LCI methodology report 2002

A PDF file of the Executive Summary and the Table of Contents is available for download from the bottom of this page.

Life Cycle Inventory Study for Steel Industry Products

Selecting the most appropriate materials for any application depends on the consideration of a range of technical and economic factors including, for example, functionality, durability and cost. A further and increasingly important factor for material specifiers in a world where sustainable development is a key issue is the associated environmental performance of material applications both from a manufacturing and product performance perspective.

Among the tools available to evaluate environmental performance, Life Cycle Assessment (LCA) provides a holistic approach to evaluate environmental performance by considering the potential impacts from all stages of manufacture, product use and end-of-life stages, sometimes called the 'cradle-to-grave' approach.

LCA generally comprises four major components:

1. Goal and scope definition;
2. Life Cycle Inventory - data collection and calculation of an inventory of materials, energy and emissions related to the system being studied;
3. Life Cycle Impact Assessment - analysis of data to evaluate contributions to various environmental impact categories; and
4. Interpretation - where data are analysed in the context of the methodology, scope and study goals and where the quality of any study conclusions is assessed.

A life cycle inventory (LCI) study has been carried out by the International Iron and Steel Institute (IISI) to quantify resources use, energy and environmental emissions associated with the processing of fourteen steel industry products from the extraction of raw materials in the ground through to the steel factory gate. The study was carried for 1999-2000 data by the IISI with technical liaison and co-ordination through an IISI LCA Forum, based on data collated within IISI member companies. LCI data were calculated for products derived via the blast furnace/basic oxygen furnace route (based on iron ore and steel scrap) and the electric arc furnace route (mainly based on steel scrap). Downstream processing into manufactured products, their use, end of life and scrap recovery processes have not been included in the inventory, making this a 'cradle-to-gate' study. The boundaries of the study can be extended to include downstream activities particularly in collaboration with customers who are applying LCA's to their product systems.

Goals

The primary goals of the study were to develop a unified and rigorous LCI methodology for steel products worldwide in accordance with the IISI Policy Statement on LCA and related ISO14040 set of standards to provide reliable data to meet requests from customers and external studies. Further goals were to promote the environmental credentials of steel and to develop steel industry expertise in the subject.

Scope

The fourteen products included in the study are the main finished products of the steel industry. They include hot rolled coil (with and without pickling), cold rolled coil (with and without finishing), hot dip and electrically galvanised sheet, painted sheet, tinplate and tin-free sheet, tubes, sections, plate, rebar/wire rod, and engineering steels. The products are of general relevance to a wide range of downstream applications including those in the construction, automotive and packaging sectors.

Stainless steel products were not included but a separate study has is being carried out to provide data on these; the results of the global study will be available in the near future, whereas the European study is available now.

In total, 50 sites operated by 28 companies, including 34 blast furnace operations, 13 electric arc furnace operations, and 3 direct reduction operations participated in the study. The companies contributing data to the LCI study account for 39.7% of global crude steel production outside of the former USSR and China. Companies in Europe, and Far East Asia were well represented and a typical range of operating configurations included, North America is included in the global averages. This level of coverage maintains the IISI LCI study one the most representative LCI studies ever carried out for a material and this provides a sound basis for LCA studies relating to steel.

Methodology

The quality and relevance of LCA/LCI results, and the extent to which they can be applied and interpreted, depends critically upon the methodology used. It is therefore important that methodology is transparent and well documented. ISO standards have been developed to provide guidance on methodological choices and to set down rules for transparency and reporting. To date, the relevant ISO standards have been published are:

1. ISO 14040, which sets down the 'Principles and Framework' of LCA,
2. ISO 14041, on 'Goal and Scope Definition and Inventory Analysis'.
3. ISO 14042, on 'Life Cycle Impact Assessment', and
4. ISO 14043, on 'Life Cycle Interpretation'.

The goal of the IISI project was to produce LCI's with sufficient scope to facilitate the range of emerging impact assessment methods in future studies.

The IISI LCI study has been fully reported in accordance with ISO 14040 and ISO 14041 and has undergone critical review from an independent Critical Review Panel (CRP) of LCA specialists. This approach improved the integrity of the study and can help guide methodology. The full CRP Report is included in the report.

The main CRP conclusions were:

"The International Iron and Steel Institute has done a commendable job in the planning, design and implementation of the IISI Worldwide LCI Database for Steel Industry Products. This database will be a valuable resource for LCA studies involving steel products.

