MAH Critical Tasks (MCTs)

Introduction

Major Accident Hazard (MAH) Critical Tasks (MCTs) are essential activities designed to prevent or mitigate the consequences of MAHs. These tasks ensure the functionality and integrity of MAH-critical elements when required, maintaining overall safety.

Objective of MAH Critical Tasks (MCTs)

The primary objectives of MCTs are to

• Identify all tasks essential for preventing major accidents or minimizing their impact.
• Conduct gap analysis aligned with international safety standards to ensure task compliance.
• Validate recommendations through workshops focusing on ALARP (As Low As Reasonably Practicable) principles and Cost-Benefit Analysis (CBA).
• Utilize a structured methodology to comprehensively document and manage MAH Critical Tasks.

Data Collection and Analysis

Comprehensive data collection is vital for identifying MCTs. Key sources include:

• Plant operating manuals, HAZOP reports, SIL reports (LOPA), and critical procedures.
• Interactive observations, document reviews, and personnel interviews.
• Bow Tie Diagrams to visualize and manage MAH scenarios.
• Workshop outcomes that provide validated MCT lists.

Definition of MCTs

A task qualifies as an MCT if its failure could directly cause or escalate a MAH. These tasks are often associated with:

• Human interventions critical to operational safety.
• Actions necessary for maintaining MAH-critical elements.

MCT Assessment Process

The assessment involves:

• Evaluating tasks to determine required competencies and skill sets.
• Conducting site surveys to support gap analysis.
• Documenting competency criteria in Performance Standards.

Human Factors Assessment (HFA)

HFA ensures personnel can execute MCTs effectively under expected conditions. Key factors include:

• Challenges related to human performance (e.g., multitasking, fatigue).
• Adequacy of human-equipment interfaces.
• Clarity of task definitions and procedural support.
• Decision-making under stress.
• Feasibility of escape or evacuation during task execution.

Performance indicator checklists guide the HFA process through observations and interviews. Findings are documented in the MCT report.

Verification and Training

• Clearly defined and suitable for emergency scenarios.
• Supported by robust competency frameworks.

Training programs educate personnel on the importance of MCTs and the identification process.

MCT Register

A dedicated MCT register for each facility includes:

• Personnel competencies and experience records.
• Performance Standards documentation.
• Verification and competence assurance frameworks.
• Audit reports and workshop outcomes.

ALARP Demonstration

Risk reduction measures follow a hierarchy:

1. Eliminate hazards.
2. Substitute with less hazardous alternatives.
3. Isolate or segregate hazards.
4. Engineer prevention and mitigation measures.
5. Implement organizational controls.
6. Use personal protective equipment (PPE).

Cost-Benefit Analysis (CBA)

CBA evaluates recommendations unless:

• Basic engineering studies are necessary.
• Alarm and control logic modifications are minor.
• Updates to SOPs and minor provisions are suggested.

MCT Identification Workshop

Workshops engage stakeholders and independent facilitators to validate MCTs. Outcomes include:

• Detailed MCT lists for each facility.
• Results of gap analysis.
• Defined competency requirements.
• Human Factors Assessment findings.
• Clear links between MAHs, MCTs, and task definitions.

Documentation and Action Tracking

• Traceability of MCT assessments and updates.
• Periodic reviews and updates to recommendations.

Key documentation includes:

• MCT classification and ranking.
• Mapping of recommendations to CCPS PSM elements.
• ALARP and CBA study results.
• Workshop minutes and signed agreements.