Bharat Petroleum Corporation Ltd.
BPCL - LPG BOTTLING PLANT
SIDCO INDUSTRIAL ESTATE, Kappalur, Uchapatti Village, Thirumangalam Tehsil, Madurai Dist., Tamil Nadu
RISK ANALYSIS STUDY REPORT
July 2017
RiskChem Engineering
CHENNAI
Project Summary Page
1. Report No.
1705
2. Report date
JULY 2017
3. Title & subtitle
RISK ANALYSIS FOR BPCL’s NEW LPG BOTTLING PLANT AT KAPPALUR,
MADURAI DIST., TN
4. Reporting organization
name
&
address
RISKCHEM ENGINEERING
#4 FIRST STREET, VGP GOLDEN BEACH SOUTH PART III
CHENNAI 600 119
98401 44908
044 2453 0699
consultancy@riskchem.com
Ph:
Fax:
email:
5. Supporting
organization name &
address
BPCL- LPG BOTTLING PLANT
UCHAPATTI VILLAGE,
THIRUMANGALAM TEHSIL,
MADURAI DISTRICT,
TAMIL NADU.
6. Sponsoring
organization
reference(s)
Email dated 29 April 2017
7. No. of pages
Main Report
Appendices
37
26
Summary
 The report presents the results of the RRA studies undertaken for new LPG Bottling Plant
proposed to be setup by BPCL in the SIDCO Industrial Estate at Kappalur, Madurai, TN.

The exercise has been undertaken in compliance with The Manufacture, Storage and Import
of Hazardous Chemicals Rules, 1989 (Amended 2000) that govern installations involving
hazardous chemicals

The methodology and guidelines given in INDIAN STANDARD HAZARD IDENTIFCATION AND
RISK ANALYSIS - CODE OF PRACTICE (IS 15656:2006) were adopted for the analysis.

Risk analysis tools used in the assessment include consequence and probability analyses.

The assessment was based on site and operation related information provided by the client.

The findings are the result of the application of the best available techniques and practices
applicable to the project. The conclusions drawn are the educated and unbiased opinion of the
consultant.
Dr. A Koshy
(Project Consultant)
Summary of Risk Analysis Report
A rapid risk analysis study was undertaken for BPCL’s proposed LPG Bottling plant at Kappalur,
Madurai Dist in July 2017. The main findings are summarized below.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
The exercise has been undertaken in compliance with The Manufacture, Storage and
Import of Hazardous Chemicals Rules, 1989 (Amended 2000) that govern installations
involving hazardous chemicals
The methodology and guidelines given in INDIAN STANDARD - HAZARD IDENTIFCATION
AND RISK ANALYSIS - CODE OF PRACTICE (IS 15656:2006) were employed for the analysis.
Risk analysis tools used in the assessment include HAZID, consequence and frequency
analyses.
The consequences from twenty potential hazardous scenarios envisaged in the plant have
been described and quantified.
The consequences with significant impact on life & property include thermal radiation
from jet-fires, & flash fires, overpressures from VCE and projectiles from vessel explosions.
Calculated damage distances were projected on the site layout to demarcate vulnerable
areas with respect to plant personnel, property and the public.
The effects of events such as flash fires and jet fires were found to be localized within the
plant. Effects of VCEs may extend beyond the plant boundaries.
The frequencies of each of these events were estimated considering the safety systems in
place for detection and control of leaks, and found to be low.
The maximum frequency of events evaluated inside the plant is of the order of 10-09/ yr,
and occurs during filling of tanker lorries, which is not a continuous activity.
The individual risk levels are of the order of 10-07/ yr, which is in the ALARP region, when
compared with criteria for hazardous industries given in IS 15656: 2006, where risk
numbers upto 10-05/ yr are the maximum tolerable and below 10-08/ yr are considered
negligible.
