Safety Critical Element & Design Performance Standards Awareness

Definition

Safety Critical Element (SCE) is part of an installation and such of its structure, plant equipment and systems (including computer program) or any part thereof the failure of which could cause or contribute substantially to the release of a hazard with Major Risks. or A purpose of which is to provide the barrier to prevent or limit the effect of a major accident. In short it is a physical equipment that prevent, control, and limit the major accident. SCE as known as hard barrier.

Categories

There are 8 categories of hard barriers or SCE Group

• Structural Integrity
• Process Containment
• Ignition Control
• Detection System
• Protection System
• Shutdown System
• Emergency Response
• Life Saving

Each barrier will consist of one or more SCEs, for example like this list below.

1. Structural Integrity

• Structure (Jacket/ Vessel Hull/ Foundation/ Piles, etc.)
• Topsides Structure (Helideck, Crane Pedestal, Bridges, Flare Tower, etc.)
• Heavy Lift Cranes and Mechanical Handling
• Stability Systems (Ballast, Bilge, Cargo, etc.)
• Vehicles and Mobile Plant
• Mooring System/ Station Keeping/ Dynamic Positioning System
• Drilling Systems
• Concrete and Onshore Structure
• Well Structure

2. Process Containment

• Pressure Vessels
• Heat Exchanger
• Rotating Equipment
• Tanks
• Piping Systems
• Onshore/ Offshore Pipelines
• Relief System (PRV, SPV, PVV, etc.)
• Well Hydrocarbon Containment
• Fired Heaters
• Gas Tight Floors/ Walls
• Tanker Loading Systems
• Helicopter Refuel Equipment
• Well Control Equipment
• Moveable and Temporary Equipment

3. Ignition Control

• Hazardous Area Ventilation
• Non-hazardous Area Ventilation
• Certified Electrical Equipment (Ex rated)
• Cargo Tanks Inert Gas System
• Electrical Earthing Continuity and Earth Bonding
• Fuel Gas Purge System
• Inert Gas
• Miscellaneous Ignition Control Components
• Flare Tips Ignition System/ Air Emission Monitoring

4. Detection System

• Fire and Gas Detection
• Security Systems
• Water in Condensate or Moisture in Gas

5. Protection System

• Deluge Systems
• Explosion Protection
• Helideck Firefighting System
• Fire Water Pumps
• Fire Main and Other Distribution System
• Passive Fire Protection (Doors, Walls and Penetrations)
• Gaseous Fire Suppression Systems
• Fine Water Spray Systems
• Sprinkler System
• Power Management System
• Fixed Foam Systems
• Sand Filtration/ Removal System
• Chemical Injection Systems
• Collision Avoidance Systems
• Met. Ocean Gathering Data Systems

6. Shutdown System

• Emergency Shutdown (ESD) Control System
• Emergency De-pressurisation (Blowdown)
• High Integrity Pressure Protection System (HIPPS)
• Well Isolation
• Pipeline Isolation Valve (Riser)
• Emergency Shutdown Valve (ESDV)
• Subsea Isolation Valves (SSIV) System
• Drilling Well Control Equipment
• Instrument Air

7. Emergency Response

• Temporary Refuge/ Primary Muster Area
• Escape Routes
• Emergency/ Escape Lighting
• Internal, External, and Emergency Communication
• Uninterruptable Power System (UPS)
• Helicopter Facilities
• Emergency Power
• Manual Fire Fighting Equipment
• Process Control and Alarms
• Bundling and Drains (Hazardous and Non-hazardous)
• Oil Spill Contingency/ Wastewater Management

8. Life Saving

• Personal Surviving Equipment
• Rescue Facilities
• TEMPSC/ Lifeboats
• Alternate Means of Escape (Life Rafts or Scramble Nets, etc.)

Each SCE group has a Design Performance Standard (DPS) to define minimum requirements to ensure SCE effectiveness in managing Major Accident. Purposes of DPS are:

-?????????Design and construct it right

-?????????Integrity assurance

-?????????Avoid SCE design flaws*

*Holes in swiss cheese mode are indicate design flaws in SCE.

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Design Performance Standard (DPS)

Below is 5W1H of DPS.

1.??????Why do we need DPS?

To design and construct it right.

2.??????What is in DPS?

It contains the FARSI model. They are:

• Functionability: Purpose of SCE is to be able to prevent, detect, or mitigate a hazardous event or people.
• Availability: proportion of time that SCE will be required to perform on demand.
• Reliability: how likely the SCE is to perform on demand or probability that SCE will function when required without failure.
• Survivability: how well the SCE will survive during or after major accident, like fire, explosion, etc.
• Interaction: the SCE in question dependent upon other SCEs to operate otherwise interacts with other SCEs.

3.??????When do we develop DPS?

During FEL 3 and updated in detailed design phase. FEL 3 is the 3rd stage of Front-End Engineering Design (FEED).

4.??????Who involved in DPS?

Project team, like project manager, engineers, etc.

5.??????How do we develop DPS?

By completing the DPS as per SCE DPS procedure from each company.

DPS Form Template

Form Template for creating DPS has 3 main sections, they are:

• Header section: SCE Group and SCE Goal
• Body section: Performance Criteria, FARSI Model, and Assurance
• Document sign off

Each company usually has its own DPS form template. DPS shall be approved by Project Manager and endorsed by respective Project Technical Discipline Authority (P-TA) for each SCE group.