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Fire Station, GIDC, Ankleshwar- 2
disasterm@dataone.in
dpmcank@sancharnet.in
Ph. No. – (02646) 220229, 653101
Disaster Prevention & Management Centre
Hazard Assessment and Risk Hazard Assessment and Risk Management Techniques forManagement Techniques for Industries Industries
Prepared by :Prepared by : VIJAY ASARVIJAY ASARChief Co-ordinator, DPMC
Disaster Risk Management
The systematic process of using administrative decisions, organisation, operational skills and capacities to implement policies, strategies and coping capacities of the societies and communities to lessen the impacts of environmental and technological disasters.
Disaster Risk Reduction
The conceptual framework of elements considered with the possibilities to minimize vulnerabilitiies and disaster risk throughout a society, to avoid (prevention) or to limit (mitigation and preparedness) the adverse impacts of hazards.
What is system What is system safety?safety?
The system safety concept is the application of
special technical and managerial skills to the
systematic, forward-looking identification and
control of hazards throughout the life cycle of a
project, program, or activity. The concept calls for
safety analyses and hazard control actions,
beginning with the conceptual phase of a system
and continuing through the design, production,
testing, use, and disposal phases, until the activity
is retired.
Chemical hazardsChemical hazards Type of chemical hazards
Material hazard : Hazardous nature of chemicals like Inflammable, explosive, toxic, corrosive, reactive, radioactive, reducing, oxidizing, decomposing or incompatible.
Process hazards : In process, chemical and physical change, chemical reaction, pressure, temperature, level, flow, quantity and other parameters create.
Vessel hazards : The vessels and equipments in which the chemicals are stored, handled or reacted pose.
Chemical hazardsChemical hazards Type of chemical hazards
Control hazards : The inadequate, defective, under design or wrongly modified control devices or their of failure cause.
Fire hazards : Fire or explosion
Toxic hazards : Affluent disposal and gaseous emissions bring pollution and toxic hazards.
Handling hazards : Leaks, spills and splashes cause.
Chemical hazardsChemical hazards Physical hazards or health hazards
Physical Hazards : Corrosives, Explosives etc.
Health Hazards : Toxic, Irritants and Oxides.
Accident an emergency hazard
Absence, nonuse or failure of fire fighting equipments, personal protective equipments, emergency control devices
The HazardThe Hazard
A potential condition or set of conditions, either
internal and/or external to a system, product,
facility, or operation. Which, when activated
transforms the hazard into a series of events that
culminate in loss (an accident). A simpler and
more fundamental definition of hazard is a
condition that can cause injury or death, damage
to or loss of equipment or property, or
environmental harm.
Hazard Analysis at various Hazard Analysis at various stages of Project Executionstages of Project Execution
Process Hazard Process Hazard ManagementManagement
Process Hazard Management includes: Hazard identification. Hazard Assessment. Accidental vapour cloud release (flammable and/or
toxic). Engineering approaches to mitigation. Design features for emergency control. Process Safety Management (PSM). Planning for counter measures. Emergency response planning (ERP-onsite). Alerting local authorities and public.
Some important elements of PSM.: Employee Participation Process Safety Information (PSI) Process Hazard Analysis (PHA) Operating Procedure Training Contractor Safety Pre-Startup Safety Review Mechanical Integrity Hot Work Program Management of Change (MOC) Incident Investigation Emergency Planning & Response Compliance
Audits
Process Hazard Process Hazard ManagementManagement
Initial startup
Normal, temporary & emergency operations
Normal shutdown
Startup following a turnaround or after an
emergency shutdown
Operating limits
Consequences of deviation steps required to
correct or to avoid such deviation
1.1. Operating Procedures
Process Hazard Process Hazard ManagementManagement
Safety & Health considerations Precautions necessary to prevent exposure,
including engineering controls Administrative controls & personal protective
equipment Controls measure to be taken if physical
contact or airborne exposure occurs Quality control for raw materials & control of
hazardous chemical inventory levels Safety systems & their functions.
1.1. Operating Procedures
Process Hazard Process Hazard ManagementManagement
Construction & equipment is in accordance with design specifications
Safety, operating, maintenance & emergency procedures are in place & are adequate
Modified facilities meet the requirements contained in Management of Change
Training of each employee involved in operating a process has been completed.
2.2. Pre-Startup Safety Review
Process Hazard Process Hazard ManagementManagement
The technical basis for the proposed change
Impact of change on safety and health Modifications to operating procedures Necessary time period for the change Authorization requirements for the
proposed change Up-date of Process Safety information
(PSI), PHA & Operating procedures.
