Section 4 Emergency Shutdown for Electrical Equipment

401. Emergency conditions due to drilling operations

1. In view of exceptional conditions in which the explosion hazard or fire may extend outside the hazardous areas, special arrangements are to be provided to facilitate the selective disconnection of shutdown of :

(1) ventilation systems, except fans necessary for supplying combustion air to prime movers for the production of electrical power;

(2) main electrical generators and prime movers, including the ventilation systems for these;

(3) emergency generators;

(4) emergency equipment except those items listed in 402.; and

(5) all electrical equipment outside Zone 1 areas, except where of a certified safe type for Zone 1

applications.

2. In the case of units using dynamic positioning systems as a sole means of position keeping, special consideration may be given to the selective disconnection or shutdown of machinery and equipment associated with maintaining the operability of the dynamic positioning system in order to preserve

the integrity of the well.

3. Disconnection or shutdown should be possible from at least two strategic locations, one of which is to be outside hazardous areas.

4. Shutdown systems that are provided to comply with Par 1 are to be so designed that the risk of unintentional stoppages caused by malfunction in a shutdown system and the risk of inadvertent op-

eration of a shutdown are minimized.

5. A recommended sequence of shutdowns specified in above Subparagraph (1) is to be included in the Operating Booklet stipulated in Ch 1, 105.

402. Equipment to remain operational after emergency shutdown.

1. Equipment which is located in spaces complete shutdown as given in above

other than enclosed spaces and arranged to be operated after

401. 1 is to be suitable for installation in Zone 2 locations.

Such equipment which is located in enclosed spaces is to be suitable for its intended application to

the satisfaction of the Society.

2. At least the following facilities are to be operable after an emergency shutdown.

(1) Emergency lighting required by Ch 6, 202. 6 (1) to (7) for half an hour ;

(2) Blow-out preventer control system ;

(3) General alarm system ;

(4) Public address system ; and

(5) Battery supplied radio communication installations.