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QUANTITATIVE RISK ANALYSIS REPORT BPCL: BUDGE BUDGE OIL INSTALLATION

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FOREWARD

Quantitative risk analysis can be defined as “The development of a quantitative estimate of risk based on engineering evaluation and mathematical techniques for combining estimates of incident consequences and frequencies in correlation with measures to combat accidental menace”. It also helps to determine what damage could be caused by accidental releases of toxic, flammable or explosive materials and the incidents which could lead to their release. When such incidents represent a major hazard to life or property, then efforts should be made to reduce damage, which the incident could cause as well as reduce the probability of such incidents occurring. Probability of such occurrence can well be minimized by altering such things as the manufacturing process, the safety systems, the procedures for training, testing and maintenance. For reducing the damage which the incident could cause the measures adopted could be introducing process changes or alternative process, reducing the inventories of hazardous materials, providing robust secondary containment system, modifying site layouts, removing to a different site of safer ambience or by improving control and management techniques. Carrying out a risk analysis study is a statutory requirement in India under the Factories Act 1948 for factories coming under the preview of “Hazardous Process” as defined in the act. This is required while obtaining permission for the initial location of the factory or when any expansion is proposed or as a regular process to be augmented periodically as per the need. Statutory authorities can also call for risk analysis study to be carried out by a plant if in their opinion it is deemed to be necessary. The risk analysis study along with disaster analysis survey is being undertaken BY M/S SONAR BHARAT ENVIRONMENT & ECOLOGY PVT.LTD, KOLKATA, at the behest of M/S BHARAT PETROLEUM CORPORATION LIMITED, OIL INSTALLATION, BUDGE BUDGE, WEST BENGAL.

The whole objective was to evaluate the consequences of a fire / explosion occurring in the terminal and to evaluate their system, procedures, practices and infrastructure to deal with such incidents.

Various products handled by the Terminal are : Motor Sprit (MS) High Speed Diesel (HSD) Superior Kerosene Oil (SKO) Light Diesel Oil (LDO) Furnace Oil (FO) Aviation Turbine Fuel (ATF) Ethanol


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CONTENTS

Sl.No. Description Page No.

Chapter -1 Executive Summary 3-6

Chapter -2

Installation Details

7-17

Chapter -3 Process Description

18-18

Chapter-4 Risk Analysis 19-23

Chapter-5 Hazard Identification 24-25

Chapter-6 Maximum credible accident analysis (MCAA) approach

26-45

Chapter-7 Risk Assessment

46-51

Chapter-8 Consequence Analysis 52-72

Chapter-9 Risk and Failure Probability 73-74

Chapter-10 Recommendation & Conclusion 75-77


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Chapter-1

EXECUTIVE SUMMARY

BUDGE BUDGE OIL INSTALLATION of BHARAT PETROLEUM CORPORATION LIMITED LTD. is situated at BUDGE BUDGE, Dist : 24 Parganas (S) in West Bengal. The Installation was commissioned in the year 1910. Facilities at the installation being very old, are in immediate need of replacement. The company therefore proposes a revamping programme for the installation. It plays a crucial role in the distribution of petroleum oils to 5 districts around 24 Parganas (S). The products are received through road, rail & barge etc. Mode of transportations and dispatched to the consumers is through road and rail. It occupies an important place in the Bharat Petroleum Oil distribution network. The products handled by the Installation are MS, HSD, SKO,ATF, FO , LDO & Ethanol.

The total area covering in the installation is 39 Acres. NEAREST FACILITIES : Name of Place Telephone No FIRE STATION - Budge Budge (2 KM) Approx. 24701271 POLICE STATION - Port Police Station, Budge Budge 24701213 (1 KM) Approx.

- GOVT. HOSPITAL - Budge Budge ESI Hospital, 24701396 Mahestala (4.5 KM) Approx. AMBULANCE - Budge Budge Municipality 24701366 (1.5 KM) Appeox. RAILWAY STATION - BUDGE BUDGE (3 KM) Approx BUS STAND - Budge Budge (2 KM) Approx.


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ADJOINING PROPERTIES

The population density is around 3700 / Km2 around the installation. There are some shops on the south-east and habitation on the north at a distance of more than 0.5 km from the terminal.

The terminal is bounded on the east by MG Road, River Hooghly on the west, BPCL’s Lube Plant, Tank farm for lube storage & LDO on north and HPCL tank farm and HPCL Tanker loading Gantry on south.

STORAGE FACILITIES:

Present gross tankage capacity of the Installation is 78086 Kl in 18 above ground and 9 underground tanks.

The existing tanks and other allied facilities like TLF Gantry will be dismantled.

11 above ground tanks and 9 underground tanks along with other facilities like new TLF gantry and TW gantry, automation Equipments will be installed in phases.

In the 1st phases 11 aboveground and 9 underground tanks will be dismantled.

11new above ground tanks and 9 new underground tanks, TLF gantry will be installed while existing 9 above ground tanks with aggregate capacity of 50522 Kl will remain in operation till commissioning of the 1st phase..

In the 2nd phase, 9 existing above ground tanks will be demolished and 6 new above ground tank will be installed. After commissioning of the 11 new above ground tanks & 9 underground tanks capacity of the installation will stand at 50522 Kl.


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MANPOWER OF BUDGE BUDGE INSTALLATION :

Total manpower of the Terminal is 246 as mentioned hereunder:

SR. INSTALLATION MANAGER - 01 SR.MANAGER LOBP INCHARGE - 01 OFFICER - 35 STAFF (Clerical & Field) - 59 SECURITY (COMPANY) - 15 SECURITY (Contractor) - 26 WORKMAN (Contractor) - 109 TOTAL = 246

ACTIVITIES

BUDGE BUDGE Installation of BHARAT PETROLEUM CORPORATION LIMITED is involved in the process of receipt, storage and distribution of petroleum products. There is no manufacturing process involved in the present activities of BUDGE BUDGE Installation. These petroleum products are received by BTPN wagons from NRL / Haldia refineries and part of LDO is also received by marine tankers from KRL / outside countries.

.


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The main facilities are summarized as under

Storage

Proposed .- 11 Above Ground and 9 Under Ground tanks)

TLF Gantry 2 Gantry of 8 bays each with 16 loading points..

Tanker wagon unloading facility – Tank wagon Gantry for unloading 50 BTPN wagons.

DG Sets. 3 no’s rating of which are 500 KVA -2 125 KVA -1

FIRE FIGHTING FACILITIES Fire Water Storage. 2 x 4976 kl Jockey Pumps. 2 x 60 kl Fire Water pumps. 3 x 682 kl, 2 x 682 kl(Stand by) Storage Tank with active water protection.

I. Fixed Roof & Floating Roof tanks are fitted with sprinkler System and foam system.

II. Floating Roof tanks are planned with Rim seal protection. III. Hydrants Monitors are provided at all strategic point including TLF area, Tank farms, Pump House, Tank Truck parking area, etc.

Fire extinguishers. As per OISD-117

Hydrants & Monitors. As per OISD-117


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Chapter 2

INSTALLATION DETAILS

2.0 INTRODUCTION

M/s B.P.C.L will has undertaken a revamping programme for replacement of

the existing tanks along with other facilities like TLF gantry etc. The

Installation is located on a plot measuring 39.acres

2.1 DESCRIPTION OF INSTALLATION FACILITY

Tank Wagon Loading / Unloading facility, and unloading from the

Ocean Tankers. Tank Farm Truck Loading facilities/TW loading facility. Fire- fighting system including 2 nos. fire water tanks each of 4976

KL capacity Electrical installation Instrumentation Drinking water and rain water Harvesting System. Building Utility

LAND, LOCATION AND LAYOUT

Budge Budge oil installation of Bharat petroleum corporation limited . Is

situated at Budge Budge, dist: 24 parganas (s) in West Bengal. The installation

was commissioned in the year 1910. It plays a crucial role in the distribution of

petroleum oils to 5 districts nearer to 24 parganas (s). The products are

received through road, rail & barge. Mode of transportations for dispatch to the

consumers are through road. It occupies an important place in the Bharat

Petroleum oil distribution network. The products handled by the installation are

MS, HSD, SKO, ATF, FO, LDO, MTO & SBP.

The layout has been prepared strictly as per prescribed OISD standards and

guidelines. The safety distances are maintained as per the standard

guidelines. The road network is designed in such a way that the movement of

vehicle carrying bulk petroleum products is smooth.


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PROCESS DESCRIPTION AND OPERATING PROCEDURES

The Product are received through BTPN railway wagons / Ocean Tankers

Unloading of different products in their designated tanks through TWD Pumps

Storage in Above Ground Tanks & Under Ground Tank

Loading in Tank Wagons & Tank Trucks through TWF/TLF Pumps

.

The detail process descriptions are discussed below :

2.2 PRODUCT PIPELINE SYSTEMS

The pipeline from railway siding / jetty to installation and within the terminal

have been constructed and designed in accordance with relevant API

codes/OISD standards.

The following pipeline systems are in existence:

a) From the Unloading Gantry to the terminal unloading pump house:

Dedicated pipelines for HSD / MS / SKO / FO /LDO/ ATF have been laid in

between two spurs to receive products from rakes. Products are received

through BTPN wagons, Ocean Tankers. Pipe lines have been laid between

the jetty and the storage tanks for receiving products from the Ocean

Tanker.

b) Pipelines within the terminal consists of the followings :

1. Pipelines from Unloading pump house to the Tank Farm : There

are dedicated pipelines for individual products.

2. Pipelines from Tanks to Loading pump house : There are dedicated

pipelines for individual products.


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Pipelines from Loading pump house to the TLF Gantry. There are dedicated

pipelines for individual products. Tank wise dedicated pipelines have been

provided. The lines connecting the loading arms are of 3”NB Size. The loading

arms and the metering assembly are of 3”NB Size.

2.3 Receipt

Petroleum products are received through:

1) Tank wagons received is mainly from Numaligarh

2) Import through Ocean Tankers

2.4 Petroleum Product Unloading

Petroleum products received by BTPN wagons at TW unloading gantry

located at site. Materials are unloaded through pumps earmarked for each

product. dedicated pipe lines for HSD/SKO/FO/MS/ATF/ LDO have been laid

to receive product from rakes.

Ocean Tankers are unloaded from Budge Budge oil jetty through dedicated

pipe lines.

Tank Wagon Unloading Pumps


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2.5 TANK FARM:

The POL installation is provided with storage tanks for Class A, B & C

petroleum products.

