User Manual

Fire Safety and security measures
37
Building Technologies A6V10283843_a_en
Fire Safety & Security Products 05.2010
All detected events must be verified and acknowledged by operating personnel.
The detection quality and detection accuracy depend heavily on the planning of the
operating environment (lighting, etc.) and configuration.
Fig. 14 Car video smoke detection in tunnel
To detect the smoke with video detection system the max detection distance has to
be ~20x of camera mounting height, max. 100 m. It has also limitation by the mini-
mum contrast ratio and motion haziness in the image background. A minimum il-
lumination of 40 Lux (reflected) is recommended in order to get reliable results.
The camera has to have a minimum sensor size of ½ “ CCD. The lenses minimum
requirements are:
– Minor boundary haziness
– High light intensity – F1.2 / F1.0 / (F0.9 aspharic)
– DC – controlled blends
– Focal length range of 3 mm – 18 mm with ½“cameras
– Most often used focal length at ½“:
– 12 mm or 18 mm in the tunnel driving area
– 3, 6 or 8 mm for storage / emergency refuge / rescue areas
It is important for the housing installed in tunnel to have the following characteris-
tics:
– Resistance to corrosion (~10 years) – Stainless steel 1.4571 or similar
– Humidity and water resistance – IP 66 or higher
– Protection against pollution – Tunnel
– No reflection into the camera lens – Non-reflecting and slant mounting of face
late
– Easy to replace – Plugable connecting cable
– Heating – Glass heater advantageous
The location of the camera installation depends of the tunnel characteristics as:
– Tunnel length
– Number of tunnel sections
– Number of lanes
– Geometry (round, square, etc)
– One-way traffic / oncoming traffic
– Traffic volume of passenger vehicles / freight vehicles
– Illumination