fire station, gidc, ankleshwar- 2 [email protected] [email protected] ph. no. – (02646)...

Fire Station, GIDC, Ankleshwar- 2

[email protected]

[email protected]

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


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


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


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


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)


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)


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 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)


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)


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.



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.



Sl. No.


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



Sl. No.


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.

fire station, gidc, ankleshwar- 2 [email protected] [email protected] ph. no. – (02646)...

Documents

process hazards

control of hazards

handling hazards

vessel hazards

explosion toxic hazards

adverse impacts of hazards

hazard identification

hazard analysis