NOISE AND VIBRATION CONTROL Episode 10 potx

... characteristics and the sound pressure level data have become detached, and the noise control analyst or engineer has no concrete data for designing noise control treat- ments. Sones and phons are ... this manual, and their use for noise control purposes is of little value. When offered data in sones and phons, the noise control engineer should request the original o...

Ngày tải lên: 13/08/2014, 05:22

... the sound power level (Lw), in dB re 10- 12 watts, of the supply fan and the diffusers are determined. (1) Fan Lw. From equation 10- 5 and table 10- 13. Octave Band Center Frequencies 63 125 250 500 ... Diameter Octave Band Frequency (Hz) (inches) 63 125 250 500 100 0 2000 4000 8000 Lined elbows 5 to 10 0 0 1 2 3 4 6 8 11 to 20 0 1 2 3 4 6 8 10 21 to 40 1 2 3 4 5 6 8 10 41 to 80...

Ngày tải lên: 13/08/2014, 05:22

... 1992 Beranek, Leo L., Noise & Vibration Control, The Institute of Noise Control Engineering, Washington, DC, 1988 Schaffer, Mark E., A Practical Guide to Noise and Vibration Control for HVAC Systems, ... 1988 Harris, Cyril M., Shock & Vibration Handbook, 3rd Edition, McGraw-Hill, New York, NY 1988 Beranek, Leo L. & Ver, Istvan L., Noise and Vibration Cont...

Ngày tải lên: 13/08/2014, 05:22

... 9-1 CHAPTER 10. NOISE AND VIBRATION MEASUREMENTS Objective 10- 1 10- 1 Sound and Vibration Instrumentation 10- 2 10- 1 Measurement of Noise and Vibration in Buildings 10- 3 10- 2 Measurement of Noise and Vibration ... 9-4 B-1. Bandwidth and Geometric Mean Frequency of Standard Octave and 1/3 Octave Bands B-6 UFC 3-450-01 15 May 2003 1 UNIFIED FACILIT...

Ngày tải lên: 13/08/2014, 05:22

... -16 -19 -21 -22 -23 -24 -25 100 00 -10 -14 -19 -21 -22 -23 -24 -25 -26 20000 -10 -15 -20 -22 -24 -26 -27 -30 -30 Infinite -10 -15 -21 -24 -27 -30 -33 -36 -39 above 100 0 Hz). Therefore, the high-frequency Room ... arithmetic average of noise levels in the 500-, 100 0-, and 2000-Hz octave frequency bands. SIL values apply for average male voices (reduce values 5 dR for female voic...

Ngày tải lên: 13/08/2014, 05:22

... Airborne noise and structureborne vi- bration radiated as noise may intrude into these occupied floors if adequate controls are not in- cluded in the building design. The approximate octave band “TL” ... 25 -14 +3 3.7 -6 31 -15 +2 4.7 -7 40 -16 +1 6.1 -8 50 -17 0 7.7 -9 63 -18 -1 9.7 -10 80 -19 -2 12.0 -11 100 -29 4-2

Ngày tải lên: 13/08/2014, 05:22

... paths (paths 2 and 3) of noise and vibration caused by airborne excita- tion of walls and columns in the mechanical equipment room. These paths make it impossible to achieve the low noise levels ... area “A” (which is the product of the two lengths “a” and “b”). At twice the distance, 2d, the lengths a and b are expanded to 2a and 2b, and the result- ing area over which th...

Ngày tải lên: 13/08/2014, 05:22

... 54 44 37 31 27 24 22 21 Col. 8 Noise Excess (dB) 31 108 52 56 8 48 63 109 52 57 9 48 125 112 52 60 10 50 250 110 53 57 11 46 500 108 53 55 12 43 100 0 105 53 52 13 39 2000 100 54 46 14 32 4000 95 57 38 15 23 8000 91 60 31 16 15 ... of Indoor NC-25 Noise SPL Curve Excess (dB) (dB) (dB) 31 108 52 5 51 8 63 109 52 5 52 9 125 112 52 6 54 10 250 110 53 8 49 11 500 108...

Ngày tải lên: 13/08/2014, 05:22

... the architect and engineer to problems of noise and vibration. This is an important first step to noise control. Without awareness, the noise problem is ignored in the design, and later problems ... the various sources, fan noise will control the noise level in the low frequency range, air terminal units will control in the mid-frequency range, and air outlets will co...

Ngày tải lên: 13/08/2014, 05:22

... re- quired to achieve near inaudibility. The noise and vibration control methods given here are designed to be simple to follow and to put into use. If these methods and recommendations are carried out, with ... 32 -109 0 Table 8-7. Vibration Isolation Mounting for Boilers. 8-15 TM 5-805-4/AFJMAN 32 -109 0 Table 8-12. Vibration Isolation Mounting for Transformers. 8-20 TM 5-80...

Ngày tải lên: 13/08/2014, 05:22