Additional risk reduction measures have been suggested in the report to further lower the
estimated risk of the operations. These include measures for:
i. Control of leak/ spill at the TLDG
ii. Control of leak at the MSV
iii. Prevention of leak and ignition at the carousel
iv. Layout considerations
v. Vapour cloud dispersal
vi. Ensuring reliability of critical instruments
vii. Limitation of activities in the immediate vicinity of the boundaries
A site-specific emergency plan which takes into account low frequency events such as VCE
and BLEVE must be developed prior to commissioning.
Efforts at risk reduction should be continuous, as risk levels should be considered in a
relative manner.
Contents
CHAPTER I.
PROJECT DESCRIPTION
1
1.1
PREAMBLE
1
1.2
DESCRIPTION OF THE SITE
1
1.3
DESCRIPTION OF THE PROPOSED FACILITY
2
1.4
SCOPE OF RISK ANALYSIS STUDIES
7
CHAPTER II.
PRELIMINARY HAZARD IDENTIFICATION
8
2.1
PREAMBLE
8
2.2
HAZARD CLASSIFICATION BASED ON NFPA AND INHERENT HAZARDS OF LPG
8
2.3
FINDINGS OF PAST ACCIDENT ANALYSIS
8
2.4
HAZARD POTENTIAL BASED ON FIRE & EXPLOSION INDEX
9
2.4.1 Analysis of F&EI Results
2.5
CHAPTER III.
SUMMARY
CONSEQUENCE ANALYSIS
9
10
11
3.1
PREAMBLE
11
3.2
CONSTRUCTION OF HAZARDOUS SCENARIOS
11
3.3
CONSEQUENCE MODELING
13
3.4
CONSEQUENCE OUTPUTS
13
3.5
QUANTIFICATION & CRITERIA EMPLOYED
14
3.5.1 Damage Criteria for heat radiation effects
14
3.5.2 Damage Criteria for overpressure effects
15
3.6
WORST CASE SCENARIO & DAMAGE CONTOUR
3.6.1 Secondary events and Cascade Effects
3.7
CHAPTER IV.
OBSERVATIONS
PROBABILITY ASSESSMENT & RISK FROM THE PLANT
16
20
21
22
4.1
PREAMBLE
22
4.2
EVALUATION OF THE SAFETY SYSTEM
22
4.3
PROBABILITY ASSESSMENT
24
4.3.1 Events in the accident chain and safety features
24
4.3.2 Estimation of Probability
24
4.4
OBSERVATIONS
26
4.5
EVALUATION OF RISK
26
4.6
RISK CRITERIA
27
4.7
RISK TO PERSONNEL INSIDE AND OUTSIDE THE PLANT
27
4.7.1 Risk from Secondary Events
4.8
CHAPTER V.
