The functional unit (Packaging model)

This article covers in detail the functional unit used in the Packaging (and its variants) model

According to ISO 14044, the functional unit expresses the quantified performance of a product system for use as a reference unit. According to the ADEME guidelines for LCAs comparing packaging systems, the definition of the functional unit is recommended to include:

• The function(s) (“what”):

  • Usually, the main functions of the packaging are to contain, preserve and transport / store a product. Additional secondary functions can be (for consumer goods): grouping products (or consumption units), enabling/facilitating product manufacture, facilitate product packaging, facilitate product use, inform and/or promote the product

  • It is further recommended to precise the targeted market segments (specificity of the packed products, e.g. still or sparkling water) and the type of points of sales

• The quantity (“how much”): the reference amount of product assessed

• Other specificities describing “how” the function is fulfilled (e.g. storage temperature)

• The required duration of the function (“how long”)

• The geographical scope (areas of production and consumption)

• The time horizon (e.g. current or prospection situation)

In practice, in the Packaging model, the user can choose among the following three ways for modelling the defined functional unit (FU):

• Per litre

• Per unit of primary packaging unit

• Custom: defining the number of functional units per packaging

The sections below provide examples of functional units and illustrates the corresponding ways of modelling in the tool.

Example: One litre of sparkling water

We define our functional unit as “Packing and distributing 1 litre of sparkling water in France while ensuring by appropriate protection that the product reaching the point of consumption fulfils quality standards, at least over the period determined by the “best before” or “use by” dates indicated on the packaging".

• Example of assessed primary packaging: PET bottles of 50 cl
• Reference flow: 2 bottles of 0.5 l
• Fields required in Pilario
  • Primary packaging volume: 0.5
  • Primary packaging's content weight: 500
  • Functional unit choice: Per litre
• Pilario automatically calculates the number of bottles needed to fulfil the FU (and so it displays the number in the Reference flow as 2 primary packaging unit / FU). This is used when presenting the results.

Example: A serving dose of 25 cl of juice 

We define our functional unit as: "Packing and distributing a serving dose of 25 cl of juice on the go in Germany while ensuring by appropriate protection that the product reaching the point of consumption fulfils quality standards, at least over the period determined by the “best before” or “use by” dates indicated on the packaging".

• Example of assessed primary packaging: PET bottles of 50 cl
• Reference flow: 0.5 bottles of 0.5 l
• Fields required in Pilario
  • Primary packaging volume: 0.5
  • Primary packaging's content weight: 500
  • Functional unit choice: Custom functional unit
  • Name: 25 cl serving

• Pilario automatically presents the results taking into account this 0.5.

Example: One (1) manual tooth brush 

We define our functional unit as: "Packing and distributing in Europe one packaging for a manual tooth brush produced in China in 2024"

• Example of assessed primary packaging: A packaging containing 1 tooth brush
• Reference flow: 1 unit of packaging
• Fields required in Pilario
  • Primary packaging volume: doesn't apply
  • Primary packaging's content weight: desired value
  • Primary Functional unit choice: Per unit of primary packaging
• Pilario automatically presents the results directly taking into account a 1 to 1 calculation.

Example: One thousand (1000) manual tooth brushes 

We define our functional unit as: "Packing and distributing in Europe 1000 manual tooth brushes produced in China in 2024"

• Example of assessed primary packaging: A packaging containing 3 tooth brushes
• Reference flow: 333 primary packaging unit per functional unit
• Fields required in Pilario
  • Primary packaging volume: doesn't apply
  • Primary packaging's content weight: desired value
  • Functional unit choice: Custom functional unit
  • Name: 1k toothbrushes

• Pilario automatically presents the results taking into account this 333 primary packaging unit / FU.

The amounts of packaging used as reference in the tool are defined for packing an amount of product as delivered at the gate (out) of the producer site. This amount of product cannot be distinguished from the amount effectively used by the consumer since, as a limit of the tool, the product losses (and associated packaging losses) taking place at distribution, further storage, retail and use phase are not modelled in the tool.

To ensure that systems are effectively comparable, particular attention must be paid to the definition of the functional unit in case of comparison. Indeed, according to ISO 14044, “Comparisons between systems shall be made on the basis of the same function(s), quantified by the same functional unit(s) in the form of their reference flows. If additional functions of any of the systems are not taken into account in the comparison of functional units, then these omissions shall be explained and documented. As an alternative, systems associated with the delivery of this function may be added to the boundary of the other system to make the systems more comparable. In these cases, the processes selected shall be explained and documented”.