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A 1973 report cites a university study of fifty cases of people complaining about a "low throbbing background noise" that others were unable to hear. The sound, always peaking between 30 and 40 Hz (hertz), was found to only be heard during cool weather with a light breeze, and often early in the morning. These noises were often confined to a 10 ...
The hissing of high voltage transmission lines is due to corona discharge, not magnetism. The phenomenon is also called audible magnetic noise, [1] electromagnetic acoustic noise, lamination vibration [2] or electromagnetically induced acoustic noise, [3] or more rarely, electrical noise, [4] or "coil noise
The infiltration rate is the volumetric flow rate of outside air into a building, typically in cubic feet per minute (CFM) or liters per second (LPS). The air exchange rate, (I), is the number of interior volume air changes that occur per hour, and has units of 1/h.
An air handler, or air handling unit (often abbreviated to AHU), is a device used to regulate and circulate air as part of a heating, ventilating, and air-conditioning system. [1] An air handler is usually a large metal box containing a blower, furnace or A/C elements, filter racks or chambers, sound attenuators, and dampers. [2]
At the furnace, cool air passes into the furnace, usually through an air filter, through the blower, then through the heat exchanger of the furnace, whence it is blown throughout the building. One major advantage of this type of system is that it also enables easy installation of central air conditioning , simply by adding a cooling coil at the ...
The furnace, built on the outside of the workshop, featured earthen pipe-like air vents with hundreds of tiny holes in them and a prototype chimney to ensure air goes into the furnace to feed the fire and smoke comes out safely. [39] Passive ventilation and passive cooling systems were widely written about around the Mediterranean by Classical ...
Respiratory sounds, also known as lung sounds or breath sounds, are the specific sounds generated by the movement of air through the respiratory system. [1] These may be easily audible or identified through auscultation of the respiratory system through the lung fields with a stethoscope as well as from the spectral characteristics of lung sounds. [2]
The majority of guidance available for design of heat and smoke building vents installed in buildings is restricted to nonsprinklered, single-story buildings. [4] This is partly a historical consequence of the installation of heat and smoke vents following the August 1953 General Motors, Livonia, MI major fire in a nonsprinklered manufacturing facility which effectively stopped the production ...