We have found this LCI study well constructed and adhering to the requirements of the International Standards ISO 14040, 14041 and 14043 relating to Life Cycle Inventory Analysis (LCI), with a few reservations:

• We missed a listing of data quality requirements as specified in ISO 14040, clause 5.1.2.3, in spite of data quality generally being well documented, especially for the core steel manufacturing processes.
• We did not find the requirement in ISO 14041, clause 6.4.2 to be fulfilled with respect to excluded upstream processes and the treatment of data gaps in the upstream processes. This also implies that we found the sensitivity analyses inadequate to assess and describe the potential effects of these exclusions on the outcome of the study, as required in ISO 14041, clause 5.3.5.
• The interpretation section of the draft report did not conform to ISO 14043, especially with respect to interpreting the results in relation to the goal and scope (applications) of the study.

Our critical remarks should be seen as suggestions for improvement and does not challenge our overall impression of a very thorough and dedicated study, which contributes significantly to the state-of-the art of practical LCI studies.

We wish to express our gratitude to IISI for providing the opportunity to review this work in detail, and for the constructive atmosphere in which our comments have been received." Critical Review Report, 25 June 2002.

IISI welcomes the comments made by the critical review panel, and is in full agreement with the majority of the critical review panel report. IISI believes that the critical review process was an essential step in the Worldwide LCI for steel products and considers that the report adds value to the methodology report.

In response to the CRP's report, the IISI accepts that due to the large number of upstream modules in the model, not all will have the same allocation procedure and data quality. The standards required by the database owner for the software model are high, allocation procedure is detailed in the information facility of each module used, and is subsequently listed in full in Appendix 6 of the IISI methodology report. IISI accepts that with respect to ISO14041, clause 5.1.2.3, particularly precision and uncertainty, the information is limited due to the fewer datasets available for input to the study, but otherwise we consider this to be adequate for the purpose of the study, and upstream data (mainly from DEAM) quality information is available. Upstream data sourced directly by IISI (e.g. iron ore) is consistent with the data quality of the primary data for steel processes.

In view of the comments made on the completeness of the interpretation, the IISI believes that the whole report contributes to the interpretation phase, and that the report has been enhanced to cover aspects of interpretation covered in ISO14043. Overall, we believe that the results have been analysed, and the limitations of the study explained, to provide the transparency and confidence that these data are adequate for LCA's using steel.

Results

The LCI results provide 'cradle to gate' (of the steel factory gate) data on all the major raw materials, energy usage, air and water emissions, and wastes for each of the fourteen steel products included in the study. In total about 450 data categories (flows) have been quantified but for simplification 43 major flow categories are presented in summary tables for communication to third parties. These flows include average values for air and water emissions that were fully accounted in the data collection exercise. Other emissions data were included but site measurements and/or upstream data quality on these emissions were thought to be insufficient to generate reliable averages.

Both worldwide and regional averages (Western Europe, Far East Asia and Rest of the World) are available provided that a minimum of three sites contributed data for that product. Additional information includes the number of sites contributing to the average and minimum, maximum and variance for each LCI flow. These data indicate the variation across individual sites and can be used to facilitate sensitivity analyses. The LCI results aggregate the contributions of between 150 and 250 process units depending on the product.

IISI intends to pursue continuous improvement of the data quality with time. This will include further updates of the data and expanding the range of reliable data categories as measurement techniques become more widespread. Further efforts will also be made to acquire data for upstream operations directly from suppliers, making the data more regionally relevant and reducing the dependence of results upon generic databases.

Availability of Data

LCI data can be obtained via the online request facility on the IISI website, which in turn informs the relevant LCA Managers within member companies and organisations across the world. Contact names can be obtained from IISI. The normal procedure is to complete a questionnaire describing the intended application of the data and to discuss this with the LCA Manager. This will help to ensure that the IISI methodology and results can be applied appropriately and will be compatible with the goals of the study.

Conclusions

The IISI LCI study has generated one of the largest, most rigorous and representative databases of any material. The results can be used reliably to assist decision-making and for evaluating the performance of steel products in the context of sustainable development.

The results also provide the opportunity for steel companies to benchmark and evaluate improvement measures to their processes and product systems.

Steel industry expertise has been enhanced by involvement in the study and the industry is now better equipped to provide technical support to customers and users of steel on LCA issues.

The program of the IISI LCA Forum (launched after the first study) to keep the database up to date and further enhance the methodology and understanding of the study has been successful in raising the profile of LCA within the steel industry, and to its customers. Recommendations for improvement concerning both the documentation and the data will be highly welcome.

For LCA to be used as reliable tool for decision making high quality data, sound methodology and transparent reporting are essential. This study is a major step towards enhancement of these standards and the steel industry intends to continue and encourage this trend in its future programme of work.

LCI Executive Summary.pdf