Product MS HSD SKO FO ETHANOL

Class A B B C A

The tanks for Class A are floating roof tanks and fixed roof tanks are provided

for Class B & class C products. The design and construction of storage tanks

are according to Indian regulations IS 803 and/or API 650. All tanks are

provided with sprinklers and foam feeding devices as per the OISD

regulations. All the storage tanks are equipped with automatic level indicators

with high / high high level alarms.

The design of the installation is according to Indian standards OISD 117,116

and as per recommendation of Chief Controller of Explosives, Nagpur

(CCOE)


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STORAGE

Storage of products: The following storage capacities are envisaged:

PROPOSED ABOVE GROUNG STORAGE

SL NO

TANK NO DIA (M) LENGTH (M) GROSS CAPACITY

PRODUCT

1 T1 29.00 13.500 8917 HSD 2 T2 29.00 13.500 8917 HSD 3 T3 20.00 13.500 4241 ATF 4 T4 20.00 13.500 4241 ATF 5 T5 24.00 12.000 5429 MS 6 T6 24.00 12.000 5429 MS 7 T7 12.60 13.500 1683 SKO 8 T8 12.60 13.500 1683 SKO 9 T9 20.00 13.500 4241 FO 10 T10 20.00 13.500 4241 LDO 11 T11 4.00 16.000 200 Ethanol

PROPOSED UNDERGROUNG STORAGE

SL NO

TANK NO DIA (M) LENGTH (M) CAPACITY PRODUCT

1 UG T1 3.20 12.60 100 SPEED 2 UG T2 3.20 12.60 100 SPEED-97 3 UG T3 3.20 12.60 100 HI-SPEED 4 UG T4 3.20 12.60 100 ATF 5 UG T5 3.20 12.60 100 SLOP 6 UG T6 4.00 16.00 200 HEXANE 7 UG T7 4.00 16.00 200 MTO 8 UG T8 4.00 16.00 200 SBP 9 UG T9 4.00 16.00 200 ETHANOL


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Tank Truck Loading Pumps

2.6 Fire detection and protection system

The fire protection and detection system are in accordance with OISD 117.

Portable fire extinguishers of 10-75 kg are installed on pump stations, tank

farms and buildings, the size depending on the object concerned. Electrical

rooms are protected by Carbon dioxide (CO2) fire extinguishers. Mobile fire

fighting vehicles with foam monitors, hoses, etc.have been provided. Fixed

fire fighting monitors are located at the pump station and truck loading

gantries, each with a capacity of 144 m3/hr. sufficient hydrants are installed in

the POL installation, with the hydrants spaced at a maximum distance of 30m.

The tanks are equipped with fixed cooling water and foam installations and

mobile vehicles and equipment (monitors, hoses, branch pipes, etc.) are

provided to handle field fires.


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Table below will show fire water storage tank, fire water pumps,

Fire Water Storage Tank

Sr.No No’s Capacity (KL) 1 2 4976

Fire Water Pump

Sr.No Category No’s Capacity 1

Main Pump ( Engine Driven)

3 682 KL/Hr

2 Stand By 682 KL/Hr

2 Jockey Pump ( Electric Motor Driven)

1 60 KL/Hr

1 Stand By 60 KL/Hr

FIRE ALARM SYSTEM

Conventional type Fire alarm systems are provided in following areas; a) Truck Loading b) Tank Farm c) Office / Admn. Building d) Sub-Stations

SOURCE OF SIGNALING

The source of signaling is considered as ESD. These are considered for

the areas where manual warning is to be initiated on notice of fire. They

are mostly provided for open areas or near to access doors, truck

loading, pump house, tank farm, administrative building, etc.


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2.7 ELECTRICAL INSTALLATION

The scope covers the basic concepts of the following:

Receiving of HT Power supply from Main 11kV Power Grid Distribution Transformer. Distribution of LT power supply. Cabling System. Building and Area Lighting. Approach Road Lighting (Approx. 1.2 kms) Earthing and Lightning Protection. Power Factor Improvement. Battery Bank & Battery Charger. UPS system. Diesel Generating Set.

2.8 PLANT AUTOMATION SYSTEM

CCTV Cameras will be installed for supervision of key activities in the

installation (e.g. pump stations, truck loading facilities and other strategic

areas) as well as for the supervision of security of the installation.

The fire water pumps will be activated automatically. The jockey pump will

maintain the pressure automatically.

VHF communication system containing a base station with antenna (1 set) and

number of portable VHF Trans-receivers (41 sets) with charger units will be

provided for providing communication within the plant premises. The base

station will be located in the administrative office. Public address system is at

the security room.

The fire water pumps will be activated automatically. When the fire-water

header pressure is low, the jockey pump maintains the pressure automatically.

The foam is sucked through Venturi system. The storage installation is having

3 KM range siren for onsite /off site disaster management.


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Automation in the operational activity will be implemented .Automated

operation on tank body valve when product level reaches critical height.

Installation of ROV, High High level Alarm, lader gauge, Servo level gauge,

ESD, Safety PLC to be integrated with process fields

2.9 HYDROCARBON DETECTORS

The Class-A tank farm and product pump house manifold are planned to be

equipped with Hydrocarbon detectors. These detectors will sense any

leakages and communicate the same to the control room with audible alarm

at Tank farm locations.

Main objective of the Hydrocarbon Detectors is to detect hydrocarbon gas

concentrations in the Installation and initiate alarm or shutdown system as the

case may be, at pre-defined levels to prevent any hazardous events and act

as independent safety layers for mitigation of consequences to achieve

overall process safety requirements of the plant. Hydrocarbon Detection

system is designed to perform its function during normal, abnormal and

design basis conditions. Control system is based on open architecture system

topology with fault tolerant network capabilities.

The major components of the TFMS system are as follows:

Field Instruments

Radar Level gauge

Local Level Indicator

a. Automation System for Petroleum Product Loading Stations

The automation system for truck loading stations consists of the following

sections: This system ensures optimization of economy and safety in

operation.


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Volumetric Flow Meters

Batch Controllers

Plant control system Programmable Logic Controller (SMPS)

Operator’s Interface console

i. Metering System

ii Batch Controller

iii Plant control system Programmable Logic Controller (SMPS)

iv Control and Interlocking System

v Integrated Control System

vi Emergency Shutdown System

2.10 WATER SUPPLY SYSTEM

Drinking Water System

Water requirement for domestic and other purposes are met from

supplies by KMWSA

Rain Water Harvesting System

There is a well laid out Rain water Harvesting System

Waste Water Treatment

Waste water is generated due to area cleaning /housekeeping and

occasional tank cleaning operations (Once in five years) at the POL

terminal.

Oil contaminated waste water is generated mainly from pump areas,

manifolds, truck loading, etc. only when spillage is washed with water as

well as occasional tank washing. The direct discharge areas i.e. those

areas within the POL terminal where leakage is likely to occur during

normal operations is to be provided with leak-proof curbing. These

curbed areas are connected to the Oil-Water Separator (OWS) system

for treatment of oily wastewater generated. Indirect discharge areas

such as dykes, etc. are connected to the OWS. The capacity is


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adequate to take care of, the oily waste water to be handled from the

facility during the monsoon season.

The separated oil consisting of a comparatively dry floating layer is

removed and is drained into a common draw –off pipe discharge to the

oil pit. This collected oil is sold to third party for off-site recovery or

recycling.

Separate storm water drainage system is provided at the facility. The

non-contaminated rain water is discharged directly to a drain However,

particularly during the monsoon; any oil-contaminated rain water is led

to the OWS for treatment prior to discharge.


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Chapter-3

PROCESS DESCRIPTION

RECEIVE PETROLEUM PRODUCTS

BY TANK WAGON/OCEAN

TANKER

STORE IN ABOVE GROUND (FIXED & FLOATING ROOF TANK) UNDER GROUND TANKS.

LOAD TANK WAGON AND TANK TRUCK

FOR DELIVERY,


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Chapter-4

RISK ANALYSIS 4.1 PREAMBLE

As the Installation handle various petroleum products which have got potential

of fire / explosion hazard for itself, hence it is necessary to evaluate the Risk

due to the Installation. Accordingly, M/s. Sonar Bangla Environment & Exports

(P) Ltd. (SBEE) has been retained by M/s.BPCL as consultant to carryout

Risk Analysis Study for the proposed revamping project.

4.2 SCOPE OF THE STUDY

The risk assessment has been carried out in line with the requirements of

various statutory bodies:

Identification of potential hazard areas;

Identification of representative failure cases;

Identification of possible initiating events;

Assess the overall damage potential of the identified hazardous events

and the impact zones from the accidental scenarios;

Consequence analysis for all the possible events;

4.3 PROPOSED FACILITY

M/s B.P.C.L will has undertaken a revamping programme for replacement of

the existing tanks for storage of MS, HSD, SKO, FO, LDO & ATF and small

quantity of ethanol. Proposed storage capacity of each product is given

below:


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PROPOSED ABOVE GROUNG STORAGE

SL NO

TANK NO DIA (M) LENGTH (M) GROSS CAPACITY

PRODUCT

1 T1 29.00 13.500 8917 HSD

2 T2 29.00 13.500 8917 HSD

3 T3 20.00 13.500 4241 ATF

4 T4 20.00 13.500 4241 ATF

5 T5 24.00 12.000 5429 MS

6 T6 24.00 12.000 5429 MS

7 T7 12.60 13.500 1683 SKO

8 T8 12.60 13.500 1683 SKO

9 T9 20.00 13.500 4241 FO

10 T10 20.00 13.500 4241 LDO

11 T11 4.00 16.000 200 Ethanol

PROPOSED UNDERGROUNG STORAGE

SL NO

TANK NO DIA (M) LENGTH (M) CAPACITY PRODUCT

1 UG T1 3.20 12.60 100 SPEED

2 UG T2 3.20 12.60 100 SPEED-97

3 UG T3 3.20 12.60 100 HI-SPEED

4 UG T4 3.20 12.60 100 ATF

5 UG T5 3.20 12.60 100 SLOP

6 UG T6 4.00 16.00 200 HEXANE

7 UG T7 4.00 16.00 200 MTO

8 UG T8 4.00 16.00 200 SBP

9 UG T9 4.00 16.00 200 ETHANOL


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4.4 Hazard Identification

Identify potentially hazardous materials that can cause loss of human life/injury, loss of properties and deterioration of the environment due to loss of containment.

Identify potential scenarios, which can cause loss of containment and consequent hazards like fire, explosion and toxicity.

4.5 Consequence Analysis

Analysis of magnitude of consequences of different potential hazard

scenarios and their effect zones. Consequence analysis is a measure of potential hazards and is

important for taking precautionary measures for risk reduction as well as mitigation of effect in case of such accidents happening.

