Page 476 - Handbook of Electrical Engineering

MISCELLANEOUS SUBJECTS 465

18.2.2.4 Operation and control of lighting systems

Navigation lighting systems can be fitted with a device to automatically switch on 15 minutes before
sunset until sunrise or whenever the visibility is less than 2 sea miles. There can also be a manual
override device to enable the navigation aids to be switched on during unusual conditions or for
maintenance and testing etc.
Failure of any of the navigation lights can be indicated in the central control room and in the
radio room.

In the event of failure of the main white lights control equipment, control should automatically
be transferred to the secondary system, which would cause the secondary and the main lights to flash
in synchronism, and generate an alarm in the central control room and the radio room.
All subsidiary lights should operate in synchronism.
The secondary and subsidiary lights can be equipped with an automatic lamp changer or
multiple filament bulb. This provides a minimum of one standby lamp or filament which will be
automatically activated in the event of a filament failure. Filament failure should produce an alarm
in the central control room and the radio room until a defective bulb is replaced.

On long narrow structures or structures linked by bridges where lights may otherwise be
several hundred metres apart, intermediary 3 mile red lights should be mounted in positions to deter
vessel from colliding with the central sections of the structure of bridges.
The secondary and subsidiary lights should be capable of operating for 96 hours from a battery
power source which is independent of the main supply. The equipment would normally operate on
the main AC supply, with automatic switching to an alternative AC supply in the event of main
supply failure, and automatic switching to battery supplies when no AC supply is available.

18.2.3 Navigation Buoys

Navigation marker buoys can be wave or solar powered or alternatively fitted with batteries. They
would be retained in a position to facilitate quick manual launching, and provision should be made
for ready inspection and maintenance of batteries.

18.2.4 Identification Panels

The structure identification panels usually consist of black letter and figures one metre high on a
yellow background with illumination or be on a retro-reflective background.

18.2.5 Aircraft Hazard Lighting

Hazard lighting should be provided on all projections from the structure which could present a danger
to helicopters approaching the platform. Positions where it would be impractical to fit red lights due
to the possibility of damage or difficulty of maintenance caused by high temperature, such as flare
towers and exhaust stacks, would be flood lit from convenient locations.