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LCA and the Working Environment

3 The EDIP screening method

3.1 The general methodology

Development of the EDIP method for assessment of the working environment was part of the Environmental Design of Industrial Product programme (the EDIP-programme). The programme was sponsored by the Danish EPA, and the participants were five major Danish industrial companies as well as institutes at the Technical University of Denmark.

3.1.1 Purpose

The purpose of the EDIP project was:

1. To develop methods for environmental assessment of complex industrial products,
2. To develop guidelines for design and construction of environmental friendly industrial pro.ducts,
3. To develop a database and a computer based tool as support for environmental assessment, and
4. To implement the methods and tools in the companies participating in the project.

3.1.2 The overall content of the methodology

The purpose of the EDIP project was, as mentioned, to perform an environmental assessment of products. For this purpose a quantitative process assessment method for LCA was developed within the project. The assessment parameters used within the EDIP method are shown in Table 3.1. According to the table the method operates with three groups of assessment parameters: environmental effects, resource consumption, and working environmental effects.

Table 3.1. Assessment parameters used in EDIP.

Most of the effect potentials are relatively straightforward to handle in the quantitative assessment method. However, the quantitative assessment of the effect potentials "ecotoxicity" and "human toxicity" demands much more work. To avoid too much unnecessary work, screening methods have been developed. These screening methods can help in the decision of identifying the potential contributes to human toxicity or ecotoxicity.

3.1.3 The general principles of the methodology

The EDIP methodology is based on the following steps:

• Inventory : the data (e.g. resource consumption, emissions to air and water, waste etc.) from the product system are measured, calculated or estimated
• Classification: the inventory data are classified by their potential to cause impacts, e.g. use of non-renewable resources, global warming and ozone depletion
• Characterisation: the data are characterised with respect to the impact categories, i.e. equivalence factors are used to determine the impacts from several sources to an impact category.

These steps follow the principles outlined in the ISO 14040-series and are generally accepted as a sound methodology in LCA.

The aggregated impacts are subsequently normalised by relating them to the average annual impacts caused by one person in a relevant geographical area (the World/Denmark). In doing so, the contribution to an impact category is related to the potential impact from the society's activities as a whole.

Finally, the impacts are weighted using international or Danish political stated reduction targets for different impacts or specific compounds. Hereby it is assessed which of the potential impacts from a product system that are the most important.

These steps of the EDIP methodology differ slightly from the ISO 14040 standard, where only a weighting step is recommended. There is, however, little doubt that the normalisation step used in the EDIP methodology adds significant information, provided that the mechanism and principles are scientifically based and understood by the decision-makers.

3.1.3.1 The working environment in EDIP

EDIP operates with three different methods for assessing the working environment, a screening method, a process assessment method, and a sector assessment method.

The screening method is a chemical screening method and thereby only covers the chemical working environment of an LCA. The chemical screening method can be used early in the product development or together with the process assessment method. In the last-mentioned case the chemical screening will be a preliminary step for the quantitative assessment with the purpose of deciding which processes to include in the process assessment.

The process assessment method can be used in the assessment of the manufacturing process in the company and possibly for those subcontractors who are able and willing to supply the information needed.

The sector assessment method can be used together with the process method, in processes where specific working environmental data not are available (Hauschild, 1996, Broberg & Rasmussen, 1996).

3.1.4 Combined environmental and working environmental assessment

The assessment parameters used in the EDIP method are shown in Table 3.1. The method operates with three groups of assessment parameters (environmental effects, resource consumption, and working environmental effects), which all play an equal role in the methodology.

All three groups of assessment parameters are related to the same functional unit and measured by the same environmental unit - the person equivalent. Because the same basic assessment method is used, it is possible to aggregate over several steps in the life cycle and to compare the results from assessment of the working environment with other impact categories.

The data describing the working environment are collected from different sources depending on the assessment method used. For use of the chemical screening method, information about the chemicals used in the specific processes is needed. The screening scores the processes by relating them to European and national lists of dangerous substances, and lists of substances with special effects.

The process assessment method requires more specific data from the company. Examples are information concerning impacts due to accidents, chemicals, noise, and monotonous repetitive work. Furthermore, it should be stated how much of the company's production time that is used to manufacture the examined product in each of the processes.

