1. Copper in Green Buildings
Being “green” isn’t always the most economical option for residential and commercial
buildings, but it can help reduce overall operating expenses and costs in terms of
reduced repairs and maintenance in the long term, thus making initial capital
investment in these aging-friendly materials a wise decision. Few people realize
that buildings have the greatest impact on climate change -- more than
transportation and industry -- because they consume so much electricity and natural
gas, and they're all powered by power plants that themselves produce carbon
emissions. Copper can be found making an impact throughout any building.
According to Tom Dietsche, LEED Program Manager, USGBC, “Green Building
projects that can earn LEED points include those that have incorporated recycled
content materials, such as copper, which promotes sustainability and helps to
reduce the impact of new material extraction on the environment."
Copper is possibly the greenest commonly used architectural metal today. Copper
plays an essential role in the modern building, from recycled cladding and roofing
systems, to high-tech plumbing and heating systems using tube and fittings which
are manufactured from recycled copper. Even the wire and cable systems and
monitoring equipment depend on upsized copper wire to maximize system efficiency,
eliminate power quality issues, and play a key role in green power systems. Copper
and copper alloys are also used in the manufacture of interior design fixtures and
decorative objects. Handles, door knobs and lock cylinders are current hardware
items found in homes around the world. As the most frequently used processing
methods, copper sheeting, tubing and wiring produce most of the copper objects
around us. Copper sheet is light in weight, easy to work and join, visually
attractive and extremely durable. It resists attacks by air and moisture. Copper
alloys, such as bronzes and brasses (Copper, alloyed with aluminium and zinc
principally) are also used in architectural design, offering a variety of colours and
finishes, combined with copper's exceptional characteristics.
Copper is a key component of many energy-saving technologies. For example,
passive solar water heating systems employ copper to capture and convert
sunlight into heat. Copper heat exchangers efficiently transfer the thermal energy
absorbed by the solar collector to the home’s hot water system. Sunlight is abundant,
renewable and, even where it is not readily available, can supplement a home’s hot
water needs virtually cost-free once a system is installed. Another option to
consider for home heating is a Direct Exchange (DX) geothermal system, which
uses a refrigerant directly circulating in underground copper tubing to extract or
disperse heat. By exploiting the earth’s constant temperature, DX systems efficiently
heat and cool homes and commercial buildings, reducing and in many cases
eliminating the need for standard air conditioning and heating. Keep in mind
that even standard units benefit significantly as a result of the higher energy-
efficiency performance they can derive from copper heat-exchange components.
Builders can use copper to conserve energy through the installation of a heat
exchanger for wastewater recovery. This type of heat exchanger typically has a
large-diameter copper pipe wrapped in thin-wall copper tubing. Warm wastewater
flowing through the larger pipe transfers its heat to the outer coil carrying the home’s
domestic water, which in turn reduces the amount of electricity or gas needed to
make hot water.
Use of copper plumbing avoids the controversial use of polyvinyl chloride (PVC), a
potential carcinogen according to the US Environmental Protection Agency. (US-

2. EPA). It is specified for use in most commercial plumbing, and is used extensively as
a tubing material in HVAC systems. Copper used for plumbing tube; sheet products
such as cladding, flashing and roofing applications; heating and cooling systems; and
the copper found in brass or bronze builders hardware and fixtures can be recycled
over and over with no loss of its physical attributes.
Another option for green plumbing systems is radiant heating that uses copper to
circulate water or a heat transfer fluid. Hot water recirculating systems that rely on
copper tubing for efficient fluid transfer are also gaining in popularity. Unlike more
conventional hydronic or forced-air heating methods, radiant heat systems radiate
energy directly to an area’s objects and its inhabitants. Because this is a more
efficient way to transfer heat, a building can achieve a level of comfort and warmth
at a lower overall temperature, saving energy and reducing heating costs. These
systems not only increase energy efficiency, they help to conserve water as
well. The most efficient systems are designed to operate only when needed, so
energy is not required to circulate water all of the time. In addition, it offers several
attributes that make it ideal for fire sprinkler systems.
The building industry has long valued the beauty, longevity and practicality of
copper. It is one of the few architectural metals commonly used without the
application of a coating or finish applied to retain and enhance its natural appeal and
long life. Its high ductility makes it easily formable--so it is easy to work with and
ideal for cladding complicated details and shapes. Copper is also naturally
resistant to weathering and decay, and can be alloyed with other commonly
available metals to increase its strength and performance characteristics, color, and
tarnish resistance. Thus making it an important material for sustainable, green
building projects.
