Ventilation system designers may be guilty of professional negligence by working with inaccurate noise data and, even worse, they may be unwittingly causing Sick Building Syndrome. Ewen Rose reports
Unless requirements are laid out in codes, control of noise in buildings is often an afterthought. The measures taken to control noise, however, are invariably linked to other building subsystems. Mechanical and plumbing subsystems generate noise; the design of walls, ceilings and floors affects sound transmission.
In this study, we have tested more than 80 silencers of different sizes (from O 250 to 1250), length, insulating thickness and with or without central pod. The attenuation, measured at several velocities between 0 - 8 m/s, was compared to some literature estimations and has shown strong differences. They induce that literature estimations should be used only in the same conditions they were made and, not too widely, as it is currently done because real knowledge of the influence of parameters is lacking.
Typical HVAC noise may produce an uncomfortable environment, leading to the associated problems of general dissatisfaction and reduced productivity. It is not sufficient to have good thermal, lighting, and air cleanliness conditions if the noise is disturbing. In this paper, noise comfort is considered, with special emphasis on the developing criteria for low-frequency noise.
The objective of this one-day seminar was to address the issues of design and provision of low energy ventilation strategies for non-domestic buildings located in urban and city centres where external air and noise pollution may be of prime concern. Current concerns about energy usage and C02 emissions have led to an increasing number of buildings, both new builds and major refurbishments, employing low-energy ventilation strategies such as natural or fan-assisted ventilation.
Night cooling is a viable technique in the UK, but there is no suitable commercially available equipment. The BRE has been testing prototype ventilators and concludes that they work although weather, security and acoustics issues need to be addressed.
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