Hochiki IFD-E User Manual

Page 4

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Hochiki Europe (UK) Ltd


In fact, the flame detector will detect fires at distances of up to 40 metres, but the flame size at such
distances needs to be proportionally greater in order to be sure of reliable detection. Thus the yellow
flickering flame that can be detected at 25m, provided that its size is not less than 0.1m², will have to be
0.4m² in order to be detected at 40metres.

In a rectangular room the distance from the flame detector to the fire is calculated by the formula:

In the example shown in Fig 1 the room in which the flame detector is to be installed measures 20m x
10m x 5m; the maximum distance from the detector to the flame will therefore be:

Fig 1

Calculation of distance from detector to flame

Field of View

The flame detector has a field of view of
approximately 90°, as shown in the diagram

Fig 2

Conical field of view of the flame detector