A laboratory room 16 x 10 x 8 ft high must be ventilated so that the air in the room is exchanged….
A laboratory room 16 x 10 x 8 ft high must be ventilated so that the air in the room is exchanged twice per minute. The resistance to the flow is a short exhaust duct with a set of screened louvers over a vent (K = 1). Choose a fan whose level of sound power is less than about 70 dB in order to allow for low speech interference levels within the lab. 4.8.. The laboratory room of Problem 4.7 has walls, ceiling, and floor treated with an absorbent padding roughly equivalent to heavy carpeting. Estimate the sound pressure level at the room center (x = 8 ft) if the fan is in an end wall. Compare the results to the criterion for speech interference in Table 4.2. TABLE 4.2 Specific Sound Power Level Data Fan type 63 125 250 500 1000 2000 4000 8000 bpi 3 35 35 34 32 31 26 18 10 35 35 34 32 31 26 18 10 3 40 38 38 34 28 24 21 15 2 Centrifugal airfoil blade Centrifugal backwardly curved blade Centrifugal forward curved blade Centrifugal radial blade Tubular centrifugal Vane axial Tube axial Propeller 48 45 43 43 38 33 30 29 5-8 46 43 43 38 37 32 28 25 4-6 42 39 41 42 40 37 35 25 6-8 44 42 46 44 42 40 37 30 6-8 51 48 49 47 45 45 43 31 5-7 Source: Specific Sound Power Level Data for Fans and Blowers from Graham, J. B., 1991, ASHRAE Handbook: HVAC Applications, American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. With permission. Note: Octave Center Band Frequencies, Hz.
Attachments:
phpuyetdz_4651099499738692751.png
phpotfs3p_5099746356384392515.png
A laboratory room 16 x 10 x 8 ft high must be ventilated so that the air in the room is exchanged…
