In order to deliver credible sustainable construction it is imperative that, at the design stage, the entire life of the building is considered. The four key life stages; manufacture, installation, building use and end of life should all be taken into account when aiming to deliver sustainable construction projects.

Many building envelope system manufacturers have a proactive approach to sustainability and have had their products sustainably assessed to look at the amount of CO₂ produced during the manufacturing and installation phases of a project.

CA Building Products’ roof and cladding systems have been analysed by Corus, with the investigations conducted in accordance with international standard ISO 14040-3. Corus has used the same standard to produce Environmental Product Declarations for a number of other manufacturers, for both built-up and foam composite panel systems.

A cradle to installation approach to sustainable buildings may show that a similar level of CO₂ is created during the production and installation of both foam-blown composite panels and built-up roof and cladding systems, so building designers and specifiers may be forgiven for believing that both products are virtually the same when it comes to sustainability. However, their relative environmental impact varies enormously during demolition and disposal at the end of the building’s service life. To provide a logically sustainable building, all stages of the building life cycle must be considered and a cradle to cradle approach should be adopted. In order to do this, the building end of life costs need to be taken into account.

The end of the building’s life is perhaps the most overlooked of the key life stages, as this is often seen as something that is at least 25 to 30 years away, therefore, should not be a consideration at the start of the building life.

When a building comes to the end of its usable life it will need to be disposed of, which will inevitably lead to a sustainability cost and, with some buildings, possibly a financial cost associated with its disposal. Building owners, designers and specifiers should, therefore, be asking the question; what happens at the end of the building’s service life?

When a building is dismantled very little care is made as to how the roof and walls are removed. If the roof and walls have been clad using a built-up system such as CA’s Twin-Therm^® system, it is easily dismantled and there is also an opportunity for the steel within the systems to be either re-used or more likely recycled, meaning that some of the initial ‘unavoidable’ CO₂ can actually be recovered during the recycling process. For a Twin-Therm^® roof, Corus’ Environmental Product Declarations calculate this recovery figure at 44%.

Furthermore, as the insulation within our systems are non-deleterious it can either be sent to land fill, used as cavity wall insulation or returned to the factory and re-used.

In stark contrast, during demolition and disposal at end of life, foam insulated composite panel CO₂ emissions rise to almost three times the level produced during manufacture, delivery and installation. This conclusion assumes that the disposal would follow current best practice via the fridge recycling route.

It is necessary for all foam insulated composite panels that were manufactured before 2004 to be disposed of through the fridge recycling route, due to the presence of blowing agents that contain ODP (Ozone Depletant Potential) and pose a potential pollution threat to the water table and the atmosphere. The EC Regulation 2037/2000 even states that, due to their make-up they cannot be cut, crushed or disposed of by any other means. The fridge recycling process is complicated and expensive. The panels must firstly be removed carefully from the building without being bent, torn, cut or broken - any damage at this stage would release the harmful substances - and they need to be delivered flat in order to go through the correct disposal process.

There also seems to be some confusion over the ODP-free material manufactured since 2004, as building owners, specifers and building designers often believe that these are exempt: however, in 25 years or so, when an average industrial building reaches the end of its life, there will be no visible way of knowing whether or not the foam insulation is pre- or post- 2004. The 2005 Montreal Protocol, therefore, advised governments globally that it will have to be recycled in exactly the same way.

To complicate things further, post-2004 panels are often blown with Pentane, which is in isolation a highly combustible substance from the same chemical family as Butane and Propane. Selected as the new blowing agent for its very low ODP, this accelerant clearly brings with it a complete new spectrum of threats to installation contractors, building tenants and demolition engineers alike. One need look no further for evidence of this than several high profile fires that occurred throughout the UK in late 2007. Moreover, the potentially explosive nature of the blowing agent means that recycling plants must ensure it is processed in a specially isolated area with a nitrous oxide atmosphere, with all the attendant costs this attracts.

The industry as a whole is now facing high environmental and financial costs associated with the disposability of foam insulated composite panels.

Images courtesy of Corus