Value unit - TX

Value Unit refers to the unit in which an environmental indicator or quantitative measure is expressed. It defines the scale and type of the result value, such as kilograms of CO₂-equivalent or megajoules of energy.

Value Units are essential for ensuring comparability, validity, and consistency across Life Cycle Assessment (LCA) declarations and sustainability data exchange using the IMDE model.

Purpose

The Value Unit indicates the unit of measurement for the value being reported, independently of what it is reported *per* (e.g., per kilogram or per functional unit). It answers the question: “What is the quantity expressed in?”

Examples

Common Value Units used for environmental impact indicators are shown below, along with standardized or recommended keys:

Value Unit	Key	Description	Indicator Example
kg CO₂eq	kgCO2eq	Kilogram of carbon dioxide equivalent	Climate Change / Carbon Footprint
m³	m3	Cubic meter of freshwater	Water Use
MJ	MJ	Megajoule (energy unit)	Primary Energy Demand
kg Sb eq	kgSbeq	Kilogram of antimony equivalent	Resource Depletion (Abiotic Resources)
kg PM2.5 eq	kgPM25eq	Kilogram of fine particulate matter equivalent	Air Pollution (Particulate Matter)
kg SO₂ eq	kgSO2eq	Kilogram of sulfur dioxide equivalent	Acidification
mol H⁺ eq	molHplusEq	Moles of hydrogen ion equivalent	Acidification Potential
kg N eq	kgNeq	Kilogram of nitrogen equivalent	Eutrophication (Terrestrial)
kg P eq	kgPeq	Kilogram of phosphorus equivalent	Eutrophication (Freshwater)
CTUe	CTUe	Comparative Toxic Unit for ecosystems	Ecotoxicity
CTUh	CTUh	Comparative Toxic Unit for humans	Human Toxicity

Note: Keys follow commonly used abbreviations in ILCD/PEF datasets and ISO unit symbols where applicable. Compound units such as “kg CO₂eq” or “kg Sb eq” reflect impact-specific normalization factors used in LCA characterization models.

Characteristics

• May be expressed as standard SI units (e.g., kg, m³, MJ)
• May be expressed as derived or compound units (e.g., kg CO₂eq, MJ primary energy, kg Sb eq)
• Units should be consistent with international LCA standards (e.g., ILCD, PEF, EN 15804)

Use in IMDE

The Value Unit is part of the environmental impact declaration structure in IMDE and is applied per Indicator:

• Example:

 * EnvironmentalImpactIndicator: CFP {Climate Foot Print)
 * Value: 0.98
 * Value Unit: kgCO₂eq
 * Reference Unit: kg (see Reference Unit)

This separation ensures reusability of indicators across products, geographies, and life cycle stages while preserving semantic clarity.

See Also

• Reference Unit
• LCA Environmental Impact Indicators
• Functional Unit - TX
• IMDE Data Model