Edwards Signaling Catalog

More documents

Recommendations

Info

3. Ambient Sound Conditions: The frequency of the signaling device selected should be as different from the background noise as possible. The signal should override this noise by a minimum of six decibels. Usually, the noisier the area, the louder the signal required and the greater the number of signaling devices required. Over the years, horns and bells have been the most popular signals because their varied tones can be heard over most ambient conditions. See the table on page 27 for typical dB levels associated with various activities. 4. Size of Area to be Covered: The larger the area, the louder the signal required or the greater the number of units required. As a rule of thumb, sound output drops by approximately 6 decibels each time the distance between the sound source and the human ear is doubled. For example: Source in dB Feet from Source 116 dB 10 110 dB 20 104 dB 40 98 dB 80 92 dB 160 If a signal is rated at 116 dB at 10 feet, then a signal twice as loud would be rated at 122 dB at 10 feet. In an application where the ambient noise level was 92 dB, the signaling device in the above example would adequately cover a distance of approximately 80 feet. Better coverage is frequently obtained by the use of several signals of lower dB rating than by using one very loud signal, (providing the signals can be positioned to advantage). 5. Mounting Considerations: The surface that the signal is mounted to can markedly affect the signal’s performance. A horn, for example, should be rigidly mounted to a sturdy surface so that all of its energy is directed into the sound output and not absorbed by the wall. A buzzer, however, can sound much louder if mounted on a resonant surface because it will act as a “sound board” for the buzzer. TM www.edwardssignaling.com 29
TM Science of Sound The Nomograph pictured below can be used to calculate dB over distance. 30 www.edwardssignaling.com
Page 1 and 2: TM www.edwardssignaling.com Smarter
Page 3 and 4: *Frog not included
Page 5 and 6: TM New Products New Product 825 Nig
Page 7 and 8: TM New Products New Product 107XBR
Page 9 and 10: TM Product Selection Pages Make the
Page 11 and 12: TM TM 140 Years New Edwards & Compa
Page 13 and 14: TM www.edwardssignaling.com Signali
Page 15 and 16: TM NEMA Enclosure Ratings NEMA Defi
Page 17 and 18: TM Hazardous Location and Explosion
Page 19 and 20: TM Hazardous Location and Explosion
Page 21 and 22: TM Science of Light Physical Princi
Page 23 and 24: TM Science of Light Luminous flux T
Page 25 and 26: TM Science of Light Photometers Pho
Page 27 and 28: TM 26 www.edwardssignaling.com
Page 29: TM Science of Sound AUDIBLE SIGNALI
Page 33 and 34: TM 32 www.edwardssignaling.com
Page 35 and 36: TM Product Index 1 VISUAL SIGNALS W
Page 37 and 38: TM Solar Beacons Multi-Mode LED 825
Page 39 and 40: TM Solar Beacons Multi-Mode LED 825
Page 41 and 42: TM 1 VISUAL SIGNALS StackLight 200
Page 43: TM StackLight 200 Class 70mm Clear

Edwards Signaling Catalog

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?