5
2.2 Detection environment investigation
VFDS™ designers have to collect the field environment as below.
Field scale (length, width, height)
Field scale is the area that VFDS™ system applies detection to. In order to setup the
VFDS™ system components correctly, designers have to measure the field dimensions,
including length, width, height, special characteristics and so on.
Field illumination condition
VFDS™ requires a minimum luminosity of 70 Lux in the detected area in day time color
mode detection. Field illumination condition affects smoke detection function and becomes a
basic factor when designing VFDS™ system. The best interior lighting source is normal
white light (fluorescent light). 70 Lux as an average illumination condition is strongly
recommended. (Normal Brightness for normal industrial environment is 250~300 Lux).
Illumination is the brightness level of object, and unit measure is Lux. (Averagely each
square meter with one lux light on is defined as 1Lux)
Field illumination control
There are specific cameras for VFDS™ to achieve precious detection and minimize the
possibility of false alarm
.
Indoor / Outdoor (Day/night): CHQ-8986WTM(8) -> No infrared light built-in.
Outdoor (Day/night): CHQ-8917DVFP(C) -> Infrared light built-in
Indoor (Day /Night): CHQ-8939DVF -> Infrared light built-in
If interior illumination is stable without illumination changes, it is not necessary to choose
the camera with Infrared light. VFDS™ is working as color detection mode then.
VFDS™ will turn to monochrome detection mode in low illumination environment. The
camera will need to be equipped with infrared light or extra infrared illumination device is
required.
Outdoor environment is changeable where requires Auto-iris lens for the cameras. In order to
Luminance source
luminous flux-
Integrating Spheres
luminous intensity
-
Photometer
Luminance-
luminance meter (cd/m
2
)
Luminous Emittance
(lm/cm2)
Luminance (Lux) -
Luminance meter
Eye
Reflector
