Why we choose Green building materials

Environmental impact categories:

Whereas the big picture of environmental damage is still some way from being realised, progress is being made at the individual manufacture scale. Industrial processes are being analysed and inventories built up to measure a wide variety of environmental impacts. Categorising the range of impacts has generally resolved into definitions commonly employed by Life Cycle Assessments (LCAs) and Environmental Product Declarations (EPDs):

Quantifying the overall environmental impact of construction is complex and currently unaccounted for, but some salient figures provide a lead:

• The construction sector worldwide currently accounts for more than 11% of global GDP (PwC, 2011)
• Construction accounts for around 40% of the total flow of raw materials into the global economy
• Construction in the UK accounts for around 90% of all non-fuel mineral use
• The UK's building stock accounts for 50% of CO₂ emissions, construction adds another 7%

Climate change

The headline environmental issue. Usually through the consumption of the fossil fuels as energy, manufacturing processes are responsible for 'greenhouse gas' emissions - the main being carbon dioxide (CO2). The energy used to extract the raw materials and the production process for a product is known as 'embodied energy'.

• By reducing the amount of energy from oil, coal and gas used in manufacturing processes, there is a corresponding drop in the quantity of greenhouse gas.

• Reduction in fossil fuel energy used in manufacturing is achieved through using less energy in materials production (efficiency) and / or increasing the proportion of 'renewable energy' such as that produced by wind or hydro.

Mineral resource extraction

Includes metal ores such as iron, copper, aluminium, 'rare metals' and uranium; minerals such as the 'non-renewable' fuels gas and oil (see below); and building materials such as aggregates, stone and clay.

The extraction, processing, and transport of minerals all have impacts on the environment, as well as risking the health and safety of those working in the industry.

The un-extracted quantities of the various minerals naturally vary enormously. For example clay and stone exist in abundance whereas formerly common metals such as copper are increasingly difficult to extract. The 'rare metals' used in electrical products are found in very few locations - mainly in China where their extraction and exportation are severely controlled.

Our children and succeeding generations are unlikely to be offered the same resource opportunities that are being exploited by ourselves and previous generations.

• Reducing our dependence on mineral extraction is essential if we are to provide for a sustainable future.

• Resource efficiency, either through reducing mineral useage and/or making use of increasing quantities of recycled material, should be built into product design; products should ultimately avoid becoming 'waste' and being consigned to landfill.

Human toxicity

One of the achievements of the environmental movement has been the disclosure of industrial processes that are dangerous to humans and the environment. Particularly disturbing has been the revelation of the hazards associated with everyday products and materials used in our homes and workplaces. Such products include paint, carpets and flooring as well as furniture and some construction products.

Debate continues concerning the risks posed by chemicals used in building products. Amongst the substances currently in the limelight are included Formaldehyde, widely used as a binder, and PVC with its multitude of uses.
The leading source of guidance about dangerous chemicals is the European REACH (Registration, Evaluation and Authorisation of Chemicals) regulation. REACH lists Substances of Very High Concern (SVHC) that continues to grow and includes such compounds as the DEHP, a plasticiser commonly found in PVC.

Though a large number of chemicals have been examined, the bulk of the 140, 000 substances involved have yet to be assessed.

• Products that we use should be free of dangerous chemicals.

Ecotoxicity to freshwater and land

The pollution of our land and water is self-evident and worldwide. Since the industrial revolution our environment has taken the knock. Even now, after years of legislation, and our rivers having become safe to swim in and waste tips landscaped, our industrial processes continue to pollute water and earth. Ecotoxitiy is the potential for biological, chemical or physical 'stressors' to damage these ecosystems.

• We should work to limit the pollution that is the bi-product of our lifestyles and industrial processes.

Fossil fuel depletion

Our way of life depends on the use of fossil fuels to stimulate economic growth. The most flexible of these fuels is oil. 'Peak oil' is the point in time when the maximum rate of global extraction happens. That peak oil happens is obvious, the only question is when. Opinion varies, some say that it has already happened; most opinion would look to a maximum rate occurring within the next 10 - 15 years, with the most optimistic putting there faith in a longer period still.

We all rely on oil in particular for not just fuel, but also the raw material that gives us plastic, a multitude of chemicals, medicines and clothing.

Oil should be understood as a capital resource, not an income.

• Alternatives to building products made from plastic should be used where available.

Waste disposal

By now there can hardly be a household in the country that is not aware of the concept of waste. Brown, blue, and green bins compete to block our pavements and driveways. Building workers anguish about which skip to deposit unwanted material. But this is all but a small price to pay in addressing one of the absurdities of the industrial consumer age.

Construction waste contributes around 100 million tonnes of waste to landfill (DEFRA), around 3x the amount of domestic waste.

