VIEWPOINT
O, L, And F –
And Don’t Forget Q –
What Fabricators Need To Know
About The New Building Regs By Strafford Cooke, Technical Director, Mila Anyone who reads the trade press will know that the first of the new Building Regs come into force in June this year. Approved Document O is all about controlling overheating and can mostly be managed through external shading, Approved Document L sets new U-Value/WER limits for windows and glazed doors, and Approved Document F covers the need for ventilation in increasingly airtight homes. The reason why these Docs have been released first is that they form part of the government’s Future Homes strategy, which aims 42 WINDOW NEWS | APRIL 2022
to reduce carbon emissions from new homes by 30% now and by 80% by 2025, but we can expect other relevant Docs to follow. From a hardware perspective, the new Part O isn’t significant, but Part L is likely to mean an increase in triple glazing which, in turn, will place extra demands on hinges. I would advise fabricators who are in any doubt about the right specification of hinge to take advice from their hardware supplier. However, it is Part F which is likely to have the most impact on our industry because it requires trickle vents to be fitted in virtually all new and replacement windows,
unless alternative mechanical ventilation is in place. From a personal perspective, I think this is totally counter-intuitive to the whole Future Homes strategy – why increase the thermal performance of windows and then cut a hole in them? I recognise the need to increase ventilation, particularly post Covid, but this feels like a sledgehammer to crack a nut. There are also a number of practical issues around the new Part F as well: • what about the impact on noise levels in busy urban areas? • what about the fact that some installations where there is more than one window will inevitably be overspecced and overventilated if trickle vents become the default option? • what about the fact that the current testing regime for Part L allows U-Values to be assessed without trickle vents, just as it allows doors to be assessed without letterplates?