3.3. Management of Change (MOC)
Process Hazard Process Hazard ManagementManagement
Engineering & administrative controls Detection methods for providing early
warning of releases Consequences of failure of engineering
and administrative controls Facility site Human factors Qualitative evaluation of a range of the
possible safety and health effects of failure of controls on employees and others
4.4. Process Hazard Analysis (PHA)
Process Hazard Process Hazard ManagementManagement
HAZID is an automated hazard identification tool for continuous process plants and principle features of
Sectionalizing the process plant into several units Generation of hazardous incident scenarios Use of models to distinguish between the
feasible and infeasible scenarios Use rules to detect plant configuration problem.
HAZID TechniqueHAZID Technique
HAZID TechniqueHAZID TechniqueHAZID Process
Divide the Process Plant into smaller section
Generate Hazardous Incident Scenarios
Identify the feasible Scenarios only
Identify plant configuration problem
Generate output in HAZOP table
The HazardThe Hazard
Hazard severity
Category
Name Characteristics
I Catastrophic Death
Loss of system
II Critical Severe injury or morbidity
Major damage to system
III Marginal Minor injury or morbidity
Minor damage to system
IV Negligible No injury or morbidity
No damage to system
The HazardThe Hazard Possible hazard likelihood
Description Level Specific Individual Item Fleet or Inventory
Frequent A Likely to occur frequently Continuously experienced
Probable B Will occur several times in life of an item
Will occur frequently
Occasional C Likely to occur sometime in life of an item
Will occur several times
Remote D Unlikely but possible to occur in life of an item
Unlikely but can reasonably be expected to occur
improbable E So unlikely, it can be assumed occurrence may not be experienced
Unlikely to occur, but possible
The HazardThe Hazard Hazard Assessment Matrix
Frequency of Occurrence
HAZARD CATEGORIES
ICatastrophic
IICritical
IIIMarginal
IVNegligible
(A) Frequent 1A 2A 3A 4A
(B) Probable 1B 2B 3B 4B
(C) Occasional 1C 2C 3C 4C
(D) Remote 1D 2D 3D 4D
(E) improbable 1D 2E 3E 4E
The HazardThe Hazard Hazard Assessment Matrix
Hazard Risk Index HRI
1A, 1B, 1C, 2A, 2B, 3A I
1D, 2C, 2D, 3B, 3C II
1E, 2E, 3E, 3E, 4A, 4B III
4C, 4D, 4E IV
Suggested Criteria
Unacceptable
Undesirable (Management decision required)
Acceptable with review by management
Acceptable without review
The HazardThe Hazard Relationship of qualitative probability
ranking to quantitative values
Description LevelFrequency of occurrence
Potential relationship to Quantitative Value
Frequent A High 10-1
Probable B Occasional C Medium > 10-3
Remote D > 10-4
Improbable E Low > 10-6
The Concept of RiskThe Concept of Risk
Risk: ”Chances or possibility of accidental losses
or undesired consequences."
The probability of a dangerous event posed by a
hazard, over a definite time period of exposure or
The frequency at which such events will occur
and results in fatalities to certain number of
people and
The consequence of such events in terms of
expected number of fatalities per year.
Risk = (Probability) x (Consequences)
Consequence Analysis or Semi Quantitative Risk AnalysisAssessment of possibilities --- By use of various hazard
identification techniques like * Preliminary Hazard Analysis
(PHA) * Hazard & Operability Study * Safety Audit * Fault tre analysis * Event tree analysis, etc.
EFFECT MODELSConceiving a credible scenario by hazard identification techniques
• Computation of physical effects of the scenario by suitable models like:
-- Outflow model -- Dispersion model -- Unconfined vapour cloud explosion models -- Jet fire dimensions -- Damage from shock wave on BLEVE -- Fire ball radiation damages -- Pool fire radiation damages etc.
TECHNIQUES AVAILABLE
o Fire & Explosion Index (Dow Index) and Toxicity Index
o Calculation of damages likely from the fires,explosions and toxic releases and combining the damages with probabilities of occurrence in terms of Individual Risk and Societal Risk.
( The later is more objective for estimating the distances likely to be affected)
The Mathematical Models Available to Compute the Effects-- Release rate of liquids under pressure.-- Distance of Lower Explosive Limit in the
windward direction.-- Contours of LEL concentrations at the ground
level.-- Mass of gas within explosive range (For
unconfined vapour cloud)-- Shockwave damage on ignition of unconfined
vapour cloud explosion.-- Mass of gas in explosive range on BLEVE.-- Fire Ball Radius.-- Fire ball duration.-- Radiative flux.-- Thermal Dose.
