Allocation
partitioning the input or output flows of a unit process to the product system under study

ancillary input
material input that is used by the unit process producing the product, but does not constitute a part of the product
EXAMPLE A catalyst.

category endpoint
attribute or aspect of natural environment, human health or resources, identifying an environmental issue of concern

characterization factor
factor derived from a characterization model which is applied to convert the assigned LCI results to the common unit of the category indicator
NOTE The common unit allows aggregation into category indicator result.

comparative assertion
environmental claim regarding the superiority or equivalence of one product versus a competing product which performs the same function

completeness check
process of verifying whether information from the preceding phases of an LCA or an LCI study is sufficient for reaching conclusions in accordance with the goal and scope definition

consistency check
process of verifying that the assumptions, methods and data are consistently applied throughout the study and in accordance with the goal and scope definition
NOTE The consistency check should be performed before conclusions are reached.

Coproduct
any of two or more products from the same unit process.

data quality
characteristic of data that bears on their ability to satisfy stated requirements

elementary flow
(1) material or energy entering the system being studied, which has been drawn from the environment without previous human transformation
(2) material or energy leaving the system being studied, which is discarded into the environment without subsequent human transformation

energy flow
input to or output from a unit process or product system, quantified in energy units
NOTE Energy flow that is input may be called energy input; energy flow that is output may be called energy output.

environmental aspect
element of an organization's activities, products or services that can interact with the environment

environmental mechanism
system of physical, chemical and biological processes for a given impact category, linking the LCI results to category indicators and to category endpoints

evaluation
life cycle interpretation_ second step within the life cycle interpretation phase to establish confidence in the results of the LCA or LCI study
NOTE Evaluation includes the completeness check, sensitivity check, consistency check, and any other validation that may be required in accordance with the goal and scope definition of the study.

feedstock energy
heat of combustion of raw material inputs, which are not used as an energy source, to a product system
NOTE It is expressed in terms of higher heating value or lower heating value.

final product
product which requires no additional transformation prior to its use

fugitive emission
uncontrolled emission to air, water or land
EXAMPLE Material released from a pipeline coupling.

functional unit
quantified performance of a product system for use as a reference unit in a life cycle assessment study

impact category
class representing environmental issues of concern to which LCI results may be assigned

intermediate product
input to or output from a unit process which requires further transformation

input
material or energy which enters a unit process
NOTE : Materials may include raw materials and products.

interested party
individual or group concerned with or affected by the environmental performance of a product system, or by the results of the life cycle assessment

life cycle
consecutive and interlinked stages of a product system, from raw material acquisition or generation of natural resources to the final disposal

life cycle assessment (LCA)
compilation and evaluation of the inputs, outputs and the potential environmental impacts of a product system throughout its life cycle

life cycle impact assessment
phase of life cycle assessment aimed at understanding and evaluating the magnitude and significance of the potential environmental impacts of a product system

life cycle interpretation
phase of life cycle assessment in which the findings of either the inventory analysis or the impact assessment, or both, are combined consistent with the defined goal and scope in order to reach conclusions and recommendations

life cycle inventory analysis
phase of life cycle assessment involving the compilation and quantification of inputs and outputs, for a given product system throughout its life cycle

life cycle impact category indicator
quantifiable representation of an impact category
NOTE The shorter expression "category indicator" is used throughout the text of this International Standard for improved readability.

life cycle inventory analysis result (LCI result)
outcome of a life cycle inventory analysis that includes the flows crossing the system boundary and provides the starting point for life cycle impact assessment

NORMALIZATION
Many methods allow the impact category indicator result to be compared by a reference (or Normal) value. This means the impact category is divided by the reference. The reference may be chosen, but often the average yearly environmental load in a country or continent, divided by the number of inhabitants, is used as the reference.

After normalization, the impact category indicators all get the same unit (usually 1/yr), which makes it easier to compare them. Normalization can be applied on both characterization and damage assessment results. (SimaPro 5 Reference Manual)

Output
material or energy which leaves a unit process
NOTE : Materials may include raw materials, intermediate products, products, emissions and waste.

Practitioner
individual or group that conducts a life cycle assessment

process energy
energy input required for a unit process to operate the process or equipment within the process excluding energy inputs for production and delivery of this energy

product system
collection of materially and energetically connected unit processes which performs one or more defined functions
NOTE : In this International Standard, the term "product" used alone includes not only product systems but can also include service systems.

raw material
primary or secondary material that is used to produce a product

reference flow
measure of the needed outputs from processes in a given product system required to fulfill the function expressed by the functional unit

sensitivity analysis
systematic procedure for estimating the effects on the outcome of a study of the chosen methods and data

sensitivity check
process of verifying that the information obtained from a sensitivity analysis is relevant for reaching the conclusions and giving recommendations

system boundary
interface between a product system and the environment or other product systems

transparency
open, comprehensive and understandable presentation of information

uncertainty analysis
systematic procedure to ascertain and quantify the uncertainty introduced into the results of a life cycle inventory analysis due to the cumulative effects of input uncertainty and data variability
NOTE Either ranges or probability distributions are used to determine the uncertainty in the results.

unit process
smallest portion of a product system for which data are collected when performing a life cycle assessment

waste
any output from the product system which is disposed of

WEIGHTING
Some methods allow weighting across impact categories. This means the impact (or damage) category indicator results are multiplied by the weighting factors, and are added to forma a total score. Weighting can be applied on normalized or non-normalized scores, as some methods, like EPS, does not have a normalization step. (Source: SimaPro 5 Reference Manual)

Abbreviated terms:

LCA - life cycle assessment
LCI - life cycle inventory analysis
LCIA - life cycle impact assessment