Giving acoustics a fairer hearing

There have been many papers and articles written regarding noise levels in hospitals, and, in most of these, the subject is the sound levels in medical areas only. It has been stated that, since 1960, the sound levels in a typical medical area have risen as follows:

          Day Time Night Time
1960 57 dB(A)  42 dB(A)
 Today 72 dB(A)  60 dB(A)

 The sound levels recommended for hospitals by the World Health Organization (WHO) in its 1995 noise guidelines suggest that levels in patient rooms should not exceed 35 dB(A). [see panel for an explanation of the term dB(A)]. It is a common belief that patients’ health improves more rapidly in quieter surroundings. Over the past 50 years an increase in overall sound levels has occurred generally, and certainly not solely in hospitals. Some of the main reasons for the increase in noise in hospitals are given in Susan Witterick’s article on acoustics, ‘Making the right noise with hospital design’ in the October 2011 issue of Heath Estate Journal.1 There is some uncertainty as to whether building contractors, engineers, and architects, as well as individuals from other disciplines, are seeking to avoid considering acoustics. Experience has shown that often the acoustic consultant attends a ‘kick-off’ meeting, usually chaired by a project manager, and it appears that people attending from other disciplines do not to wish to discuss acoustics. It also appears that many professionals working in other disciplines do not know what questions to ask an acoustics consultant, in so much as they have no real idea of what may be of acoustic significance. We therefore have a failure to communicate that can see acoustic matters and acoustic design being left out of the process until, as often happens, an acoustics consultant such as me receives a phone call about a project that he or she has had nothing to do with up until that point. A project manager or chief engineer may then be on the line saying they have ‘a little bit of a noise problem’.