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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 ...
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.
The above equations calculate the steady state mass flow rate for the pressure and temperature existing in the upstream pressure source. If the gas is being released from a closed high-pressure vessel, the above steady state equations may be used to approximate the initial mass flow rate. Subsequently, the mass flow rate decreases during the ...
= cross-sectional area of opening, ft² (assumes equal area for inlet and outlet) C d = Discharge coefficient for opening (typical value is 0.65) g = gravitational acceleration, around 32.2 ft/s² on Earth H d = Height from midpoint of lower opening to midpoint of upper opening, ft T I = Average indoor temperature between the inlet and outlet ...
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]
For buildings with one or two floors, h is the height of the building and A is the flow area of the openings. For multi-floor, high-rise buildings, A is the flow area of the openings and h is the distance from the openings at the neutral pressure level (NPL) of the building to either the topmost openings or the lowest openings.
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Orifice plate showing vena contracta. An orifice plate is a thin plate with a hole in it, which is usually placed in a pipe. When a fluid (whether liquid or gaseous) passes through the orifice, its pressure builds up slightly upstream of the orifice [1] but as the fluid is forced to converge to pass through the hole, the velocity increases and the fluid pressure decreases.