This report has been prepared by applying the standard techniques of risk assessment and the information provided by Budge Budge BPCL.

4.6 Glossary Of Terms Used In Risk Assessment

The common terms used in Risk Assessment and Disaster Management are elaborated below: “Risk” is defined as a likelihood of an undesired event (accident, injury or death) occurring within a specified period or under specified circumstances. This may be either a frequency or a probability depending on the circumstances. “Hazard” is defined as a physical situation, which may cause human injury, damage to property or the environment or some combination of these criteria. “Hazardous Substance” means any substance or preparation, which by reason of its chemical or physico-chemical properties or handling is liable to cause harm to human beings, other living creatures, plants, micro-organisms, property or the environment. “Hazardous Process” is defined as any process or activity in relation to an industry, which may cause impairment to the health of the persons engaged or connected therewith or which may result in pollution of general environment. “Disaster” is defined as a catastrophic situation that causes damage, economic disruptions, loss of human life and deterioration of health and health services on a scale sufficient to warrant an extraordinary response from outside the affected area or community. Disaster occasioned by man is factory fire explosions and release of toxic gases or chemical substances etc.


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“Accident” is an unplanned event, which has a probability of causing personal injury or property damage or both. “Emergency” is defined as a situation where the demand exceeds the resources. This highlights the tropical nature of emergency “It is seen after experience that enough is not enough in emergency situations. Situations of this nature are avoidable but it is not possible to avoid them always.” “Emergency Preparedness” is one of the key activities in the overall management. Preparedness, though largely dependent upon the response capacity of the persons engaged in direct action, will require support from others in the organization before, during and after an emergency.

4.7 SCOPE OF STUDY

The risk assessment has been carried out in line with the requirements of various statutory bodies for similar type of projects: Identification of potential hazard areas Identification of representative failure cases Identification of possible initiating events Assess the overall damage potential of the identified hazardous events

and the impact zones from the accidental scenarios; Consequence analysis for all the possible events; Furnish specific recommendations on the minimization of the worst

accident possibilities.


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FLOW CHART FOR RISK ANALYSIS STUDY

YES

START

PLANT VISIT

DATA COLLECTION PROCESS DESCRIPTION PROCESS CONTROL LOOPS PRI/PFD OPERATING MANUAL START UP/SHUT DOWN PLOT PLAN METEOROLOGICAL DATA PAST ACCIDENTS DATA ALL RELEVANT PHYSICAL CHEMICAL DATA OF

SELECT THE

CLASSIFY VESSEL/EQUIPMENT

INVENTORY ANALYSIS

CALCULATE EFFECT

IDENTIFICATION OF HAZARD

IS FE/FET IN SEVERITY

ADOPT CHECK LIST APPROACH

CONSEQUENCE

PLOT DAMAGE DISTANCE


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Chapter-5

HAZARD IDENTIFICATION 5.1 INTRODUCTION

Identification of hazards in the terminal is of primary significance in the

analysis, quantification and cost effective control of accidents involving

chemicals and process. A classical definition of hazard states that hazard is in

fact the characteristic of system/plant/process that presents potential for an

accident. Hence, all the components of a system/plant/process need to be

thoroughly examined to assess their potential for initiating or propagating an

unplanned event/sequence of events, which can be termed as an accident.

Typical schemes of predictive hazard evaluation and quantitative risk analysis

suggest that hazard identification step plays a key role.

Estimation of probability of an unexpected event and its consequence form

the basis of quantification of risk in terms of damage to property, environment

or personnel. Therefore, the type, quantity, location and conditions of release

of a toxic or flammable substance have to be identified in order to estimate its

damaging effects, the area involved and the possible precautionary measures

required to be taken. The following two methods for hazard identification have

been employed in the study.

Identification of hazardous storage units based on relative ranking

technique, viz, Fire-Explosion and Toxicity index (FE & TI); and

Maximum Credible Accident Analysis (MCAA)


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5.2 CLASSIFICATION OF MAJOR HAZARDOUS SUBSTANCE

Hazardous substances may be classified into three main classes namely

flammable substances, unstable substances and toxic substances.

Flammable substances require interaction with air for their hazard to be

realized; under certain circumstances vapours arising from flammable

substances when mixed with air may be explosive especially in confined

spaces. However, if present in sufficient quantity such clouds may explode in

open air also.

Unstable substances are liquids or solids, which may decompose with such

violence so as to give rise to blast waves.

Finally, toxic substances are dangerous and cause substantial damage to life

when released into the atmosphere. The ratings for a large number of

chemicals based on flammability, reactivity and toxicity are given NFPA

Codes 49 and 345M.


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Chapter -6

MAXIMUM CREDIBLE ACCIDENT ANALYSIS (MCAA) APPROACH 6.1 INTRODUCTION

A Maximum Credible Accident (MCA) can be characterized, as an accident

with a maximum damage potential, which is still believed to be probable.

MCA analysis does not include quantification of probability of occurrence of

an accident. Moreover, since it is not possible to indicate exactly a level of

probability that is still believed to be credible, selection of MCA is somewhat

arbitrary. In practice, selection of accident scenarios representative for a

MCA-Analysis is done on the basis of engineering judgment and expertise in

the field of risk analysis studies, especially accident analysis.

Major hazards posed by flammable storage can be identified taking recourse

to MCA analysis. This encompasses certain techniques to identify the hazards

and calculate the consequent effects in terms of damage distances of heat

radiation, toxic releases, vapour cloud explosion etc. A host of probable or

potential accidents of the major units in the complex arising due to use,

storage and handling of the hazardous materials are examined to establish

their credibility. Depending upon the effective hazardous attributes and their

impact on the event, the maximum effect on the surrounding environment and

the respective damage caused can be assessed.

As an initial step in this study, a selection has been made of the processing

and storage units and activities, which are believed to represent the highest

level of risk for the surroundings in terms of damage distances. For this

selection, following factors have been taken into account:

Type of compound viz. flammable or toxic Quantity of material present in a unit or involved in an activity and Process or storage conditions such as temperature, pressure, flow,

mixing and presence of incompatible material.


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In addition to the above factors, location of a unit or activity with respect to

adjacent activities is taken into consideration to account for the potential

escalation of an accident. This phenomenon is known as the Domino Effect.

The units and activities, which have been selected on the basis of the above

factors, are summarized, accident scenarios are established in hazard

identification studies, whose effect and damage calculations are carried out in

Maximum Credible Accident Analysis Studies.

6.2 METHODOLOGY

Following steps are employed for visualization of MCA scenarios:

Chemical inventory analysis Identification of chemical release and accident scenarios Analysis of past accidents of similar nature to establish credibility to

identified scenarios; and Short-listing of MCA scenarios

6.3 COMMON CAUSES OF ACCIDENTS

Based on the analysis of past accident information, common causes of

accidents are identified as:

Poor house keeping

Improper use of tools, equipment, facilities

Unsafe or defective equipment facilities

Lack of proper procedures

Improvising unsafe procedures

Failure to follow prescribed procedures

Jobs not understood

Lack of awareness of hazards involved

Lack of proper tools, equipment, facilities

Lack of guides and safety devices, and

Lack of protective equipment and clothing


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6.4 FAILURES OF HUMAN SYSTEMS

An assessment of past accidents reveal human factor to be the cause for over

60% of the accidents while the rest are due to other component failures. This

percentage will increase if major accidents alone are considered for analysis.

Major causes of human failures reported are due to:

Stress induced by poor equipment design, unfavorable environmental

conditions, fatigue, etc.

Lack of training in safety and loss prevention

Indecision in critical situation; and

Inexperienced staff being employed in hazardous situation

Often, human errors are not analyzed while accident reporting and accident

reports only provide information about equipment and/or component failures.

Hence, a great deal of uncertainty surrounds analysis of failure of human

systems and consequent damages.

6.5 MAXIMUM CREDIBLE ACCIDENT ANALYSIS (MCAA)

Hazardous substances may be released as a result of failures or

catastrophes, causing possible damage to the surrounding area. This section

deals with the question of how the consequences of release of such

substances and the damage to surrounding area can be determined by

means of models.

It is intended to give an insight into how the physical effects resulting from

release of hazardous substances can be calculated by means of models and

how vulnerability models can be used to translate the physical effects in terms

of injuries and damage to exposed population and environment. A disastrous

situation in general is due to outcome of fire, Vapour Cloud explosion or toxic

hazards in addition to other natural causes, which eventually lead to loss of

life, property and ecological imbalance.


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Major hazards posed by flammable storage can be identified taking recourse

to MCA analysis. MCA analysis encompasses certain techniques to identity

the hazards and calculate the consequent effect in terms of damage distances

of heat radiation, toxic release, vapour cloud explosion etc. A host of probable

or potential accidents of the major units in the complex arising due to use,

storage and handling of the hazardous materials are examined to establish

their credibility. Depending upon the effective hazardous attributes and their

impact on the event, the maximum effect on the surrounding environment and

the respective damage caused can be assessed. The MCA analysis involves

ordering and ranking various sections in terms of potential vulnerability.

6.6 ANALYSIS OF PAST ACCIDENTS Numerous accidents involving different hydrocarbons in process plants have

been reported. Table provides a worldwide list of all such accidents reported

since 1917. More than 1000 people have received injuries of various intensity

and more than 200 people died due to these accidents. The major causes of

accident involving fraction are given below.

i) Fire, over pressure, explosions 19

Nos

ii) Overfilling, loading/unloading and pipeline ruptures 5 Nos

iii) Collision and impact of rail/road tankers during transportation 2 Nos ---

45 Nos

It can be seen that the storage areas and transportation vehicles of C

fractions are most vulnerable to accidents. More than 10 accidents out of the

45 incidents examined have ended in BLEVE situation. Rest of them has

caused fires and explosions.


Page 30 of 77

MAJOR ACCIDENT IN PROCESS INDUSTRIES (LIGHTER FRACTIONS OF HYDROCARBONS)

Sl. No.

