The initial 2010 version of Approved Document F, the government’s document outlining building regulations relating to ventilation and indoor air quality, stated that “the noise caused by ventilation systems is not controlled under Building Regulations”.
In acknowledgment of the importance of preventing excessive noise, this has since been replaced with a set of guidelines aiming to minimise noise. The document now states that mechanical ventilation systems should be “designed and installed to minimise noise”. While this is arguably vague, it cannot be denied that noise from mechanical ventilation systems can pose annoying problems, representing a major cause for concern for both installers and end users.
This edition of our blog will outline the relevant standards and guidelines, while also providing practical tips and advice on how to ensure compliance, increase efficiency, and prevent sound from your ventilation system from becoming a nuisance.
There has been a significant amount written regarding the acoustics of mechanical ventilation systems, and the general consensus is that excessive noise is one of the key factors in preventing their uptake, or even preventing their use after installation.
Brown & Gorgolewski report that “27% of respondents who had disabled their MHRV did so because of its objectionable noise”, McGill et al. include noise in their list of MVHR shortcomings, and in a study of 40 low-carbon homes, Baborska-Narozny and Stevenson found that “30% of occupants reported switching off fans because of noise”. The positive effects of MVHR systems on occupants’ health and with regard to the environment have been equally well documented. If we are to capitalise on the many benefits of such systems, it is essential that noise emissions be considered and appropriately addressed.
An article published in the International Journal of Ventilation, entitled “How loud is too loud?”, identifies a list of potential causes of excessive noise in ventilation systems. These include problems during the:
Evidently care must be taken during all steps of a mechanical ventilation project to ensure it complies with regulations on ventilation acoustics The Noise Policy Statement for England refers to a Significant Observed Adverse Effect Level, the level above which noise exposure can have a significant adverse effect on health and quality of life. While document F does not require noise testing, it does offer guidelines, stating that a ventilator operating under normal conditions should not produce noise levels in excess of 30 dB (A) in noise-sensitive rooms such as living rooms and bedrooms, and 45 dB in less sensitive rooms.
Many manufacturers and installers suggest playing it safe in this regard, by aiming for a level of around 24 -26 dB (A). Irrespective of the benefits with regard to alleviating the annoyance of continuous background noise, reducing noise emissions will ultimately have an beneficial impact on the overall efficiency of the system. Our article discussing the importance of energy-efficient ventilation can be consulted here.
How to reduce the noise generated by a ventilation installation
Below you will find a list of tips and essential practices that will assist you in planning and implementing an efficient mechanical ventilation system in your build, keeping unwanted noise to a minimum.
While there is no such thing as a silent ventilation system, there are a wide range of noise-insulating wraps, and silencers that can help attenuate excessive noise. It is better to prevent noise from becoming an issue by tackling it at source, during design and installation, before resorting to methods to address an already noisy system. If you have any questions or require assistance with regard to selecting products, or dimensioning and planning your installation, the experts at EnviroVent will be happy to assist you. And for an introduction to the world of mechanical ventilation, check out our beginner’s guide, here.
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