When using the sector assessment method similar data should be collected. However, it should be noted that the data in this case represents the average working environmental impacts from the entire sector instead of the specific company and thereby - everything being equal - will lead to higher uncertainty.

3.2 Working environmental assessment methodology

3.2.1 Purpose and goal

The purpose of the working environment project within EDIP was

• to develop a method for including working environmental parameters in LCAs based on the methodical framework described by SETAC and the EDIP programme,
• to use the developed method for assessing the working environmental impacts in the life cycle of five industrial products (reference products),
• to identify the critical working environmental impacts of the reference products and point out the possibilities for improvements of new products in progress,
• to outline the principles for good working environmental construction of industrial products, and
• to describe and evaluate the use of the developed methods and tools in product development within the companies participating in the project (Broberg & Rasmussen, 1996).

The EDIP programme includes the working environment in LCAs for three reasons:

• The working environment should be included in LCAs to avoid working environmental deterioration when production processes are changed. LCAs will often be the basis of production changes or development of new products with lower environmental burdens. These changes determine the choice of production materials and processes, which directly influence the working environment.
• Including assessments of the working environment in LCAs makes it possible to prevent working environmental problems when the LCAs are used in the technological planning.
• The working environment should be included in LCAs because some working environmental problems are of life cycle character, e.g. by chemical substances following the product throughout its entire life cycle (Broberg & Rasmussen, 1996).

The screening method has been developed to serve several purposes. First of all the screening can be used to assess chemical substances on the basis of their inherent properties. This is important because it is often difficult to get detailed information about the chemical burden outside the companies' own production.

Secondly, the screening can be used at an early level in the product development, where the detailed production information is not yet known or when a general comparison between alternative materials and processes is wanted.

Thirdly, the purpose of the screening is to point out the life cycle processes that can burden the chemical working environment and to give an early idea of the working environmental properties of a material or product. The important processes and materials are then later on examined further by the process assessment method. To save time, the qualitative screening method is used to find the important processes quickly for the quantitative assessment.

3.2.2 Scope of the methodology

3.2.2.1 System boundaries

The system boundaries for the screening method with regard to the inclusion of life cycle phases are not mentioned in the description of the method. It is assumed that the screening method in principle can be used in all phases of the life cycle if the necessary data exist. The entire life cycle is therefore in principle covered by the working environmental assessment. However, only work-related processes are examined. Private use of the products is not included as a part of the working environmental assessment as this is not covered by legislation. Furthermore, only chemical working environmental problems are included in the screening as the chemical burden is one of the largest working environmental problems in Denmark (Broberg & Rasmussen, 1996).

Allocation is not used in the screening method because the method is merely used preliminary to find the chemically burdened processes that should be examined further, e.g. by using the process assessment method. Otherwise the impacts are allocated by production time (Broberg & Rasmussen, 1996).

3.2.2.2 Impact categories

The working environmental impacts included in the screening method are only related to chemicals. The screening includes the potential effects of the chemicals by assessing the inherent properties of the chemicals. The actual effect that occur because of an exposure is very difficult to describe because the effect depends on the size of the exposure, the time exposed, the exposure route, the individuality of humans etc. The potential effects are listed in Table 3.2 below.

Table 3.2. Working environmental effects included in EDIP's screening method

3.2.2.3 Data requirements

The data needed are found at process and/or company level. Some data can be found in literature; others at the examined companies.

The necessary data for the EDIP screening method can be divided into three groups.

• Group one is the inventory data from the process description, which include a list with names of substances and materials used at the individual life cycle processes (preferably with the attached CAS-numbers).
• Group two is information on the potential effects of these chemicals according to Danish and European legislation.
• Group three is an evaluation of the potential exposure to the listed chemicals.

The chemicals to be listed in group one do not only cover the chemicals in the production but also auxiliary materials, breakdown products, impurities, etc. (Broberg & Rasmussen, 1996).