Year Location Chemical Event Deaths/Injuries

01 1944 Cleveland, Ohio Gasoline Fire & Explosion

128 D, 200-400 I

02 1949 Perth, NJ Hydrocarbon Fire 4 D 03 1955 Whiting, Ind. Naphtha Explosion 2 D, 30 I 04 1956 New York, USA Ehylene -- -- 05 1958 Signal Hill, California Oil Forth Fire 2 D 06 1962 Ras Tanura, Saudi

Arabia Propane Fire 1 D, 114 I

07 1963 Rexas, USA Polypropylene Explosion - 08 1964 Fackass Flats, Mev. Hydrogen Explosion - 09 1966 Feyzin, France Propane Fire &

Explosion 18 D, 81 I

10 1966 Larose, La NGL Fire (on pipeline)

7 D

11 1966 W. Germany Methane Explosive (failure of pipe)

3 D, 83 I

12 1967 Buenos Aires Propane -- -- 13 1968 Pernis, Netherlands Oil slopes Explosion 9 D, 85 I 14 1968 Terrylown, USA Propane -- -- 15 1968 Kennedale, Texac Gasoline Explosion (on

road tnkers) 28 I

16 1969 Pnerts la Cruz Light Hydrocarbon

Explosion 5 D

17 1970 Liden Niji Oil Refinery Fire -- 18 1970 Port Hudson, MO Propane Explosion (on

pipeline) --

19 1970 Mont Belview, Tex Butane Explosion (on pipeline)

--

20 1971 Longview, Tex Ethylene Explosion 4 D, 60 I 21 1972 Hearne, Tex Crude Oil Fire &

Explosion 1 D, 2 I

22 1972 Lynchbriod Va Propane Fire & explosion 1 D, 2 I 23 1972 Netherlands Hydrogen Explosion 4 D, 4 I, 24 1972 New Jersey, Turnpike,

New Jersey Propane Explosion (on

road tanker) 2 D

25 1972 Brazil Butane Explosion UVCE

37 D, 53 I

26 1972 Billings, Mont. Butane Explosion 4 I 27 1973 St. Amandles-Eaux

France Propane Explosion (on

road tanker) 5 D, 40 I

28 1973 Staten Island, NY Gasoline Fire (in empty storage tank)

40 D


Page 31 of 77

Sl. No.

Year Location Chemical Event Deaths/Injuries

29 1974 Decatur, III Propane Explosion (on railway)

7 D, 152 I

30 1974 Florida, USA Propane Explosion -- 31 1974 Griffith Ind. Propane Fire -- 32 1974 India Crude Oil Explosion -- 33 1974 Czechoslovakia Ethylene Explosion UVCE 14 D, 79 I, 34 1974 Mississippi,

USA Butane Explosion UVCE 24 I,

35 1975 Beck, Netherlands

Hydrocarbons Explosion 1 D

36 1975 Lousiania, USA Propane Flammable -- 37 1975 Philadelphia Pa Crude Oil

Vapour Explosion 8 D, 2 I

38 1975 Antwerp Belgium

Ethylene Explosion UVCE --

39 1976 Los Angles, California

Gasoline -- 6 D, many injured

40 1977 India Hydrogen Explosion 20 I 41 1978 Waverly, Tenn Propane Explosion (on

railway) 12 D, 50 I

42 1979 Bantry Bay, Eise Oil Explosion (on oil tanker at terminal)

50 D,

43 1988 India Naphtha Pool Fire 25 D, 23 I


Page 32 of 77

PAST ACCIDENTS (C3 Fraction)

Table-10

Accidents Year

Date Country Address Injuries Scene

5230 1951-0707

USA Port Newwark, New Jersy

11 Explosion and fire of 70 tanks at a tank yard

3914 1955-0719

D Ludwigshafen 2 Explosion and fire at tank wagon

4255 1956-0729

USA Amarillo, Taxes .> 32 BLEVE of 3 oil tanks

8888 1956-1022

USA Cottage Grove, Oregon

12 BLEVE of LPG storage tank

0224 1957-0108

CDN Montreal 1 Overflow butane sphere

0375 1958-0103

D Celle Explosion of tank wagons

353 1959-0528

USA MC KAittrict 2 Explosion of storage tanks

308 1966-0104

F Feyzin 48 Explosion of tanks at refinery

3906 1968-0101

USA Dunreith BLEVE of tank wagon after derailment caused by broken rail

307 1969-1205

USA Laurel, Mississippi 33 Derailment of train with 15 tank wagons, Explosion & Fire

7624 1969-1203

NL Unknown Rupture of tank by fire

361 1970-1621

USA Cresent City, LLinols

66 Derailment and explosion of nine tank wagons

373 1971-1019

USA Houston, Texas 50 Derailment of 18 tank wagons explosion and fire

3891 1971-1118

NL Nieuwenhoorm Explosion of cylinder caused fire of Terminal

3455 1972-0209

USA Twksburry, Massachusetts

21 Collision tank vehicle with lines of tank causing BLEVE of storage tank

681 1972-0330

BR RIO De Janerio 53 BLEVE of a l tank

2521 1973-0705

USA Kingam, Arizona 96 BLEVE of tank wagon caused explosion and fire of LPG distribution plant

471 1973 USA New York Rupture of propylene of storage tank, level of tank


Page 33 of 77

Accidents Year Date

Country Address Injuries Scene

2549 1974-0111

USA West Saint Paul, Minnesoia

6 Explosion of tank

2544 1974-0212

USA Oneonta, New York 25 Derailment and explosion of tank wagons

667 1974-0417

D Bielefeld, Brackwedde

Derailment of 36 tank wagons, fire explosion and BLEVE

7527 1974-1202

NL Haariennermeer- 1 Fire at car repair

4260 1975-0622

USA DES Moines, IOWA 3 Derailment and rupture of tank wagons

7352 1976-0825

NL Loosdrecht Fire and explosion in car

3918 1976-0831

USA Gadsen, Alabama 28 Explosion of tank vehicle and storage tanks during transipment

2071 1976-1126

USA Belt, Montana 22 Derailment and explosion of several tank wagons

4137 1977-0206

USA Boynton Beach, Florida

BLEVE of LPG cylinders caused by derailment freight train

669 1977-0220

USA Dallas, Taxas 1 Derailment of tank wagons

4235 1977-0423

USA Long Island, New York

1 BLEVE cylinders on lorry

3377 1977-0519

USA Hawley, Pennsylvania

Fire and BLEVE of tank on tar

2522 1977-0519

USA Pocono Mountains Pennsylvania

1 Leakage supply line caused explosion vans

618 1978-0222

USA Waverly, jernessee 43 Derailment of several tank wagons caused by broken wheel

2119 1978-0530

USA Texas City, Texas 10 11 tank explored by unknown cause in 45 minutes

209 1978-1218

NL NIJMEGEN BLEVE of tank vehicle at fuel station during transshipment

2736 1978-1218

NL Zwolle 6 Explosion of gas cylinder in measure car

1591 1979-0549

NL Vlaardingen 2 Fire in van and explosion of gas cylinder

1639 1979-0601

NL S. Gravenzande 2 Explosion of gas cylinder during fire in barn

1634 1979-0704

NL Ostflakgee Explosion of two cylinders and one oil tank


Page 34 of 77

Accidents Year


2575 1979-0713

NL Rotterdam Explosion of cylinder in van

1630 1979-0817

NL De MEEM Overheating of kettle with tar caused explosion of gas cylinder

953 1979-0908

USA Pakton, Taxas 8 Derailment of 33 train wagons with chemicals, explosion and fire for 2.5 days

1568 1979-1203

NL Haarlemmermeer Explosion of tank in car

1181 1980-0105

NL Rotterdam 1 Fire in bus station, LPG tank explored

1166 1980-0108

NL Eriecom, River Waa 2 Collision of tanker “Kombi 21” and vessel “Rodort 6” explosion, fire

3922 1980-0303

USA Los Angles, California 2 Overturn and explosion of tank vehicle loaded with gasoline

0706 1980-0606

NL Rotterdam Fire in factory store

2701 1980-0804

NL RAAITE Fire in motor compartment of car, BLEVE of tank

0919 1980 NL Road Breeda to BAVEL

Mobile milling machine with gas tank explored

1520 1980-1125

NL OOSTERMOLDGE 1 Explosion of tank in car during assemble

3419 1980 D Kries Borken Weseko 2 Fire and explosion of tank vehicle

1836 1981-0302

NL Weirden Fire and explosion of gas cylinders in stored caravans

2052 1981-0409

NL Apeldoorn Fire of carabans near LPG installation

2092 1981-0510

NL Haarlem Fire and explosion of storage Barn

2504 1981-0713

NL Beuwingen 1 Explosion of gas cylinder in house

2561 1981-0816

NL Oldeholtrade, Wolvega

1 Explosion of gas tank in car by collision

3988 1981 NL Tiel 1 VW Transporter on fire, tank exploded

4350 1981 USA Unknown 17 BLEVE of cylinder in converted coach

5535 1981 6B Yately, Hahpshire Explosion of car tank in garage

7640 1982-0113

NL Alkmaar Fire and rupture of cylinder explosion of a plumber gas

3949 1982- NL Den hag Cylinder


Page 35 of 77

0525 3960 1982-

0601 NL Haarklem Explosion of a cylinder in

car Accidents Year


3972 1982-0621

NL Grootbroek 1 Cycling person hit fatally by fragment of cylinder

4054 1982-0626

CDN Blairmore, Alberta Derailment and rupture of several tank wagons

7642 1982-0916

NL Unknown Rupture of gas tank in car by overspeed

5681 1982-0928

USA Livingston, Louisiana Derailment freightain by overspeed

4449 1982 ET SUEZ 19 Fire and explosion of gas pipeline

8227 1984-0315

NL Unknown Plastic deformation of tank due to overtheating by fire

8228 1984-0709

NL Rosmalen Rupture of a car link due to fire

7942 1984-0723

USA Romeoville and lemont

22 Explosion and fire at refinery llinois

8235 1984-0921

NL Bruchterveld, Hardenberg

Rupture of cylinder


Page 36 of 77

RELEASE OF HAZARDOUS SUBSTANCE

POOL

VAPOUR

FLASH

IGNITION

FIRE

YES

CONTINUOUS

IGNITION

DISPERSION

VAPOUR CLOUD

EXPLOSION

PRESSURE HEAT

EFFECTS


Page 37 of 77

6.7 PROPERTIES OF MATERIALS HANDLED

Petroleum products like, Motor Spirit (MS), Superior Kerosene Oil (SKO),

High Speed Diesel (HSD) and FO are handled in the Terminal. All these

products are a combination of hydrocarbons and are highly inflammable.

Motor Spirit is a class-A type petroleum liquid (Flash Point <23°C), Superior

Kerosene and High speed diesel are of class B type (Flast Point between

23°C and 65°C) and FO are of C type(Flash point>65o)according to

convention. The products, when spilled from the containment will cause fire if

they get a contact with an ignition source. Incomplete combustion of these

hydrocarbons may generate carbon monoxide, which may cause toxicity as

well as explosion. However, fire is the main hazard. Lower the flash point,

higher is the possibility of ignition and hazard. The light hydrocarbons will

evaporate from these petroleum oil liquids, which may catch fire if they get

into contact with an ignition source. Properties of the products handled are

given in Table.

