2 FIRE AND GAS DETECTION SYSTEM: CHARACTERISTICS
As described in the following paragraphs, detectors have been primarily selected on the basis of the phenomenon characteristics to afford the most certain and quick detection.
2.1 FIRE DETECTION
Fire Detectors are approved and suitable for the fire types expected within each Platform area. Detectors are weather resistant or provided with weather protection, unless placed in environmental controlled areas. Detectors incorporate extensive self-diagnostics and alarm in the event of a detector fault condition.
In enclosed space the following detectors have been installed:
• Heat (rate of rise).
• Flames.
• Smoke or Combustion Gas.
In open areas or in case of enclosures with strong ventilation, the following detectors have been installed:
• Flames.
• Heat (fusible plugs network dedicated to wellheads and linear heat detector cables for equipment handling flammable materials installed in open area).
Power supplies and electric circuit necessary for the operation of the System are monitored for loss of power and fault conditions as appropriate. Occurrence of a fault condition initiates a visual and audible fault signal (distinct from a fire signal) at the operator workstation of ICSS at NA/Q-PIII and at NA/Q-PI Control Room.
There are not less than two sources of power supply for the electrical equipment used in the operation of the fire detection and fire alarm System, one of which is an emergency source. The supply is provided by separate feeders reserved for that purpose.
Such feeders runs to an automatic change-over switch situated in, or adjacent to, the control panel for the Fire Detection System.
The table below, form DNV-OS-D301, provides a guideline for the selection of Fire Detectors for some typical areas: