The issue of noise and ventilation in dwellings is very significant for occupants, yet currently under-researched and poorly understood even within our industry. Current requirements for noise levels described in planning conditions, British Standards and WHO Guidelines are not typically associated with ventilation conditions. There is a marked absence of research into occupants’ acceptance of noise from mechanical ventilation systems – noise level criteria are based on environmental noise levels that limit the adverse effects on sleep, ie while people are sleeping. In contrast, the problem with noise from mechanical systems is that it can be annoying, especially when occupants are in the process of falling asleep. During this period, people can be significantly affected by noise levels that are much lower than those that may interfere with sleep itself. Thus an unintended adverse consequence of noise from mechanical systems is that is causes people to turn down or off their ventilation systems. Our article How loud is too loud? Noise from domestic mechanical ventilation systems in the International Journal of Ventilation (limited free eprints while stocks last) describes these issues.
Some of this work is incorporated into the Acoustics, Ventilation, Overheating: Residential Design Guide, published by The Association of Noise Consultants in December 2019.
Read our response to the 2019 consultation for Approved Document F. The problem is closely related to issues with providing a suitable holistic environment for noise, air quality, thermal comfort – see our blog here for more discussion on the subject of opening windows. We are developing this associated work through the Association of Noise Consultants, where our work towards producing a design guide is described here. See our post on attenuated passive ventilation options for illustrations of a range of design solutions.
Jack gave a presentation to the Institute of Acoustics workshop in 2015 on Noise from domestic mechanical ventilation: how loud is too loud; read about it here. This work has been developed into a full conference paper for the 38th AIVC Conference, 2017, looking for evidence from around the world of people’s tolerance to noise from domestic mechanical services. Evidence from many countries indicates that when people find the noise from ventilation systems to be objectionable, they turn the ventilation down or off entirely, and suffer the adverse effects of poor air quality. More research is needed to determine the range of noise levels and quality of noise that may be tolerable, and an interim target is suggested based on the available information.
The first step for acoustic practitioners is to associate a ventilation condition required under Part F of the Building Regulations with the noise level limits. This is detailed in our conference paper and presentations listed below:
How loud is too loud? Noise from domestic mechanical ventilation systems, J Harvie-Clark, N Conlan, W Wei, M Siddall, Proc 38th AIVC, Nottingham, 2017
Problems in residential design for ventilation and noise, J Harvie-Clark and M J Siddall, Proceedings of the Institute of Acoustics Vol 35 Pt 1 2013
The same issues are expanded and discussed in our articles published in the Acoustics Bulletin:
Problems in residential design for ventilation and noise Part 1: natural ventilation, Acoustics Bulletin Nov / Dec 2013.
Problems in residential design for ventilation and noise Part 2: mechanical ventilation, Acoustics Bulletin Jan /Feb 2014.
Currently different local authorities each take a different view as to whether their requirement to control internal levels from external noise ingress is associated with any particular ventilation condition: generally ventilation requirements and provision are poorly understood.
In a separate but related issue, noise from domestic mechanical ventilation systems currently represents a significant risk to the industry. Other European country’s recent experience has been that regulation of noise from these systems is required to avoid excessive levels, which result in occupants turning the systems off. In modern airtight homes, insufficient ventilation is a very real risk, and associated with many adverse health effects of which most people are unaware.
Noise from domestic ventilation systems, Poster presentation at Institute of Acoustics Conference 2014.
Noise and ventilation in dwellings: Problems and opportunities, Forum Acusticum, Krakow, Poland 2014.