|Quality Management and Safety Engineering (BSc) - MST 326|
Life Cycle Assessment/Analysis (LCA).
PowerPoint presentation: 153 KB
Life Cycle Assessment factsheet (InnProBio)
Resources for environmental impacts and Life Cycle Assessment (LCA)
Concern for environmental issues is not a new phenomenon: key dates ..and.. definitions of eco-efficiency.
A key political concept in this context is Sustainability, and related issues are covered on the Environmental Management Systems page.
Life Cycle Assessment
ISO14040:2006(E) defines four different phases for Life Cycle Assessment. Brady  defines the four phases as follows:
The framework set out in the standard then requires:
ISO14040:2006(E) suggests that when "setting the system boundary, several life cycle stages, unit processes and flows should be taken into consideration, for example, the following:
There is a problem in measuring the "sustainability" of any particular set of circumstances. A fully Quantitative Life Cycle Analysis would address the balanced requirements arising from (technical), economic, environmental, social and governance issues (the latter three issues are often abbreviated to ESG). Further, there is growing momentum to consider direct (Scope 1), indirect within the company (Scope 2) and indirect within the value chain of the reporting company (Scope 3) emissions [What are Scope 3 emissions?, Carbon Trust].
However, there are a diverse set of issues addressed by different bodies and no agreed weighting, such that each analyst can produce results favourable to the case they wish to make. For example, the sources analysed in the Table below undertake very different analyses for sustainability criteria.
|Green Guide to Composites prepared by BRE Environment and NetComposites||Azapagic, Emsley and Hamerton ||DEFRA/DTI Strategy for Non-food Crops and Uses ||Department of Trade and Industry Technology Programme 2005||Avery: Leadership for Sustainable Futures |
|Climate change||global warming potential||air pollution
(including greenhouse gases)
|energy consumption ..|
share of renewable energy resources
|Fossil fuel depletion||abiotic resource depletion||substitution of fossil fuels||energy intensity/mass intensity||consumption of fossil fuels per capita|
|Ozone depletion||ozone depletion potential|
|Human toxicity in air and human toxicity in water||human toxicity potential||toxicity and gas releases|
|Ecotoxicity||aquatic toxicity potential||biodiversity|
|Waste disposal||waste management
|Acid deposition||acidification potential|
|Eutrophication (over-enrichment of water courses)||eutrophication potential||water pollution|
|Summer smog (low level ozone creation)||photochemical oxidants creation potential|
|Minerals extraction||abiotic resource depletion||impacts on non-renewable resources .. resource depletion||recycled/rare resources|
|impacts on renewable resources||use of renewables .. recyclability|
|service life and intensity|
|exposure to risk (to health at work)||health and safety|
|strengthening rural communities||exclusion from access to services|
|rural employment generation||employment||low unemployment|
|countryside recreation opportunities|
|social acceptability issues||social conditions/inclusion||social inequality|
|average life expectancy|
|innovation||access to information|
|human capital formation||under-education|
|distribution of wealth|
The Defra/DTI study further divides the issues it lists:
To quote Avery :
"Pressure to focus on the environment in the USA now comes from the financial sector. Some investors make financial decisions based on studies suggesting that environmentally friendly companies perform better financially . Environmentalism is becoming a question of risk management and credit rating. For example, insurance companies put environmental pressures on clients; banks and other financiers impose environmental conditions on firms seeking loans; some consumers consider environmental issues in purchasing decisions. In these and other ways, the trend towards greater emphasis on the environment is translating into more traditional corporate terms of risk management, meeting consumer demands and the cost of capital. This makes it less an external environmental issue than a strategic part of the business".
Azapagic et al [3, 7] have published a coherent system for the determination of environmental impact classification factors under the following eight categories:
Azapagic et al [3, 7] provide some guidance on the quantification of the above environmental impacts in Appendices to their books. In , it is proposed that the Value Function Approach can be used to aggregate information from the three groups of sustainability factors (economic, environmental and social/cultural). The most commonly used aggregation model is the additive aggregation in which the value function V(ai) is constructed from the partial value functions vj(ai) defined over a set of criteria j:
where wj is the weight given to each criterion j and ai is a particular alternative from amongst the set under consideration. The partial value functions are usually standardised so that the worst outcomes are allocated a value of zero and the best outcomes are allocated a value of one (or 100). The weighting is then indicative of the relative gain associated with an improvement in the system.
Life Cycle Assessment is the subject of the ISO14040 series of standards:
Ayres  has published an interesting critique of life cycle analysis and identifies that the methods and models underlying many scenario building efforts and the published LCAs are "inadequate to their stated purpose".
Whilst ISO/TR14047:2003 identifies eight factors for concern similar to the eight environmental impact classification factors in Azapagic et al, these are not necessarily the only issues that need to be considered. A recent Global Innovation Outlook Report on Water states that "we have never learned how to efficiently manage water .. [but] we will not have the luxury of this ignorance in the future". Professor John Anthony Allen introduced the concept of "virtual water" in 1993. It is a basic measurement of the water required to produce various goods, especially where those goods are traded. The calculation includes irrigation, industrial processes (and discharges) and transport, but does not consider the source of the water being used. Hoekstra developed the concept of a "water footprinting" to determine the total water impact of an individual, business or nation. This measurement estimates the direct and indirect water consumed and/or polluted over unit time. The measurement distinguishes between freshwater (blue water), evaporated water (green water) and polluted water (grey water).
The EU Concerted Action AIR-CT94-2028 considered harmonistion of environmental life cycle assessment for agriculture .
References for Life Cycle Analysis: