Introduction

There are a multitude of indicators to quantify the environmental performance of a product. These indicators can be directly derived from methods used in life cycle analysis. These indicators can then be used to communicate about the environmental performance of a product to the customer as part of an environmental display.

A major interest related to the use of indicators is their best rendering, ease of understanding compare to LCA results which detail a large number of indicators on the whole life cycle of the product. These indicators can be focused on one type of environmental impact (on water, on land, on air, etc..) and a particular phase of the lifecycle (eg the end of product life). However, it should be careful not to use too few or too many indicators focus on pain of not taking into account other significant environmental aspects of the product.

Indicators can also be useful, especially during the development phases of a product to evaluate, or simulate the impacts of a product in development. They require less time, data and resources that a life cycle analysis. They identify, at the early stages of design, the critical aspects of a product on the environment.

Finally, using a number of relevant and appropriate indicators it is possible to have a global vision of a company’s efforts to reduce the environmental footprint of its products. These indicators can be used to define quantifiable goals to be achieved.

MET matrix

The MET matrix is not really an indicator; it does provide a qualitative and quantitative evaluation of a product. This matrix focuses on three aspects of a product:

• the materials,
• the energy,
• toxicity.

However, this matrix is not specifically oriented towards the end of life of product but throughout the life cycle. To be completed it requires a multidisciplinary team but its implementation is simple and fast.
At the end, it provides a simple document and adapted to communicate, and a document that illustrates the actions to implement.

Phase of life cycle	Materials	Energy	Toxicity
Materials production	Identification and quantification of the materials of the system	Evaluation of the energy generated by the production of these materials, their transformation of their transport to the site of production or assembly	Identification of potentially toxic materials but also the waste generated during the phases of mining and processing
Manufacturing	Identification of auxiliary materials required for the production	Evaluation of energy consumption related to production	Identification of waste produced during the production phase
Distribution	Identification of materials required packaging	Evaluation of consumption related to packaging and transport to the retailer	Identification and quantification of emissions related to consumption. Identification of packaging waste
Use	Identification of materials related to the use such as consumables or maintenance	Evaluation of consumption in the use phase	Identification and quantification of waste associated with the use or maintenance
End of life	Identification of materials needed to manage end of life product	Energy needed for the management of the end of life of the product	Identification and quantification of waste generated during the end of life (including reused or recycled materials)

Table 1: MET Matrix (Techniques de l’ingénieur)

The choice of a material for eco-design is performed based on several criteria more or less relevant according to the envisaged lifetime of the product:

Material selection guidelines for ecocompatible products
		Lifespan of the product
		Short	Medium	Long
1 - Materials with low environmental impacts
	Short distribution chain
	Renewable
	Nontoxicity
	Eco-efficiency
2 - Material lifetime extension
	Material durability
End of life	Recyclability
	Biodegradability
	Energy recovery
	Landfill disposal
3 - Ethics
	Material producers environmental strategies and policies

Table 2: Materials choice strategy – (Study: Allione C, et al.)

KEPIs

The KEPI (Key Environmetal Performance Indicator) method is based on the results of a life cycle analysis in order to propose a series of indicators based on the most significant aspects of a product on the environment. This method is a method which is adaptable on an individual basis for each type of product. By focusing on a few relevant indicators, this method provides a rapid assessment of the environmental performance of the product and limit the need of data collection during the inventory life cycle of the product.

To be efficient, this method must:

• Provide clear results (easily understandable),
• Require a limited amount of data,
• Require little computing time,
• Be based on the physical and chemical characteristics of the product,
• Do not require extrapolation of results of impact assessment.

The indicators selected must be simple to evaluate, be based on a scientific approach in order to be reliable and be sure to cover the significant impacts of the product on the environment.

The example below shows the indicators that have been implemented in the case of a mobile phone (P. Singhal & al., 2004).

Based on the peformance of a life cycle analysis, the following environmental impacts were analyzed ^*:

• Energy consumption,
• Global warming potential,
• Acidification potential,
• Potential ozone depletion,
• Photochemical oxidation potential,
• Potential of human toxicity,
• Potential of resource depletion,
• Air pollution.

^* These impacts were analyzed using the assessment method: Eco-Indicator 99

This study has been conducted to determine the components and materials which have the greatest impacts compared to impact categories previously selected.
This should lead to the development of indicators related to earlier derived results.
Key indicators of environmental performance (KEPI) that have been proposed as a result of this study for the phases of « production », « distribution » and « use » of mobile phones are:

Phase of the life cycle	Manufacturing	Distribution	Use
Proposed indicators	Gold quantity	Number of componants in the mobile phone	Energy consumption in sleep mode
	Area of printed circuit board x number of layer
	Total area of dies (of integrated circuit)
	Bromine quantity
	LCD screen area
	Quantity of solder paste
	Copper quantity in charger and cables

Table 3: Proposed KEPIs on a cell phone (Study: P Singhal & al.)

These results cannot in any case apply unchanged. They nevertheless shwo how a life cycle analysis may allow the development of such indicators.

Other kind of indicators

Quantitative evaluation of the disassembly of a product

The proposed tool below is used to quantify the difficulty of removing a component from a product and therefore to assess quantitatively the difficulty of disassembling a product. This product evaluation helps improve product design and identify weaknesses (in view of disassembly).

Table 4: Assessment grid of a product disassembly (Study: Ehud Kroll and Thomas A. Hanft)

This grid is used as follows:

To assess the complexity of disassembly of a product, all the steps that will allow performing the steps of disassembly of the product should be performed step by step. Each (different) dismantled component corresponds to a row of the grid.

The grid consists of fourteen columns:

1. Each different component removed is identified,
2. In case there is a repetition of components (e.g. screws) the amount is shown,
3. The third column is particularly important. It is to be determined if the component which is removed is necessarily required in the product. This allows identification of opportunities to reduce parts. For a component to be necessary in the product, it must meet the following three rules:
   1. While using the product, can the component move, is there a relative motion to other parts when they are fixed ? Only the large displacements that cannot be absorbed by elastic links and adjustments can cause a positive response.
   2. Should the part be composed of a different material or isolated from other assembled parts ? Only fundamental reasons related to the material properties are eligible.
   3. Should the piece be separated from others otherwise assembly or disassembly of another part would be impossible?

   Example: if the component in question consists of three screws, and if only a screw is really needed the figure of the column is: 1. However if the presence of screws is not necessary the number of the column is: 0.

4. Here we describe the basic operation is performed for removal of the piece:

Un Unscrew	Tu Turn	We Wedge, Pry	Cu Cut
Re Remove	Fi Flip	De Deform	Pu Push, pull
Ho Hold, Grip	Sa Saw	Dr Drill	Ha Hammer
PE Peel	Cl Clean	Gr Grind	In Inspect

Table 5: Abbreviation of basic operations of disassembly

1. Number of repetition of the basic task of 4.
2. Here we describe the tool needed:

Unscrewing:
PS	Philips screwdriver
FS	Flathead screwdriver
ND	Nutdriver
FW	Fixed-end wrench
AW	Adjustable wrench
SR	Socket with ratchet
AK	Allen key
PW	Power wrench
Cutting and breaking:
KN	Knife
WC	Wire cutter
SH	Handheld shears
DR	Drill
PG	Handheld power grinder
GW	Grinding wheel
HS	Hachsaw
SS	Power saber saw
BS	Power band saw
HM	Hammer
CH	Chisel
PB	Prybar
Gripping and fixturing:
VS	Vise
PL	Pliers
Other:
BR	Brush
RG	Rag
ST	Special tool


Table 6: Abbreviation of removal tools
3. to 11.: It is estimated by the difficulty of removing the piece according to:
   1. Its accessibility,
   2. Positioning: Here we evaluate the precision necessary to position the tool required for disassembling
   3. The force required,
   4. The base time: e.g. an unscrewing operation takes longer than a turning operation. Base time means: the time needed to perform the operation without difficulty, without taking into account the time to position the tool or overcome the resistance of the assembly.
4. The subtotal can aggregate the difficulty of the operation for each component. This is the sum of columns to .
5. The total score for each row (or component) is used to weight the difficulty and the number of identical components. It is the multiplication of columns and .

The total score of the product is obtained by adding all scores for each component.

Once this analysis has been performed an indicator of the effectiveness of the design (for disassembly) can be determined:

This indicator reflects the efficiency with which the components are assembled to the disassembly of the product.
The higher the indicator, the more optimal is the design. A value of 100% corresponds to the assembly of components whose efficiency of disassembly is ideal: in a product composed of a minium number of parts, each component can be removed with a minimum of difficulty in a minium of time with a minimum number of tools.

Using the grid, we can also estimate the time required for disassembling the product:

Global indicators of eco-design

Finally, we can define more global indicators to quantify eco-efficiency of a product. Indeed, regardless the eco-design strategy adopted by the company it necessarily covers around eight major areas including:

1. Reduce the number of different materials and choosing the most appropriate materials;
2. Reduce the environmental impact of the production phase;
3. Optimize the distribution phase;
4. Reduce the environmental impact of the use phase;
5. Extense the useful lifespan of the product;
6. Simplify the disassembly of the product;
7. Product design for reuse and reuse;
8. Product design for recycling.

The following eleven indicators allow to take into account all of these areas. Most of these indicators are relative: they are unitless. Therefore, they are comparable from one product to another while with an absolute measure (eg weight of a material in kg) would make comparisons complicated when the weight of products changes as this is often the case with electronic products.

Indicator	Name	Formula	Desired trend
1	Reusable parts	Weight of reusable parts ÷ Total weight of product	Increase
2	Recyclables materials	Weight of recyclable materials ÷ Total weight of product	Increase
3	Reversible joints	Number of reversible joints ÷ Number of total joints	Increase
4	Same material joints	Same material joints ÷ Number of total joints	Increase
5	Parts with label	Number of parts with label ÷ Total number of different parts	Increase
6	Tools for disassembling	Number of necessary tools ÷ Number of total joints	Reduce
7	Time for disassembling	Total time to take appart all joints of a product	Reduce
8	Intelligent materials	Weight of clever materials ÷ Total weight of product	Reduce
9	Time for battery changing	Time for replacement of batteries (or other user-serviceable parts)	Reduce
10	Laminated or compound material	Weight of laminated or compound material ÷ Total weight of product	Reduce
11	Painted, stained or pigmented surfaces	Painted, stained or pigmented surface ÷ Total surface of product	Reduce

Table 7: Global eco-design indicators (Study: Carlos C. et al)

References

– Cristina Allione, Claudia De Giorgi, Beatrice Lerma, Luca Petruccelli – 2011

– Proposal for new quantitative eco-design indicators: a first case study – Carlos Cerdan, Cristina Gazulla, Marco Raugei, Eva Martinez, Pere Fullana-i-Palmer – 2009

– Quantitative Evaluation of Product Disassembly for Recycling – Ehud Kroll et Thomas A. Hanft – 1998

– Key Environmental Performance Indicators (KEPIs): A new approach to environmental assessment – P Singhal, S Ahonen, G Rice, M Stutz, M Terho, H van der Wel – 2004

– Techniques de l’ingénieur – Éco-concevoir, les outils et méthodes – ref. 22745.0276 – french