Materials: A Guide to the
Selection of Environmentally Responsible, E&FN Spon Press,
London.
Global Green USA (no date), Green Building Materials: Selection
and specification guide.
Green Building Council Australia (2004), Green Star - Office
Design v.1, Green Building Council Australia , Sydney, viewed
11 /01 /2005 .
Greening the Building Life Cycle (2000), Life Cycle Assessment
Tools in Building and Construction, Case studies: Embodied
Energy (inpuUoutput) Analysis of a Range of Building Designs,
Commercial case studies: Small Office 1 and 2, Environment
Austral ia, viewed 23/02/2005 .
OECD (2002), Design of Sustainable Building Policies: Scope for
Improvement and Barriers, OECD, Paris.
OECD (2003), Environmentally Sustainable Buildings: Challenges
and Policies , OECD, Paris.
Pears, A. (2000), 'Pitfalls in Consideration of Energy in Lifecycle
Analysis', in proceedings of the Second National Conference on
Lifecycle Assessment: Pathways to Eco Efficiency, 23 to 24th
February 2000, VUT Conference Centre Melbourne, viewed
23/02/2005 .
Roodman , D.M. and Lenssen, N. (1995), A Building Revolution:
How Ecology and Health Concerns are Transforming Construction,
Worldwatch Institute, Washington, DC.
The Australian Journal of Construction Economics and Building [VoI5, No 21 I 17
Scheuer, C., Keoleian , G.A. and Reppe, P. (2003), 'Life Cycle
Energy and Environmental Performance of a New University
Building: Modelling Challenges and Design Implications', Energy
and Buildings, vo1.35, no.1 0, pp.1 049-64.
Suzuki , M. and Oka, T. (1998), 'Estimation of Life Cycle Energy
Consumption and CO2 Emission of Office Buildings in Japan ',
Energy and Buildings, vo1.28 , no.1 , pp.33-41.
US Environmental Protection Agency (2004), Environmentally
Preferable Purchasing Terms, US Environmental Protection
Agency, Viewed 31 /01 /2005 < http://www.epa.gov/epp/abouU
eppterms.htm#terms-e >.
Woolley, T. and Kimmins, S. (2000), Green Building Handbook
Vol 11: A Guide to Building Products and their Impact on the
Environment, E&FN Spon, London.
18 The Australian Journal of Construction Economics and Building [VoI5, No2J
APPENDIX l' DESIGNINC'S TOP TEN LESSONS LEARNED FOR SPECIFYING PREFERABLE MATERIALS
1. Be careful of greenwash.
2. There is no avoiding research - allow for time and resources to enable good decision making:
use existing tools e.g. EcoSpecifier, the Environment Design Guide, case studies, interne!.
use contacts.
attend conferences to keep up to date.
develop an in-house assessment system/checklist - check out the one page materials questionnaire on EcoSpecifier as an
example.
be patient with and communicate clearly with suppliers.
work towards developing an in-house materials database and staff education strategies to learn from the process.
3. Bring materials to the front of the design process.
4. Rethink preconceived notions of material selection and application.
5. Design in solutions that minimize material consumption, e.g. maximize natural/integrated (not applied) finishes , therefore
materials to be a natural backdrop to form , not a primary aesthetic.
6. Understand what you are specifying so you don 't get caught out later:
cost and time implications - be prepared that some items may cost more due to availability, but demand will eventually bring
prices down.
suitability of the product for the intended application.
7. Collaborate with local environmental groups - they can be a good source of information.
8. Be more amenable to variations in visual finish control to minimize material wastage through rejection:
develop a good relationship/commentary with the builder to ensure project objectives and quality are delivered.
where options exist, choose a process that gives a good result with the least risk of material wastage.
where a more refined finish is required , limit it to smaller areas.
9. Be realistic about life span design considerations e.g. if the design aims at flexibility or is faddish , then demountability,
recyclability and reuse may be more important than long term durability.
10. Don't get lost in the enormity of the exercise - take it in small bites and don't feel the need to reinvent the wheel every time.
Making a small improvement is better than none at all.
The Australian Journal ofConstruction Economics and Building [VoIS, No 2] I 19