Data on the effects of the chemicals can be found and are generally available. Data on the potential exposure are more difficult to find, but the screening method only demands data on a very low level ("no exposure", "no knowledge", "exposure exists"), which makes it easier to find the data or come up with educated guesses. The exposure is estimated with the use of knowledge about the process and about the chemicals, e.g. open or closed process, existence of process ventilation, existence of contact with the chemical, and physicochemical parameters (Broberg & Rasmussen, 1996).

3.2.2.4 Inventory parameters

The necessary inventory parameters are, as listed above, a list of the chemical substances, and the potential effects and exposure of these substances.

Collection of the inventory data for the chemical screening is carried out individually, because the data collection merely is at a screening stage. It can, however, be beneficial to collect data on emission of the chemicals for the external environment at the same time.

The necessary workload for performing the chemical screening is low. When a precise identification of the chemicals have been made, the screening can be carried out by the use of toxicity data based on EU-classification, lists from Danish authorities concerning carcinogenic, reprotoxic, allergenic, and neurotoxic (CRAN) substances, and data about the potential exposure (often common knowledge or educated guesses).

3.2.2.5 Impact assessment

The chemical screening process reviews the exposure and effects of the chemical substances, and thereby evaluates how burdened the chemical working environment is. The purpose of the screening is merely to pinpoint important processes for the inventory and the impact assessment at an intermediate stage in the assessment. For a chemical working environment to be burdened there has to be both an exposure and an effect of some kind. The screening method is therefore based on a matrix consisting of the two parameters "exposure to" and "toxic effects of" the chemicals, see Table 3.3.

The chemical substances are given a score on the basis of their toxic properties and effects, and a score based on the risk of exposure to that chemical. If a chemical substance have more than one potential toxic effect the score is determined by the highest score. The score of a substance with both a carcinogenic and irritating effect will, for example, be 8. The final score is found by multiplying the effect score with the exposure score (Broberg & Rasmussen, 1996).

Table 3.3. EDIP's total screening method (simplified). Final score is given in brackets ().

The final score can be used to compare different alternatives, and if handled with care the screening method can be used to choose between alternatives. Care should be taken because the screening is a very general assessment with a relatively high uncertainty. However, the screening can be used as a guide in development work.

It is suggested that the choice between alternatives can be carried out by selecting the alternatives with no final score of 16, then selecting the alternatives with no score of 8, and so on. Furthermore, the final scores can be added for the entire life cycle. However, this number will only have limited value, because the final score does not represent the true chemical burden of the pro.cesses in the life cycle as substances with unknown exposure are given a medium score (Broberg & Rasmussen, 1996).

No aggregation of the results is used within the screening method. Likewise, further assessment or weighting is not carried out as the method merely is regarded as a preliminary screening method.

The chemical screening method does not live up to the ISO 14040 standard in all respects. Primarily, because it only addresses the chemical aspects, and secondly, because the assessment is not based on the actual emissions, but on the inherent properties of the chemicals. Thirdly, the classification, characterisation and the weighting is carried out in one step by using the developed matrix for the screening.

3.3 Cases

No cases have been documented for use of the chemical screening method. The screening method was developed late in the process of developing the process assessment method, because the detailed level of the process assessment method led to the need of a screening method. Therefore the screening method has not been used on any cases.

3.4 Discussion

In this section we discuss the strong and weak sides of the EDIP screening method. The text therefore reflects the opinion of the project group. The purpose of the discussion is partly to evaluate the screening method and partly to be able to learn from these strong and weak sides, and thereby be able to set guidelines for the "perfect" working environmental LCA.

Firstly, the strong and weak sides are summarised in this discussion (Table 3.4), whereupon the points are elaborated. Secondly, an overview of our evaluation of the working environmental LCA is given and finally, suggestions for improving the method are discussed.

Table 3.4. Strong and weak points of EDIP's chemical screening method.

3.5 Methodical requirements

3.5.1.1 Integration with the general LCA-methodology

EDIP's chemical screening method can in principle be used in all phases of the life cycle. It has no direct integration with the general EDIP LCA-methodology. The screening method is primarily developed as an auxiliary tool for the process assessment method, in order to save time in the data collection phase.

The screening is very similar to the screening method in MUP. The screening for exposure is, however, not as elaborated as in MUP. In MUP the exposure is given a score based on different physicochemical parameters, whereas EDIP gives some guidelines, based on process specific information, for how to determine whether an exposure exists or not.