PROPERTIES OF LIQUID HANDLED

Properties Products

MS SKO HSD FO

1 Boiling point, ºC (range)

30-150 150-300 260-380 50-215

2 Density at 15 ºC 0.73 0.81 0.80 0.95 3 Flash point, ºC <23 >35 >32 >66 4 Vapour press. At 38 ºC

(kg/Cm2 abs) 6-10 0.2 0.1 <0.1 psi

5 Heat of combustion BTU/LB

18,800 21700 18,700 18,800

6 Auto ignition temp ºC 280 210 380 220-250 7 LFL (% V/V) 1.4 0.5 .5 1 8 UFL (% V/V) 7.6 5.0 5.0 5

LFL : Lower Flammability Limit UFL: Upper Flammability Limit


Page 38 of 77

6.8 HAZARDS OF EQUIPMENT/PIPELINE HANDLING PETROLEUM PRODUCTS

The hazard of equipment/pipeline handling petroleum products is the potential

loss of integrity of the containment with subsequent release of liquid causing

fire. The pipelines carry large quantities of petroleum liquid. A rare pipeline

fracture would release large quantities of hydrocarbons. The products would

get collected in the neighbourhood of the pipeline and may lead to a fire

hazard if it gets source of ignition and proper precautions are not taken.

Catastrophic failures of the shell of a storage tank are very rare phenomenon,

which may occur due to earthquake or due to aerial bombardment during war.

However, vapour coming out through the vent line of fixed roof tank or through

vapour seal round the shell in floating roof tanks may be ignited through

lighting. However, such cases are also very rare. In such cases the whole

tank may be on fire. Corrosion in the tanks may cause small holes causing

release of petroleum liquid from the tanks. However, in such cases the oil will

be contained in the dyke. In case of oil spill collected on ground an oil pool will

be formed. An ignited pool of oil is called Pool Fire. It creates long smoky

flames. The wind may tilt the flame towards ground causing secondary fires

and damages. Radiation from the flame can be very intense near the fire but

falls of rapidly beyond 3-4 pool diameters. Such fires are very destructive

within the plant area and near the source of generation.

In case of formation of holes on the above ground pipeline the liquid may

escape in the form of jet and may catch fire if it gets an ignition source.

Damage due to heat radiation from such jets is mostly limited to objects in the

path. However, the ignited jet can impinge on other vessels and the pipelines

causing domino effect.


Page 39 of 77

6.9 BRIEF REVIEW OF INBUILT DESIGN SAFETY

The followings the minimum consideration have been made for tanks:

a) The design and construction of the tanks are carried out according to the

API 650 (latest edition). The floating roof tanks are designed for an internal

pressure equal to atmospheric pressure. Class B fixed roof tanks are

designed for 1.0 kPa of over pressure and -0.5 kPa of vacuum. The design

product filling and withdrawal rates for tanks shall be 1500 cbm/hr

irrespective of the pump-in and pump-out rates. There are separate

nozzles for Product inlet and outlet. All tank drains (rest evacuation and

water drain off) shall be installed at the lowest point of the tank, in order to

guarantee good draining.

b) Annular bottom plates shall be provided for all above ground storage

tanks.

c) Tank bottom design shall include butt welded annular plates. Rectangular

and sketch plates are lap welded such that there is positive and

uninhibited flow of water across the tank bottom to the centre sump. Any

pad or permanent structure in the tank has been provided with appropriate

weep holes to avoid the entrapment of water.

d) Tank shell is butt welded. Consecutive tiers offset by one third of a plate

length such that the vertical butt welded seams are only in line every third

tier.

e) Tank roof design for cone roof are with internal roof truss with a frangible

fillet weld to be made between top curb angle and roof plates which will

rupture in case of tank internal explosion in preference to rupture of the

tank at any other location.


Page 40 of 77

f) All tanks shall be equipped with surrounding handrails, staircases etc.

g) Appropriate spiral stairways shall be provided to each Tank for efficient

operations. Stair treads and walkways are made of open galvanized

grating.

h) Each tank will be provided with roof manholes, and with two shell

manholes orientated at 180 to each other in order to facilitate venting prior

to tank entry.

i) Fixed Roof Product tanks have been provided with pressure– vacuum (PV)

valves with 100 % capacity redundancy. Floating roof tanks are fitted with

free vents with 100% redundancy in venting capacity. Floating Roof Tanks

shall be provided with RIM Vents and other standard accessories. The

Underground tanks shall be provided with free vent. The vent outlets for

free vents are provided with birds nets with appropriate holding devices

j) Appropriate manual dip hatches and gauge nozzles shall be fitted to the

roof of each tank.

k) Tanks shall be fitted with an appropriate number of earthing bosses,

holding down bolts, wind girders and water spray deflectors according to

code requirements and local climatic condition.

l) The tanks shall be provided with sprinklers and foam feeding devices

according to the regulations.


Page 41 of 77

m) Underground tanks shall be installed in underground pit. The pits shall be

backfilled with sand/murrum. The tanks shall be provided with holding

down arrangement. External Wrapping and Coating are provided to take

care of Soil corrosion.

n) The product storage tanks in the tank farms shall be equipped with level

indicators. For sampling and hand gauging a separate guide pole shall be

installed. Gauging poles in the floating roof tanks are hot dip galvanised

after cutting the slots.

o) The tanks shall be properly earthed for protection against lightning and

discharge of possible static electricity.

6.9. Product Pipeline Systems

The pipeline from railway siding to terminal and within the terminal is

constructed in accordance relevant API codes/OISD standards.

The entire pipeline system shall be protected against thermal expansion by

way of a properly designed pressure relieving system connected to the

product tanks.

Pump House at the Terminal

Sufficient numbers of Loading and Unloading Product Pump Units (PPUs)

shall be installed, which are connected to the pipelines.

The thermal relief valve system has been designed in such a way that the

outlet of TRV end up to the corresponding product tank. The pipe material and

structural steel are painted to protect against atmospheric corrosion.


Page 42 of 77

6.10 Fire detection and protection system

Fire Protection System has been designed for fighting fire for 4 hrs. The

firewater system has been designed as per OISD standards. In addition

portable fire fighting equipments have been placed at the pump station, tank

farms, truck loading station, sub-station and office building for use as first-aid.

Key features are:

Fixed Roof tanks shall be fitted with Water Sprinklers system and fixed

foam pouring system.

In addition to OISD requirements all Fixed Roof tanks shall be provided with roof

cooling arrangement

Floating Roof tanks shall be provided with Sprinklers and Foam system.

Hydrants/ Monitors shall be provided at TWD siding, TLF area, Tank Farms,

Pump Houses, office/ lab etc.

The installation will made in such a way, that

1) The source of fire would be recognized and registered by the fire

alarm,

2) The water pumps shall be activated for fighting fire,

3) Sufficient foaming agents to fight the fire shall be available at least for 1

hour,

4) The necessary fire fighting measures can be carried out within few

minutes.

Necessary steps are taken to ensure starting of fire protection drill once the

alarm is raised by the fire alarm system. Portable fire extinguishers of 10 - 75

kg shall be installed on pump stations, truck facilities and buildings; the size

depends on the object concerned. Electrical rooms are protected by Carbonic

Acid (CO2) fire extinguishers. Furthermore, mobile fire fighting with foam

monitors, hoses, etc. shall be also considered.


Page 43 of 77

Fixed fire fighting monitors shall be located at all places of operation e.g. the

pump houses, TWD siding , Tank farms, and truck loading station, each with a

capacity of 144 m³/h. Sufficient hydrants have been installed in the tank

storage terminal, distance between two monitors / hydrants is maximum 30 m.

Water Supply Water storage Tanks (2 No’s of 4976 KL Each above ground) shall be

installed for supplying water for 4 hours without external supply. A closed loop

pipeline system ensures that all parts of the tank storage terminal will be

supplied with extinguishing and cooling water. Fire water will be supplied

from KMWSA.

Foam Devices

The tanks shall be equipped with fixed foam pipelines. As the tanks of class A

products are floating roof tanks, only a rim fire with a foam application rate of

12 LPM/sqm have been taken into account. For all other tanks full surface

with 5 LPM/sqm foam rate have been considered. The surface cooling rate

shall be 3 LPM / sqm for all tanks within 30 m of the tank on fire while for other

tanks it shall be 1 LPM/sqm. Foam shall be sufficient for a one hour extinguishing

process.

For surface / spill fires foam spraying on the tank farms shall be executed by

fixed and/or mobile monitors and hoses.

Sufficient portable fire extinguishers, hoses, monitors, fire protection suits,

breathing apparatuses etc. are available as per requirement.

Tank fields

The water accumulated during fire fighting within the tank farms can be

released from the separate emergency drain pipes with butterfly valves

through the surface drain to channel leading to Oil water separator units or to

the outside surface drain through an oil trap depending upon the

contamination level of the water. The valves are usually closed and sealed.


Page 44 of 77

6.11. Safety valves

To prevent building of pressure and consequent damage two numbers of pressure

vacuum valves will be provided on the roof of Tank no 5 & earmarked for storage of

M.S

6.12 Fire Alarm System

Conventional type Fire alarm system will be provided in following areas;

a) Truck Unloading/Loading (Manual Call Points)

b) Tank Farm (Manual Call Points).

c) Office / Admn. Building .

d) Sub-Stations .

6.13 Source of Signaling

The source of signaling is considered as manual call points. These are

considered for the areas where manual warning is to be initiated on

notice of fire. They are mostly provided for open areas or near to access

doors, truck loading, pump house, tank farm, administrative building, etc.

6.14 Portable Fire Fighting Apparatus

Following types of fire extinguishers and other fire fighting apparatus

specified for installation in vulnerable areas of the plant, administrative

block, control room, fire water pump house. MCC etc as per OISD

guidelines.


