Hazard Identification Techniques on
Chemical Emergency Planning
Dr. Asit K Patra
Disaster Management Institute
Bhopal
Terminology
1. Hazard: A chemical or physical condition that has the
potential for causing damage to people, property and the
environment.
Example: Chlorine storage in Water treatment Plant
LPG storage in Bottling plant
Pressurised pipeline carrying Natural Gas
2. Risk: A measure of human injury/economic loss in
terms of both the incident likelihood and the magnitude of
loss or injury
Relation between Hazard and Risk
Terminology
3. Risk Analysis
-A Quantitative or qualitative estimate of risk.
4. Risk Assessment
Process of utilising Risk Analysis results with respect to a reference.
5. Disaster/Emergency
Serious disruption of life, injury/death
Affected large number of people and area
Mobilisation of resources in case of those necessary during normal
operation.
Terminology
6. On-site and Off-site
On-site: Consequences are confined within the plant
premises
Off-site: Consequences crosses the plant boundary.
On-site Planning: As per Schedule 11 of MS&IHC Rules
Off-site Planning: As per Schedule 12 of MS&IHC Rules
Accident Outcomes
(i) Fire: Pool, Jet, Flash, Fireball
(ii) Explosion : BLEVE, VCE, Dust Explosion
(iii) Release of Toxic gas/vapour
BLEVE
AN INDUSTRY AFTER VCE
POOL-FIRE
JET- FIRE
Parameters to study Consequences of
Accidental Release Scenarios
(A) Fire : Thermal Radiation (Various damage
levels)
(B) Explosion : Overpressure (Various damage
levels)
(C) Toxic Release : Concentration (Various
damage levels)
A. Through Specific Checklist:
B. Qualitative review : OSHAS/MSDS
Identification
Techniques of
Potential
Hazards
C. Quantitative or Semi-Qualitative Method:
HAZOP/FMEA/FTA/LOPA/Dow Fire & Explosion
Index Etc.
HAZOP = HAZard and OPerability Study
 Method for identifying (and assessing)
HAZOP- a
hazard
identification
tool
problems that may represent risks to
personnel or equipment, or prevent
efficient operation
 Systematic and qualitative method
based on the use of
guide- words
Multi- disciplinary team effort
*** Qualitative and Quantitative
INTENTION
Procedure of
HAZOP
DEVIATION
CAUSES
CONSEQUENCES
HAZARDS
OPERATING DIFFICULTIES
Process
HAZOP
Guide Words
HAZOP Flow
Chart
HAZOP
Work-sheet
- An analysis of the system/plant equipment,
their failure modes, effect of each failure mode
on the system/plant.
Failure Mode
and Effect
Analysis
(FMEA)
• Failure Mode – Description of how equipment
fails (open, closed, on, off, leak etc.)
• Effect of Failure Mode - System response or
accident resulting from the equipment failure.
IDENTIFY ELEMENTS OF SYSTEM
IDENTIFY FUNCTIONS
IDENTIFY FAILURE MODES
PROCEDURE
OF FMEA
IDENTIFY EFFECTS OF FAILURE MODE
IDENTIFY POSSIBLE CAUSES
IDENTIFY EFFECT ON THE SYSTEM
IDENTIFY EFFECT ON OTHER SYSTEMS
FINAL RISK ASSESSMENT
TAKE ACTION TO REDUCE RISK
When to use
Design : FMEA can be used to identify additional protective
features those can be readily incorporated into the design.
Construction: FMEA can be used to evaluate equipment
changes resulting from field modifications.
Operation: FMEA can be used to evaluate an existing facility
and identify existing single features those represent potential
accidents as well as to supplement more detailed hazard
assessment such as HAZOP or FTA.
FMEA identifies single failure modes and is not efficient in
identifying combinations of equipment failures that lead to
accidents.
Fault Tree Analysis (FTA) - A Tool in Risk
Analysis
FAULT
TREE
ANALYSIS
(FTA)
- A technique to estimate incident frequencies.
A tool to find out the contribution of equipment
failure and human /operator error in an accident
event.
- A Logic gate based graphical representation of
the interrelationships between equipment failure
and a specific accident
 Consequence Zones (Overpressure/Radiation flux/Toxicity)
• Red Zone:
– Collapse of Buildings ,Distortion in Steel Structure.
– Complete Burning of human Body.
– Lethal for 50% of healthy people (Toxic Release).
• Orange Zone:
– Partial Collapse of Buildings, Slight distortion in Steel
Structure.
– Third degree burns to human body.
– Immediately dangerous to life & health(Toxic Release).
• Blue Zone:
– Second degree burns to human body if unable to reach in
cover within 20 seconds.
– Breakage of Window panes, Projectile limit.
– Short term Exposure Limit.(Toxic Release).
Planning : Engineering,
Administrative and Legal
PREVENTION
PREPAREDNESS
RESPONSE
RECOVERY
For Further Information, Please contact:
asitkpatro@gmail.com
Thanks