10
Installation
Models 2-120 and 2-240
Federal Signal www.fedsig.com
Installation
Electrocution or severe personal injury can occur when making electrical
connections, drilling holes, or lifting equipment. Therefore, installation should
be performed by experienced electricians in accordance with national and
local electrical codes and ordinances, including any state or local noise control
ordinances.
Determining a Suitable Location
The output level of an the sirens are capable of causing permanent hearing
damage. To prevent excessive exposure, carefully plan the siren location and
post warnings where excessive levels may be encountered. Refer to OSHA 29
CFR 1910.95 for safe exposure limits.
Do not expose personnel to sound levels above 123 dBC.
Careful consideration of the factors affecting the propagation of sound from the siren
and the response of the human ear to the sound will optimize the ability of the siren
to effectively warn the community. Follow Federal Emergency Management Agency
(FEMA) guidelines when designing the warning system.
The reduction of signal intensity as distance from the siren increases and the minimum
desired signal level at the fringe of the area to be covered are important considerations
when choosing a siren installation site. As the distance from the siren increases, sound
level losses accumulate. These losses are a result of weather conditions, the terrain,
obstructions in the sound path, and the pitch of the sound and the height of the siren.
Optimum sound propagation conditions occur when no obstructions exist in the sound
path, the terrain is hard and flat, and the air is blowing away from the source. Under these
conditions, you can expect a 6 dB loss per distance doubled. A loss per distance doubled
of 10 dB is typically experienced because atmosphere is rarely calm, terrain may not be
flat, and buildings or other obstructions are frequently present in the sound path.
Using a 10 dB per distance doubled loss factor, the following sound levels are predicted
for the sirens in the following table.
Table 4 Sound levels predictions
Distance
Model 2
100 feet (30.5 m) the sound level is 102 dB
200 feet (61 m) the sound level is
94 dB
400 feet (122 m) the sound level is 86 dB
