GP6, GP10 and GP12 Sirens
INSTALLATION AND MAINTENANCE
1.
Installation
a. Fix siren to a firm level base at a minimum height of 3m above the ground and free
of side or top obstructions.
b. For best all round sound propagation mount the unit at a height of 4.5 to 6m with
50m clear radius all round.
c. Figure 1 overleaf shows a polar plot of the sound output from the sirens in free
space.
Please note that the propagation of sound in air is affected by the following factors
which must be accounted for when calculating the coverage of the siren:
• Variations of the propagation speed in the air
• Attenuation of the sound during propagation
• Wind and turbulence of the atmosphere
• Obstacles placed in the vicinity of siren and listener.
• Ambient noise levels
d. The plot assumes ideal free-field conditions.
The following losses must be taken into account during commissioning:
• Sound attenuation loss over distance in free-field conditions without obstructions.
Distance in Metres
GP6
Audibility
1
30
100
95
200
89
500
81
1000
75
2000
69
135
140
145
105
110
115
GP10
100
105
94
86
80
74
dB(A)
GP12
99
91
85
79
• Attenuation in decibels per kilometre due to absorption of sound in air (10°C,
90%RH).
At 500 Hz frequency the attenuation is 1.6 dB(A)/kilometre
• Absorption due to fog in decibels per kilometre.
At 500 Hz frequency the attenuation is 1.0 dB(A)/kilometre
The two figures provided for sound absorption in clear air and fog are sound losses
in addition to the typical sound losses experienced over distance indicated in the
table above.
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GP6 and GP10 Single Ended Sirens - Polar Plot of Sound Output (dBA @ 1m)
0
150
145
140
135
130
125
120
345
15
330
30
315
45
300
60
285
75
GP6 Siren
270
90
GP10 Siren
255
105
240
120
225
135
210
150
195
165
180
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GP12 Double Ended Siren – Polar Plot of Sound Output (dbA @ 1m)
0
15
345
30
330
315
45
60
300
285
75
270
90
255
105
240
120
135
225
210
150
195
165
180
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