Both the methods are closely related and as such Mond Index was developed as an extension of DOW index. Primarily, Dow index calculates the Fire & Explosion index for a process unit taking into consideration the flammability and reactivity of the material handled in the process units under the general and special process condition. Mond Index on the other hand uses specifically the material toxicity in addition to the other aspects.
Dow and Mond IndicesDow and Mond Indices
Fire & Explosion index :(F & E1) = MF x (GPH) (SPH)
Toxicity Index : Th + Ts (1+GPH+SPH) 100
Where, MF = Material Factor
SPH = Special Process Hazard
GPH = General Process Hazard
Th = Toxicity factor based on the NFPA hazard index (0 – 4)
Ts = Correction factor (additional penalty) for toxicity based on Maximum Allowable Concentration (MAC) value in ppm
Dow and Mond IndicesDow and Mond Indices
Dow and Mond IndicesDow and Mond IndicesToxicity Factors and Correction Factor
for MAC valuesNFPA Index
NumberToxicity Factory
(Th)
0 0
1 50
2 125
3 250
4 325
MAC (in ppm) TS
5 and blow 125
Between 5 and 50 75
50 and more 50
GPH includes processes e.g. exothermic reaction,
endothermic reactions, hydrogenation, alkylation,
isomerisation, sulphurization, neutralization,
esterification, oxidation, polymerization,
condensation, halogenation, nitration, loading-
unloading operation, enclosed process units,
inadequate drainage and proper access etc.
different penalties are assigned for different
processes.
General Process Hazard (GPH)
Process Hazard Process Hazard ManagementManagement
SPH includes special hazards posed due to
process parameters like temp., pressure,
flammability ranges (UEL, LEL) of material and
issues like internal and external corrosion, leakage
from joints etc. additional penalties are assigned
for special process hazards. Selection of the
process units which may contribute to a fire or
explosion or toxic release
Special Process Hazard (SPH)
Process Hazard Process Hazard ManagementManagement
The material factor which are the functions of flammable and reactivity can be calculated by the following way ;
Find out flash point of a material or HCV by multiplying heat of combustion by the vapour pressure of that substance at 27’ C.
Find out flammability factor from the next table from the flash point data or HCV value.
Find out the adiabatic decomposition temp. of the substance.
Find out the reactivity factor from the table from decomposition temp. value.
Process Hazard Process Hazard ManagementManagement
Dow and Mond IndicesDow and Mond Indices
Table for finding out Material Factor (Mf) from the table
Calculate Mf from following Table from Left to Right
Decomposition temp. Td Deg K
< 830 830 - 935
935 - 1010
1010 - 1080
> 1080
Flash HCV Reactivity …………………
Pt. kJ bar/ mol FL
0 1 2 3 4
None < 4 x 10-5 A 0 0 14 24 29 40
>100 4 x 10-5 2.5 M 1 4 14 24 29 40
40-100 2.5 - 40 A 2 10 14 24 29 40
20-40 40 – 600 B 3 16 16 24 29 40
< -20 > 600 I 4 21 21 24 29 40
L Material Factor MF
ITY
Procedure for Calculating Procedure for Calculating the Indicesthe Indices
Identify the most process units for risk point of view.
Determine the material factor (MF) for each process units (flammability & reactivity of material)
Determine the Fire & Explosion Index (F&EI) and the problem exposure area for each process unit from the formula.
Calculate the Maximum Probable Property Damage (MPPD).
Indices and the Extent of Hazard
F & E index Toxicity Index Degree of Hazard
1 – 60 1 – 6 Light
61 – 96 6 – 10 Moderate
97 – 127 > 10 Intermediate
128 – 158 > 10 Heavy
> 159 > 10 Severe
Risk AnalysisRisk AnalysisGeneral Principles of Risk Analysis
1. All relevant risks are systematically addressed Identify major, don’t concentrate on minor Consider those aspects of work which are
hazardous Take into account & critically assess existing safety
controls & measures provided
2. Address what actually happens Actual practice, not instruction Consider non-routine operations Pay attention to changes/interruptions
Risk AnalysisRisk AnalysisGeneral Principles of Risk Analysis
3. Include all who could be affected, including visitors, contractors, and general public
4. Take into account, and objectively assess, control measures
5. The level of protection measures should match the level of risk (i.e. risk within the ALARP region)
6. In most cases, make a rough assessment first, find out the need for detailed assessment and carry out the same, if needed.
