Apollo 55000-024 Installation & Maintenance Manual - Page 3

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Apollo 55000-024 Installation & Maintenance Manual

Sensitivity setting

A sensitivity switch is used to set the sensitivity of the IR

For most practical purposes the switch should be set to Class 1 (default setting), the sensitiv-

ity required to detect flames as described in the section 'Quantities required and position-

ing of detectors'.

In exceptional cases the IR

Flame Detector may be set to Class 3 operation in order to

avoid nuisance alarms being caused by radiation sources that are close to the detector

and can not be moved.

The rotary sensitivity switch is located on the detector rear behind the label. To set to Class

3, rotate the switch 90° clockwise. To return the sensitivity switch to the Class 1 setting,

rotate the switch 90° counter clockwise. Reseal label or seal hole with suitable sealant if the

sensitivity has been changed.

Installation

The IR

Flame Detector is mounted on any XP95 or Discovery base and would normally be

wall or ceiling mounted preferably on an adjustable bracket to adjust the angle of view.

The standard base mounting is used for horizontal viewing, e.g., along corridors or along

the length of industrial processes or vertical viewing inside fume cupboards or over

hoppers.

Flame detectors should be fitted to solid walls or rigid constructions that do not move and

are not subject to vibration.

The IR

Flame Detector must be assigned an address by addressing the XPERT card in the

usual way. A list of address settings is shown in Table 2.

Wiring

The flame detector has five connections: – Line 1, + Line 2, +Remote, –Remote and func-

tional earth/screen. The connections are accessed by removing the detector from it's

base. See Fig 4 for connection diagram.

From control panel

Fig 4 IR

Flame Detector base connections

Terminal Descriptions

+L2

+Line IN and OUT

–L1

–Line IN and OUT

+Remote LED

–R

–Remote LED

EARTH

Functional Earth/Screen (Isolated)

Flame Detector to Class 1 or Class 3.

R+

R–

To next device

EARTH

Quantities required and positioning of detectors

The number of detectors required and their positioning depends on:

•

the anticipated size of the flame

•

the distance of the flame from the detector and

•

the angle of view of the flame detector

The IR

Flame Detector is designed to operate to Class 1 performance as defined in EN54:

Part 10. The detector will, therefore, detect a yellow flickering flame of approximately 0.1m²

or a clear flame of 0.25m² at 25m.

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 40 metres. In

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

formula:

L² + W² + H²

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 distance from the detector to the flame will therefore be:

20² + 10² + 5²

= 22.9m

Height

Width

Length

Fig 1 Calculation of distance from detector to flame

The IR

Flame Detector is often positioned at the perimeter of the room, pointing directly at

the area of the anticipated flame or at the centre of the area to be protected. If the detec-

tor cannot 'see' the whole of the area to be protected, one or more additional detectors

may be required.

The IR

Flame Detector is not affected by normal light sources but should be positioned so

that sunlight does not fall directly onto the viewing window.