What is sustainability

“The term (greenwash) is generally used when significantly more money or time has been spent advertising being green, rather than spending resources on environmentally sound practices. This is often portrayed by changing the name or label of a product, to give the feeling of nature, for example putting an image of a forest on a bottle of harmful chemicals.” (Wikipedia)

When choosing building materials and products, architects, specifiers, developers and clients will increasingly be concerned about environmental issues. This may be because rules, regulations and policies enforce this or because of a genuine ethical decision to ensure that buildings are as sustainable as possible.

However, there is a great deal of confusion and misunderstanding of what green and sustainable buildings actually are. At present there is no commonly accepted definition of sustainability. The Brundtland definition, however, is frequently quoted. The Brundtland Report of the world Commission on Environment and Development defines sustainable development as follows:

“Humanity has the ability to make development sustainable – to ensure that it meets the needs of the present without compromising the ability of future generations to meet their needs.” (WCED 1987)

How are informed decisions made about what materials to use and who sets the standards that can validate such decisions? As policies and thinking about sustainable construction are changing so rapidly, can there be any real degree of certainty about the best thing to do?

What is SustainabilityDistinguishing between being good for the environment and what has become known as “greenwash” is not always easy. “The term (greenwash) is generally used when significantly more money or time has been spent advertising being green, rather than spending resources on environmentally sound practices. This is often portrayed by changing the name or label of a product, to give the feeling of nature, for example putting an image of a forest on a bottle of harmful chemicals.” (Wikipedia)

Scientific work to evaluate and improve the environmental impact of galvanizing has been based on analysis of genuine data and this avoids greenwash as any claims that are made can be backed up with good peer reviewed science. However, it is not easy to make comparisons between products and materials as there are so many different methods of analysis and claims that are made. A level playing field to compare environmental credentials does not yet exist, though it may come in time.

Why is sustainability important?

A review of the literature on green building will make it clear that there are a wide variety of interpretations available. Some are very technocratic whereas others refer to new age mystical ideas! Rarely is a holistic approach adopted in which every aspect of environmental impacts is considered.

What is SustainabilitySome see environmental issues as only about saving energy or improving building services. Many people associate green building with adding renewable energy to buildings and adopting micro generation. In many cases the materials that are used are fairly low down on the list of concerns for the designer or client. On the other hand some advocate using straw-bales and mud to create low impact buildings with purely natural materials.

This plurality of approach can also be found when looking at environmental assessment tools and methods. Some are concerned with assessment systems for buildings and others for materials as though they are two different things when in fact they are completely inter-related. The other difference is whether assessment tools are to design buildings or assess them once they are built. If assessment systems are not useful as design tools, then they are essentially measuring the impact once the damage has been done.

How should sustainability be interpreted?

There is a need for a consumers’ guide to environmental assessment tools . The European Commission has mandated the European standards organisation, CEN, to develop a standardised system for assessing the environmental performance of buildings. This work began in 2004 and was expected to be completed in late 2009. Meanwhile, several other national schemes have been developed to suit national circumstances, such as Ecoquantum (Netherlands); LEGEP (Germany); Haute Qualitié Environnementale (France). In Spain, the US LEED system has been used to assess sustainable building in public projects.

Sustainability metrics

In the UK and USA, market leaders such as BREEAM and LEED dominate the field. While these two systems are well-known, the selection of building materials and methods represents only a small part of the tool. Generally, BREEAM and LEED are seen as making a useful contribution to advancing the cause of greener buildings but they are not without their critics.

LEED certification

Many maintain that a LEED certification plaque is no guarantee that a building deserves accolades for good green design. Industry professionals commonly complain that the credit system unevenly recognizes energy use. For example, because each LEED credit is worth one point (out of a possible 69), it’s possible for a building to receive 26 points – enough for a plaque – without obtaining a single point for energy efficiency.
This is arguably the most important green building metric, and critics note that this loophole allows owners to slap a few green elements – from a green roof to preferred parking spaces for hybrid vehicles – on top of an otherwise conventional building in order to score easy LEED points.

Key components of a full life cycle inventory for construction products

In 2004, the Green Building Alliance, a Pittsburgh-based coalition of environmental groups, compiled an anonymous electronic survey of architects, engineers, contractors, and others who had worked on green building projects. On a recent building, one respondent had received one LEED point for installing a $395 bike rack, the same score as for a $1.3 million heat recovery system that would help save the owner around $500,000 annually in energy costs.

how-should-it-be-interpretedThe US Green Building Council promotes the LEED system of assessment and recently in the UK, a Green Building Council has also been established. Similar organisations exist in Australia and other countries. In addition to such overall methods of assessing buildings, there is a maze of systems for assessing the environmental impact of materials. These are sometimes taken into account in building design assessment tools, but not always.

In 1988, a Construction Products Directive was adopted by the European Union and is currently being considered for amendment. It had been hoped that this would lead to a harmonisation of environmental standards for building products throughout Europe. Even though many building products now exhibit the “CE” mark, this does not provide any guidance to its environmental provenance. While a number of EU measures have driven forward the agenda for sustainable construction, in particular, pressure to reduce pollution and remove toxic chemicals from buildings, there has not been an overall strategy for sustainable construction.

Tools for assessing environmental performance

There are two important tools that are used to assess environmental performance of construction products – Environmental Product Declarations (EPDs) and Life Cycle Assessment (LCA).

In fact, these two tools are closely linked, as an EPD uses LCA to calculate the magnitude of the impact categories that are included in the declaration.

