Risk Assessment Tools
Selecting, Modifying and Applying
Methods
UCM Risk Assessment Symposium
November 5, 2015
Bruce Lyon, CSP, PE, ARM, CHMM
Hays Companies
Risk Assessment Tools
1.
2.
3.
4.
The Hazard Analysis and Risk Assessment Process
Assessment Methods
Selecting and Modifying Methods
Applying Methods
Hazard Analysis and Risk Assessment
Hazard Analysis
Identify Hazards
and Exposures
Anayze Range of
Severities
Risk Assessment
Identify Hazards
and Exposures
Choose a Severity
Consequence (S)
of Concern
Analyze how event
could occur and its
Likelihood (L)
Estimate Risk
Level
SxL=R
Definitions
Risk Assessment
• Overall process of risk identification, risk analysis and risk evaluation.
(ISO Guide 73/ANSI/ASSE Z690.1-2011)
• A process that commences with hazard identification and analysis,
through which the probable severity of harm or damage is
established, followed by an estimate of the probability of the incident
or exposure occurring, and concluding with a statement of risk.
(ANSI/ASSE Z590.3 PtD Standard)
Risk Assessment
The purpose: to determine whether the level of risk is
acceptable, or whether more needs to be done to
control or reduce the risk.
The process should be carried out in a rational, logical
and structured manner.
Risk Assessment within the Risk Management
Framework
Establish Risk
Criteria
Monitor /
Review
Document
Establish
Context
Risk
Assessment
Process
Assemble
Team
Identify
Hazards
Treat Risks
Evaluate
Risks
Analyze
Risks
ISO 31010/ANSI Z690.3 Methods
1.
Brainstorming
17.
Cause and Effect Analysis
2.
Structure Interviews
18.
Layers of Protection Analysis
3.
Delphi
19.
Decision Tree Analysis
4.
Checklists
20.
Human Reliability Analysis
5.
Preliminary Hazard Analysis
21.
Bow Tie Analysis
6.
Hazard and Operability Studies (HAZOP)
22.
Reliability Centered Maintenance
7.
Hazard Analysis and Critical Control Points (HACCP)
23.
Sneak Analysis
8.
Toxicity Assessment
24.
Markov Analysis
9.
Structured What-if Analysis
25.
Monte Carlo Analysis
10.
Scenario Analysis
26.
Bayesian Statistics and Bayes Nets
11.
Business Impact Analysis
27.
FN Curves
12.
Root Cause Analysis
28.
Risk Indices
13.
Failure Modes and Effect Analysis
29.
Consequence/Probability Matrix
14.
Fault Tree Analysis
30.
Cost/Benefit Analysis
15.
Event Tree Analysis
31.
Multi-Criteria Decision Analysis
16.
Cause and Consequence Analysis
Z590.3 PtD Methods
1.
2.
3.
4.
5.
6.
7.
Design Safety Reviews
8. Failure Modes and Effect
Analysis
Checklists
9. Fault Tree Analysis
Risk Assessment Matrix
Preliminary Hazard Analysis 10.Management Oversight and
Risk Tree (MORT)
What-if Analysis
What-if/Checklist Analysis
Hazard and Operability
Studies (HAZOP)
ANSI Z10 Methods
1.
2.
3.
4.
5.
Design Reviews
Brainstorming
Checklists
Consequence/Probability Matrix
Risk Assessment Matrix
Selecting Risk Assessment Tools
Consider the following:
• What is the Application (New Design; Existing System; General or
Specific Hazards)
• What is the Level of Detail Needed
• What is the Complexity of the System
• What is the Size of the System
• What Resources are Available
Selecting Risk Assessment Tools
As a general rule, when selecting a risk assessment method, the
simplest tool or tools that provide sufficient information to make an
appropriate risk management decision is advised.
No single assessment tool is able to meet all of the requirements for
risk assessment, as all tools have limitations and weaknesses.
Modified tools may be necessary (and even desired)
Often a combination of tools is necessary.
Selecting Risk Assessment Tools
Fundamental Tools commonly used include:
• Checklists
• Brainstorming
• JHAs and JRAs
• Preliminary Hazard Analysis
• What-if Analysis
• Failure Mode and Effects Analysis
• Bow Tie Analysis
• Risk Matrix
Checklist Tools
Used to identify common hazards
Industry/process specific checklists
Can be customized for application
Easy to use, but limited to existing list
Generally followed by other risk analysis and evaluation tools
Brainstorming
Used to identify potential hazards and scenarios
Can be structured or unstructured
Requires a facilitator to lead session and record ideas
Generally followed by other risk analysis and evaluation tools
Brainstorming
1.
2.
3.
4.
5.
State Goal
No Critical Remarks
Generate Ideas
Record Everything
Evaluate and Qualify
Job Hazard Analysis (JHA)
Used to identify job steps, hazards and controls
Helpful in job training and incident investigation
Does not include an ‘assessment of risk’, just identification of hazards
and controls
Job Hazard Analysis (JHA)
Job Risk Assessment (JRA)
Simple tool
Same as JHA but includes a ‘risk assessment’ of each hazard
Allow hazards and corrective measures to be prioritized by ‘risk level’
Job Risk Assessment (JRA)
Preliminary Hazard Analysis
An ‘Initial Analysis’ tool
Used to identify hazards and control measures for new designs or
existing systems
Used when limited information is available
Allows for risk levels to be prioritized for further assessment and
management
Preliminary Hazard Analysis Example
Winery Risk Assessment
100% Liquid Sulfur Dioxide (SO2) used
for dosing large tanks inside buildings.
