Viewpoints

Andrew Champ, business development director, Rockwool, welcomes the revision to the Approved Document L: Conservation of fuel and power.

At Rockwool we welcome the revision to Part L 2010 and fully support the need to reduce the overall demand for energy through increasing the minimum levels of energy efficiency for building fabric and services.

The new measures, detailed in the Approved Documents published recently, include practical steps that builders can take to make buildings greener, while at the same time ensuring that more efficient, air-tight homes and offices are sufficiently ventilated.

The new measures, which are being introduced from the 1st October of this year, will not only assist in cutting emissions but play a crucial part in achieving zero carbon policies by 2016.

It is clear the amendments will still enable builders and designers to achieve compliance through the efficiency of the building fabric alone and without the need to use onsite energy generation.

For house building, a particularly interesting aspect of Part L is the requirement to limit heat loss through the Party Wall.

Contrary to previous assumptions, party cavity-walls are not zero heat loss walls. Following extensive work carried out by Leeds Metropolitan University on the Stamford Brook project, it is now understood that cavity party walls can act like a chimney with heat energy being lost up through the party wall.

In order to reduce this heat loss and to claim a zero U-value, Part L will require that all new cavity party walls are effectively sealed at all exposed edges and that the cavities are fully filled with an insulation material such as a mineral wool. Of course, the flexibility of the whole house design approach means that the designer may choose not to take such measures but this would need to be offset by improving the thermal performance of other parts of the building envelope.

The introduction of requirements to eliminate the Party Wall Bypass Effect supports the drive to deliver ‘real-life’ energy efficiency, closing the gap between designed and as-built performance.

Rockwool is actively involved in developing both “built-in” and “retrofit” Robust solutions to meet these new proposals.

The new efficiency measures will also come into play when people choose to carry out work to existing buildings including extensions and conversions, fabric renovations, replacement windows and boilers.

Dealing with carbon emissions from inefficient existing buildings is a major challenge for our country so this a will help lower the nations carbon emissions.

www.rockwool.co.uk