Technical Consultant’s comments – Patrick England

Aluminium, the everlasting metal

There appears to be a lack of appreciation, on behalf of those who are carrying out Life Cycle Assessments (LCA) for aluminium used in construction, of the longevity of window products manufactured from aluminium. This is also having a prejudicial effect on the energy ratings applied to aluminium windows.

Yet there is excellent evidence of the long life span of aluminium window products, for example, one project I am involved in is the refurbishment of the windows at the Bodleian Library, Oxford University. The windows in this building are still the original ones installed in 1938, some 72 years ago, yet they still protect the Library today (as they have done since installation) from the ravages of the weather. This project I am involved in is not one where they will be removed, the aluminium scrapped and the windows replaced. The majority of them are to be refurbished, many of them in-situ, and in that process it is envisaged that the original frames will still be functional 100 years from the date of installation.

Evidence like this raises serious questions about the BRE’s Green Guide rating for aluminium windows for which they assume a useful life of only 40 years!

Data is available that shows that up to 95% of aluminium in building is being recycled and fed back into the supply chain for aluminium products highlighting that aluminium material will still be in use in hundreds of years’ time.

To optimise the benefits of this in Germany a system is being trialled where all aluminium windows, doors, curtain walling removed from a building are put into segregated scrap, and this scrap goes to a smelter which produces billet for window, door and curtain walling extrusions thereby guaranteeing, and providing traceability of 100% of the aluminium waste being recycled into the manufacture of new extrusions.

Even in the UK I have been involved in two fairly large window replacement contracts where all aluminium removed from the building has been segregated and sent to a reprocessor. While the reprocessed material will not necessarily be used for the extrusion of aluminium window profiles we are continually learning the benefits of effective recycling.