Page 45 of 77

Sl. No. Type of Area Protable Extinguishers

i Lube Godown 1 No. 10 Kg DCP extinguisher for every 200 m2 or min.2 Nos. in each Godown whichever is higher.

ii Lube filling shed 1 No. 10 Kg DCP extinguisher for 200 m2 or min. 2 Nos.in each Shed whichever is higher.

iii Storage of Class-A/B in packed containers and stored in open/closed area

1 No. 10 Kg DCP extinguisher for 100 m2 or min. 2Nos. in each Storage Area whichever is higher.

iv

Pump house upto 50 HP (Class A & B) Above 50-100 HP Beyond 100 HP

1 No. 10 Kg DCP for 2 pumps. 1 No. 10 Kg DCP for each pump. 2 Nos. of 10 kg or 1 no. of 25 kg DCP for each pump

v Pump House (Class – C) Up to 50 HP Above 50 HP

1 no. 10Kg DCP for every 4 pumps up to 50 HP. 2 nos. 10 Kg DCP or 1x25 kg DCP for 4 pumps.

vi Tank Truck loading and unloading for POL/specially products

1 No. 10 Kg DCP extinguisher for each bay plus 1 No. 75 Kg DCP extinguisher for each gantry.

vii Tank wagon loading and unloading gantry (siding)

1 No. 10 Kg DCP extinguisher for every 30 m of gantry/siding plus 1 No. 75 Kg DCP extinguisher for each gantry/siding.

viii Above ground tank

2 Nos. 10 Kg DCP extinguishers for each tank plus 4Nos. 25 Kg DCP extinguishers for each Tank Farm positioned at four corners. In case of adjoining tank farms, the no. of 25 Kg extinguishers can be reduced by 2 nos. per tank farm.

ix Under ground Tank Farms

2 N o s. 10 Kg DCP extinguisher for each Tank Farm

x Other Pump House 1 No. 10 Kg DCP extinguisher for every two pumps or min 2 Nos. 10 Kg DCP extinguisher for each Pump House whichever is higher.

xi Admn. Building/Store House 1 N o. 10 Kg DCP extinguisher for every 200 m2 or min. 2 Nos. 10 Kg DCP extinguishers for each floor of Building/Store whichever is higher.

xii Generator Room upto 250 KVA Above 250 KVA

1 no. 10 kg. DCP AND 1 NO. 4.5 KG. CO2 for every generator 2 nos. 4.5 kg. & 1 no. 10 kg. DCP

xiii Main Switch Room 1 No. 4.5 Kg CO2 extinguisher for every 25 m2 plus 1No. 9 Liter sand bucket.

xiv Computer Room/Cabin 2 N os. of 2 Kg CO2 or 2 Nos. of 2.5 Kg Clean Agent extinguisher per Computer Room and 1 No. 2 Kg CO2 or 1 No. 1.0 Kg Clean Agent extinguisher per cabin.

xv Security Cabin 1 No. 10 Kg DCP extinguisher per cabin. xvi Canteen 1 No. 10 Kg DCP extinguisher for 100 m2 . xvii Laboratory 1 No. 10 Kg DCP extinguisher & 1 No. 4.5 Kg CO2

extinguisher. xviii Effluent Treatment Plant 1 No. 75 Kg. & 2 nos. 10 Kg. DCP Extinguisher xix Workshop 1 No. 10 Kg DCP extinguisher & 1 No. 2 Kg CO2

extinguisher. xx Transformer 1 No. 10 Kg. DCP extinguisher per transformer. xxi UPS/Charger Room 1 No. 2 Kg. CO2 extinguisher.


Page 46 of 77

Chapter-7

RISK ASSESSMENT

7.1 Introduction

The Budge Budge Installation of Bharat Petroleum Corporation Ltd which

includes the facilities for receipt, storage and dispatch of petroleum products

mainly poses fire hazard due to unwanted and accidental release of

hydrocarbons. However, due safeguard has been taken in design, installation

and operation of the system to prevent any unwanted release of hydrocarbons

from their containment. However, in the event of release of hydrocarbons from

their containment, there is a risk of fire. The chances of explosion are less.

This section deals with various failure cases leading to various hazard

scenarios, analysis of failure modes and consequence analysis.

Consequence analysis is basically a quantitative study of hazard due to

various failure scenarios to determine the possible magnitude of damage

effects and to determine the distances up-to which the damage may be

affected. The reason and purpose for consequence analysis are manifolds

like.

Computation of risk

Aid better plant layout

Evaluate damage and protective measures necessary for saving

properties & human lives

Ascertain damage potential to public and evolve protective measures

Formulate safe design criteria and protection system

Formulate effective Disaster Management plan

The results of consequences analysis are useful for getting information about

all known and unknown effects that are of importance when failure scenarios

occur and to get information about how to deal with possible catastrophic

events. It also gives the plant authorities, workers district authorities and the

public living in the area an understanding of the hazard potential and remedial

measures to be taken.


Page 47 of 77

7.2 Modes of Failure

There are various potential sources of large/small leakages in any installation.

The leakages may be in the form of gasket failure in a flanged joint, snapping

of small dia pipeline, leakages due to corrosion, weld failure, failure of loading

arms, leakages due to wrong opening of valves & blinds, pipe bursting due to

overpressure, pump mechanical seal failure and many other sources of

leakage.

7.3 Damage Criteria

The damage effect of all such failures mentioned above are mainly due to

thermal radiation from pool fire or jet fire due to ignition of hydrocarbons

released since the petroleum products are highly inflammable specially Motor

sprit oil whose flash points are low.

The petroleum products released accidentally due to any reason will normally

spread on the ground as a pool or released in the form or jet in case of

release from a pressurized pipeline through small openings. Light

hydrocarbons present in the petroleum products will evaporate and may get

ignited both in case of jet as well as liquid pool causing jet fire or pool fire.

Accidental fire on the storage tanks due to ignition of vapour from the tanks or

due to any other reason may also be regarded as pool fire.

Thermal radiation due to pool fire or jet flame may cause various degrees of

burns on human bodies. Also its effect on inanimate objects like equipment,

piping, building and other objects need to be evaluated. The damage effects

due to thermal radiation intensity are elaborated in the Table .


Page 48 of 77

DAMAGE DUE TO INCIDENT THERMAL RADIATION INTENSITY

Incident Thermal Radiation Intensity

KW/M2

Type of damage

37.5 Can cause heavy damage to process equipment, piping building etc. (100% lethality)

32.0 Maximum Flux level for thermally protected tanks.

12.5 Minimum energy required for piloted ignition of work(50%lethality)

8.0 Maximum heat flux for un insulated tanks

4.5 Sufficient to cause pain to personnel if unable to reach cover within 20 sec. (% of 1st Degree Burn)

1.6 Will cause no discomfort to long exposure.

0.7 Equivalent to solar radiation

PHYSIOLOGICAL EFFECTS OF THRESHOLD THERMAL DOSES

Dose Threshold KJ/M2

Effect

375 3rd Degree Burn

250 2nd Degree Burn

125 1st Degree Burn

65 Threshold of pain, no reddening or blistering of skin caused.

1st Degree Burn > Involve only epidermis, blister may occur example-

sun Burn.

2nd Degree Burn > Involve whole of epidermis over the area of burn

plus some Portion of dermis.

3rd Degree Bun > Involve whole of epidermis and dermis;

subcutaneous Tissues may also be damaged.


Page 49 of 77

In case of Motor Spirit having relatively higher vapour pressure, there is a

possibility of vapour cloud explosion. Damage effects due to blast over pressure is

given in Table.

DAMAGE EFFECTS DUE TO BLAST OVER PRESSURE

Blast Over Pressure (Bar) Damage Type

0.30 Major Damage to Structures

0.17 Eardrum Rupture

0.10 Repairable Damage

0.03 Damage of Glass

0.01 Crack of Windows

7.4 Dispersion and Stability Class

In calculation of effects due to release of hydrocarbons dispersion of vapour

plays an important role as indicated earlier. The factors which affects

dispersion is mainly Wind Velocity, Stability Class, Temperature as well as

surface roughness. One of the characteristics of atmosphere is stability,

which plays an important role in dispersion of pollutants. Stability is

essentially the extent to which it allows vertical motion by suppressing or

assisting turbulence. It is generally a function of vertical temperature profile of

the atmosphere. The stability factor directly influences the ability of the

atmosphere to disperse pollutants emitted into it from sources in the plant. In

most dispersion problems relevant atmospheric layer is that nearest to the

ground. Turbulence induced by buoyancy forces in the atmosphere is closely

related to the vertical temperature profile.

Temperature of the atmospheric air normally decreases with increase in

height. The rate of decrease of temperature with height is known as the Lapse

Rate. It varies from time to time and place to place. This rate of change of


Page 50 of 77

temperature with height under adiabatic or neutral condition is approximately

1 °C per 100 metres. The atmosphere is said to be stable, neutral or unstable

according to the lapse rate is less than, equal or greater than dry adiabatic

lapse rate i.e. 1°C per 100 metres.

Pasquill has defined six stability ranging from A to F

A = Extremely unstable

B = Moderately unstable

C = Slightly unstable

D = Neutral

E = Stable

F = Highly Stable


Page 51 of 77

7.5 Selected Failure cases The mode of approach adopted for consequence is first to select the probable

failure scenarios. The failure scenarios selected are indicated Table.

LIST OF FAILURE CASES Sl.No Failure Scenarios Likely

Consequences Credible/

No Credible Failure

Frequency 1 Tanks on Fire

i. MS Tank ii. SKO Tank iii. HSD Tank iv. FO Tank v. ATF Tank

Thermal Radiation

Partially credible

5 x 10-6

2 Vessel connection failure for inlet / outlet lines of MS.SKO,HSD(Road tanker loading)

Thermal Radiation for MS,SKO & HSD and also explosion for MS

Partially credible

5 x 10-6

3 TLF Pumps discharge lines Full bore failure for MS,SKO & HSD (Road Tanker Loading)

do

Non Credible

3 x 10-6

5 Gasket failure in pump discharge line SKO,MS, & HSD (Road Tanker Loading Pump)

Thermal radiation Credible 0.5 x 10-6 P/H of opration.

6 Failure of 3’ dia loading arm MS,SKO,HSD

-do- Partially Credible

3 x 10-8 P/H of operation

7 Failure of 3’ dia unloading hose MS,SKO,HSD

-do- Credible 3 x 10-5P/H of operation

8 Mechanical seal failure for MS.SKO & HSD pumps for Tank truck loading

Thermal radiation Credible

It will be seen that most of the probable cases of failures have been considered for consequence analysis.


Page 52 of 77

Chapter-8 CONSEQUENCE ANALYSIS :

8.1 Consideration for Maximum credible Accident scenario: HAZARD ASSESSMENT (QUANTIFICATION) 8.1.1 Hazard Distances In The Event of Storage Tanks on Fire Scenario-1 Calculation of hazard distance due to storage Tank on Fire (HSD)

Tank Farm

Tank No.

