NetComposites
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Purpose and Scope

This guide has been created to enable the composites sector to understand the environmental and social impacts associated with composite production and assist with the decisions made about material and process choice. The materials and processes modelled are rated from A (good) through to E (poor). Twelve different environmental impacts are individually scored and totalled to give an overall environmental impact summary rating. Two social impact ratings are also given.

When measuring environmental impact it is important to consider all the influences through the life of the product, the process known as Life Cycle Assessment (LCA). Because this guide concentrates on materials and manufacturing, as opposed to in-service performance, the impacts associated with products beyond the factory gate (the use, maintenance and disposal stages of the life cycle) have not been assessed.

With the system boundaries for the LCA defined, three typical product types have been chosen to reflect a range of different components typically manufactured using composites:

  • A double curvature panel - this has a surface area of 1m2 with a panel stiffness equivalent to a 4 mm thick chopped strand mat laminate
  • A flat sandwich panel - measuring 8m by 1m with a 25mm thick core, having a panel bending stiffness equivalent to a sandwich panel with 4mm thick chopped strand mat skins
  • A complex moulded component - with a volume of 770 cm3

Similarly, production processes and materials have been selected to provide a balance between systems that are commonly used across the majority of the composites industry and emerging materials with the potential to provide an environmental benefit. For this reason, materials such as hemp fibre and self-reinforced polypropylene have been included in the guide, but materials that are more specific to a single sector (for example aramid fibre) have not been included.

Within each specific process there are still many processing variations (eg. mixing, curing and trimming method) in addition to the material choice possibilities. To enable fair comparisons, a base case has been selected for each process and is used throughout the guide to allow the merits of each process variation to be assessed.