SUMMARY
MAJOR FINDINGS & RECOMMENDATIONS
30
30
31
5.1
PREAMBLE
31
5.2
MAIN FINDINGS OF CONSEQUENCE ASSESSMENT
31
5.2.1 Primary events
31
5.2.2 Secondary event
32
5.3
FINDINGS FROM PROBABILITY ANALYSIS FOR INDIVIDUAL EVENTS
32
5.4
RISK CLASSIFICATION OF CREDIBLE EVENTS
33
5.4.1 Estimation of Individual risk
5.5
RISK REDUCTION MEASURES
33
34
5.5.1 Safety Measures at Tanker Lorry Decanting Gantry
34
5.5.2 Measures at Mounded Storage Vessel (MSV)
34
5.5.3 Prevention of leaks & fires in filling/ carousel area.
35
5.5.4 Layout consideration
36
5.5.5 Vapour cloud dispersal
36
5.5.6 Reliability of critical instruments:
36
5.5.7 Limitation of Activities beyond the plant
36
5.6
SITE SPECIFIC EMERGENCY PLANNING
37
5.7
CONCLUSION
37
APPENDIX 1
DESCRIPTION OF UNITS AND OPERATIONS AT AN LPG BOTTLING FACILITY - RECEIPT,
STORAGE AND FILLING SYSTEMS
38
APPENDIX 2
MATERIAL SAFETY DATA SHEET
49
APPENDIX 3
PAST ACCIDENT ANALYSIS
51
APPENDIX 4
FIRE AND EXPLOSION INDEX WORKSHEET
55
APPENDIX 5
METEOROLOGICAL DATA
56
APPENDIX 6
MODELS USED IN CONSEQUENCE ANALYSIS
57
APPENDIX 7
OUTPUTS FROM CONSEQUENCE CALCULATIONS
58
APPENDIX 8
IDENTIFYING INDEPENDENT PROTECTION LAYERS (IPLS) – LAYERS FOR DEFENSE AGAINST
A POSSIBLE ACCIDENT
65
LIST OF ABBREVIATIONS
BLEVE
Boiling Liquid Evaporating Vapor Explosion
BPCL
Bharat Petroleum Corporation Limited
BMCG
Bharat Metal Cutting Gas
CAS
Credible Accident Scenarios
CCA
Cause-Consequence Analysis
CSA
Cross Sectional Area
DG
Diesel Generator
DV
Deluge Valve
GD
Gas Detectors
HAZID
Hazard Identification
IS
Indian Standard
LFL
Lower Flammable Limits
LoPA
Layer Of Protection Analysis
LPG
Liquefied Petroleum Gas
MT
Metric Tonnes
MCC
Motor Control Center
MSDS
Material Safety Data Sheet
OISD
Oil Industry Safety Directorate
PI
Pressure Indicator
PM
Preventive Maintenance
ROV
Remote Operated Valve
SRV
Safety Relief Valve
TLDG
Tanker Lorry Decanting Gantry
UFL
Upper Flammable Limits
VCE
Vapor Cloud Explosion
Risk Analysis Report
LPG Bottling Plant, BPCL Kappalur, Madurai
Project Description
CHAPTER I.
1.1
Preamble
Bharat Petroleum Corporation Limited (BPCL) proposes to put up a new LPG bottling
plant of 44 TMTPA capacity at the SIDCO Industrial Estate located at Uchapatti Village,
in Madurai District of Tamil Nadu state. The plant aims to cater to the LPG requirement
of Madurai, Theni and Dindugal districts.
LPG will be received through tank trucks from Pallakad LPG bulk dispatch terminal
and stored in 3 Mounted Storage Vessels, each of capacity 3 X 900 MT. LPG will be
pumped from storage bullets to filling shed where cylinders will be filled, using a
24 point electronic filling carousel, and dispatched through road.
LPG bottling has been identified as potentially hazardous activity as per the MSIHC
Rules, under which the occupier is required to conduct safety studies prior to
commissioning of new plants. Hence BPCL has undertaken to conduct a rapid Risk
Analysis (RRA) Study for the proposed plant at the conceptual stage.
The management of the plant has entrusted the risk analysis studies to be carried out
by consultants from RiskChem Engineering (RCE), Chennai.
1.2
Description of the site
The proposed LPG bottling plant is located at SIDCO Industrial Estate, Kappalur,
Madurai in an area of 22.15 acres, adjacent to the HPCL LPG bottling plant and the
HPCL POL terminal. The site is located 20 km from Madurai city and has the benefit
of good road network with connectivity to NH 44 that ensures smooth movement of
bulk lorries.
As the site is within the SIDCO Industrial Estate, there are no settlements in the vicinity
and the plot is free from any unauthorized encumbrance and overhead LT/ HT lines
etc. Key features of the site are given in table 1.1.
