Designing BS Oct:Layout 1
06/11/2009
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bs news S October/November 2009
Designing Building Services Eoghan Plunkett, lead building services engineer with PM group, has 21 years experience in design, installation, commissioning, testing and balancing, and hand over of building services systems in the healthcare and industrial sector, both at home and abroad. Over the past 12 years he has worked in the Irish building services industry and has drawn on his experiences in Germany to bring several new products to the sector, often being given the tricky jobs that require someone with a good feel for fine design, coupled with a conscious commercial awareness. Email: eoghan.plunkett@pmg.ie
Office HVAC attenuation – ‘sounds’ good! be fit for purpose, complying with regulations for lighting levels, temperature requirements, humidity requirements and noise levels. This article concerns itself with the last and in many ways one of the most important environmental conditions, noise. Here the focus shall be on what is noise, where it is produced within an office environment (where
Noise attenuation – good design practice for engineers A pleasant office working environment is one that fulfills all statutory requirements for the environmental conditions required for the operations being carried out within the occupied space. It must Middle Ear Inner Ear
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it originates), what are its effects and what can be done about it.
Noise definition Simply put, a noise is anything that can be perceived by our ear as a sensation of that organ. Noises can be unnoticeable, pleasant, annoying, unpleasant and damaging. Sound consists of energy generated by a source and transmitted by pressure fluctuations of the medium through which it travels (air, water, earth and structures). The unit of measurement of sound is the decibel (dB). Table A on the facing page demonstrates different everyday noise sources at their level of measurable value as perceived by the ear.
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Sound pressure
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30
The audible spectrum of sound pressure that the ear can hear lies between 0.00002 pascals (Lower threshold) and 20 pascals (upper threshold). If the unit pascal (Pa)