Rain Noise on Composite Roof Structures

Bad weather always looks worse through a window… and sounds worse on composite roof structures. The issue of rain noise on roofing structures has come to the fore in recent years, particularly in relation to educational facilities. During the wet summer of 2007 there were a number of reports stating that rainfall on composite roof structures in school examination rooms and halls had resulted in noisy conditions and poor speech intelligibility affecting the aural examinations. The Department of Education are keenly aware of this issue but there is little specific guidance given in the Technical Guidance Document (TGD-020).
To an extent this is due to the fact that rain noise is not a very tactile subject and defining what is acceptable is like stating how long is a piece of string. The ISO have outlined a draft document (ISO 140-18) which is designed to measure the impact sound insulation of roof when excited by rainfall. However the real problem is that it is impossible to replicate these test conditions in the real world. Therefore it is difficult to outline an acceptable criterion or decibel level within a given space.
In order to mitigate against excessive noise due to rainfall the roof design should be considered in light of the component roof parts, details and sub ceilings. Moreover the activity taking place in the space below should be reviewed and its noise sensitivity determined.
iAcoustics we can’t stop the rain from falling but we can help you design so you don’t hear it.

New Wave of Acoustic Guidelines

Are these the first rumblings of a seismic shift in the Building Regulations in Ireland? At iAcoustics we’re not so sure. The distinct lack of acoustic regulation in Ireland for many years has forced the acoustics industry to look to our near neighbours in the UK to seek clarity on the fundamental noise issues affecting the Irish building industry. But in more recent times the UK’s strong regulatory framework has in some respects been replaced by guidelines and accreditation schemes. This backdrop has incentivised the construction industry to take a holistic view of a buildings footprint, including the acoustic and noise control elements. So can we expect the same in Ireland?
The healthcare sector in Ireland has begun to adopt the UK’s Health Technical Memorandum in terms of designing and building new hospital and healthcare facilities. The fundamentals of this document look to provide acoustic comfort within the facility, preserve speech privacy and confidentiality between spaces and limit the impact on noise upon near neighbours. HTM 08-01 has tended to be issued as a mandatory compliance document and therefore is more akin to the regulatory acoustic documents.
In the area of office acoustics the BREEAM and LEED accreditation schemes have begun to be adopted primarily by the large multinationals operating in Ireland. The BREEAM scheme has considered the issues of speech privacy between offices and speech intelligibility in boardrooms and video conference rooms. Meanwhile the LEED accredition scheme has been readily implemented by many of the American foreign multinationals operating within Ireland and takes strong heed of sound insulation between offices. Both schemes have considered the acoustic aspects of an office building and offered easily attainable credits.
The era of light touch acoustic regulation may be coming to a close and in its place a move towards a holistic view of a buildings, including the acoustic and noise control elements.