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Approved Document L

Ben Penson, Chair of the Association of Composite Door Manufacturers, on the details of the new Approved Document L

Now that Approved Document L has been published and its requirements and standards are stated in black and white, it is time to take a closer look at how it will impact the door market.  Previous revisions to the document, specifically with regard to existing dwellings, have by and large bypassed entrance doors and focused specifically on windows. This is set to change.

The new regulations, which come into effect on 1st October 2010, demand a big step up in the energy efficiency of entrance doors. As a reminder, Document L of the Building Regulations for England and Wales sets the standard of energy efficiency in buildings, clearly setting out regulations for both new and existing buildings.

The overriding requirement of the new document for entrance doors is a significant increase in performance. For replacement doors in existing dwellings, Approved Document L now demands a U value of 1.8 W/m2K – a considerable step forward from the 3.0 W/m2K required by the outgoing regulations. This stated U value is applicable regardless of whether the door is greater or lesser than 50% glazed.

New build energy efficient levels are determined by the Standard Assessment Procedure (SAP) calculation, which calculates the carbon dioxide emission rating for the entire building envelope – not just each individual element. Having said that, maximum limiting U values are set for these elements, with the new document requiring a U value of 2.0 W/m2K compared with the 3.3 W/m2K permitted in the 2006 version.

In reality, as developers strive for higher ratings under the Code for Sustainable Homes, it is likely that performance specification significantly more onerous than the prescribed limiting values will be required.

It is clear to see from Approved Document L that performance requirements for entrance doors have taken a huge leap forward and many traditional door constructions will struggle to comply. The significant exception is the composite door industry which has been producing energy-efficient products for the new build and refurbishment markets for several decades.

Typically, composite doors incorporate high-density, CFC- and HCFC-free foam cores which provide excellent insulation and have high-performance thermal properties. By nature of their make-up, composite doors are more effective at keeping heat in, and cold out, than wooden or PVC-U panel doors. As almost 50% of carbon emissions are from buildings, entrance doors can play – and do play – a big part in reducing the carbon footprint.

Composite door fabricators have been leading the way with energy efficiency in the door industry for years. Many composite door constructions available today not only meet the new Approved Document L, but exceed it – providing solutions for developers looking to future-proof properties in line with the performance improvements expected in the 2013 and 2016 revisions. Certain manufacturers also offer a variety of upgrade packs to enable the developer to tailor the level of energy efficiency in accordance with the specific needs of the project.

This forward-thinking approach should give specifiers peace of mind and the assurance needed that there are a variety of composite door options available for all external door applications that are fully compliant with the forthcoming insulation requirements. In addition to their excellent thermal properties, composite doors also provide all the added benefits of enhanced security, weather resistance and low maintenance.

The new regulations open up an opportunity for the door industry to market itself to housebuilders, specifiers and retailers on a high-performance, high-quality basis. Manufacturers should be prepared to evidence their claims with clear and concise documentation that can be used to pass the positive message on to the end consumer.

With U values becoming more challenging to achieve, and the need to be able to deliver a lower end number, it is now more important than ever to pay particular attention to the evidence supporting the thermal performance claims. Ensure that calculations stated are for the complete door set, including any relevant glazed area. Declared U values should be calculated by a competent person or ideally a UKAS accredited organisation. Alternatively, U values can be ascertained through hot box testing but reports should only be accepted if completed by a UKAS accredited laboratory.

So come October this year, the bar will have been raised and the building industry will need to step up to deliver the new requirements of Approved Document L.


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