Q1 - How much will foam insulated cladding panels cost me to dispose of?
Q2 - What fire risks are associated with foam insulated cladding panels?
Q3 - How do foam insulated cladding panels perform acoustically in comparison to built-up systems?
A recent Corus Colors Colorcoat® Technical Paper ‘End of life options for pre-finished steel buildings’ explores the comparative end of life options facing foam insulated cladding panels and built-up systems. The ease of recycling and disposal of building components at the end of a building’s useful life has an important impact on its overall environmental impact. Increasingly clients and developers want to reduce the “carbon footprint” of their building and look to minimize end of life environmental impact.
A copy of the Corus report can be opened and/or downloaded below. Some of the conclusions are shown below:
Using an assumed best practice route for disposal and recycling of a pre-finished steel-based cladding system Polyurethane (PUR) and Polyisocyanurate (PIR) foam panels, via a fridge recycling/gas capture route results in disposal costs of £8m2, contrasted with -£1m2 (cost benefit) for built-up steel cladding and a £2m2 cost for mineral wool insulated panels.
Potential disposal problems anticipated in the Corus Technical Paper may be exacerbated by the predicted annual arisings of composite panels entering the waste stream. Assuming a 2% year-on-year growth, panel waste could exceed 10million m2 by the year 2040.
The use of substances with positive ozone depleting potential (ODP)* in foam insulated panels was banned under the 1997 Montreal protocol. This came into effect in the UK in December 2001 and means that foam insulated cladding panels manufactured before 2001 may contain substantial ozone depleting substances like Chlorofluorocarbons (CFC) and Hydrochlorofluorocarbons (HCFC). Foam insulated cladding panels containing CFC and HCFC are classified as hazardous waste under the European Waste Catalogue due to their ecotoxicity.
The replacements to CFC and HCFC are Hydrocarbons (mainly Pentane based) and Hydrofluorocarbons (HFC) and are not considered ODS. However, they do have high global warming potential (GWP)** and are very flammable with vapour points generally less than 40°C. Future legislation may restrict emissions of these gases to the atmosphere during recycling and require collection and separate disposal of these gases.
Corus Colors Colorcoat® Technical Paper ‘End of life options for pre-finished steel buildings’ 2006.
End of life - the effect of regulation on disposal of insulation materials
Chunghwa - links to the news stories
*Ozone depleting Potential (ODP)
The integrated change in total ozone per unit mass emission of a specific compound, relative to the integrated change in the total ozone per unit mass of CFC-11.
Source; EEA. 1999. Environment in the European Union at the turn of the century. Page 101. Environmental assessment report No 2
**Global warming potential (GWP)
The global warming potential of a gas refers to the total contribution to global warming resulting from the emission of one unit of that gas relative to one unit of the reference gas, carbon dioxide, which is assigned a value of 1.
For example, if methane has a global warming potential of 21, it means that 1 kg of methane has the same impact on climate change as 21 kg of carbon dioxide and thus 1 kg of methane would count as 21 kg of carbon dioxide equivalent.
Source: based on American College & University Presidents Climate Commitment Implementation Guide
Recent changes in legislation underline a new fire prevention approach which asks designers to identify fire risks at an early stage and try to remove them. An example would be to remove all combustible materials from areas of risk.
The government has published guidance for risk assessment following introduction of the Regulatory Reform Fire Safety Order (RRFSO). This recognises the risks associated with combustible panels. The ‘Fire safety risk assessment, factories and warehouses’ guide states “The potential for fire development involving mineral fibre cores is less than that for panels containing polymeric cores. Therefore, in areas where this is considerable life risk, it may be appropriate to consider replacing combustible panels.”
Despite the claims of some panel manufacturers, no foam plastic, be it, polyurethane [PUR] or polyisocyanurate [PIR], is non-combustible when tested to BS EN ISO 1182. “Any combustible material will ignite if heated to a sufficiently high temperature in air, in the case of PIR/PUR foams this would need to be about 450°C”. Source: British Rigid Urethane Foam Manufacturers’ Association [BRUFMA]. To put this into a real fire context – the minimum temperature in a developed fire is of the order 700ºC.
The designer cannot prevent bad workmanship, damage during maintenance and abuse during the life of a building. However, a low risk non-combustible approach to fire design can anticipate these possible dangers by specifying systems, where such failures and events cannot expose combustible materials. If all materials used in a building are non-combustible it is more likely that the final design solution will deliver low fire risk.
A design using a combination of non-combustible and combustible materials relies on one to deliver the protection to the other. Predicted reaction and resistance to fire is based on the results of laboratory tests and assumes good workmanship. There are also doubts on how far results of fire tests in laboratories can be achieved on site. Viewed as a design approach, it is likely that this will involve more risk
British Standard Institute (BSI) ‘PAS 79: 2005 Fire Risk Assessment. Guidance and a Recommended Methodology’ 2005.
HM Government ‘Fire safety risk assessment, factories and warehouses’ 2006.
The performance of typical foam insulated cladding panels will provide a significantly lower sound reduction and therefore lesser acoustic performance than a typical built-up system, illustrated by the test results below.
Acoustic performance is measured by assessing the decibel (dB) sound reduction over a frequency weighted to the human ear – 100Hz to 5000Hz (5KHz). The average of this sound reduction is called the SRi, or Sound Reduction Index.
An 80mm foam core composite panel with 0.5mm outer and 0.4mm inner steel faces has an approximate SRi of 25dB. A single sheet of 0.7mm trapezoidal profile steel has an approximate SRi of 24dB. The SRi of a standard built-up roof system is 45dB.
(based on Euroclad Elite System 2.25, a typical built-up roof system achieving 0.25W/m2K U value). In the case of sound reduction the greater the dB figure, the better the sound reduction and therefore the larger decrease in noise.
The decibel difference in this case is 20dB, however bear in mind that a 3dB difference equates to a doubling of power and a 10dB difference is required to double the subjective volume. A 1dB difference over a broad frequency range is noticeable to most people, while a 0.2dB difference can affect the subjective impression of a sound.
Foam insulated cladding panels are building products used to clad steel-framed buildings. Whilst foam insulated cladding panels can comply with current regulatory standards there is increasing scepticism regarding the end of life disposal of foam insulation, and considerable confusion as to the actual combustibility of the products.
The insulation is most commonly Polyurethane (PUR) or Polyisocyanurate (PIR) and current blowing agents can include HFCs and the flammable chemical compound Pentane. This results in panels that either contain inherently flammable chemicals or with global warming potential more than 900 times greater than Carbon Dioxide. Blowing agents (also known as foaming agents) are used to foam plastics to impart a cellular structure into the resins via processing techniques.
One issue with foam insulated cladding panels is the ever-changing make-up of the foam and the blowing agents used, usually in reaction to or anticipation of legislative changes, making it difficult to know the exact composition and nature of a foam insulated cladding panel.
Euroclad Elite Systems may offer you a lower risk building envelope when considering the following points:
There is an established route for recycling and disposal of built-up systems which is actually cost-positive, generating £1/m2 at the end of its useful life.
Euroclad Elite Systems use non-combustible insulation that can be considered a low fire risk.
Acoustic performance of Elite Systems is better, in tested examples, than foam insulated composite panels with significant differences in sound reduction of external noise.
For more information on Euroclad Elite Systems please visit www.euroclad.com
Euroclad Ltd - Company Registration Number: 1502586
