(IV-7-3) General Safety
(IV-7-3) General Safety
(IV-7-3) General Safety
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Rules <strong>IV</strong> Industrial Services<br />
Part 7 Offshore Technology<br />
Chapter 3 <strong>General</strong> <strong>Safety</strong><br />
Section 9<br />
Fire and Gas Detection Alarm Systems<br />
C.4 For areas provided with automatic pressure water spray systems, separate alarm loops per<br />
section are to be allocated.<br />
C.5 <strong>General</strong>ly the number of the detectors shall not exceed 20 per alarm loop. The number of detectors<br />
grouped in each loop within a machinery space should not exceed 10.<br />
C.6 Manually actuated alarms, i.e. Manual Alarm Call points (MAC), may be incorporated in a loop<br />
together with automatic alarms.<br />
C.7 The arrangement and number of fire detectors have to be such that all areas with an increased<br />
fire risk are covered. This applies in particular to Transformer and Reactor rooms/areas, Medium<br />
and High Voltage Switchgear Rooms, Machinery spaces (e.g. Generator enclosures/rooms and control<br />
and working spaces).<br />
C.8 Detectors should not be mounted close to ventilation outlets or in positions where the flow of<br />
air may affect their operation, or where they are liable to suffer mechanical damage.<br />
C.9 Ceiling-mounted detectors shall normally be located at least 0.5 m from walls.<br />
C.10 The maximum distance between detectors (and the maximum area monitored) shall not exceed<br />
the following figures:<br />
• for heat detectors: 9 m (37 m 2 )<br />
• for smoke detectors: 11 m (74 m 2 )<br />
The distance from walls shall not exceed<br />
• for heat detectors: 4.5 m<br />
• for smoke detectors: 5.5 m<br />
C.11 The installation of a type tested aspirating smoke detection (ASD) system can be approved by<br />
GL. The arrangement and setup of an ASD system shall be such that a detected fire can be clearly assigned<br />
to a fire zone.<br />
Concerning the arrangement and dimensioning of the sampling pipes of the ASD system the manufacturer<br />
requirements shall be strictly followed.<br />
D<br />
Public Address and <strong>General</strong> Alarm System<br />
D.1 Public address system<br />
D.1.1 In addition to the general emergency alarm a public address (PA) system is generally required<br />
on all normally or temporarily manned Offshore Substations. The PA system shall be operable from strategically<br />
important locations and from the central control station. It shall be audible throughout the accommodation<br />
area, at the crew’s normal working places and at the strategically important locations.<br />
D.1.2 If the public address system is used to transmit the general emergency alarm (PA/GA system),<br />
the following requirements shall be fulfilled:<br />
• The requirements for the general emergency alarm shall be satisfied.<br />
• At least two amplifiers are to be provided, each of them separately supplied and fused.<br />
• At least two loudspeaker circuits, supplied from separate amplifiers, are to be installed in each fire<br />
zone, respectively in its subdivisions.<br />
• The loudspeaker circuits are to be so arranged that transmission at a reduced loudness is maintained<br />
in the event of a failure of an amplifier or loudspeaker circuit.<br />
• Where loudspeakers with built-in volume controls are used, the volume controls must be disabled by<br />
the release of the alarm signal.<br />
Edition 2013 Germanischer Lloyd Page 9–3