Siemens FDCW221 Technical Manual page 28

Project engineering
28
Building Technologies
Fire Safety & Security Systems
To determine the actual attenuation at the location of the receiver, the guide values
of the construction elements along the radio transmission distance as listed in the
table must be added.
Construction element
Partition
dry bricks
dry concrete
Lime-sand brick
Lime-sand brick plan elements
Wooden wall construction
Timber panel wall
Humid bricks
Coated plaster plate (double wall)
Steel concrete
Thick, wet brick wall
Calculation example:
A radio gateway is mounted under a steel concrete ceiling. The separation walls
are made from concrete.
A
Radio gateway with the transmission distances A, B, C
Fig. 9
Distance A: 5 m Free space + steel concrete ceiling
Distance B: 15 m Free space + steel concrete ceiling +
concrete wall
Distance C: 10 m Free space + concrete wall
Result:
The distances A and C can be operated
The radio detector on the distance B cannot be reached.
Additional attenuation
< 1 dB
approx. 6 dB
approx. 6 dB
approx. 8 dB
approx. 8 dB
approx. 8 dB
approx. 8 dB
approx. 10 dB
approx. 15 dB
approx. 30 dB
> 40 dB
B
C
≈40 + 30 = 70 dB
≈67 + 30 + 6 = 103 dB
≈57 + 6 = 63 dB
009865_b_en_--.doc
11.2007