House depressurization is a ubiquitous, dangerous problem. As regional mechanical codes move toward consolidation into one International Mechanical Code, now is the time to add a performance testing requirement for house depressurization.
Providing safe storage for documents and documentary records within new and existing buildings is a problem faced by many building designers and owners/managers. This Bulletin sets out the common causes of damage and the specific storage criteria for commonly used documents and documentary records, as well as outlining methods to satisfy these criteria.
The issue of sound quality in offices and other occupied spaces has been of continuing interest since the 1950s. Existing assessment methods do not adequately account for the Low-frequency background sound ( < 250 Hz) produced by operating heating, ventilating, and air-conditioning (HVAC) systems, in particular, Low-frequency rumble. This paper discusses the results of ASHRAE-sponsored research in which more than 75 HVAC noise samples were collected, normalized, and categorized in terms of sound quality.
Fans and their associated ventilation ducts are amongst the major sources of airborne noise encountered within a submarine. Health & Safety Standards require that the ship's crew are not exposed to unnecessary high levels of noise and have a suitable environment free from intrusive noise in order to work and rest. The problem with noise emitted from fans and ducts in submarines can be categorised as follows:
An intensive review indicates that among the existing formulae on the sound attenuation in long enclosures, only the geometrical reflection model seems relatively practical. Computations with this model show the following for rectangular long enclosures: with a larger cross-sectional size the relative attenuation from a given section is less but the absolute attenuation with reference to the source power is greater; the efficiency of absorbers is higher when there is less absorption; and obtain a higher attenuation, the absorbers should be evenly arranged in a section.
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