Functional/declared unit

Functional/declared unit

In building life cycle assessment or EPD declared/functional unit is the unit per which the results are provided.

The functional unit defines the impact results for certain service level the product provides. For instance, for insulation products, it could be 1 m2 of insulation which ensures a thermal resistance of 1.5 m2/WK
during 50 years. It is normally used in product EPD calculations when impacts related to the product use phase are also given. If the function of the product in the building level is not known (e.g. if the product has several applications in the building) or when the study does not consider all the life cycle modules declared unit is used instead of functional unit. It represents the physical quantity of the product such as 1 m2 of 50 mm thick insulation or 1 kg insulation.

Which units does One Click LCA support?

For product level calculations, the unit can be freely chosen based on the product and life cycle stages studied.

For buildings, most of the LCA tools of One Click LCA provide results as a total for the whole building and per 1 m2 of building area (different area definitions can be used). Additionally, other units such as impacts per 1 m2 of building/year of building use or impacts per user amount may be available for some tools.

    • Related Articles

    • Impact assessment / characterisation methodology in One Click LCA

      CML methodologyFor all the tools targeting for European markets, the impact assessment methodology is CML –IA 2012, which is the methodology required by the European EN 15978 and EN 15804 standards. CML methodology was created by the University of ...
    • Impact assessment categories

      One Click LCA supports all the 24 impact categories listed in EN 15804 based on CML methodology and 6 TRACI impact categories. However, the impact categories offered for each of the calculation tool depend on the purpose of the tool. For instance, ...
    • Life cycle stages

      Building life cycle stages are the different periods of a building’s lifetime. For instance: raw material harvesting, manufacturing of products, use phase of the building, end of life. In the European markets the building life cycle stages are ...
    • Service life of materials

      A product’s service life is its period of use in service. Service life is necessary to calculate replacement impacts of the construction material, within the calculation period. LCA and LCC use normally the service life of a building as a calculation ...
    • Databases incorporated in One Click LCA

      For One Click LCA most of the materials’ environmental impacts are based on manufacturer or product category EPDs, collected from 26 (and counting) different EPD databases, as well as information from building material manufacturers. Moreover, we ...