Bowties - a risk communication tool_tcm4-590258.pdf

Bowtiesa risk communication toolDNV Healthcare Risk Forum

30th October 2013

Det Norske Veritas AS. All rights reserved.

What we will cover today- Introduction (risk recap using a Bowtie)- The uses of Bowties- Useful rules/guidance to follow to develop quality Bowtie diagrams- Workshop

Introduction (risk recap using a Bowtie)

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How do accidents happen?

Causes

Consequences

Barrier 1 Barrier 2 Barrier 3

Harm /Loss


RISK ACTIONS: Actions to better manager your risks. They can include adding barriers, strengthening barriers and assurance / verification of barriers.HAZARD: Condition or practice with the potential to cause harm to people, the environment, reputation, assets or business impact. EVENT: The release or loss of control of the hazard being modeled in a Bowtie. Note: Events are sometimes referred to as risk events or top events.CAUSE: Event, situation, or condition that results, or could result, directly or indirectly in an accident or incident. Note: Causes are sometimes referred to as threats.

CONSEQUENCE: Direct, undesirable result of an accident sequence usually involving a loss or damage, e.g. financial, production, customer loss and/or damage to brand, assets, people, the environment, etc.

BARRIER: Barriers are physical risk reduction measures (devices, systems, or actions).PREVENTIVE BARRIER: Barriers to the left of the event (before it has happened). They reduce the likelihood of the event. Preventive barriers are sometimes referred to as controls.

MITIGATION BARRIER: Barriers to the right of the event (after it has happened). They reduce the severity of the consequence event. Note: Mitigation barriers are sometimes referred to as contingencies or recovery measures.

Conse-quence

Conse-quence

Conse-quence

Cause

Cause

Cause

Risk Management explained using a Bowtie

Hazard

Event

Barrier

Barrier Barrier

Greater than one in ten per patient year 7 Medium High High High High

One in ten to one in a hundred per patient year 6 Medium Medium High High High

One in a hundred to one in a thousand per patient year

5 Low Medium Medium High High

One in a thousand to one in ten thousand per patient year

4 Low Low Medium Medium High

One in ten thousand to one in a hundred thousand per patient year

3 Low Low Low Medium Medium

One in a hundred thousand to one in a million per patient year

2 Low Low Low Low Medium

L

i

k

e

l

i

h

o

o

d

Less than one in a million per patient year 1 Low Low Low Low Low

A B C D E Negligible / Very Low

Low (Minimal Harm)

Moderate (Short Term

Harm) Severe (Long

Term/Perm. Harm)

Fatality (one or more)

NPSAs Patient Safety Risk Matrix

Consequence

Initial Risk

Barrier

Barrier

Reduce Likelihood

Barrier

Barrier

Barrier

Reduce Consequence

Severity

Reduced Risk

Risk Management Activities and Actions(Processes, procedures tomaintain and assure / verify that barriers are in place andeffective)

The uses of Bowties


Simple Communication - To explain a risk


Simple communication To explain barrier types


Simple communication To explain barrier strengths


Simple communication To explain barriers degrading


Simple communication To explain barriers criticalityOnly strong barrier

/ control on a branch

Repeating barrier / control

Few barriers / controls


Simple communication To Management System, etc.Direct link to procedures

and requirementsDirect link to

design standards

Defined Responsibilities


Use in accident investigations

This is a simple BSCATTM BowTie that presents the investigation of the root causes for failures of barriers in an event on the cause side of a BowTie using SCAT (Systematic Causal Analysis Technique). Why barriers on the consequence side failed are yet to be investigated. Note that only one branch on the causal side is shown, as this was the path that lead to the event. For each barrier / control the immediate cause (green text), root cause (red text) and the management system element that failed (blue text) are shown. This can now be used to explain to those not undertaking the accident investigation what happened. It illustrates that two areas of their safety management system need to be addressed, namely safety hazard identification and evaluation and process safety leadership.

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Use in accident investigations

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Useful rules / guidance to follow to develop quality Bowtie diagrams

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Useful rules bowties and barriers Causes / threats should be specific and unique (single route to the event)

Any or all consequences / impacts could result (multiple routes from the event)

Barriers / Controls:- Should be independent of each other- Stop occurrence of the risk event - Should be equipment or activities (pieces of paper are not barriers!)- Stop a cause or consequence of the risk event- Reduce the magnitude of the consequence on the risk event- Can appear more than once on the bowtie diagram, however they:- Should appear on one side of the bowtie only (generally)- Should appear only once on any branch in the bowtie diagram

Workshop Develop Bowtie

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Workshop

Consequence

Consequence

Consequence

Cause

Cause

Cause

Hazard

Event

Instructions:Place on the diagram barriers that help prevent or mitigate the event


Safeguarding life, property and the environment

www.dnv.com

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Documents

Bowties - a risk communication tool_tcm4-590258.pdf