Environmental Project, 907 – LCA and the working environment – 4 Goal and scope definition and inventory analysis

LCA and the Working Environment

4 Goal and scope definition and inventory analysis

The international standards ISO 14040 and ISO 14041 states that "The goal and scope of an LCA shall be clearly defined and consistent with the intended application" (ISO, 1997/1999).

As the discussion in the present report does not consider specific applications some of the elements in the standard are only addressed very briefly while other elements are discussed in detail because they are of general importance.

4.1 Goal of the study

The specific goal of a LCA study does not necessarily change when the working environment is included in the impact assessment. It will, however, often be necessary to state explicitly to what extent the assessment of the working environment will be taken into account when the goals of the study are to be met.

4.2 Function, functional unit and reference flow

Assessment of the working environment should be done by using the same functional unit as for the other parts of methodology. Thus, including the working environment should have no effect on the definition of the functional unit or the reference flow.

4.3 System boundaries

Ideally, the system boundaries for the LCA should be the same whether or not the working environment is included, i.e. the same unit processes are included. It should, however, be observed that some processes often are omitted from the LCA because they are assumed to have only a minor environmental impact. It is at present not known whether this assumption also is true for the working environmental impacts, and a previous omission of a process from the system boundaries should therefore be reconsidered.

One important difference from a general LCA is that the working environmental impacts in the use phase of a product can not be included, neither for the general consumer nor in professional settings. The reason for this is it is not possible to allocate the impacts in a given sector to specific products. As an example, muscolo-sceletal disorders in office workers can very seldom be attributed to a specific chair, table, personal computer or mouse, but are rather the result of an interaction between the general office layout, the specific furniture, the tasks to be done, the organisation of the work and the worker.

It should also be observed that precise information on many processes can not be found in the database. Instead, it is recommended that the practitioner use data for a process that resemble the actual process as much as possible. The choice of process should be addressed in the LCA report.

4.3.1 Description of the data categories

The data categories are described in section 2.1.1. These categories are available in Danish working environmental statistics, but may have a different format or be less detailed in other countries.

In order to reduce the number of data (and impact) categories, nine different kinds of accidents have been integrated into two headings, i.e. "Total number of accidents" and "Fatal accidents". This loss of detail is considered to be of minor importance as the primary aim is to establish an overview of the impacts as such and not to distinguish between e.g. injuries and sprains to arms and legs.

4.3.2 Criteria for inclusion of inputs and outputs

The criteria for inclusion of inputs and outputs is not a specifically related to working environmental impacts. In short, the present methodology and the database is developed to be used with the other parts of the EDIP-methodology, i.e. the life cycle should be covered as far as possible (the number of unit processes) with as detailed as impact assessment as possible (the number of impact categories).

In the end, the choice of which in- and outputs to include is made by balancing the necessary efforts with the additional information that can be obtained. For the moment being it is recommended that assessment of the working environment follows the assessment of the other impact categories, i.e. it is assumed that the processes included in the LCA generally will cover the working environment satisfactory. If experience shows that this is not always the case, it will be very straightforward to include additional processes with a significant impact on the working environment but with only minor impact on the environment.

4.4 Data quality requirements

The ISO 14040 standard series states that "Data quality requirements specify in general terms the characteristics of the data needed for the study. Data quality requirements shall be specified to enable the goals and scope of the LCA study to be met."

The following paragraphs highlights the most important issues that should be taken into account when defining the data quality requirements and subsequently be addressed in a LCA report where the methodology has been used.

4.4.1 Time-related coverage

As for all other inventory and assessment data in LCA, the methodology aims at using as recent data as possible. However, in order to minimise statistical variations an average of the information for the previous three years (1995-1997) has been used when establishing the database.

4.4.2 Geographical coverage

The database that is developed for use in the method is almost exclusively based on Danish statistics. The primary reason for this is that with a limited budget the project group considered it more important to collect Danish information on a broad range of sectors rather than collecting information on a few selected sectors from a broader range of countries.

This must be kept in mind when interpreting the results, i.e. the practitioner and the commissioner must know that the results reflect the impacts as if all unit processes had taken place in Denmark.

This is obviously not the case for very many products, and the lack of an international database must at present be regarded as a major flaw in the method. On the longer term, however, it is suggested that comparable information from other countries is produced using the same procedure. The statistics on goods production is uniform from one country to another and the calculation of the amount of produced goods in a given sector is relatively straightforward. The statistics on occupational accidents and injuries vary from country to country, but will most often include common elements. When combining information from different countries it should however always be stated how an aggregation of the information has been performed.

