assignment_2 - the walls and ceiling are ½ in Gypsum...

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IE 5513 Assignment #2 (25 points) Due Feb. 10th, 2011 1) You are in charge of purchasing and installing a large compressor for the facility that you work in. The manufacturer stated the sound power level is 100 db. Determine the sound pressure level in the work room given that the room constant R is 2458 sq ft and the nominal working distance (r) from the machine is 10 ft. Investigate the situation for the following scenarios: a) Compressor in the middle of the room b) Compressor at one end of the room c) Compressor in the corner of the room 2) A worker performs three operations per day. The duration and sound level for each are as follows: Operation 1, 3 hr, 95 dB (A); operation 2, 4 hr, 90 dB (A); Operation 3, 1 hr, 97 dB (A). a. What is the time weighted average exposure value? b. Is protection required based on OSHA standards? 3) A room measuring 60 ft wide, 85 ft long, and 15 ft high with a sound power level of a 110 dB (A) source at 1000Hz located in the room. The floor of the room is concrete and
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Unformatted text preview: the walls and ceiling are ½ in Gypsum nailed to 2x4 studs. a. Calculate the room constant R To reduce sound the sound levels the ceiling is modified to include acoustic tiles. The tile has an absorption coefficient of .8 at 1000 Hz. b. What is the noise reduction, NR, after this modification? 4) An HVAC engineer needs to determine the sound reduction in a circular duct. The duct is 50 ft long and has a diameter of 36 in and is lined with 1” thick glass fiber material. At the inlet end is a fan that produces an SPL of 120 dB over all frequencies. Determine the noise reduction at the end of the duct for the 125 to 4000 Hz using Table 23-4. Plot your results in Excel. 5) An enclosure is made of 1/2-in thick gypsum board. Inside the enclosure is a noisy machine. Determine what reduction in noise will actually occur at 1000 Hz if. a) There is a 20% opening in the enclosure. b) There is a 5% opening in the enclosure....
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This note was uploaded on 02/19/2011 for the course IE 11 taught by Professor G during the Spring '11 term at Minnesota.

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assignment_2 - the walls and ceiling are ½ in Gypsum...

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