In order for LCAs and EPDs to be generated for a particular process or product, it is necessary to have reliable and representative life cycle inventory (LCI) data.

Key sustainability terms

Embodied carbon
Is the total amount of carbon dioxide gas (or equivalents) emissions associated with the energy embodied in a product (C CaLC 2006).

Carbon footprint
A carbon footprint is a measure of the impact of human activities on the environment in terms of the amount of greenhouse gases produced, measured in units of carbon dioxide.

Embodied energy
Embodied energy is the sum of the total primary energy consumed in the manufacture and supply of products. This would normally include the energy used in extraction, processing and refining, transport, production, packaging and delivery to the site in a condition ready to use without further processing. There are two common ‘flavours’ of embodied energy: cradle-to-gate and cradle-to-site. Here ‘gate’ refers to the factory gate where the product is manufactured. The difference in the two definitions is the energy associated with transporting the product from factory to site of use. Most references suggest this difference is usually small in comparison to the cradle-to-gate values.

Life cycle embodied energy
Is calculated from cradle-to-grave and therefore includes energy use during the useful life of the product, energy associated with end-of-life processes and final disposal and/or recycling.

What is the meaning of non-renewable?
Examples of non-renewable resources are ores and fossil resources like coal and oil. In the EPD®-system, peat is considered a non-renewable resource.

What is the meaning of renewable?
Renewable resources are resources that are being renewed relatively fast. Examples are wood and agricultural products and energy sources such as: wind energy, solar energy, tidal energy, hydroelectric power, marine current energy and biomass energy. Geothermal energy is also considered renewable because there is so much of it, it can hardly be depleted.

Resource, recycled
Recycled resources have already been used at least once. If a product is made of recycled resources, only those environmental impacts associated with recycling the resource is attributed to the product.

Global warming
Global warming is measured in kilogram CO2 – equivalents. Global warming is the gradual increase, over time, of the average temperature of earth’s atmosphere and oceans sufficient to induce changes on the earth’s climate. This increase on earth’s temperature is related to the increase of the emission of gases, such as, CO2, methane, water vapour, nitrous oxide and CFC’s, among others, from anthropogenic (man made) sources, mainly from the burning of fossil fuels. Europe´s emissions in 1990 corresponded to 8,700 kg CO2-equivalents per person. Burning 1000 litres of petrol in a car generates approximately 2,500 kg CO2 as a comparison.

Photochemical smog
Potential photochemical ozone creation, or summer smog, is measured in kg ethene equivalents (C2H4). Increased levels of ozone at ground level, arise through the reaction of volatile organic compounds, for example ethene, with oxygen compounds or oxides of nitrogen in air and under the influence of sunlight, so called photochemical oxidation. The effects on human health are amongst others, irritation of eyes and mucous membranes as well as impaired respiratory function. Ground level ozone also has severe effects on vegetation, resulting in agricultural production losses. Europe´s emissions in 1990 corresponded to 20 kg ethene equivalents per person. Burning 1000 litres of petrol in a modern car generates around 1 kg ethene equivalents as a comparison.

Eutrophication is measured as the amount of oxygen consumption a substance causes when released in the environment. For example, nutrients like nitrogen released in a lake leads to an increased production of planktonic algae. The algae sink to the bottom and are broken down with consumption of oxygen in the bottom layers, causing a dead environment at the bottom. The most significant sources of nutrient enrichment are the agricultural use of fertilizers, the emissions of oxides of nitrogen from energy production and waste water from households and industry. Europe´s emissions in 1990 corresponded to 298 kg O2 per person. Burning 1,000 litres of petrol in a modern car leads to the consumption of around 10 kg oxygen as a comparison.

Acidification is measured in amount of hydrogen ions (H+) created when a substance is converted into an acid. These acids (often referred to as acid rain) are best known for the damage they cause to forests and lakes. Less well known are the many ways acid rain damages freshwater and coastal ecosystems, soils and even ancient historical monuments, or the heavy metals these acids help release into groundwater. The most important man-made emissions of acidifying gases are sulphur dioxide (SO2) and nitrous oxide (NOX) from combustion processes. Europe´s emissions in 1990 corresponded to 38700 mol H+ per person.

Ozone depletion
Ozone depletion is measured in CFC-11 equivalents. Ozone existing in the stratosphere (upper layer of the atmosphere) functions as a protective layer against ultraviolet radiation harmful to life on earth. The emission of CFC’s and tetracloromethane gases, among others, is responsible for the decrease of ozone concentration in the upper atmosphere, with negative consequences to life on earth, such as the increase in skin cancer incidence. Europe´s emissions in 1990 corresponded to 0,2 kg CFC-11 equivalents per person.

Waste to recycling
Waste to recycling includes all waste, for example scrap metal, which is sent away from the manufacturing plant to be used again in another product, often after some form of treatment.

The average European
It is easier to understand what the environmental impact category indicators in an EPD means, if they are compared to something. One possibility is to compare with the average environmental impacts of a person living in Europe in 1990. Europe´s emissions divided by its inhabitants in 1999 were: 8,700 kg COequivalents; 20 kg ethene equivalents; 298 kg O2; 38,700 mol H+; 0,2 kg CFC-11.
(explanations based on information provided by website of the EU-funded Stepwise EPD project COOP-CT-2004-513045)

Why is it important?

In many cases the materials that are used are fairly low down on the list of concerns..

How should it be interpreted?

There is a need for a consumers’ guide to environmental...

Key Sustainability Terms

The following list of key sustainability terms used in the construction industry...