4.4.3 Technology coverage

As the database was established using information on whole sectors, the figures can be assumed to describe average conditions with respect to the technological level.

The range used to calculate average conditions must be assumed to be very broad. There is little doubt that the working environmental impacts per kilo product will be different if small/light products (e.g. nails and screws) are compared to big/heavy products (e.g. railroad tracks). In order to minimise the potential error, a database has been established for different product types from different sub-sectors where possible.

The effect of changing from old fashioned to modern technology cannot be assessed using the methodology. Introduction of new and more efficient technology commonly reduces the working time per produced unit and - accordingly - also the impacts per produced unit. There is, however, a risk that more efficient technology may increase the impacts on the musculo-sceletal system through an increased amount (or intensity) of monotonous and repeated work. It is also possible that the use of more efficient technology can change the psycho-social working environment in a negative direction, e.g. by people working alone instead of in teams.

4.4.4 Precision, completeness and representativity of the data

4.4.4.1 Precision and completeness

As indicated in the previous paragraphs the described methodology is a compromise between the demand for precise information on a given unit process on one hand and the demand for a broad database on the other.

It is evident that the precision will be low when information on the sector level is used. The ideal situation is to have sectors with a large and uniform output (one or very few products), but this can only be achieved in a very few cases. Instead, an iterative process had to be applied, the first iteration being to identify sectors with a suitable number of reported occupational accidents and diseases.

This approach made it possible to establish a broad database in a batch process. The project group selected a number of "interesting" sectors, and the possibility of calculating production volumes for these sectors were discussed with a statistician from the Statistics Denmark. Some of the selected sectors were excluded following the discussions while others were defined slightly different. The database is therefore considered to be almost complete with respect to the number of processes for which the requested information can be derived. It may, however, be possible to establish similar information for other processes, e.g. production of food products, if a special need arise.

4.4.4.2 Representativity

The representativity has also been discussed in the previous paragraphs. It is obviously a drawback that only Danish working environmental conditions are addressed in the database, but also here a compromise had to be made in the project. This time the compromise was made between the demand for a broad database (many processes) and the possibility of establishing more (international) data sets for a few processes, thereby being better able to discuss the representativity.

Data sources similar to those used in the present methodology can be found in most industrialised countries, and it is therefore possible to establish the same information from other countries, at least with respect to some of the impact categories addressed by Danish statistics..

Establishing information from other countries will improve the usefulness of the method significantly. It will not only be possible to compare the working environmental impacts for a given economic activity, but it will perhaps also be possible to establish the requested information for processes that are assessed with a great uncertainty by using Danish figures.

4.4.4.3 Missing information

The major problem in using data from other countries is that there are differences in the way the working environmental impacts are reported. Many countries only report the number of accidents and/or the number of muscolo-sceletal injuries, while incidents of cancer, allergy, hearing damages etc. are not reported. The database is thus not complete in these cases, and the importance of the missing information should be considered in the interpretation of the results.

The present database emerged as a result of a batch process and it is therefore not possible to pinpoint the most problematic data sets by using a formal methodology. It is however obvious that the production of many raw materials is limited in Denmark and the assessment of this part of the life cycle is therefore associated with an inherent uncertainty. The following examples can illustrate the problem:

The most common plastic raw materials (e.g. PE, PP, PVC, PS and PET) are not produced in Denmark. In order to establish a figure for plastic production, the average impacts per kilo produced product in the Danish chemical industry (sector 232000) was used. Information from the same sector in other countries may prove to be more differentiated, allowing a calculation of the impacts in the plastics processing sector as a whole or - more ideally - for production of specific plastics.
Production of iron and steel (sector 271000) is described in two ways. Firstly by using information from one Danish company, which uses recycled steel as the main raw material, secondly by using average Swedish data, primarily for production of virgin steel. The latter set of data only contain information on accidents, but it is worth noticing that the accident frequency is twice as high in Denmark as in Sweden. Other countries also have a larger number of steel-producing companies using both iron ore and recycled steel as raw material. Again, it would be interesting to be able to discriminate between different countries and different processes.
Production and processing of lead, zinc and tin is contained under one heading in the developed database. Although the world wide production volume is low compared to plastic and steel production, it may be possible to pinpoint countries where the production volume is sufficiently high to enable more precise calculations.

