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The amount of ventilation in an ETS area is equal to the amount of an ETS-free area plus the amount V, where: V = DSD × VA × A/60E V = recommended extra flow rate in CFM (L/s) DSD = design smoking density (estimated number of cigarettes smoked per hour per unit area) VA = volume of ventilation air per cigarette for the room being designed (ft ...
Research aiming at the development of natural ventilation systems featuring heat recovery have been made as early as 1993 where Shultz et al. [8] proposed and tested a chimney type design relying on stack effect while recovering heat using a large counterflow recuperator constructed from corrugated galvanized iron. Both supply and exhaust ...
In a nozzle or other constriction, the discharge coefficient (also known as coefficient of discharge or efflux coefficient) is the ratio of the actual discharge to the ideal discharge, [1] i.e., the ratio of the mass flow rate at the discharge end of the nozzle to that of an ideal nozzle which expands an identical working fluid from the same initial conditions to the same exit pressures.
Round duct is made using a continuous spiral forming machine which can make round duct in nearly any diameter when using the right forming die and to any length to suit, but the most common stock sizes range evenly from 4" to 24" (10-60 cm) with 6"-12" (15-30 cm) being most commonly used. Stock pipe is usually sold in 10' (300 cm) joints.
Displacement ventilation is best suited for taller spaces (higher than 3 meters [10 feet]). [2] Standard mixing ventilation may be better suited for smaller spaces where air quality is not as great a concern, such as single-occupant offices, and where the room height is not tall (e.g., lower than 2.3 meters [7.5 feet]).
is the area of the duct, is the velocity of the fluid. The practicalities of mine ventilation led Atkinson to group some of these variables into one all-encompassing term: Area and perimeter were incorporated because mine airways are of irregular shape, and both vary along the length of an airway.
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However, they are seldom used as the actual basis of design or calculation. For example, residential ventilation rates are calculated based on area of the residence and number of occupants. [5] Non-residential ventilation rates are based on floor area and number of occupants, or a calculated dilution of known contaminants. [6]