NOISE AND VIBRATION CONTROL Episode 3

Tham khảo tài liệu 'noise and vibration control episode 3', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 3-8 Col. 1 Octave Band Center Frequency Hz Col. 2 Measured at 6 ft. Distance dB Col. 3 R1 of Measurement Room ft Col. 4 REL SpLD1R1 from Fig. 5-1 dB Col. 5 R2 of Mechanical Equipment Room ft Col. 6 REL SPLD2R2 from Fig. 5-1 dB Col. 7 Col. 4 minus Col. 6 dB Col. 8 2R Col. 2 minus Col. 7 dB 31 81 350 -8 250 -7 -1 82 63 85 350 -8 250 -7 -1 86 125 87 boo -9 boo -10 1 86 250 90 1 50 750 3 87 500 96 b8o 850 -13 92 1000 91 500 -10 1200 -15 5 86 2000 88 500 -10 1200 -15 5 83 hooo 83 500 -10 1200 -15 5 78 8000 72 500 -10 1200 -15 5 67 Table 3-5. Summary of Data and Calculations Illustrating Use of Equation 3-1. TM 5-805-4 AFJMAN 32-1090 Table 3-6. Summary of Data and Calculations Illustrating Use of Equation 3-2. Col. 1 Octave Band Center Frequency Hz Col. 2 PWL of Source dB Col. 3 Room Constant Col. 4 REL SPL from Fig. 5-1 dB Col. 5 SPL at Distance dB 31 95 400 -10 85 63 93 600 -12 81 125 94 800 -13 81 250 95 1200 -15 80 500 99 1600 -16 83 1000 102 2000 -17 85 2000 108 2000 -17 91 4000 105 2000 -17 88 8000 94 2000 -17 77 3-9 TM 5-805-4 AFJMAN 32-1090 CHAPTER 4 SOUND ISOLATION BETWEEN ROOMS 4-1. Objective. This chapter provides data and procedures for estimating the changes in sound levels as one follows the energy flow path from a sound source to a receiver through building components such as walls floors doors etc. First the sound pressure levels in the room containing the source drop off as one moves away from the source as described in chapter 3. Then at the walls of the room some sound is absorbed some is reflected back into the room and some is transmitted by the walls into the adjoining rooms this also occurs at the floor and ceiling surfaces . The combined effects of this absorption reflection and transmission are the subject of this chapter. 4-2. Sound Transmission Loss TL Noise Reduction NR And Sound Transmission Class STC . With the knowledge of the acoustical isolation provided by walls and floors it is possible to select materials and .