Table 1.1
Key features of the site
Nearest Main Road
Maravapatty – Villur – Kallikudi Road
Nearest High Way
NH- 44
Nearest Railway Station
Thirumangalam (6.6 Km)
Main Station: Madurai Railway Station (18 Km)
Nearest Bus Station
Periyar Bus stand, Madurai (16 Km)
Nearest Airport
Madurai International Airport (16 Km)
Nearest Water Body
Vaigai River (15 Km)
Periya Maravankulam lake (5 Km)
Sengulam Lake (7 Km)
The site is well connected by road and has access to all the infra-structural facilities
available at Madurai, including well-equipped hospitals and health care facilities.
The location is in the zone of moderate seismic activity.
Fig 1.1 shows the satellite map of the proposed site and the vicinity.
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Risk Analysis Report
LPG Bottling Plant, BPCL Kappalur, Madurai
Fig 1.1 Satellite image of the proposed location
As seen from the satellite image, there is no densely populated area within 2 km radial
area from the periphery of project. While several industries are located within the
SIDCO Industrial Estate, the proposed site is bounded by IOCL terminal and HPCL POL
Terminal on the west and HPCL LPG plant on the south. Empty plots lie to the north
and east of the selected site. A railway track runs the northern boundary
1.3
Description of the proposed facility
LPG will be received through tank trucks from Palakkad LPG bulk dispatch terminal
for onsite storage in 3 Mounted Storage Vessels, each of capacity 900 MT. From these
storage units, LPG is to be drawn for filling cylinders, which, after due testing and
sealing are dispatched to various destinations. The plant capacity is 44 TMTPA.
LPG will be pumped from storage bullets to filling shed where cylinders will be filled
using a 24 station electronic filling carousel, and dispatched through road. The
carousel is proposed to be run on an assured minimum productivity level of
163 MT/shift for filling 5.0/14.2/ 19.0/35.0/47.5 kg cylinders. The types of cylinders
are Domestic/Commercial/BMCG.
Facilities are also provided for unloading tanker lorries and loading road tanker lorries
with filled cylinders for distribution of LPG in bulk to end-users on the vicinity.
The key features of the operation are summarized below in table 1.2
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Risk Analysis Report
Table 1.2
LPG Bottling Plant, BPCL Kappalur, Madurai
Key features of operations at the site
S. No
Particulars
Units/ Items
1.
Receipt operation
LPG is received through road tankers
2.
Storage Vessel
3 nos. x 900 MT capacity mounded storage vessels (MSVs)
3.
Filling / Empty
Cylinder Shed
Shed size -65 m X 29 m
4.
Carousel
1 x 24 station Flex Speed Electronic carousel
Minimum productivity level of 163 MT/shift
5.
Evacuation unit or
degassing unit
Separate shed of 20 m x 8 m shall be provided
6.
Manual filling
machine
Conveyor line shall be provided for filling of 19/ 35 and
47.5 Kg cylinders
7.
Filled Cylinder
Storage Shed/
Loading/ Unloading
Finger
Shed of size 65 M X 17 M with 10 M X 15 M Fingers (2 nos)
loading platform (to accommodate 2 Lorries at a time) will
be provided to store and load the filled cylinders.
Filled cylinder
tanker and despatch
75 no. trucks with filled cylinders despatched every day
Tanker Lorry Gantry
6 Bay TLD gantry of size 16 m X 5.5 m (each) for unloading
of tank lorry shall be provided with MFM on common
header to facilitate automation.
8.
9.
LPG vent pipeline shall be provided with 30 m clear
distance all round
5 Kg/14.2 kg/19 kg/35 Kg/47.5 capacities of filled
cylinders
Maximum 405 no. filled cylinders can be loaded in a single
truck
All unloading bays will be provided with suitable loading
arms with break-away type coupling and earthing
interlocks.
6 tankers can be unloaded at the same time
10.
LPG Pump /
Compressor Shed
The pump house will be of size 20 m x 8 m
2 nos. LPG pumps (50 m3/ hr, 160 M Head) for bottling
2 no. LPG compressor (150 CFM) for unloading of bulk tank
lorries.