Dimension Dia & Height(m)

Capacity (KL)

Product Tank Type

1 T1 29.00 x 13.50 8917.00 HSD Fixed Roof Storage tank of HSD on Fire .Entire roof surface will burn

METEOROLOGICAL DATA CONSIDERED

Temperature(Max) 36.8o C/ 309.8oK Humidity(Min) 41%

Maximum temperature of 36.8o C and minimum relative humidity of 41 % have been

considered for the calculation of hazard distance.

Result

Event No Scenario

Tank diameter

Radiation Intensity inside tank

Hazard Distance from the centre of the tank (m)

(m) (kW/ m2) 37.5 kW/m2

21.5 kW/m2

12.5 kW/m2

4 kW/m2

1. HSD

29 36.15 Within

Tank Within Tank 16.3 29.5

.


Page 53 of 77

Scenario-2 Calculation of hazard distance due to storage Tank on Fire (MS)

Tank Farm

Tank No.


Capacity (KL)

Product Tank Type

2 T5 24.00 x 12.00 5429 MS Floating roof

Storage tank of MS on Fire.Entire roof surface will burn



Maximum temperature of 36.8o C and minimum relative humidity of 41 % have

been considered for the calculation of hazard distance.

Result

Event No Scenario

Tank diameter



(m) (kW/ m2) 37.5 kW/m2

21.5 kW/m2

12.5 kW/m2

4 kW/m2

2. MS

24 26.60 Within

Tank 13.30 16.60 27.30


Page 54 of 77

Scenario-3 Calculation of hazard distance due to storage Tank on Fire (SKO)

Tank Farm

Tank No.


Capacity (KL)

Product Tank Type

3 T7 12.60 x 13.50 1683 SKO Fixed Roof Storage tank of SKO on Fire.Entire roof surface will burn





Result

Event No Scenario

Tank diameter



(m) (kW/ m2) 37.5 kW/m2

21.5 kW/m2

12.5 kW/m2

4 kW/m2

3 SKO

12.60 42.05 Within

Tank 8.00 11.80 26.1


Page 55 of 77

Scenario-4 Calculation of hazard distance due to storage Tank on Fire (ATF)

Tank Farm

Tank No.


Capacity (KL)

Product Tank Type

3 T9 20.00 x 13.50 4241 ATF Fixed Roof Storage tank of ATF on Fire .Entire roof surface will burn





Result

Event No Scenario

Tank diameter



(m) (kW/ m2) 37.5 kW/m2

21.5 kW/m2

12.5 kW/m2

4 kW/m2

4 ATF

20.00 35.70 Within

Tank 11.70 15.50 23.80


Page 56 of 77

Scenario-5 Calculation of hazard distance due to storage Tank on Fire (FO)

Tank Farm

Tank No.


Capacity (KL)

Product Tank Type

3 T10 20.00 x 13.50 4241 FO Fixed Roof

Storage tank of FO on Fire .Entire roof surface will burn





Result

Event No Scenario

Tank diameter



(m) (kW/ m2) 37.5 kW/m2

21.5 kW/m2

12.5 kW/m2

4 kW/m2

5 FO

20.00 36.05 Within

Tank Within Tank 14.3 26.5


Page 57 of 77

8.1.2 HAZARD DISTANCES IN CASE OF POOL FIRE

Scenario -1 (Spillage within dyke area, complete containment failure)

Calculation of hazard distance in case of pool Fire – (MS)

Tank Farm

Tank No.


Capacity (KL)

Product Tank Type

Pool Area M2

2 T5 24.00 x 12.00 5429 MS Floating roof 4279


Temperature(Max ) 36.8o C/ 309.8oK

Humidity(Min)

41%

Maximum temperature of 36.8o C and minimum humidity of 41 % have been considered for the calculation of damage distance in the case of pool fire radiation heat intensity in KW/M2

Result

Sl no Scenario

Pool Area Radiation Intensity inside pool

Distance from the edge of the pool (m)

(m2) (kW/ m2) 37.5 kW/m2

21.5 kW/m2

12.5 kW/m2

4 kW/m2

1. MS 4279 20.05

Within pool

Within pool

2.3 37.05

Scenario -2(Spillage within dyke area, complete containment failure)


Page 58 of 77

Calculation of hazard distance in case of pool Fire – (HSD)

Tank Farm

Tank No.


Capacity (KL)

Product Tank Type

Pool Area M2

1 T1 29.00 x 13.50 8917 HSD Fixed Roof 7727



Humidity(Min) 41%


Result

Sl no Scenario



(m2) (kW/ m2) 37.5 kW/m2

21.5 kW/m2

12.5 kW/m2

4 kW/m2

1. HSD 7727 20.00

Within pool

Within pool

1.7 27.00


Page 59 of 77

Scenario -3(Spillage within dyke area, complete containment failure)

Calculation of hazard distance in case of pool Fire – (SKO)

Tank Farm

Tank No.


Capacity (KL)

Product Tank Type

Pool Area M2

3 T7 12.60 x 13.50 1683 SKO Fixed Roof 3982



Humidity(Min) 41%


Result

Sl no Scenario



(m2) (kW/ m2) 37.5 kW/m2

21.5 kW/m2

12.5 kW/m2

4 kW/m2

3 SKO 3982 20.03

Within pool

Within pool

1.4 26.00


Page 60 of 77

8.1.3 CALCULATION OF HAZARD DISTANCE DUE TO POOL FIRE

PIPELINE RUPTURE AT TLF GANTRY

Scenario -1 Pipeline rupture (open area) Specification considered 1. Product MS 2. Pipeline dia 300mm 3. Pump discharge 300KL/H 4. Duration 900 Second(There will always be people around the area. Spillage is likely to be identified within the short period and hence 5 min duration is considered ) 5. Pump discharge pressure 4Kg/M2

METEROLOGICAL DATA CONSIDERED


Humidity(Min) 63%

Maximum temperature of 36.8o C and minimum humidity of 41 % have been considered for the calculation of damage distance in the case of pool fire radiation heat intensity in KW/M2 Quantification of hazard

Sl no Scenario

Radiation Intensity inside pool

Distance from the centre of the pool (m)

(kW/ m2) 37.5 kW/m2

21.5 kW/m2

12.5 kW/m2

4 kW/m2

1. MS 20.60 Within Pool Within Pool 46.77 80.67


Page 61 of 77

Scenario -2 Pipeline rupture (open area) Specification considered 1. Product HSD 2. Pipeline dia 500mm 3. Pump discharge 450KL/H 4. Duration 900 Second(There will always be people around the area. Spillage is likely to be identified within the short period and hence 5 min duration is considered ) 5. Pump discharge pressure 4Kg/M2



Humidity(Min) 41%


Sl no Scenario



(kW/ m2) 37.5 kW/m2

21.5 kW/m2

12.5 kW/m2

4 kW/m2

2 HSD 20.3 Within Pool Within Pool 82.26 144.06


Page 62 of 77

Scenario -3 Pipeline rupture (open area) Specification considered 1. Product SKO 2. Pipeline dia 150mm 3. Pump discharge 120KL/H 4. Duration 900 Second(There will always be people around the area. Spillage is likely to be identified within the short period and hence 5 min duration is considered ) 5. Pump discharge pressure 4Kg/M2



Humidity(Min) 41%


Sl no Scenario



(kW/ m2) 37.5 kW/m2

21.5 kW/m2

12.5 kW/m2

4 kW/m2

3. SKO 20.01 Within Pool Within Pool 29.22 40.02


Page 63 of 77

8.1.4 CALCULATION OF HAZARD DISTANCE DUE TO POOL FIRE FOR GASKET FAILURE IN PUMP DISCHARGE LINE

Scenario -1 Gasket Failure (25 % of the perimeter of Gasket) Specification considered 1. Product MS 2. Pipeline dia 300mm 3. Gasket Thickness 0.5mm 4. Pump discharge 300KL/H 5. Duration 1800 Second 6. Pump discharge pressure 4Kg/M2


Temperature(Max) 36.8o C/ 309.8oK

Humidity(Min) 41%


Quantification of hazard

Sl no Scenario



(kW/ m2) 37.5 kW/m2

21.5 kW/m2

12.5 kW/m2

4 kW/m2

1 MS 20.3 Within Pool

Within Pool 22.51 42.31


Page 64 of 77

Scenario -2 Gasket Failure (25 % of the perimeter of Gasket) Specification considered 1. Product HSD 2. Pipeline dia 500mm 3. Gasket Thickness 0.5mm 4. Pump discharge 450KL/H 5. Duration 1800 Second 6. Pump discharge pressure 4Kg/M2



Humidity(Min) 41%



Sl no Scenario



(kW/ m2) 37.5 kW/m2

12.5 kW/m2

12.5 kW/m2

4 kW/m2

2 HSD 20.3 Within Pool

Within Pool 75.6 61.99


Page 65 of 77

Scenario -3 Gasket Failure (25 % of the perimeter of Gasket) Specification considered 1. Product SKO 2. Pipeline dia 150mm 3. Gasket Thickness 0.5mm 4. Pump discharge 120KL/H 5. Duration 1800 Second 6. Pump discharge pressure 2Kg/M2



Humidity(Min) 41%



Sl no Scenario



(kW/ m2) 37.5 kW/m2

21.5

kW/m2

12.5 kW/m2

4 kW/m2

3 SKO 20.2 not attained

not attained 17.92 29.12


Page 66 of 77

8.2 VAPOUR CLOUD MODELING

SCENARIO: 1 (Complete containment failure due to pipeline rupture within the dyke area )

Specification considered

Tank Farm

Tank No. Dimension Dia & Height (Mtrs)

Capacity (KL)

Product

2 T5 24.00 x 12.00 5424 MS

METEROLOGICAL DATA CONSIDERED Temperature( Min ) 36.8o C/ 309.8oK Humidity( Max) 85% Atmospheric Stability Very stable- F Wind Velocity( Min) 11 KMPH

Wind Direction ( larger vapour cloud) S.W

Pasquill Category F ( Very stable)

Dispersion outputs for MS release from 500mm dia pipeline Calculation of distance upto LFL/ UFL Result

Event No

Material Spilled

Release mode

Spill area (dyke area)

Evaporation/ Dispersion Rate

Distance up to LFL

Distance up to UFL

14000 ppm 76000 ppm

m2 (kg/s) DW CW DW CW

1. Motor spirit Continuous 4279 103.58 35 24.3 9.3 11.2

(DW – Down Wind; CW – Cross Wind)


Page 67 of 77

Consequence output for Unconfined Vapour Cloud Explosion (UVCE) In the event of MS vapour cloud finding source of ignition after complete release of 5444 KL MS

Damage distances from Vapour Cloud explosion from rupture of 400 mm Pipeline

Event No Material Spilled

Meteorological Conditions ( max) Wind Speed 2 km/hr Stability F

Amount in Explosive Limits (kg)

Damage Distance in meters for Different Overpressure

0.3 bar 0.1 bar 0.03 bar 0.01 bar

1. Motor spirit 586 96.1 152.4 321.2 789.6


Page 68 of 77

8.3 REFERENCES/ MODELS USED

The calculations were conducted using OUTFLOW/ SOURCE STRENGTH ESTIMATION and CONSEQUENCE models as per the Indian Standards IS 15656: 2006 HAZARD IDENTIFICATION & RISK ANALYSIS - CODE OF PRACTICE and internationally accepted models and equations. RiskChem Engineering uses its proprietary software for consequence analysis based on these models and equations. The software has been in use over the past 15 years and the results have been accepted by various regulatory authorities in India and abroad. A copy has been purchased by the Factory Inspectorate of Tamil Nadu

POOL FIRE MODEL

Guidelines for Evaluating the Characteristics of Vapour Cloud Explosions, Flash fires and BLEVEs, (1994) by Center for Chemical Process Safety of the American Institute of Chemical Engineers1, NY.