Soft temper copper is very malleable and best suited for applications like intricate
ornamental work. With the development of cold rolling, the gauge or thickness of the
copper could be reduced without compromising its durability and low maintenance
properties--producing light weight, stronger copper product forms that maintain much
of the formability and ease of installation of soft temper for building systems where
intricate detail is not needed. Because of its excellent mix of strength and formability,
cold rolled is the most common copper temper currently used in building
construction. Copper’s long service life and low maintenance properties have lead to
its application for a variety of building systems and types.
Some of the world's most distinguished architects are using copper for its supreme
combination of technical and aesthetic properties. The Metropolis Museum of
Science in Amsterdam, designed by Renzo Piano, is clad in green pre-patinated
copper. In Stockholm, the copper-roofed museum designed by Marianne Dahlbäck
and Göran Månsson, winners of an architectural competition attracting 384 entries,
houses the Vasa, the only intact seventeenth century ship in the world. Increasingly,
copper and brass are the materials of choice for interior designers such as Andrea
Ponsi ('The Copper House', 1990's) in creating original contemporary furniture.
Copper facts for green buildings
Lightweight
Copper when used as a fully supported roof covering is half the weight (including
substrate) of lead and only a quarter of tiled roofs, with consequent savings in
supporting structure and materials generally.

3. Low Thermal Movement
With a thermal expansion value 40% less than both zinc and lead, properly designed
copper roofs minimise movements due to thermal changes, avoiding deterioration
and failure. In addition, the high melting point of copper ensures that it will not “creep”
or stretch as some other metals do.
Indefinite Life
Copper roofs have been known to perform well for over 700 years and it is invariably
substrates - not the copper itself - which eventually fail.
No Maintenance
Copper does not require any decoration, cleaning or maintenance. It is therefore
particularly suited for areas which are difficult or dangerous to access after
completion.
Durable
Copper exposed to the outside protects itself by developing a patina over time, which
can reform if damaged, ensuring extreme durability and resistance to corrosion in
virtually any
atmosphere. Unlike some other metals, copper does not suffer from underside
corrosion.
Cost-effective
With its indefinite life and unique visual characteristics, copper roofing is often found
on prestigious buildings and might be perceived as a “premium” material. However,
recent independent research has shown that, because of light weight and other
benefits, copper roofs are comparable with zinc, stainless steel, aluminium and
even some clay and concrete tiles when considering overall roofing costs (including
structure). Copper roofing is considerably less expensive than lead, Welsh slate or
hand made clay tiles. Using life cycle costings, the research also reveals copper as a
more cost-effective material than virtually any other for roofs with a 30 year or
greater life, due to its durability, maintenance free nature and ultimate salvage
value. With the growing interest in copper roofing by building designers, contractors
are becoming increasingly familiar with prefabrication, mechanised seaming and
other cost saving techniques. The cost competitiveness of copper is resulting in its
use on a much wider variety of building types than in the past - not just on prestigious
projects. To maximize the low maintenance benefit of the cladding, copper can
be used for sun shading. The use of copper on the façade also contributes
substantially to minimizing the expected maintenance requirements of the building.
Copper’s properties mean the cladding is essentially maintenance free, which
reduces the operating costs of the building. Beyond the financial rewards,
environmental benefits include eliminating the need for chemical or artificial
coatings or finishes.
Durability & Lifespan
Copper roofing and cladding exposed to the elements develop a protective patina
over time which can reform if damaged. This ensures extreme durability and
resistance to corrosion in virtually any atmospheric conditions and, unlike some
other roofing metals, copper does not suffer from underside corrosion. Consequently,
it is invariably the supporting substrates or structure which eventually fails rather than
the copper cladding itself and copper roofs have been known to perform well for over
700 years. Similar empirical evidence cannot be provided for more recently
developed cladding materials such as stainless steel, even though long life spans
(e.g. 100 years) are claimed for them.

4. Copper’s patination process is complex, involving initial formation of copper oxide
conversion films, gradually interspersed over a number of years with cupreous and
cupric sulphide conversion films, and culminating with conversion of the sulphide
films to the green copper sulphate patina.
The rate of corrosion from the copper surface decreases with patination and is
considered to average between 0.0001 and 0.0003mm per year. For a 0.6mm thick
sheet, this equates to no more than 5% corrosion over 100 years. The lifespan of
copper roofing and cladding can therefore be regarded conservatively as 200 years,
subject to substrate and structure, and this is endorsed by experience. Naturally, this
has a significant effect upon comparative whole of life assessments in terms of
energy consumption,CO2 generation and cost.
