Page 190 - Offshore Electrical Engineering Manual

CHAPTER

Telecommunications – 17

Internal and External

INTERNAL COMMUNICATIONS

The communications system installed on an offshore installation provides the nec-
essary facilities to operate the installation safely in normal conditions and also to
provide communication facilities to control an emergency by:

1. Enabling messages and alarms to be broadcast throughout the installation.
Note that there will be the need for secure communications between the control
rooms, lifeboat and helideck muster stations and any secondary (fall-back)
locations where communications have been provided for emergency situa-
tions when the main control point (process control room, bridge, etc.) has been
compromised.
2. Communicating with the neighbouring installations (if any).
3. Communicating with vessels carrying out installation-related activities, and the
standby vessel.
4. Portable communications for platform personnel.
5. Emergency communication for key personnel (e.g., OIM) to shore incident
rooms.

A typical package would consist of the following:
An emergency intercom system designed for use in hazardous areas. The system
should be installed in a ring, to provide communication between control points and
muster areas even if any one of the cables interconnecting the stations is severed, or
the platform ac power supply is not available. The system would normally provide:

• Two channel communications (one channel each for control points and mus-
ter points) with the option of ‘All Call’ simultaneous transmission on both
channels.
• For reliability, full battery backup should be provided for each outstation, with
outstation health and audio line continuity monitoring.

A UHF (FM) radio repeater system installed to enhance full duplex radio com-
munications between personnel using hand portables. In the event of failure, the hand
portables are normally equipped with simplex channels to allow communications,
hand portable to hand portable, directly between personnel on the facility.
A radio paging system with facility for sending verbal messages that may be
accessed from the installation telephone system(s), enabling key personnel to be
paged.

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