SPILL MODEL

Spreading and Evaporation

Shell SPILLS model (Fleischer 1980)

Guidelines for use of VAPOUR CLOUD DISPERSION MODELS by Hanna and Drivas

(1996) by Center for Chemical Process Safety of the American Institute of Chemical Engineers*' NY

VAPOUR CLOUD EXPLOSION

Shock wave model

a) TNO, Methods for the Determination of Possible Damage (Green Book), CPR

16E, 1st ed. (1992).

b) Hanna, S. R., Drivas, P. J.

Guidelines for use of VAPOUR CLOUD DISPERSION MODELS by Hanna and Drivas (1996) by Center for Chemical Process Safety of the American Institute of Chemical Engineers', NY


Page 69 of 77

DENSE GAS MODELLING

Heavy gas dispersions based on Thorney Island Observations (1985).

Guidelines for use of VAPOUR CLOUD DISPERSION MODELS by S R Hanna and P J Drivas (1996) by Center for Chemical Process Safety of the American Institute of Chemical Engineers', NY

EFFECTS OF THERMAL RADIATION

World Bank (1985) Manual of Industrial Hazard Assessment techniques Office of Environmental and Scientific Affairs, World Bank, Washington, D. C.

EXPLOSION DAMAGES

Guidelines for Evaluating the Characteristics of Vapour Cloud Explosions, Flash fires and BLEVEs, (1994) by Center for Chemical Process Safety of the American Institute of Chemical Engineers', NY


Page 70 of 77

8.4 ACTION DURING FIRE

8.4.1 Storage Tank in Fire

a) A fire burning at the vent will not normally flash back into tank and

explode, if the tank contains product since flame arresters are provided

b) Start cooling of tanks by using water sprinklers provided on tanks as well as

by wet jets.

c) Close all valves since any removal of product will result in air being sucked

inside, with the resultant flash back and explosion.

d) Close manhole covers of other tanks if they are open. Also stop loading /

Receipt of tank wagons, into / out of the tank since it will result in eviction of

vapour due to displacement and subsequent intensification of fire.

e) Use foam to extinguish fire. Small fire can be handled with portable fire

extinguishers.

f) Fire in tank will normally burn quietly till the oxygen is consumed unless

temperature of the product is allowed to increase uncontrolled. Hence, care

must be taken to ensure that product temperature does not go high by cooling

with water sprinklers & jets. This also avoids possibility of tank rupture due to

hydrostatic pressure

g) When sufficient air vapour mixture is available inside the tank as in the case

during removal of products from tank on fire there is a distant possibility of

tank roof collapse or blow out. In such cases, immediate action should be

taken to ensure that the fire does not spread to other areas. If there is product

spill to outside, foam should be used to cover the same.

H) In such cases, foam should be pumped inside the tank for blanketing the fire

and simultaneously taking action to cool the tank shell with water and also

removing the product by pumping it cut to some other tank.


Page 71 of 77

i) Uncontrolled use of water on the burning product will result in product spill over

and spread of fire. In the case of heavy ends this will result in boil over and

frothing at the surface.

j) When heavy ends like HSD burn, a layer of hot oil is formed below the surface,

which extends towards the bottom. Temperature of this layer is of the order of

250° C to 300° C much above the boiling point of water. When water turns into

steam, it expands appx. 1600 times and this result in boil over. The boil over

may overflow the tank resulting in spreading of fire. Hence, in such fire, cool

down the tank by continuous water jet on the tank shell, transfer the product to

other tanks and judiciously use foam to smoothen fire.

8.4.2 Pool Fire at TLF Gantry.

A) Discharge DCP to prevent fire from spreading.

B) Shut down the pumps by cutting of power supply.

C) Remove any person who is working in the effected area.

D) Close the valves of either side to starve the fire close all tank wagon valves and

manifold valves.

E) Put foam on burning oil spills

F) Put foam on oil spills. Do not splash burning oil.

G) Use DCP or CO2 fire extinguisher on electrical fire.

H) Wet down the structure close to the fire with water

8.4.3 Gasket Failure

a. Stop Pumping

b. Close the valves of either side of flange

c. Dig pits to collect oil.

d. Built earth dykes around the oil pool to prevent spreading of burning oil.

e. Take care of the oil dropping from the leak even after extinguishing fire as

fire may occur again due to heating of oil dropped. Try to collect the oil in

containers.

f. Take action for replacement of gasket/ repair leak with due care.

.


Page 72 of 77

8.5.4 General

a) In case of F/R tanks, fires normally occur at F/R seats. Efforts should be

made to put foam in the correct place simultaneously cooling the tank shell

from outside

b) Incase of Oil spill the same should be blanketed with foam in order to

avoid contact with source of ignition.

c) Use DCP or CO2 fire extinguisher on Electrical fire.

d) Wet down structure close to the fire with water.

e) Discharge DCP to prevent fire from spreading.

f) In case flammable liquid pool due to containment failure, pipeline rupture

within the dyke area it is suggested to cover the flame with foam blanket.


Page 73 of 77

Chapter-9

RISKS AND FAILURE PROBABILITY

The term Risk involves the quantitative evaluation of likelihood of any undesirable

event as well as likelihood of harm of damage being caused to life,property and

environment. This harm or damage may only occur due to sudden/accidental release

of any hazardous material from the containment. This sudden/accidental release of

hazardous material can occur due to failure of component systems. It is difficult to

ascertain the failure probability of any system because it will depend on the

components of the system. Even if failure occurs, the probability of fire and the extent

of damage will depend on many factors like,

A) Quantity and physical properties of material released.

B) Source of ignition

C) Wind velocity and direction

D) Presence of population, properties etc nearly.

Failure frequency of different components like pipes, valves, instruments, pressure

vessels and other equipment manufactured in India are not available. The statutory

authority has tried to collect the information and form an acceptable data bank to be

used under Indian condition.

Failure frequency data for some components accepted in U.S.A and European

Countries are given Table.


Page 74 of 77

FAILURE FREQUENCY DATA

Sl.No Item Failure Frequency / 106 years

1 Shell Failure a) Process/pressure vessel b) Pressurized Storage Vessel

3 1

2 Full Bore Vessel Connection Failure (Diameter MM) <25 40 50 80 100 >150

30 10 7.5 5 4 3

3 Full Bore Process Pipeline Failure D< 50mm 50<d<150mm D>150mm

0.3* 0.09* 0.03*

4 Articulated Loading / Unloading arm Failure

30 x 108 **

* Failure frequency expressed in (n/106 years) ** Failure frequency expressed in (hr of operation)


Page 75 of 77

Chapter-10

RECOMMENDATIONS & CONCLUSIONS

The recommendations & conclusions as revealed from Risk Analysis study are as

follows:

i) The individual Risk value of 1.0 E-6/ year as evident from the ISO Risk

contour is not always confined within the plant premises.Hazard distances

arrived from the consequence analysis also reveals that in most of the

cases hazard is not always confined within the plant premises.

ii) Health check and maintenance of the equipment including storage tanks and

pipelines should be done at regular intervals to avoid any major failure.

History sheet of all major equipment giving the details of fabrication data /

design data to be maintained.

iii) Instruments and trip interlocks should be checked and calibrated at regular

intervals to prevent any wrong signaling and consequent failures.

iv) Fire fighting system as well as portable fire-fighting appliances should be

always kept in good working condition. Safety appliances should be also

checked and kept in good working condition.

v) Mock Drills should be conducted at regular intervals.

vi) To reduce the failure frequency due care has been taken in design,

construction, inspection and operation. Well-established codes of practices

have been followed for design, inspection and construction of the facility.

vii) The installation should be operated by experienced personnel trained for

operation of such facility and also in fire fighting. Safe operating practice (

SOP) to be drawn and critical SOP to be displayed near the TLF,Tankfarm,

Pump house and manifold


Page 76 of 77

viii) Smoking should be strictly prohibited inside the installation.

ix) Non -sparking tools should be used for maintenance to avoid any

spark.

x) The storage tanks, pipelines and facilities in Tank Lorry Filling Shed

should be properly earthed to avoid accumulation of static electricity.

Bounding to be ensured for TLF operation. Tripping arrangement

recommended in case of failure in earthing / bounding system.

xi) Entry of personnel should be restricted inside the licensed area.

xii) A elaborate Disaster Control Management Plan containing a mutual

aid agreement should be drawn to meet major exigencies.

xiii) Two High Velocity Long Range (HVLR) monitors are to be positioned

for each tank farm area specially for MS, HSD & SKO tank farm.

xiv) Rim Seal protection system is to be maintained properly.

xv) Failure data must be recorded.

xvi) Maintenance schedule is to be drawn and the same should be

strictly adhered to.

xvii) Vapour Clooud Consequence and its recommendation to be included.

xviii) VDS should be installed and to be continuously monitored

xix) High level alarm to be connected to MOV so as to close the valve and to

be maintained properly.

xx) ESD to be maintained in order


Page 77 of 77

xxi) Emergency electrical panel should include fire siren system and

electrically operated gate.

xxii) Illumination in security Room , Emergency Control Room

xxiii) Illumination in the plant area, water replenishment Pump are to be

connected to emergency panel.

xxiv) MOV should have the provision of Operation from outside the dyke

through push button for emergency operation.

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