Heat Capture
The ability of the copper cladding to capture the heat of the sun in winter came as
a pleasant surprise to the building’s operators. Based on what they learned,
designers of the building have exploited this “solar wall strategy” in subsequent
projects.
Embodied Energy & Co2
An important, but often misused environmental indicator is the ‘embodied energy’ of
a material, which is the total energy consumed during every phase of each life cycle
from cradle to grave. Estimates for the various roofing and cladding metals vary
wildly, partly because of a lack of current information but also because of basic errors
such as:
• Comparing energy per tonne rather than per m2 of material, thus
misrepresenting thinner, lighter materials such as copper
• Using inappropriate life span estimates (such as 70 years for copper
compared with 100 years for stainless steel) resulting in additional theoretical
“energy use” for unnecessary re-roofing
• Ignoring current, more efficient recycling practices used in the copper
industry. The following tables provide useful, up-to-date comparisons of
embodied energy and carbon dioxide emissions for typical roofing and
cladding metals, considered over ‘whole of life’ (or ‘End of Life’).
Material thicknesses shown are typical for fully supported roofing techniques. Values
are taken from a study performed by the Fraunhofer Institute with the participation of
PE Europe GMBH Life Cycle Engineering. (Source: German Ministry for
Environmental Affairs, 2004).
Copper Stainless Steel Aluminium
Thickness (mm) 0.6 0.4 0.7
Life span (years) 200 100 100
Embodied Energy
(MJ/m2) 103.3 157.2 115.4
An important criteria of copper is its low level of embodied energy. Copper is highly
recyclable and durable and retains between 90-95% of its value relative to the cost of
new copper.3 As a result of this characteristic, the majority of copper extracted
through history is still in circulation today, used over and over in a variety of
applications. With continuing concerns about global warming, embodied CO2
emissions also provide an important indicator: for example, the BRE Environmental

5. Profiling System provides a weighting for CO2 eight times greater than that for SO2.
The following estimates, from the same source as for those above, offer guidance
Copper Stainless Steel Aluminium
Thickness (mm) 0.6 0.4 0.7
CO2 equivalent emissions
(kg/m2) 6.6 10.9 7.5
Another problem in making assessments of this sort is that available information is
invariably dated. Production processes are improving all the time in terms of
efficiency and waste limitation. In addition, the latest construction techniques such as
the long strip method offer long life, complete roofing solutions with lower costs and
embodied energy values which have yet to be properly assessed.
CDM Regulations, health and safety
Copper is non-toxic and presents no risks with long term contact. Consequently, the
legislative controls and continuing programme of health monitoring needed for site
workers and those handling other metals such as lead do not apply to copper
workers. The weight of copper needed to cover a given area is substantially less than
that of lead, reducing lifting problems - particularly at high levels. Copper is therefore
a safer alternative to lead for flashings and other weatherings - even on non-copper
roofs. Copper maintains a consistent malleability and “feel” which makes manual
working entirely predictable. Indeed, metal roofing installers show a clear preference
towards copper over other metals. It can be worked at all temperatures and, unlike
metals such as zinc, does not become brittle and break to form sharp edges in cold
weather. Copper is ideally suited to mechanisation techniques, including
preforming of trays and joints in safe locations and the use of automatic seaming
machines on roofs, minimising high level work (as recommended by the Health and
Safety Executive).
Innovation
Copper Increases Efficiency of Solar Cells : In the past, it has been more expensive
to convert solar energy to electricity, as compared to other more readily available
energy sources. But thanks to the joint effects of Siemens Solar GmbH in Munich,
Germany (a joint venture of Siemens AG and Bayernwerk AG); Siemens Solar
Industries, a limited partnership in Camarillo, California; and two joint ventures,
Siemens Showa Solar Ltd. In Singapore, and Showa Solar Energy K.K. in Tokyo,
Japan; working together with the U.S. Department of Energy's (DOE) Thin-film
Photovoltaics Partnership Program, a new breakthrough could make solar power
more plentiful and inexpensive. This group of professionals have set about testing
the capabilities of a new thin-film photovoltaic module that is created by applying a
fine film of copper indium diselenide (CIS) to a glass backing - producing a semi-
conductor. When the semi-conductor is exposed to sunlight, it actively converts
sunlight into electricity - at a cost up to 10 times less than the crystalline silicon based
cells now on the market. This record setting one-foot by four-foot module was
developed in collaboration with U.S. Government's National Renewable Energy
Laboratory (NREL). Record breaking efficiencies of more than 12 percent have been
confirmed for this new thin-film module - Siemens Solar ST40 large-area copper
indium diselenide (CIS) photovoltaic (PV) product.