Acoustic designers could be costing clients money by over-specifying acoustic solutions. Now, software has been developed that tracks how sound moves through a building and how to stop it
The acoustic environment was examined in an office building with a high prevalence of symptoms typical of the sick building syndrome (SBS). Levels of ventilation noise exceeded 70 dB in many rooms. The peak was often found in the region below 20 Hz, which is the infrasound region and generally regarded as inaudible at these levels. Symptoms attributed to exposure to low frequencies include nausea, headache, choking, coughing, visual blurring and fatigue, which appear to overlap with some of the symptoms of SBS.
The use of ceiling mounted circulating fans to provide air movement for cooling in industrial premises and animal houses is particularly essential in warm, humid climates. Methods to substantially improve the efficiency of this approach are demonstrated in this paper. Fan laws are identified as one source of strategies for increasing energy-efficiency of fans. Industrial ceiling fans are used to demonstrate that using larger, slower, fans will not only improve energy efficiency but also reduce fan noise.
ln the past, passive solar buildings were specifically designed with respect to energy and thermal comfort requirements. Within this framework a fa9ade able to collect solar energy and bring indoor suitable conditions for occupants was thought of as an optimal building device. On the contrary, little attention was paid to their acoustic behaviour.
This American National Standard describes procedures for the measurement of sound pressure levels in the outdoor environment, considering the effects of the ground, the effects of refraction due to wind and temperature gradients, and the effects due to turbulence. This standard is focused on measurement of sound pressure levels produced by specific sources outdoors. The measured sound pressure levels can be used to calculate sound pressure levels at other distances from the source or to extrapolate to other environmental conditions or to assess compliance with regulation.
This Update discusses the various factors that affect sound transmission through different types of concrete block walls, including single-leaf walls, double-leaf walls and walls with gypsum board attached. Knowledge of these factors will assist construction practitioners to design and build walls with high levels of acoustic performance economically.
This Update examines various fire-stopping techniques that meet the intent of the National Building Code of Canada (NBC) with respect to fire resistance and that do not adversely affect the sound isolation of the wall assembly. The information is derived from the results of an industry-sponsored consortium project led by the National Research Council's Institute for Research in Construction (IRC).
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