A brief description of the facilities and operations is given in Appendix 1.
Fig 1.2 shows the key plan of the LPG bottling plant
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Risk Analysis Report
LPG Bottling Plant, BPCL Kappalur, Madurai
Fig 1.2 Key plan of the LPG bottling unit up to 1 km radius
The plant layout is given in Fig 1.3 while a simplified product flow diagram is provided
in Fig 1.4.
RCE Chennai
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Risk Analysis Report
Fig 1.3
RCE Chennai
LPG Bottling Plant, BPCL Kappalur, Madurai
Layout of the LPG Bottling Plant
5
Risk Analysis Report
Fig 1.4
LPG Bottling Plant, BPCL Kappalur, Madurai
Flow diagram of the LPG Bottling Plant
MSV
Legend
Compressor
Pump
Pump
Pumphouse
Tanker
TLD Gantry
Compressor
Carousel
Filled cylinder
shed
Truck with
filled cylinders
Empty/filling shed
8
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Risk Analysis Report
1.4
LPG Bottling Plant, BPCL Kappalur, Madurai
Scope of Risk Analysis studies
The current risk analysis studies involve the receipt, storage and filling operations and
associated facilities located within the LPG Bottling Plant at BPCL, Kappalur,
Madurai.The items covered in the Risk Analysis are as follows.
1. Receipt of LPG via road tankers
2. Tanker lorry decanting facilities at the gantry with 6 bays
3. Storage of LPG within the plant in Mounded Storage Vessels in a single
cluster of three vessels of 900 MT capacity each
4. Bottling of LPG using 24 station Flex Speed Electronic carousel with
associated dynamic check scale, DGD & DPT machine
5. Filling shed & filled cylinder shed and cylinder loading facilities
6. LPG pump house
7. Tanker lorry parking area
The risk arising from the activities and operations at these locations have been
evaluated at areas within the plant where personnel may be located (MCC room, DG
room, compressor room, pump house, admin building, gate, etc.)
The elements of the risk analysis studies include
 Preliminary identification of hazards and hazardous scenarios (PHA, past
accident analysis, etc.)
 Assessment of consequences of release of LPG within the plant in terms of
radiation, blast waves, dispersion including
o
o
Effects on areas where personnel maybe located within the plant
Effects on areas external to the plant
 Estimation of frequency of the hazards
 Evaluation of proposed safety system/ elements
 Qualitative risk analysis based on risk matrix
 Recommendations based on the results of these studies
The methodology & approach for the studies are based on Indian Standards IS 15656:
2006 HAZARD IDENTIFICATION & RISK ANALYSIS – CODE OF PRACTICE. Appropriate
internationally accepted tools, techniques and mathematical models have been used.
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Risk Analysis Report
CHAPTER II.
2.1
LPG Bottling Plant, BPCL Kappalur, Madurai
Preliminary Hazard Identification
Preamble
LPG unloading, storage and distribution are inherently hazardous operations due to
the flammable/ explosive characteristics of LPG. The mere existence of hazards,
however, does not automatically imply the existence of risk for the bottling plant.
Screening & ranking methodologies techniques have to be employed to evaluate
hazards of the proposed bottling plant.
2.2
Hazard Classification based on NFPA and Inherent Hazards of LPG
The National Fire Protection Agency, US (NFPA) has classified the hazards from LPG
(considered as a mixture of commercial butane and commercial propane having both
saturated and unsaturated hydrocarbons) in the following scale:
Table 2.1
NFPA rating *for LPG
NH (Health)
1
NF (Flammability )
4
NR (Reactivity)
0
*NFPA classification for Health, Flammability & Reactivity of a chemical on a scale of 0 – 4
least to worst
Since LPG is inherently dangerous because of fire, explosion and has maximum rating
hazards it calls for special attention on the manner in which it is stored, transported
or used. Table 2.2 summarizes the physical properties of LPG
Table 2.2
Physical Properties of LPG
Property
Value
Boiling Point (C)
-40
Flash Point (C)
-104.44
Auto Ignition (C)
466
Lower Flammable Limits (LFL)
2%
Upper Flammable Limits (UFL)
10%
There are several other properties that characterize the hazard potential of a
petroleum product. As the flash point is low, LPG can form large quantities of
flammable vapour cloud on release into the atmosphere. However it requires contact
with a strong ignition source before ignition can occur.
