مهندس بترadopt the approach of providing simple, minimum facilities design and simplify process design;
minimise flammable and toxic inventories and the number of leak sources;
select more reliable equipment instead of using sparing
isolate spare or redundant equipment when not in use;
use high quality and reliable materials and equipment to minimise maintenance;
use one reliable instrument/equipment item instead of several less reliable ones;
pay particular attention to avoiding use of maintenance intensive equipment;
adopt a risk and reliability based maintenance strategy;
minimise maintenance visits in hazardous areas separating non-hazardous/hazardous equipment;
optimise equipment layouts with maximum use of natural ventilation;
segregate personnel from major hazards;
consider flow of personnel to and from worksite in relation to the major hazards;
replace hazardous materials and chemicals with less hazardous ones;
minimise the use of protective safety systems requiring high maintenance;
minimise number of ignition sources, such as fired heaters and hot surfaces.Platform Layout designed to minimize n° of people potentially involved in the running of the plant (POB = 10 operators), prevent escalation and allow escape and evacuation if necessary.
Main objectives of WELL-DESIGNED LAYOUT are:
minimizing possibility of hazardous accumulations of both liquids and gaseous hydrocarbon and providing for rapid removal of any accumulation which could occur;
minimizing ignition probability;
minimizing spread of flammable liquids/gases which may results in a hazardous event;
minimizing consequence of fire and explosions;
providing for adequate arrangement for escape and evacuation;
facilitating effective emergency response.
Dedicated areas for the installation of drainages and spill control systems have been foreseen to minimize accident likelihood and potential escalation.
Process piping, equipment, risers and conductors are routed so as to minimize the likelihood of external impacts.
For gas systems, vents and relief valves have been routed to safe location avoiding the vented volumes to be able to create a hazardous condition.
HIPPS has been provided d/s Gas Manifold to protect Separator against overpressure.
Closed/Open Drain Systems are required to:
allow quick and safe removing of liquid hydrocarbons in emergency situations;
collect direct spills to a safe location where they can be retained/recovered;
safe disposal of hydrocarbon during drain down of process vessels and equipment.
Suitable access to all areas has been provided for maintenance and emergency.
Primary method of evacuation (in case of emergency) → normal way to getting on the Platform by vessel transportation.
Secondary method of evacuation → allow a fully controlled escape to the sea by means of life-rafts (located at different decks, in strategic positions).
The general principles in the provision of Tertiary methods for escape to the sea are:
they should take into account the likely scenarios;
escape should be possible from several locations on the installation;
life-raft should be provided to protect personnel who enter the sea;
systems designed such that personnel who enter the sea can use any available lift-raft;
effective training and procedures should be provided for use of tertiary methods.
Escape routes: always unobstructed, readily accessible, well-illuminated and well-marked
Riser ESD Valves located in easily accessible, open, well-ventilated areas to avoid damage from wave impact and accidental events (e.g. fire, explosion and mechanical impact).
Safety Systems and Controls located such that they can remain operational during defined accidental events. Controls for Safety Systems located where they are accessible and available for safe, simultaneous use during an emergency.
The Emergency, UPS Systems and associated controls, etc., have been located such that they are not vulnerable to events that affect Main Power supply.
RISERS, SAFETY SYSTEMS AND ESD VALVES LOCATION INTRODUCTION
HSE DESIGN CRITERIA
PLATFORM ORIENTATION AND LAYOUT
VENT SYSTEM
SAFETY SYSTEM DESIGN
FIRE PROTECTION PHILOSOPHY
LIFESAVING EQUIPMENT AND APPLIANCES
Vent System, designed for the worst credible blow-down scenario, is designed to collect and disperse the continuous or emergency gas discharges in the Atm by means of 2 Cold Vents.
The following criteria to be considered during the design:
Provide two levels of protection.
Block valves cannot be used as regulation valves.
Provide PSVs, blow-down system and Vent system on each part of Platform, where personnel can be present, in case of accidental ignition.
Relieving systems shall meet API RP 521 requirements.
Fire detection devices to be installed on Platform equipment for automatic ESD.
Maintenance activities on process equipment will be protected by ensuring positive isolation from the process.
Provision of Emergency Generator to supply the essen