Because in the past we have been empowered to dispose of what we no longer need, we have effectively plundered natural resources and, after a relatively short period of use, disposed of those resources into large holes dug into the landscape.

• To save the unnecessary disposal of hard-won resources, to limit the quantity of energy required to process raw materials, and to reduce the extent of landfill (or sea disposal) - we need to use our resources more carefully. Products can be made to enable reuse or, if easily disassembled, for the materials to be recycled into other products. Products using no or minimal virgin material should be favoured.

Water extraction

The idea that water, particularly in the UK, is a scarce resource, takes some getting used to. Yet the fact is that we are using more water as well as suffering from a pattern of climate change that brings in turn less rainfall in the south of England. In the face of this and to meet our current needs, water authorities have resorted to extracting more water from rivers and aquifers - resulting in greater damage to natural water courses. In extreme cases (which are becoming more frequent) water rationing has had to be introduced.

• Nearly all manufacturing processes use water, some more than others.

• Our use of water in our homes has increased over the last 30 years.

• We need to reduce the amount of water used in industry as well as the amount of water we use at home. We should favour manufacturing processes that use less water and we should use water at home more efficiently through changing our useage habits as well as selecting water efficient appliances.

Photochemical ozone creation ('Smog')

Often known as 'Summer smog', ground level ozone (as apart from stratospheric ozone) is created through a reaction powered by heat and sunlight between nitrogen dioxide (NO2) and volatile organic compounds (VOCs). The mixture of chemicals results from the release of VOCs from, largely, industrial processes and the nitrogen oxides (NOX) produced by car exhausts and the combustion of fossil fuel to produce electricity.

Ground-level ozone is associated with a number of human, particularly child-related asthma and other respiratory conditions.

Ground-level ozone also damages the environment mainly by interfering with the ability of plants to produce and store food.

• Preference should be shown towards materials that are manufactured using processes that contribute few or no VOCs.

Stratospheric ozone depletion (Thinning of and holes occurring in the ozone layer)

One of jobs of the 'ozone layer' is protecting us from ultraviolet (UV) light entering through the earth's atmosphere. UV light is suspected of contributing to, amongst other things, skin cancer and cataracts as well as damage to plants and plankton in the oceans.

Ozone in the stratosphere is declining at around 4% per decade.

Known 'ozone depleting substances' (ODS) include CFCs (use of which is regulated in most countries), HCFCs, HBFCs, halon, methyl bromide and bromochloromethane (BCM).

Many ODS are also greenhouse gases, some of which are considerably more powerful than carbon dioxide in exacerbating climate change.

• Plastic foamed insulation that used HCFCs as blowing agents have been largely phased out and replaced by products that are non-ozone-depleting agents, though there is some way to go before the greenhouse gas agents are superceded as well

Acidification ('acid rain')

Acidification (aka acid deposition) occurs when emissions from the combustion of fossil fuels and other industrial process combine with water in the air to form 'acid rain'.

Chemically, Sulpur Dioxide (SO2) and nitrogen oxides (NOX) react with water, oxygen, carbon dioxide and sunlight to form sulphuric acid (H2SO4).

Airborne chemicals can travel long distances from their sources. For example, the output from coal-fired power stations in England during the up to the 1980s generated large quantities of gases that were transported by air streams across the North Sea to Scandanavia where the consequent acid deposition caused enormous damage to the forests.

With the reduction of coal-fired power stations and an increased attention to flue filtering, acidification is not so much the problem that it once was, certainly in Western Europe. The same cannot be said for Eastern European and 'developing' countries such as China and India.

Eutrophication (the results of adding fertiliser and sewage to fresh water)

Eutrophication is the increase of nitrogen and phosphorous in the fresh water environment that increases algal growth. Depending on the degree of eutrophication, severe environmental effects can develop, which degrade water quality. For example, increased phytoplankton biomass can decrease clarity, reduce levels of light, and decrease levels of oxygen, all of which ultimately damage or kill organisms that live in the water.

Though also a natural occurrence, eutrophication is often the consequence of adding nitrates and phosphates to the water courses through agricultural fertilisers or untreated sewage.

• Though not a direct impact, building materials that are derived from plants or animals should use no or reduced levels of artificial fertilisers in their production.

Nuclear waste

Almost all of the nuclear waste generated around the world is from the nuclear power industry. The waste from reactors is dangerous and will remain so for thousands of years. There is no satisfactory solution to the problem of its disposal.

Nuclear power is extremely contentious, even amongst environmentalists. Traditional environmentalism has included protest against the nuclear industry as part of its DNA. Yet with the spectre of climate change upon us, nuclear power with its zero greenhouse gases offers a route around energy produced by fossil fuels.

The jury is still out.