2.3
Findings of past accident analysis
While no major incidents involving MSVs have been reported, incidents involving transfer
operations and transport vehicles have been recorded. An analysis of past accidents
involving LPG tank lorries was carried out based on published literature. A list of recent
occurrences at LPG bulk storage plants and transportation in LPG tank lorries is given in
Appendix 3
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Risk Analysis Report
2.4
LPG Bottling Plant, BPCL Kappalur, Madurai
Hazard Potential based on Fire & Explosion Index
The next stage of hazard identification involves the estimation of Fire & Explosion
Indices for the major storage units in the facility to give the relative severity of the
units from the fire angle.
These are evaluated from the knowledge of the material hazard factor, General (GPH)
and Special Process Hazard (SPH) factors. Material Factor (MF) is the measure of the
energy potential of a particular chemical or its mixture with other chemicals. GPH and
SPH are evaluated by taking into account the exotherm or endotherm of a reaction,
material handling and transfer hazards, accessibility, severity of process conditions
and possibilities, dust and other explosions, inventory level of flammable material,
etc.
The F&EI value is then calculated as the product of MF, GPH and SPH. Detailed fire
and explosion indexing was carried out for the proposed storage units of the plant to
give the relative degree of severity of the units using the criteria given in Table 2.3.
Table 2.3
Criteria for Degree of Hazard for Fire and Explosion Index
Index range
Degree of Hazard
1-60
Light
61- 96
Moderate
97-127
Intermediate
128-158
Heavy
>159
Severe
The worksheet for the F&EI estimated for the LPG mounded storage vessel is given in
Appendix 4.
2.4.1
Analysis of F&EI Results
The result of the F&EI study for single units of storage is given in Table 2.4.
Table 2.4
F&EI Calculations -- Summary Table for Hazardous Units
Units
Max.
Qty./
unit
Material
Factor
MF
Fire & Explosion
Index
F&EI
Degree of Hazard
LPG mounded storage vessel
900 MT
21
102
Intermediate
LPG tanker
18 MT
21
74
Moderate
It can be observed that the MSV has F&EI values of 102 and falls under the intermediate
class of fire and explosion hazard, while the road tanker, with F&EI at 74 falls in the
Moderate Hazard class.
While the quantity stored within an individual cylinder is below the value that can
give meaningful results using F&EI analysis, it must be noted that filled cylinders if
exposed to sustained external heat sources can explode leading to further leaks of
LPG and damage within the plant.
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Risk Analysis Report
2.5
LPG Bottling Plant, BPCL Kappalur, Madurai
Summary
Based on the PHA, LPG is hazardous and prone to fires and explosions. Leaks of LPG if
ignited immediately may result in fires. If unignited, the leaks may build up in vapour
clouds within flammable limits and result in VCE.
Past accident analysis has revealed that accidents have occurred in filled road tankers
and filled cylinders.
The findings have established that there is a need for further investigation and
quantification of potential damage and evaluation of the proposed safety systems.
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Risk Analysis Report
CHAPTER III.
3.1
LPG Bottling Plant, BPCL Kappalur, Madurai
Consequence Analysis
Preamble
The activities at the proposed bottling plant have been assessed for potential for
release of LPG to initiate and propagate an unintentional event or sequence of events
that can lead to an accident or emergency.
The assessment was based on well-recognized and internationally accepted screening
methodologies. The analysis was conducted assuming operation steps and sequences
of action as provided by BPCL.
