Understanding sustainability in construction is critical, we believe that reducing Whole-of-Life Embodied Carbon is one of the greatest challenges faced by the building and construction sector and we all play a part.
We welcome you to read and use the definitions of key terms and phrases, with WT New Zealand as the source.
CARBON EMISSIONS
Emissions of greenhouse gas(es) to the atmosphere. Examples include combustion of
fossil fuels and greenhouse gases released from chemical reactions.
CARBON FOOTPRINT
The sum of carbon emissions and carbon removals over a full or partial product life
cycle. Equivalent to GWP-total.
CARBON FOOTPRINT OF PRODUCT (CFP)
A method for the quantitative evaluation of the carbon footprint of a product or service
system through its life cycle. Standardised by ISO 14067:2018.
CARBON REMOVALS
Removals of greenhouse gas(es) from the atmosphere. Examples include removal of
C02 from the air by plants during photosynthesis and by cement-containing materials
during carbonation.
CARBON STORAGE
The storage of carbon captured from the atmosphere for a period of time, resulting in
the temporary reduction in the concentration of greenhouse gas(es) in the atmosphere.
END-OF-LIFE EMBODIED CARBON:
Carbon Emissions associated with deconstruction/demolition, transport from site,
waste processing and disposal phases of a building’s life cycle which occur after its use
(modules C1-C4).
ENVIRONMENTAL PRODUCT DECLARATION (EPD):
Document containing data on the potential environmental impacts of a product or
service calculated using LCA following a set of Product Category Rules. An EPD must
be independently verified as compliant with ISO 14025:2006 and a relevant PCR and
published by an EPD programme operator.
FOSSIL FUEL
Any class of hydrocarbon containing materials of biological origin occurring within the
Earth’s crust that can be used as a source of energy. Fossil Fuels include coal, petroleum,
natural gas, oil, bitumen and tar sands.
GLOBAL WARMING POTENTIAL (GWP)
The heat absorbed by greenhouse gas(es) in the atmosphere, measured as carbon dioxide
equivalent. Carbon dioxide equivalent (C02e) is calculated using the intergovernmental Panel
on Climate Change’s (IPCC’s) Global Warming Potential indicator, typically using a 100-year
time horizon (GWP100), with the latest version being from the IPCC’s Sixth Assessment
report (AR6).
GWP-BIOGENIC (GWP-B OR GWPB):
Net of:
▪ Carbon Emissions from degradation of biomass via incineration, landfill, composting, or
an accounting adjustment (reported as a positive number), and;
▪ Carbon Removals from non-biogenic sources, e.g., through carbonation of cement (a
negative number).
GWP-FOSSIL (GWP-FOR GWPF):
Net of:
▪ Carbon Emissions from non-biogenic sources, e.g., combustion of fossil fuels and
emissions from chemical processes (reported as a positive number), and;
▪ Carbon Removals from non-biogenic sources, e.g., through carbonation of cement (a
negative number).
GWP-LULUC (GWP-L OR GWPL)
Carbon emissions and removals from Land Use and Land Use Change (LULUC) describes
changes in carbon stocks, such as soil carbon. EN 15804+A2:2019 does not allow negative
numbers (e.g., net sequestration of carbon in the soil) and instead requires these to be set
to zero.
GWP-STORED (GWP-S OR GWPS)
The GWP avoided by removals of CO² into biomass from all sources except native forests
(CEN, 2019, section C.2.4). GWP-stored should be a negative number, as it is a removal of CO²
from the atmosphere. In EPDs following EN 15804+A2, there will be a statement of “Biogenic
carbon content in product”. To convert this to GWP-stored, multiply by -44/12 to convert
stored elemental carbon to equivalent carbon dioxide.
GWP-TOTAL (GWP-T OR GWPT):
▪ Upfront Carbon = GWP-fossil + GWP-luluc + (GWP-biogenic-GWP-stored)
▪ Whole-of-Life Embodied Carbon = GWP-fossil + GWP-luluc + GWP-biogenic
LIFE CYCLE ASSESSMENT (LCA)
A method for the quantitative evaluation of the potential environmental impacts of a
product or service system through its life cycle. Standardised by ISO 14040:2006 and
ISO 14044:2006.
OPERATIONAL CARBON
Carbon Emissions associated with energy used to operate the building (module B6),
operational water use (module B7) and fugitive emissions of refrigerants (module B1).
In corporate carbon footprinting, these emissions are known as scope 1 and scope 2
emissions.
PRODUCT CATEGORY RULES (PCR)
A specific set of rules for completing an LCA of a particular product category and
publishing an EPD. Only EPDs conducted according to the same PCR are comparable.
The two main PCR documents for building products are EN 15804 and ISO 21930.
UPFRONT EMBODIED CARBON
Carbon Emissions caused by the production of materials, transport of materials to
the construction site and the construction of the building, prior to the building being
occupied (modules A1-A5).
USE STAGE EMBODIED CARBON
Carbon Emissions associated with materials and processes needed to maintain the
building during use such as for maintenance, repair, refurbishment or replacement
(modules B1-B5).
WHOLE-OF-LIFE EMBODIED CARBON
Carbon Emissions associated with materials and construction processes throughout
the whole life cycle of a building, excluding operational energy use (module B6) and
operational water use (module B7). This includes Upfront Embodied Carbon, Use Stage
Embodied Carbon, and End-of-Life Embodied Carbon but excludes Operational Carbon.
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