3.5.1.2 Aggregation over the life cycle

The screening method gives the possibility to aggregate the scores, but it is not possible to make a "correct" aggregation. The working hours, which are used to aggregate the impacts in EDIP's general methodology, are not included in the screening method. The final score can be added for the entire life cycle and give the total score for the specific alternative. As stated in Broberg & Rasmussen (1996), the method should, however, be used with great care as the total score does not represent the true chemical burden of the processes in the life cycle, because substances with unknown exposure are given a medium score. Furthermore, it only makes sense to add up the individual scores if the total number of processes, and the total number of chemicals used through the entire life cycle is the same for all alternatives. The final score should therefore only be used to select the chemicals and their matching processes that should be included in the impact assessment.

3.5.1.3 Comparison of alternatives

The screening method can to some extent be used to compare alternatives and to choose between them. The choice can, however, only be made if the difference between the alternatives is clear, (e.g. by choosing the alternatives that have no scores of 16), because of the general level of the screening method. Even though the choice only is possible on this level, it is significant to be able to perform a choice between alternatives (on the basis of one impact area that is!) already at the screening stage.

Even with the low level of data needed, the screening serves its purpose to leave out the processes with no relevance for the extended impact assessment, i.e. processes with either no exposure or processes using substances with no effects on human beings.

3.5.1.4 Other methodological issues

If the screening should live up to its other purposes of being able to assess the chemicals and compare alternatives, it seems that the scoring interval is too narrow. Too many processes will end up with either a score of 8 or 16, and thereby be investigated further. Even the processes with no knowledge about the exposure can end up with a score of 8. For the purpose of choosing between alternatives it is therefore necessary to widen the scoring possibilities.

In addition, the chemical screening method recommends that processes with an effect score of 1, and with an exposure score of either 1 or 2 could be examined further. These processes will, however, not be included in EDIP's process assessment method, and therefore there is no need to examine these pro.cesses any further. The screening method and the method used for process assessment should match each other in a way so that processes chosen as important by the screening process are a part of the working environmental assessment in the LCA. This imbalance can, however, be improved by expanding the process assessment method.

3.5.2 Working environmental aspects

The screening method covers only the chemical impacts, whereas the process assessment method in EDIP includes the impact categories chemical impacts, noise, monotonous and repetitive work, and accidents. Conversely, the screening covers all effect groups of the chemical working environment whereas the process assessment only includes the chemical CRAN-effects/damages (Cancer, Reproduction damages, Allergy, Neurotoxic effects). This means that a process using toxic or very toxic substances with the possibility of causing irreversible damage on human beings is chosen as a process that should be included in the LCA when applying the screening method. The process will, however, be left out of the impact assessment in the process method because only CRAN-effects are covered by this method.

3.5.2.1 No differentiation between exposure levels

The screening method does not give the possibility to differentiate between different exposure levels, because the screening method only distinguishes between an exposure and no exposure to chemicals. A small short-time exposure is not likely to produce the same effects as a long-time exposure of a large dose. However, the relation between the level of exposure and the resulting effects is very complex and can be difficult to handle in a screening method.

The screening method does not consider the use of personal safety protection equipment. This is an advantage when the purpose is to promote more working environmental friendly products and processes. Prevention is preferred over protection. The method thereby ensures that less hazardous substances will be preferred instead of using a solution with more personal protection.

The EDIP method has been used by some companies during the development of the method. One important lesson from this was that the screening also might be helpful in reducing the total amount of chemical products used by the companies (Broberg & Rasmussen, 1996). The screening method was, however, not developed to serve this purpose but this example shows that use of the screening brings the use of chemicals into focus, which then leads to a reduction.

3.5.3 Practicability

3.5.3.1 Easy to use - clear outputs

One strong point of the method is that it is easy to use. The matrix represents some simple guidelines on how to score the processes when the exposure to and the effects of the chemicals are known. Furthermore, the outcome of the screening is clear and comprehensible, because it is one single figure, which easily can be compared with another output.

3.5.3.2 No software tool available

No software tool is available for the screening method.