Preliminary Hazard Analysis Example
Risks of using 100% Sulfur Dioxide
•
•
•
•
•
Potential for releases in winery and bottling area
Lethal dose = 100 ppm (Cal-OSHA PEL = 2 ppm)
Can cause blindness
Environmental concerns (reporting requirements)
Transporting, dispensing, handling, storage concerns
Preliminary Hazard Analysis Example
Winery Risks
Sulfur dioxide gas is heavier
than air and can accumulate in
closed areas.
The configuration and lack of
ventilation in the bottling area
presented a significant risk to
employees should a SO2
release occur in the area.
Risk Criteria
Severity Level
Catastrophic (4)
Definition
Fatalities; Damage to Community, Environment, and Reputation
High (3)
Permanent Disability Injury or Illness; Multiple Injury Events
Moderate (2)
Injury or Illness Requiring Medical Attention
Low (1)
Minor Injury or First Aid Incident
Likelihood Level
Very Likely (4)
Likely (3)
Possible (2)
Unlikely (1)
Definition
Will happen under right situations; has occurred multiple times
Likely to happen under right circumstances; has occurred in past
Can happen in certain situations
Unlikely to happen; remotely possible
Very Likely (4)
Likely (3)
Possible (2)
Unlikely (1)
Low
(1)
Moderate
(2)
High
(3)
Catastrophic
(4)
4
3
2
1
8
6
4
2
12
9
6
3
16
12
8
4
SO2 Dosing Health risk from leak
using 100% or release; 2 ppm PEL;
SO2 liquid 100 ppm lethal dose;
Heavier than air. EPA
regulated product.
4
3
12
Recommended Controls
Future
Severity
Future
Likelihood
Future
Risk Level
Hazard
Current
Likelihood
Current
Risk Level
Task
Current
Severity
Preliminary Hazard Analysis Example
SO2 Dosing Health risk from leak
using 100% or release; 2 ppm PEL;
SO2 liquid 100 ppm lethal dose;
Heavier than air. EPA
regulated product.
4
3
12
Recommended Controls
Substitute 100% SO2 with 6%
liquid SO2 and K2S2O5 (potassium
meta-bisulfite) effervescent tables,
granular, powder
Future
Severity
Future
Likelihood
Future
Risk Level
Hazard
Current
Likelihood
Current
Risk Level
Task
Current
Severity
Preliminary Hazard Analysis Example
2
2
4
What-if Analysis
• A team-based, brainstorming process
• Engineering, production, maintenance, fire protection, SH&E
• Used to identify and analyze scenarios and hazards
• Typically does not include ‘risk analysis’ (severity and likelihood levels)
• Can be modified to include risk analysis
What-if Analysis
What-if Analysis
ABC – Repair Facility
Vapor Combustor Process Hazard What-if Analysis
Date: June 17 & 18, 2009
Team members: Bruce Lyon – Hays Companies; Deane Holmes – Hays Companies;
Tim G – ABC Engineer; Gary F – Env.; John K – Safety; David B - Maintenance
Pre-Startup & Vapor Combustor Purging
ID #
What if…
Causes
Effect
Safeguards
A1.
Insufficient purging
of vapor combustor
stack
Failure of assist air
blower
Will not start
A1.1 Operator training in JSA & purging
procedure
A1.2 Alarm if assist air blower fails
A2.
Steam is used to
purge the waste
gas line
Steam used to purge
system
Steam condenses
in piping without
displacing air
Nitrogen purge line
is hard piped in
system (not
possible to purge
with steam)
A2.1 Nitrogen purge line is hard piped in
system (not possible to purge with steam)
A2.2 Operator training in purging
procedure
A3.
Igniting pilots
before air is
removed from
system
Inadequate purge; lack
of purge
Fire or explosion
A3.1 Automated start up will not allow
pilot ignition before system clear purge
seal test
*Control panel software
Failure Mode and Effects Analysis
• A method used to identify the ways a system can fail
• Used for new and existing designs, products, processes and systems
• Analyzes failures individually
• FMEA identifies:
•
•
•
•
Potential failure modes
Effects of failures
The causes of failures
How to avoid the failures
Failure Mode and Effects Analysis
Bow Tie Analysis
• A combination of a fault tree and event tree analysis
• Used to provide a clear illustration of the risk pathways and control
measures
• Provides a “big picture” view of a process or system to effectively
communicate risk exposures and controls
• Attention to both preventive controls and reactive measures
• Typically lacks a risk scoring mechanism
Bow Tie Analysis
‘Striped’ Bow Tie Analysis
Risk Matrix
• A means of combining qualitative or quantitative ratings of severity
and likelihood to produce a risk level
• Used to rank risks as part of ‘risk evaluation’
• Provides a consistent method of prioritizing
• Communicates risk to management
Risk Matrix
Using a Series of Risk Assessment Tools
Hazard Analysis and Risk Assessment
Hazard ID:
Hazard Description:
Exposure Interval:
Activity/Process Phase:
Initial Risk Assessment
Hazard Targets:
Personnel
Equipment
Downtime
Environment
Product
Additional Countermeasures:
Severity Probability Risk Code
Post-countermeasures Risk Assessment
Hazard Targets:
Personnel
Equipment
Downtime
Environment
Product
Prepared by:
Severity Probability Risk Code
Countermeasure codes:
(D) Design alternation (E) Engineering
(S) Safety Device
(W) Warning
(P) Process
(T) Training
Comments:
Reviewed by:
Approved by:
Adapted from Advanced Safety Management: Focusing on Z10 and Serious Injury Prevention by Fred Manuele