Siemens FDCW221, Техническое руководство

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