4.4.4.4 Company statistics

Besides the possibility of establishing information based on national statistics it may also be possible to use company specific information. This option can especially be utilised in companies with a large and uniform product output and with a detailed statistical material on the working environmental impacts.

4.4.5 Consistency and reproducibility of the method

The method and the database are developed to provide as consistent and reproducible results as the basic statistical information allows. It is obvious that the methodology will give the same results once the system boundaries and the in- and outputs have been established. It is also obvious that the interpretation and use of the results is strongly dependent on how well the geographical and technological conditions are related to the basic statistical data.

4.4.6 Sources of data and their representativity

The data sources and their representativity is discussed previously in the report under the headings time-related coverage, geographical coverage and technology coverage.

It can be concluded from these discussions that the data sources are representative for average Danish conditions in selected sectors. If data from one sector is used to describe the conditions in another sector, e.g. when information on production of ceramic household products is used to describe the production of advanced technical ceramics, the representativity becomes uncertain. The two economic activities may have a number of common features with respect to the impacts in the working environment (e.g. by using the same type of basic raw materials and the same basic processes), but the specific choice of materials and processes will most often be very different for the two activities.

4.4.7 The uncertainty of the information

The described procedure is assumed to produce results with a low variability but a relatively high uncertainty.

One main reason for the low variability is that the Danish statistics are collected and processed by central authorities, securing that the basic data are available. Furthermore, the information is averaged over three years (1995-1997), securing that accidental or temporary variations become less significant.

The relatively high uncertainty is ascribed to the methodology as a whole. It is not possible to add any precision to the basic information, and the uncertainty of the study must therefore be thoroughly discussed in the interpretation. Guidelines for the interpretation of the working environmental LCA can be found in Chapter 6.

The only option for decreasing the uncertainty is considered to be a methodology using process specific information. This option is discussed in more detail in section 7.4.

4.5 Allocation procedures

Allocation procedures is often a very important element in LCA, i.e. the choice of allocation procedure can change the results significantly.

In EDIP97, some but not much attention was given to special problems when allocating the impacts in the working environment. The main recommendation was that the working time was used when possible to allocate the impacts between multi-output processes. If this was not possible the weight of the products was suggested as allocation parameter.

In the new method, product weight is used to allocate the impacts in a given sector. It is thus inherent in the method that two products will have exactly the same impacts if they are produced within the same sector and have the same weight, e.g. one kilo of polystyrene have the same working environmental impacts as one kilo of polycarbonate.

This is not very satisfactory, but the level of detail in the basic statistics does not allow a more precise assessment. It may be possible as a future improvement to use company specific information in order to achieve the desired level of detail, but in doing so a number of other uncertainties are introduced. Firstly, the use of company statistics will require an intensified use of allocation procedures, e.g. by using value as the basis for allocation. Secondly, the statistical basis (i.e. the production volume and the number of occupational accidents and injuries) is often relatively small on the company level, introducing a significant uncertainty regarding the data quality.

This allocation procedure is for example used when supplementing the database with information from foreign companies, e.g. raw material producers, using integrated processes in their production (see the example in section 2.4).

4.6 Aggregation over the life cycle

4.6.1 Historical remarks

Exposure time was used in EDIP97 and working time in the IVF method to aggregate impacts from different processes in the life cycle. The choice is reasonable because it gives the possibility of relatively precise assessments if a process assessment methodology is used.

In practice, both of the described process assessment methods are very time consuming and this fact caused the development of the sector assessment method in EDIP97. In order to be able to aggregate information derived from both the process and sector assessment, the sector assessment in EDIP97 also had to be related to the exposure.

In the EDIP97 sector assessment, the calculation of exposure time is based on information on the average number of accidents and injuries per year or per million working hours in a given sector as well as assumptions regarding the number of employees that are exposed to noise, chemicals etc. in a given sector. This information must subsequently be converted to damages per functional unit (e.g. per ton material) in a number of calculation steps, taking total production volumes, total number of employees and average working time in the sector into consideration.

These calculations were only examplified to a very limited extent in EDIP97, but were in the present project proven through case studies on plastics and steel to pose a large number of practical problems.

4.6.2 Aggregation in the present methodology

In the present methodology, only a sector assessment is performed. This means that the information from all unit processes in the developed database can be easily aggregated over the life cycle, i.e. there is no demand for collection of additional information, once the basic statistical information has been collected.

Information from other data sources, e.g. foreign trade statistics or company specific information, will most often not provide information on exactly the same impact categories as in the developed database. This problem is discussed further under impact assessment (section 5).