(52q) Barrier Management Using Bowtie Based Readiness Reviews for Critical Task Analysis

BowTie diagrams are shaped in the form of a bowtie to provide a simple, visual explanation of a risk that would be much more difficult to explain. BowTie diagrams can be compared to the Swiss cheese accident causation model that was proposed by Dante Orlandella and James T. Reason. The main hypothesis of this model was that hazards can be prevented from materializing into losses (consequences) by having barriers or multi layers of protection, like the multiple slices in a Swiss cheese.

BowTie based Risk Assessment is a lean, qualitative risk assessment process that provides the user with an overview of multiple potential scenarios for any hazard to recover from within a single picture. It is used to help qualify and quantify risk in various operational modes. BowTie diagrams helps to create a clear differentiation between proactive and reactive risk management. The proactive risk management is identified by the left side (threats and its prevention by proactive barriers) of the BowTie diagram and the reactive risk management is identified by the right side (consequences and preventing its escalation by recovery barriers) of the BowTie.

Work is considered critical work when there are higher levels of risk or complexity that require a significant level of preparation and control to ensure safe execution of the work. Examples of critical work are, but not limited to:

• Confined space entry
• Excavations
• Work on high voltage electrical equipment
• Crane lifts near capacity of the crane
• Work on oxygen equipment
• Hot taps and re-torquing flanges on live process lines and equipment, etc.

A critical task analysis (CTA) is a tool used to evaluate considerable risk tasks that have the potential to cause extensive harm. CTAs involve multidisciplinary teams working together using a structured process to identify barriers for preventing an event or undesired outcome, as well as mitigating actions should the event or undesired outcome occur. Since BowTies visually represents the causes, barriers, undesired primary event, mitigations, and undesired outcomes, it is the primary tool used for CTAs. Its main purpose is to ensure that all the activities associated with task execution (where hazards may be present or created) are executed safely using a standardized identification assessment, review, mitigation, and action tracking process.

For BowTie process, the use of BowTie XP program developed by CGE Risk Solutions can help facilitate visual representation of a critical task or activity. The software provides the capability to export the identified proactive or reactive barriers for validation using a readiness review process such as a Go/No-Go process. In its simplest form a Go/No-Go process validates all the proactive and reactive barriers by a simple Go or No-Go depending on whether the barrier is in place and is effective prior to embarking on the critical task. This visual representation of the barriers adds one more step at effective risk management during task execution. The GO/NO-GO process is thus meant to serve as a lean tool that encompasses both risk and readiness review requirements while validating barrier effectiveness through the latter.

This paper would like to show how a smart combination of all these three tools – Bowties, Critical Task Analysis and Readiness Reviews offers the best tool at visualizing an incident, developing, and validating the barriers that can prevent the incident by blending the best practices of both risk and readiness reviews. Examples of a successive use of this tool in plant operations will be discussed along with lessons learned.