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.