33
3
What Makes a Task
Safety Critical?
A Barrier-Based and
Easy-to-Use Roadmap for
Determining Task Criticality
S. Øie
DNV
INTRODUCTION
Several approaches to risk and barrier management integrate the contribution of
human performance and factors by addressing safety critical tasks. As demonstrated
by investigations of accidents, such as the Macondo well blowout, human interaction
with modern safety critical systems can be highly complex. Consequently, risk management practitioners are commonly faced with the challenge of pinpointing which
tasks should be devoted the most attention and resources. As such it is often necessary to determine the level of task criticality to decide on the need for more i n-depth
analysis and follow-up by use of improvements in design, procedures and training.
When dealing with a large number of tasks, this process needs to be efficient enough
to not be overly time consuming and costly. At the same time, it needs to be accurate
enough so that critical tasks are not incorrectly categorized ( and prioritized). This
chapter discusses what characteristics defines a task as safety critical and suggests
CONTENTS
Introduction
33
..............................................................................................................
Background
34
..............................................................................................................
Management of Operational Barrier Elements
35
........................................................
A Process for Mapping and Assessment of Operational Barrier Elements
37
.............
Guidance ( Missing) on How to Identify Operational Barrier Elements
38
..................
What Makes a Task Safety Critical?
41
........................................................................
Roadmap for Determining Operational Barrier Element Criticality
46
........................
What about Latent Failures ( Type A Actions)?
48
........................................................
Conclusive Summary
50
...............................................................................................
References
50
................................................................................................................
3
What Makes a Task
Safety Critical?
A Barrier-Based and
Easy-to-Use Roadmap for
Determining Task Criticality
S. Øie
DNV
INTRODUCTION
Several approaches to risk and barrier management integrate the contribution of
human performance and factors by addressing safety critical tasks. As demonstrated
by investigations of accidents, such as the Macondo well blowout, human interaction
with modern safety critical systems can be highly complex. Consequently, risk management practitioners are commonly faced with the challenge of pinpointing which
tasks should be devoted the most attention and resources. As such it is often necessary to determine the level of task criticality to decide on the need for more i n-depth
analysis and follow-up by use of improvements in design, procedures and training.
When dealing with a large number of tasks, this process needs to be efficient enough
to not be overly time consuming and costly. At the same time, it needs to be accurate
enough so that critical tasks are not incorrectly categorized ( and prioritized). This
chapter discusses what characteristics defines a task as safety critical and suggests
CONTENTS
Introduction
33
..............................................................................................................
Background
34
..............................................................................................................
Management of Operational Barrier Elements
35
........................................................
A Process for Mapping and Assessment of Operational Barrier Elements
37
.............
Guidance ( Missing) on How to Identify Operational Barrier Elements
38
..................
What Makes a Task Safety Critical?
41
........................................................................
Roadmap for Determining Operational Barrier Element Criticality
46
........................
What about Latent Failures ( Type A Actions)?
48
........................................................
Conclusive Summary
50
...............................................................................................
References
50
................................................................................................................