Transcript ENVIRONMENTAL IMPACT File

THE ENVIRONMENTAL IMPACT
OF CONSTRUCTION MATERIALS AND
METHODS
DAVID HAINSWORTH
LESSON OBJECTIVES
In today’s lecture you will be learning about :
1) The environmental impact of construction
materials
2) The environmental impact of construction
methods
The construction process not only consumes the
most energy of all sectors in the UK and creates
the most CO2 emissions, it also creates the most
waste and is responsible for the most pollution.
POLLUTION FACTS
• 10% of the UK CO2 emissions arise from the
production and use of building materials.
• Each year the UK construction industry uses 6
tonnes of building materials per head of
population.
• Materials production and construction
accounts for an estimated 122 million tonnes
of waste, or 30% of the total arising in the UK.
OBTAINING AND PROCESSING
MATERIALS
Obtaining and processing materials can affect
the environment in three main ways :
1) EXTRACTION
2) PROCESSING
3) TRANSPORTATION
EXTRACTION
• This requires heavy plant which consumes
energy and produces noise, dust and exhaust
fumes, which leads to climate change
• This process also causes a permanent change
to the landscape e.g. stone/aggregate
quarrying
AGGREGATE QUARRYING
PROCESSING
Processing the material e.g. iron ore
requires energy consuming plant, noise
and dust, and the creation of waste
products e.g. slag
BLAST FURNACE
AIR POLLUTION LEADS TO THE GREENHOUSE EFFECT AND CLIMATE
CHANGE
TRANSPORTATION
Once processed, the materials will then
need to be transported to the location
which they are to be used, using petrol and
creating exhaust fumes, which in turn causes
climate change
TRANSPORT - FUEL EMISSIONS
MATERIALS USED IN CONSTRUCTION
There are 4 main materials used in
construction and we will now look at
their specific environmental problems.
TIMBER
DEFORESTATION
MORE THAN 25% OF THE WORLD’S TROPICAL FORESTS HAVE BEEN
CLEARED SINCE 1960. WHAT IS HARDWOOD USED FOR IN
CONSTRUCTION ?
LOSS OF ANIMAL AND PLANT SPECIES
TIMBER SUMMARY
• Timber can be classed as a renewable material
(especially softwood)
• Relatively low energy used in the logging and
sawing process
• High transportation costs
METALS
METAL ORE QUARRYING
WHAT SORT OF METALS ARE USED IN CONSTRUCTION ?
METALS SUMMARY
• Metals are classed as non-renewable
• Extraction and processing uses huge amounts
of energy, causes air pollution and creates
waste products, and changes the landscape
• Decreasing ore quality makes it necessary to
extract more ore from the earth
CONCRETE
CONCRETE
WHAT IS CONCRETE MADE FROM ?
CEMENT BASED PRODUCTS SUMMARY
• Classed as non-renewable
• Made from limestone, chalk, clay, aggregate
and gypsum
• These raw materials must be mined then
processed, which requires a huge amount of
energy
• It is estimated that 8% of the total worldwide
human generated CO2 originates from cement
production
PLASTICS
PLASTICS
UPVC PRODUCTS INCLUDE WINDOWS, DOORS, SOFFIT, FACIA, RAINWATER
GOODS, ELECTRICAL AND PLUMBING COMPONENTS
PLASTICS SUMMARY
• Classed as non-renewable
• Plastics are petrol-chemical products (which use
oil during production)
• Alternative to timber
• Needs large amounts of energy to produce and
creates hazardous waste products e.g. dioxins
EMBODIED ENERGY
• The energy required to produce and transport
materials is known as the “embodied energy”
• The following chart shows the embodied
energy in several common building materials
(excluding transportation energy)
MATERIAL
TIMBER
BRICK
CEMENT
PLASTIC
GLASS
STEEL
ALUMINIUM
ENERGY FOR PRODUCTION
1
4
5
6
14
24
126
ENVIRONMENTAL PROBLEMS
ASSOCIATED WITH THE
CONSTRUCTION PROCESS
Can you think of some environmental
problems caused by the construction
of new buildings and structures ?
PERMANENT CHANGE TO LANDSCAPE
IN BUILDING THE THREE GORGES DAM IN CHINA, LARGE AREAS WERE FLOODED,
AFFECTING LOCAL VILLAGES AND WILDLIFE.
EVEN ON THE SMALLEST BUILDING SITES TREES, HEDGEROWS AND WATER
COURSES CAN BE AFFECTED.
NOISE/DUST
NOISE AFFECTS LOCAL AREAS, DUST CAN SPREAD OVER A
WIDER AREA AND CAN CONTAIN POLLUTANTS
RIVER POLLUTION
SILT RUN OFF FROM BUILDING SITES/QUARRIES
GROUND POLLUTION
RUBBISH/EXCESS MATERIALS CAN BE LEFT, SPILT, BURIED OR BURNT CAUSING
GROUND POLLUTION
LANDFILL
WASTE PRODUCTS AND RUBBISH THAT CANNOT BE RECYCLED ARE
REMOVED FROM SITE AND TAKEN TO NEARBY LANDFILL SITES, WHICH
CAUSES GROUND POLLUTION. CAN YOU THINK OF SOME EXAMPLES ?
POSITIVES AND PROGRESS
• Waste segregation and recycling is now
common on many building sites
• This not only cuts down on waste going to
landfill but conserves energy, conserves
natural resources and helps reduce
greenhouse gas emissions e.g. CO2 caused by
the manufacture of new materials
WASTE SEGREGATION
SEGREGATE TIMBER/PLASTIC/RUBBLE/PLASTERBOARD FOR RECYCLING ONSITE
CONSTRUCTING NEW BUILDINGS
Measures are now in place to ensure that
modern buildings are built with minimum
environmental impact and are designed to be
energy efficient during their life cycle
These include Life Cycle Assessments,
Environmental Impact Assessments,
Environmental Management Systems and
Government Legislation such as the Town and
Country Planning (EIA) (England and Wales)
Regulations 1999
QUESTIONS
Please feel free to ask any questions