Hochiki IFD-E User Manual
IFD-E Flame Detector
User Manual
2 Hochiki Europe (UK) Ltd
General
Description
The flame detector is designed for use where open flaming fires may be expected. It responds to the light
emitted from flames during combustion. The detector discriminates between flames and other light
sources by responding only to particular optical wavelengths and flame flicker frequencies. This enables
the detector to avoided false alarms due to such factors as flicking sunlight.
Electrical Considerations
The flame detector can be connected in many different electrical configurations depending on the
application. The detector requires a 24Vdc (14Vmin. to 30Vmax.) supply to operate. The detector can be
connected as a two-wire loop powered device increasing its supply current to signal that a flame has
been detected. See Fig 8. The supply connections to the detector are polarity sensitive.
Also available are volt free contacts from two internal relays RL1 (Fire) and RL2 (Fault or pre-alarm).
Using the relay contacts connected in a four-wire configuration the detector status can be signalled back
to control equipment. See Fig 9.
Removing the detector front cover provides accesses the detector terminals and configuration DIL switch.
See Fig.4.
Alarm Response Modes
The detector is normally configured to latch into an alarm state when a flame is detected. The supply to
the detector has to be broken in order to reset the detector.
The configuration DIL switch within the detector can be set to place the detector into a non-latching mode.
The detector can then also produce proportional analogue current alarm signals, in other words, 8-28mA
or 4-20mA. In non-latching mode the detector only produces an alarm signal when a flame is in view
resetting itself to normal when the flame has gone.
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Application for Flame Detectors
Flame detectors are used when detection is required to be:
Unaffected by convection currents, draughts or wind
Tolerant of fumes, vapours, dust and mist
Responsive to a flame more than 25m away
Fast reacting
The detector is capable of detecting the optical radiation emitted by burning material even noncarbonaceous materials. e.g. Hydrogen
Numerous other potential fire sources can be detected such as:
Liquids Solids Gases
● Aviation Fuels (kerosene) ● Coal ● Butane
● Ethanol ● Cotton ● Fluorine
● Methylated Spirits ● Grain & Feeds ● Hydrogen
● n-Heptane ● Paper ● Natural Gas
● Paraffin ● Refuse ● Off Gas
● Petrol (gasoline) ● Wood ● Propane
Typical applications examples are:
● Agriculture ● Coal handling plant ● Pharmaceutical
● Aircraft hangars ● Engine rooms ● Power plants
● Atria ● Generator rooms ● Textiles
● Automotive industry ● Metal fabrication ● Transformer stations
- spray booths ● Paper manufacture ● Waste handling
- parts manufacture ● Petrochemical ● Woodworking
Applications and Locations to Avoid:
● ambient temperatures above 55°C ● large IR sources – heaters, burners, flares
● close proximity to RF sources ● obstructions to field of view
● exposure to severe rain and ice ● sunlight falling directly on the detector optics
● large amounts of flickering reflections
● spot lighting directly on the detector optics
Quantities Required and Positioning of Detectors
The number of detectors required and their position depends on:
the anticipated size of the flame
the distance of the flame from the detector
the angle of view of the flame detector
The flame detector is designed to have a class 1 performance as defined in BS EN54-10:2002 on the
high sensitivity setting. That is the ability to detect an n-heptane (yellow) fire of 0.1m² or methylated spirit
(clear) fire of 0.25m² at a distance of up to 25m within 30 seconds.
The detector can be set to have to a lower sensitivity setting equivalent to class 3 performance. Class 3
performance is defined as detecting the same size fires as for class 1 but at a distance of only 12m.
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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
below.
Fig 2 Conical field of view of the flame detector
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Fig 3 Detector Field of View Plot
The flame detector should be positioned at the perimeter of the room, pointing directly at the anticipated
flame or at the centre of the area to be protected. If the detector cannot ‘see’ the whole of the area to be
protected, one or more additional detectors may be required.
The flame detector is not affected by normal light sources but should be positioned so that sunlight does
not fall directly onto the viewing window.
Detector Window Contamination
It is important to keep the detector window clean and checks should be carried out at regular intervals –
determine locally according to the type and degree of contamination encountered – to ensure optimal
performance of the flame detector. Although the IR detectors can detect flames when the window is
contaminated, there may be a reduction of sensitivity as shown in Table 1.
Contamination Typical percentage of normal response
Water spray 75%
Steam 75%
Smoke 75%
Oil film 86%
Salt water film 86%
Dry salt deposits 86%
Table 1 IR Detector window contamination
UV/IR detectors are more susceptible to window contamination and must be kept clean
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