Optical Contamination; Enclosed Areas; Detector Sensitivity; Detector Alarm Delay - Viking VSF303 Technical Manual

Multi spectrum ir flame detector

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Optical Contamination

There are many sources of contamination such as oil, water (deluge water, rain, and sea-spray),

snow, ice, and internal misting. Excessive contamination of the detector faceplate may result in an

increased maintenance requirement and potentially reduce the detector's sensitivity. Where

detectors are mounted at low level, care should be taken to avoid contamination (such as water and

oil) from equipment above the detector. Care should be taken in sighting the detector to minimize

the likelihood of such contamination. The detector is designed such that an optical fault is generated

when half of the detection range remains. This is indicated by the fault output and is evident by the

yellow color of the LED on the face of the detector. The optical fault condition indicates that the

detector requires cleaning or service. The optical fault indication is self-clearing.

In enclosed areas, if dense smoke is expected to accumulate at the onset of the fire, the detector

should be mounted 3 to 6 ft (1 to 2 m) below the ceiling level.

The detector's response to a fire is a function of the fuel source and how it is released, fire size and

distance, orientation to the detector and local ambient conditions. The typical figures are based on

in-house tests except when marked with the FM logo, these tests were conducted and certified by

Factory Mutual. As with all tests the results must be interpreted according to the individual

application considering all possible variables.

The detector sensitivity to different fuel sources is dependent on the radiant heat output of the flame

and the detectors typical response is shown below (see table 4). The detector will only detect

hydrocarbon fires.

The Detector can be factory configured with an Aux alarm delay (20mA) of between 0 and 10

seconds in 1 second steps over and above the normal response times of the 18mA alarm signal. If

the Aux alarm signal is delayed the 18mA alarm signal will precede the 20mA signal giving the

normal response times as tested by Factory Mutual to FM3260. The 20mA alarm signal if delayed is

considered an Aux alarm level.

VSF303 Flame Detector

Safety and Technical Manual

Form No. F_020521

Rev: 2

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