Volume 6, Number 4, December, 1998 - Noise News International

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THE TL OF A SINGLE WALL IS ESTIMATED FROM ITS SURFACE WEIGHT Transmission loss (TL) is a measure of a wall's ability to reduce a sound level. At low frequencies and small wallthicknesses, the surface weight in kg/m 2 determines the difference in level between incident and transmitted sound. If the thickness or the frequency are increased, a limit will be reached which depends on the wall material. Principle 60 TL in dB 50 limiting values 40 30 26 20 10 • ·t ,. aluminum plaster. glass O+------r----r---T-.----,------r---,---.,-----, 1000 2000 3000 5000 10000 20000 30000 50000 100000 t weight per unit area (kg/m2) x frequency (Hz) Example: What TL will be provided by a 15 mm thick chipboard panel at 500 Hz The panel weighs 10 kg/m 2 • Solution: 10 x 500 = 5000. Thus. the TL will amount to about 26 dB. 220 NoiselNews International 1998 December
Application with a thin screen. Example A sand blast operation creates excessive noise. Control Measure A separate room is constructed for the ventilation fan and other auxilary equipment. The blasting equipment is separated from other work areas with a drapery of lead-rubber fabric, which is heavy but flexible. ventilation workplace sound-isolated machine room lead-rubber drapery 1998 December NoiselNews International 221
Page 1 and 2: Volume 6, Number 4 1998 December IN
Page 3 and 4: Editorial Stllff G. Maling, Jr., Ma
Page 5 and 6: Anechoic Chambers with EMW lining T
Page 7 and 8: "Finally, an Outdoor Sound Propagat
Page 9 and 10: YOUR NEXT SOUND METER • Workplace
Page 11 and 12: Feature Noise Control Standards for
Page 13 and 14: specify in more detail relevant mea
Page 15 and 16: c: o .~ "E f---7""'lf-1I:-i~;J4'.--
Page 17 and 18: References 1. Council Directive 89/
Page 19 and 20: Feature Advances in Acoustical Stan
Page 21 and 22: (a) M 4 6:~f=========::::CI~ Fig. 3
Page 23 and 24: Adaptor for Microphone & Preamplifi
Page 25 and 26: the last twenty years and be ready
Page 27 and 28: CONTROL The illustrations in thisfe
Page 29: Application to machines with connec
Page 33 and 34: Application with light single walls
Page 35 and 36: European News A. Cops, European Edi
Page 37 and 38: Pan-American News George Maling, Pa
Page 39 and 40: Contest entry forms and other mater
Page 41 and 42: Newly published ISO and IEC Standar
Page 43 and 44: ACOUSTICS ANSI Sl.15-1997-Part 1, M
Page 45 and 46: NNI Directory Organizational and Ed
Page 47 and 48: ~----- REAL TIME ANALYSER APPLICATI
Page 49 and 50: Brazil: +55 II 8200388; +55 II 8207
Page 51 and 52: The BS-112 comes equipped with a 6-
Page 53 and 54: 518584 3754; FAX: +1 5185809525; e-
Page 55 and 56: World Conference Calendar This cale
Page 57 and 58: COLIN GORDON & ASSOCIATES Specializ
Page 59 and 60: The NewMo e 2 Real Tune Analyzer Fe

Volume 6, Number 4, December, 1998 - Noise News International

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