Oil and gas production handbook An introduction to oil ... - ABB Group

PSD and can be handled with less strict requirements.
These actions are handled by the emergency shut down system (ESD) and
process shut down system (PSD) according to functional safety
requirements and standards. Thus, a typical ESD function might require a
SIL 3 or even SIL 4 level, while PSD loops could be SIL 2 or SIL 3.
Smaller ESD systems, e.g., on wellhead platforms, can be hydraulic or
hardwired (non-programmable).
8.1.3 Fire and gas system
The fire and gas system is not generally
related to any particular process.
Instead, it divides into fire areas by
geographical location. Each fire area
should be designed to be self-contained,
in that it should detect fire and gas by
several types of sensors, and control fire
protection and firefighting devices to
contain and fight fire within the fire area.
In the event of fire, the area will be
partially shut off through closure of
ventilation fire dampers. A fire area
protection data sheet typically shows what detection exists for each fire area,
and which fire protection action should be taken in case of an incident.
The type and number of the detection, protection and fighting devices
depends on the type of equipment and size of the fire area and will vary for
different process areas, e.g., electrical rooms and accommodation rooms.
Fire detection:
• Gas detection: Combustible and toxic gas, electro-catalytic or
optical (IR) detector
• Flame detection: Ultraviolet (UV) or infra red (IR) optical detectors
• Fire detection: Heat and ionic smoke detectors
• Manual pushbuttons
Firefighting, protection:
• Gas-based firefighting, such as CO 2
• Foam-based firefighting
• Water-based firefighting: sprinklers, mist (water spray) and deluge
• Protection: Interface to emergency shutdown and HVAC fire dampers.
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