In high-hazard industries, major accident hazards are managed through identification and maintenance of Safety Critical Elements (SCEs) the systems that prevent or mitigate the effects of a major incident.
At Ifluids Engineering, we help operators in oil & gas, petrochemicals, and heavy industry clearly identify SCEs and develop robust performance standards to ensure ongoing integrity and compliance.
What is a Safety Critical Element?
A Safety Critical Element is any part of a facility (equipment, system, or structure) whose failure could lead to, or fail to prevent a major accident. These could include:
- Fire and gas detection systems
- Emergency shutdown valves (ESDVs)
- Pressure relief devices
- Blowdown systems
- Structural barriers or fireproofing
- Emergency response systems
Without proper management, even well-designed SCEs can degrade over time—introducing risk.
Why is SCE Identification Important?
The foundation of effective risk control is the proper identification of SCEs. It ensures:
- Focused inspection and maintenance efforts
- Regulatory compliance (e.g., HSE UK, API RP 75)
- Clear responsibilities in asset integrity programs
- Demonstrated commitment to ALARP (As Low As Reasonably Practicable) principles
What is Performance Standard?
A Performance Standard (PS) is a qualitative or quantitative statement of the functional performance required of an SCE. It is used as the basis for managing the risk from major hazards. Specifying and ensuring compliance with respective Performance Standards provide assurance that the SCE is in place and remain effective as a barrier to the identified MAH.
Expressed in terms of Functionality, Reliability, Availability, Survivability and Dependencies/ Interactions with other SCEs. Performance Standards are used as a basis for design and technical (operational) integrity verification.
Functionality – Define what the system is required to achieve in order to ensure design integrity.
Availability – Define the extent to which the system is required in order to retain its functional integrity.
Reliability – Define the required probability that the system or equipment will operate on demand, when required.
Survivability – Defines the external loading events such as fires, explosions or extreme weather, associated with the various MAHs against which the system is required to retain its functional integrity.
Safety Critical Elements & Risk Management
The role of Safety Critical Elements (SCEs) in system integrity is represented using a Swiss Cheese Model. Each slice of cheese represents the layer of defense in a facility and the holes represents potential weaknesses in the barrier. When these weaknesses line up, hazard can breach the defenses resulting in hazards. Strong performance standards ensure that these barriers are effective and prevent system failures.
Our Approach to Identifying Safety Critical Elements
The SCE identification process is based on Process Safety Management (PSM) systems, Hazard and Effects Management Systems (HEMS), and risk assessments and involves the following steps:
Step 1: Identification of Major Accident Events (MAEs) using hazard identification techniques like:
- Hazard Identification Studies (HAZID)
- Hazard and Operability Studies (HAZOP)
- Simultaneous Operation Studies (SIMOPS)
- Layer of Protection Analysis (LOPA)
- Safety Integrity Level (SIL) Determination
- Quantitative Risk Analysis (QRA)
Step 2: Identify Facility Systems and Elements by
- Reviewing the list of Major Accident Events (MAE) and identifying systems connected to each MAE.
- Assessing the criticality and categorizing the system.
Step 3: Categorization of Safety Critical Elements to Integrity-based SCEs or Control and Mitigation SCEs
Developing Performance Standards for SCEs:
Safety Critical Element Performance Standards are developed using FARSI model. It represents the key elements:
BowTie Model for SCE Identification
BowTie Analysis is often used to identify SCE by visually linking the cause of accidents, preventative barriers, and mitigation measures.
Key Steps include:
- A multidisciplinary team assessing the facility and related documents.
- Identify SCEs that prevent or mitigate accident events.
- Categorizing safety and environmental critical elements (SECEs).
- Providing justification for not considered certain elements safety-critical.
Conclusion
Effective management of Safety Critical Elements (SCEs) is a cornerstone of safe, reliable, and responsible operations in high-hazard industries. At Ifluids Engineering, we help clients move beyond generic checklists by offering a systematic, practical, and regulator-aligned approach to identifying SCEs and defining performance standards. Our goal is to ensure that every critical barrier performs when it’s needed most.
Whether you’re preparing a Safety Case, undergoing a third-party audit, or seeking to improve risk visibility across your asset, we’re here to support you with clear documentation, proven methodologies, and deep technical expertise. Let’s work together to strengthen your defenses and safeguard your people, assets, and reputation.