Page 420 - Offshore Electrical Engineering Manual

P. 420

CHAPTER

Maintenance and 2

Logistics

RATIONALISATION OF SPARES
The weight and space limitations of an offshore installation impose restraints on
electrical equipment installed. The restraints on the stocking of consumable spares
and spare parts are even more severe, however, and this must be always kept in mind
at the detail design stage, particularly during the procurement of the smaller drive
packages such as small pumps and compressors, distribution boards and cable acces-
sories. Sometimes a spares rationalisation can be made by using the same model of
prime mover for main generators and gas lift or export compressors, or for standby
diesel generation and diesel fire pumps.
The benefits may be listed as follows:

1. Common spare parts for different equipment, hence fewer need be stocked and
weight of spares stored is reduced.
2. The reduced number of different types of equipment that operators have to deal
with should reduce familiarisation time and hence improve safety.
3. The total weight of equipment operation and maintenance manuals and design
drawings on the average offshore installation is in excess of 10 tons, even when
the majority is on microfiche; therefore, some weight and space saving can also
be accrued by reducing their total number.
4. The cost saving associated with items (1)–(3). The offshore spares inventory
must be optimised for items most critical to
a. safety

b. the comfort of personnel (which may also affect safety)
c. oil and gas production

Small light items may be flown out quickly when required, but it should be
remembered that if an unscheduled helicopter call out is required, it could cost
£2000/h or more depending on the size of the helicopter (in 2015).

ACCESSIBILITY AND COMMUNICATIONS

Those carrying out survey or commissioning work offshore should be warned that
return travel from most, if not all, offshore installations requires customs clearance.
This means that any test and measuring equipment needs proof-of-ownership docu-
mentation or a manifest for customs clearance.

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