Foil foiled

Aluminium foil insulation will no longer be included in an amended New Zealand standard on energy efficiency (installing insulation in residential buildings) due to safety concerns.

Standards NZ has confirmed to Safeguard that the standards development committee has decided, after a second round of public comment, to remove reflective pliable membranes (aluminium foil) from NZS 4246:2006 which is currently being amended.

The committee had received feedback about the dangers of foil, including information about injuries and a number of fatalities due to electrocution that occurred in New Zealand in recent years. The committee agreed in principle to remove the section on installing those materials from the Standard (section 7). As the proposal to delete section 7 wasn’t part of the original scope of the amendment project, the committee sought further public comment specifically on the issue.

In 2007 there were three fatal accidents when homeowners stapled the underfloor foil into power cables. In another incident that year an accidently stapled cable created a direct path for electricity to run through the staple onto the foil. Fortunately the power was switched off at the time, and the problem was discovered after a fuse kept blowing. Worringly though, voltage tests on the foil had not picked up any problems as the blown fuse had isolated power from the circuit concerned.

The 2006 insulation installation standard had set down methods to ensure foil was installed safely. But one Auckland company alone, The Henshaw Group, identified over 800 houses on its books that were at-risk. The retro-fitted insulation could potentially become electrically alive where installations were not installed in accordance with the 2006 standard. There was a high probability that the electrical wiring had never been checked or isolated before the foil was installed.

In Australia, where 25,000 homes are fitted with foil insulation, there has been a huge increase in demand for insulation due to a federal government rebate. The use of plastic staples, to be eligible for the rebate, was insisted on after a 25-year-old foil installer was last year electrocuted in Brisbane. The Federal Government has meanwhile introduced a range of new measures to improve training and safety standards. Guidelines have also been developed by Australia’s Aluminium Foil Insulation Association to help installers work safely.

Standards NZ said the reasons for its decision to remove foil from the standard included the safety risks for installers and house occupants. While mitigation of those risks was covered in an appendix, those recommendations could not guarantee safety of installers, servicemen, and house occupants should they come in contact with the foil at any stage during the life of the house. But the committee also agreed that the original content of the appendix should remain in the standard for future reference.

Other concerns were the variable performance of reflective membranes, its lack of durability and increased risk of condensation forming on top of the membrane, undermining its thermal performance.

A standard is not, of itself, mandatory or legally required. A standard has to be cited in a statute or regulation in order to be mandatory. Once referenced, it becomes part of the technical regulation framework.

Standards can be used in a variety of ways to support policy. In the case of NZS 4246, the Energy Efficiency and Conservation Authority requires all its service providers under the Warm up New Zealand: Heat Smart (WUNZ:HS) programme to install insulation in accordance with NZS 4246:2006. EECA-funded programmes stopped using foil back in 2008 for reasons outlined above.  

However, this does not prevent insulation installers not operating within the WUNZ:HS scheme from offering foil as an insulation option. This includes new houses with suspended timber floors where draped foil has been used as a standard way to meet energy efficiency requirements of the Building Code.  Energy Safety’s website features information on the importance of safe installation of reflective pliable membranes

This story appeared in Safeguard Update newsletter of 25 January 2010.

For more stories visit the news story archive.

To get all the news every fortnight – subscribe now!