Life Cycle Assessment (LCA) Definitions
Life cycle assessment (LCA) is an essential part of Green Building. This explains some of the terminology.
Abiotic depletion potential | Abiotic depletion indicators capture the decreasing availability of non-renewable resources as a result of their extraction and underlying scarcity. |
Acidification | The reaction of acidic gases e.g. sulphur dioxide, with water in the atmosphere to form acid rain. |
Cradle to gate | All the stages in the manufacture of a product ‒ from extraction of raw materials, transport to factory, processing, manufacture and eventual despatch as far as the factory gate. |
Cradle to gate, with options | The life cycle stages of a product ‒ from extraction of raw materials through manufacture and despatch from the factory gate. It may also include a selection of its stages under usage and/or those under end of life. |
Cradle through construction assessment | The extension of ‘cradle to gate’ to include delivery to the construction site and all processes involved with incorporating that product into the construction works. |
Cradle to grave | This extends the ‘cradle through construction assessment’ to include maintenance of the building, any refurbishment and eventual recycling, reuse or disposal of then product. |
Declared unit | A quantity of a construction product for use as a reference unit in an EPD e.g. mass (kg), volume (m3). |
Environmental Product Declaration (EPD) | A means of reporting LCA data in a common format based on rules known as Product Category Rules (PCR). The plural of EPD is still EPD, not EPDs. |
Eutrophication | The over-enrichment of water courses (usually with nitrates and phosphates) which encourages the growth of algae and reduces the oxygen content within the water. |
Functional unit | The quantified performance of a product system for use as a reference unit in an EPD scheme e.g. the product in a 1m2 building element over a 60 year study period. |
Gate | Point at which a construction product or material leaves the factory before it becomes an input into another manufacturing process or it goes to a distributor, a factory or building site. |
Generic LCA | A type of LCA that collates data from several manufacturers of the same product to create an industry average. |
Life cycle | A collective term for all the stages covering the extraction of raw materials, through processing and manufacture, usage and end of life of a product. |
Life cycle assessment (LCA) | A methodology used to measure the environmental impact of a product at all its stages over its life cycle. |
Non-renewable energy | Energy from sources which are not defined as renewable energy sources. |
Product category rules (PCR) | A set of specific rules, requirements and guidelines for developing Type III Environmental Product Declarations for one or more products. (see below). |
Propriety LCA | The use of information from a single manufacturer so that LCA is specific to that manufacturer’s products. |
Renewable energy | Energy from renewable sources (typically non-fossil sources) e.g. solar, wind, hydro (excluding pumped-through hydro) and biomass. |
Secondary fuels | Fuels recovered from previous use or from waste which substitutes primary fuels. |
Secondary material | Material recovered from previous use or from waste which substitutes primary materials. |
Type III Environmental declarations | An environmental product declaration providing quantified environmental data on a products life cycle, using predetermined parameters and, where relevant, using additional environmental information, enabling a comparison to be made between products fulfilling the same function. |
Waste | Substance or object which the holder discards or intends or is required to discard. |