Risk AnalysisRisk Analysis Use of Probabilities in Risk
AnalysisThe risk of operational activity with hazardous materials consists of two elements The consequence of certain unwanted event The probability of certain consequences that will occur
A distinction is made between 3 types of probabilities The probability of the initiating event. The probability that designed counter measures may
function The probability of certain consequences of an accident
Risk AnalysisRisk Analysis Layers of Protection Analysis
Offsite Emergency Measures Community Alerting & Evacuation, if necessary
Onsite Emergency Measures Onsite Evacuation
Protective Measures & Control Safety Instrumented Mitigation
Protective Control & Monitoring Process alarms & Safety Instrumented Control
Process Control & Supervision
Hazardous Process
P S RXX
Nomogram of Risk Assessment
Risk AnalysisRisk Analysis Consequence BLEVE Model for Different
Static and Mobile Pressure Vessels
BLEVE Scenarios and Consequence Distances
Storage type Inventory (MT)
100% fatality Distance
1% Fatality Distance
Road tanker 12 137 M 500 M
--Do--- 20 162 M 600 M
Rail Wagon 50 218 M 700 M
Horton Sphere 140 305 M 940 M
---Do--- 1150 624 M 1834 M
Kilometer
Consequence AnalysisConsequence Analysis
Consequence Analysis for a Ammonia Tank Leak
Scenario : 20” dia. Tank having leak of NH3 from 10” pipe
Consequence : Distance to IDLH is 8.9 Km
0 2
2
2
2 4 8 106
4
0
4
Kil
omet
er
Kilometer
Consequence AnalysisConsequence Analysis
Sour (containing H2S) Natural Gas pipeline leak scenario
Scenario : full bore rupture of a 42” pipeline
Consequence : Distance to IDLH is 3.9 Km
0 2
0.5
0.5
1 1 3 4
1.5
0
1.5
Kil
omet
er
Risk AnalysisRisk AnalysisRisk control techniques / Risk Management
Inherent safe design (built-in safety) Fault tolerant measures (single or multiple
failures) Protective measures Adequate information on the residual risk Administration controls (e.g. allocation of task
to the human operator, training etc.) Other Risk Reduction measures Corrective and preventive actions Document control
Risk AnalysisRisk Analysis List of Software's Available for Risk
Analysis and Other Studies
Sl. No.
Item Description Application
1. SAFETI Onshore Risk Analysis.
2. SFU Offshore Risk Analysis.
3. CAFTAN Fault Tree Analysis.
4. ETRA Event Tree Analysis.
5. HAZSEC. HAZOP Study.
6. HAZTRAC. HAZOP Recommendation Tracking.
7. PHAST. Consequence Analysis.
8. WHAZAN Consequence Analysis.
Risk AnalysisRisk Analysis List of Software's Available for Risk
Analysis and Other Studies
Sl. No.
Item Description Application
9. EFFECTS. Consequence (Effects) Modeling.
10. DAMAGE Consequence (Damage) Modeling.
11. PC-FACTS. Failure & Accident Databank.
12. ASAP Event Tree Analysis.
13. FMECA Failure Mode Effects & Criticality Analysis.
14. ANEX Life Time Analysis & Failure Estimation.
15. E&P FORUM Hydrocarbon Leak & Ignition Database.
16. ALOHA Consequence Analysis
Risk AnalysisRisk Analysis List of Software's Available for Risk
Analysis and Other Studies
Sl. No.
Item Description Application
17. CLASS Hazardous Area Risk & Classifications
18. RISK CURVES TNO Individual & Group Risk computations
19. RISKA T Risk Analysis model of Health & Safety
Executives, UK
20. FACTS TNO Frequency Estimation Database
21. OREDA DNV Frequency Estimation Database
22. FRED Consequence Analysis software of Shell, UK
23. EAHAP Consequence modeling software of Energy
Analysts Inc. US)
Risk Communication Seven Cardinal Rules
1. Accept and involve the public as a legitimate partner.
2. Plan carefully and evaluate your efforts.3. Listen to the public’s specific concerns
(Communication is two way activity)4. Be honest, frank and open (Trust and credibility
are most precious assets)5. Coordinate and collaborate with other credible
sources6. Meet the needs of Media ( provide risk
information tailored to the needs of each type of media)
7. Speak clearly and with compassion ( Use simple non technical language with general public)
Have a Healthy Life In Safe Environment.
DISASTER PREVENTION & MGMT. CENTRE
AnklESHwar.
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