GUIDING PRINCIPLES OF CHEMICAL DISASTER MANAGEMENT

LEGAL: Indian Acts/Rules/Guidelines

TECHNICAL: Risk Assessment

IS:15656 (HIRA)/HSE (UK)/CCPS Guidelines/TNO, The Netherlands

Relevant Acts and Rules and Recent Developments

Factories Act, 1948 as amended in 1987

MSIHC Rules, 1989 as amended in 2000

The PLI Act, 1991 and amended rules 1993

Chemical Accidents (Emergency Preparedness, Planning and Response) Rules, 1996

Disaster Management Act, 2005

EIA Notifications, 2006

NDMA Guidelines on Chemical (Industrial) Disaster Management 2007

ERDMP 2010

NAP-CIDM

FATALITY RISK CRITERIA FOR LAND USE SAFETY PLANNING

RISK ANALYSIS DMI

Definition of Risk : Chance of happening ofan event (say, industrial accident) thatwill have negative/undesirableimpact on human beings, environmentand economic values.

Risk Analysis : Quantitative Estimate of Risk

(i) How often an accident/ event may occur(frequency)

(ii) Magnitude of its probable consequences.

Risk Components

DMI

C. Incident Outcome Case : Quantitative definition ofa single result of an incident outcome.

Example : A concentration of 2000 ppm (v) of Ammonia1 km downwind from a leak of 5kg/s is estimatedassuming 2m/s wind speed and stability class D.

D. Consequence : Measure of the expected effects of anincident outcome case.

Example : An Ammonia cloud from a 5 kg/s leak understability class D with 2 m/s wind speedtravelling Westerly will injure 50 people.

Contd. DMI

DMI

Assume: (i) Frequency of occurrence = 1 x 10-3 per year.

(ii) Probability of the occurrence of the incident(Ammonia leak in the pipeline) = 0.1 per year.

(iii) Conditional probability that the wind blows towardsa populated area following the Ammonia release

= 0.1Risk Value = Risk of injuring 50 people

= 1 x 10-3 x 0.1 x 0.1 = 10-5 events per year.

Risk Assessment : That Ammonia leakage is judgedhigher than acceptable and remedial measures are

required.

DMIContd.

Risk Presentation

A. Individual Risk

Frequency/year that a person will be lethally affected by the consequences of possible accidents in an installation.

Individual risk is the probability of an individual at a specific location becoming a casualty from a specific hazard.

B. Societal Risk

Cumulative frequency that a minimum number of off-site people will be killed simultaneously due to possible accidents

INDIVIDUAL RISK CONTOURS

Figure: Maximum and minimum risk lines corresponding to catastrophic failure of a

chlorine tonner (900 Kg: Indoor)

Figure: Maximum and minimum risk lines corresponding to catastrophic failure of a

chlorine tonner (900 Kg: Indoor)

Reference Books

1. Loss Prevention in Chemical Process Industries. Volume 1, 2 & 3. by F. P. Lees, 2003. Butterworth Publications.

2. Guidelines for Chemical Process Quantitative Risk Analysis. 2nd Edition, CCPS, AIChE, 2000.

Concern for man himself and his safety must always form the chief interest of all technical endeavours. Never forget this in the midst of your diagrams and equations.

------ Einstein.

DMI

For Further Information, Please contact:asitbangra@rediffmail.com

Thanks

Representation of results

Risk Uncertainty

Generic Sources

(A) Model uncertainty

Is the model adequate?

Is uncertainty introduced by mathematical/numerical approximations?

If the model is valid over a certain range, is it being used outside that range?

(B) Model input data

(i) Data may be incomplete or biased.Have all relevant equipment failures been considered?

(ii) Do the available data apply to the particular case?

(iii) Is the method of data analysis valid?

(C) Quality

(i) Has the analysis been taken to sufficient depth?(ii) Have all human error and all common-cause failures been considered?(iii) Have all important physical processes been treated?(iv) Have all important event sequences been considered?

21

Chapter – IVA (Sec. 41A to Sec. 41H)

Soon after the Bhopal gas disaster the necessity to incorporate the chapter IVA in the Factories Act 1948 by supplementing the Section 41 with Sections (41A to 41H) was realized & with in three years that is in 1987 this important chapter from the point of view of SHE was introduced in the Act to covers the safety, health & environmental aspects relating to hazardous processes.

• Sec. 41A - specifies the Constitution of Site Appraisal Committees to be formed by the State Government for the purpose of advising it to consider application for grant of permission for the initial location of a factory involving a hazardous process or for the expansion of any such factory in the state.

• Sec. 41B - specifies to ensure the Compulsory discloser of information by the occupier regarding dangers, including health hazards & the measures to overcome such hazards arising from the exposure to or handling of the materials or substances in the manufacture, transportation, storage & other processes, to the workers employed in the factory & should draw up an on-site emergency plan & detailed disaster control measures for his factory & make known to the workers employed therein & to the general public living in the vicinity. The occupier should lay down measures for handling, transportation & storage of hazardous substances in side the factory premises & the disposal of such substances outside the factory premises & publicise them in the prescribed manner among the workers & the general public living in the vicinity.

PROVISION RELATING

TO HAZARDOUS

PROCESSES

Factors Contributing to the Accident :Design The plant was over designed by 150 %, at the insistence of

the UC Head Quarters and against the advice of the UC personnel in Bhopal.

Process design allowed for long-term storage of very large quantities of MIC in tanks

A non-MIC route could have been chosen as was used by UC earlier

Water sprays were designed to reach only 12-15 meters although the gases from the flare were released at 30 meters. Connection between relief-valve vent header and the

process-vent header, allowing water ingress into the storage tank

Maximum allowable scrubber pressure was 15 psi while the rupture disc allowing the gas to come into the scrubber was set at 40 psi.

• The public, media, legislators, governments, judiciary, sociologists, lawyers, economists, NGOs became proactive• Apart from national organisations, international organisations also got involved (ILO, WHO, IAEA, UNEP, UNDP, WB, ADB, etc.)• Companies drastically reduced storage inventories,imparted better training, adopted ‘Responsible Care’Governments adopted several and severe legislations More thorough accident investigations Significant liabilities imposed Companies carry higher insurance, also mandatory PLI Accident databases to help the process industry Stricter process industry licensing requirements Colleges started teaching process safetyAIChE set-up CCPSEU set-up ECPSIndia set-up DMI in Bhopal

After-Effects: Changes ushered in by Bhopal Accident

Research Areas

Dow’s ‘Chemical Exposure Index’ for gaseous releases.•Researching in process safety management

• Good science based legislation instead of ‘knee-jerk’

reactions

• Active research in universities and industry

• CFD modeling of fire, explosions and gas dispersion

New paradigms on Inherently safer design and Technology transfer

After-Effects: Changes ushered in by Bhopal Accident

Consequence Zones

• 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).

Risk Evaluation

To identify which activity has the most important contribution to the individual and societal risk.

For each activity, to identify which accident scenarios have the most important contribution to the risk.

To determine the minimum distance between the industrial site and the off-site population.

IS:15656 (HIRA) 2006

INDIVIDUAL RISK CRITERIA FOR PIPELINES

Fatality Risk Transect of pipeline

(C) Selection of Plant Site Depend on local wind speed and direction, frequency of stagnant weather periods, topography etc.

Residential Area

Dominant Wind Direction

Plant Location

Ocean

More suitable Plant Location