3.5.3.3 Difficult to use by non-experts

While the effects are straightforward to handle, because the information can be found on European or national lists of substances, the exposure is more difficult to deal with. One weak point is that, even at this low data level, educated guesses are often needed, based on general knowledge about how the different processes are carried out. It is therefore necessary to possess knowledge about different processes, and the circumstances that will lead to an exposure to chemicals. Knowledge about the chemical working environment and chemistry in general is also necessary for carrying out the screening. If no exposure knowledge exists the "no knowledge" score for the exposure will be given, and thereby make the score unreliable.

3.5.4 Data issues

The basic data needed for giving the processes the score are names of the chemicals used and information about the human exposure to the individual chemicals. With the CAS-number potential effects of the chemicals can easily be obtained. The potential exposure to the chemicals is scarcely described which is an advantage, because less data are needed when you only have to choose between the three categories: "no exposure", "no knowledge", and "exposure exists".

It is realistic to carry out the chemical screening because the level of data needed for the screening is comparatively low, and because the data often will be available. It may, however, be necessary to come up with educated guesses for the exposure conditions.

Information about the chemicals and the exposure to the chemicals can be obtained from a work place assessment.

3.5.5 Summary of the assessment

In Table 3.5 the discussion above is summarised. The table illustrates how we evaluate the EDIP screening method. The exact meaning of the topics in the first column is described in section 1.10.

Table 3.5. Evaluation of EDIP's screening method.

Topic	Evaluation of EDIP's screening method
Methodical requirements
Integration with LCA for external environment
Applicability in LC-phases
Aggregation possible
Working environmental aspects
Coverage of WE'al issues
Graduation of exposures and effects
Practicability
Practical in use
Software tool
Transparency
Can be used by non-experts
Data issues
Data reliability
Amount of data in existing database
Data accessibility
Data can be obtained by WPA

= missing, = poor, = acceptable, = good, = excellent

3.5.6 Suggestions for improvements

One improvement that could be useful is to develop the screening method in a way so the final scores for each process can be aggregated and give a more correct total score. However, this requires that exposure score 1 for "no knowledge" is removed, because this score produces the "incorrect" total score. But the possibility to tick off "no knowledge" is on the other hand also very useful at the screening level of an LCA. At this stage there will always be data that can not be found, and it is useful to know which processes should be further examined. For this reason it will also be difficult to go into more details about the kind of exposure or the level of exposure, even though this will produce a more correct picture of the actual effects of the processes. But the data on the exposure will be too difficult to find.

Alternatively a more simple aggregation method could be used, which makes it possible to keep the exposure score of "no knowledge". This will not involve a summation of all the scores. Instead the highest score for all the individual chemicals in the entire life cycle will be used as the "total score", similar to the principle mentioned in Broberg & Rasmussen, (1996). This will in many cases not be very useful, because it is likely that exposure to a substance with carcinogenic, reprotoxic or mutagenic effects will appear somewhere in the life cycle of the examined product. If this is the case, the maximum score of 16 will end up as the "total score" for all alternatives. This method can therefore only be used if the exposure score and the effect score are described in much more details and split up in more scores, thereby producing many more levels for the final score. This method may, however, become too comprehensive to serve the purpose of a screening, but it will improve the possibility of choosing between alternatives.

3.6 References

Broberg O., Rasmussen E (1996). Forskningsrapport Arbejdsmiljø fra vugge til grav. English title: Working environment from cradle to grave. Arbejdsmiljøfondet, Copenhagen.

Wenzel H, Hauschild M, Rasmussen E (1996a). Miljøvurdering af produkter, UMIP. IPU/DTU, Miljø- og Energiministeriet - Miljøstyrelsen, Dansk Industri.

Hauschild M (ed) (1996). Baggrund for miljøvurdering af produkter, UMIP. IPU - DTU, Miljø- og Energiministeriet - Miljøstyrelsen, Dansk Industri.

English version: Environmental Assessment of Products. Volume 2: Scientific background. Chapman & Hall, 1997.

ISO (1997). ISO 14040 : Environmental management - Life cycle assessment - Principles and framework. First edition, 15.06.1997.

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