AVO Guide Launched
The Acoustics, ventilation and overheating residential design guide (AVO Guide) was officially launched at the end of January. A copy of the guide can be found here.
The document provides guidance on the importance and interdependence of acoustics, ventilation and thermal comfort in the design of good quality residential development.
The guidance helps developers and Local Authorities avoid the situation where openable windows are relied on for the control of overheating, but closed windows are needed for the mitigation of external noise; the outcome being that residents are forced to choose between high internal temperatures or high internal noise levels.
This overheating problem has become more common over the last 10-15 years due to changes to Buildings Regulations encouraging energy conservation (i.e. keeping heat in). The issue is made worse by the move towards developments with larger areas of glazing and less thermal mass and the “heat island” effect in built-up areas.
For noisier sites where windows need to be kept closed most of the time, the control of overheating can be difficult and many of the mitigation measures require consideration early in the design process. These include changes to fenestration, orientation of dwellings, ceiling heights, roof design and solar shading etc.
Research by the AVO Guide authors showed that many planning applications still include energy assessments that rely on open windows in summer and noise impact reports that rely on closed windows. This is resulting in developments with overheating issues and it is also creating problems for developers who are struggling to then comply with overheating or acoustics related planning conditions.
Most of the above overheating mitigation measures will not normally be possible within the constraints of a planning consent and this can result in an overreliance on mechanical ventilation (e.g. MVHR) and low-g-value glazing.
With the release of the guide we expect to see more Local Planning Authorities requesting ‘AVO assessments’ as part of planning applications to show that this issue has been considered from the outset. This will help ensure better quality developments and more upfront clarity on design costs and risks for developers.
If you would like to discuss how the new guide affects you or if you need a noise impact assessment for your development then please don’t hesitate to give us a call.