3.2
Construction of Hazardous Scenarios
Credible accident scenarios (CAS) were initially constructed followed by quantification
using Cause-Consequence Analysis (CCA) for the identified scenarios.
From the results of the preliminary hazard analysis, vulnerable locations were selected
where leak of vapor or liquid from the inlet/ outlet pipelines can occur. The list of
representative potential events covers mainly the release of LPG which could lead to
loss of life and/ or damage to property. The range of leak sizes representative for
small and large leaks that have been considered for the assessment are based on the
pipe sizes.
Credible accident scenarios (CAS) were initially constructed followed by quantification
using Cause-Consequence Analysis (CCA) for the identified scenarios.
Depending on the type of the operating conditions and the composition of LPG
handled, one or more of the following potential hazards/consequences could be
encountered due to loss of containment.
1. Jet Fire
2. Flash Fire
3. Vapour Cloud Explosion
Fig 3.1 gives a graphic representation of the development of the various potential
consequences, subsequent to release.
Fig 3.1 Representation of evolution of effects following release of LPG
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Risk Analysis Report
LPG Bottling Plant, BPCL Kappalur, Madurai
Based on the spill rate of LPG, the spilled amount will evaporate and form a continuous
dispersion. Such leaks/ spills will lead to the formation of flammable vapor, which if
ignited, can have severe effects. Scenarios where spill of LPG can form vapor clouds
were closely examined.
Two categories of events have been considered in the analysis: primary and secondary
events. While primary events occur due to generic failures, (aging, corrosion, etc.)
secondary events are the result of cascade potential of primary events such as heat
radiation, overpressures, etc.
The scenarios identified for the LPG loading, storage and distribution operations are
detailed in Table 3.1. The major types of consequences that may be expected under
these circumstances are flashfires, vapor cloud explosions (VCE) and jet fires.
Detailed consequence analysis was carried out for each of the identified scenarios.
Table 3.1
List of Hazardous Scenarios
S
no.
Location/
Activities
Scenario
1.
LPG lorry tanker 1a Release from SRV
(filled)
1b Level/temperature gauge leak
Potential Outcome
Spill/ Flashfire
Spill/ Flashfire
1c Rupture (100%) of drain valve on Spill/ Flashfire
tanker lorry
1d Failure of tanker lorry (filled)
Fire ball
1e Rupture (100%) of unloading VCE
arm- liquid line
1f Rupture (100%) of unloading VCE
arm- vapor line
LPG Lorry Tanker 1g Rupture (100%) of liquid line Spill/ Flash fire/ Jetfire/ VCE
(during
from tanker lorry
unloading)
1h. Rupture (100%) of vapor line Flash fire/ Jetfire/ VCE
from tanker lorry
2.
MSV
Case 1: no filling
2a. Leak (20%) of pipe section close VCE/ Flashfire
to vessel (before ROV)
2b. Leak (20%) of pipe section away VCE/ Flashfire/ Jetfire
from vessel (after ROV)
2c. Leak of drain pipe
VCE/ Flashfire/ Jetfire
2d. Leak (20%) of vapor line
VCE/ Flashfire/ Jetfire
2e. Release through Stack 10-m VCE/ Flashfire/ Jetfire
above ground level
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Risk Analysis Report
S
no.
Location/
Activities
LPG Bottling Plant, BPCL Kappalur, Madurai
Scenario
Potential Outcome
Case 2: filling of 2f. Overfilling - release through the VCE/ Flashfire/ Jetfire
MSV
SRV
3.
Transfer
from 3a. Rupture of liquid pipe line
Flashfire/ Jetfire
MSV via pump to
filling
station 3b. Rupture (100%) of liquid return Flashfire / Jetfire
pipe line
(Discharge line)
4.
Filling Shed
4a. Leak at filling point (14.2, 19 kg)
Flashfire / Jetfire
4b. Leak at filling point (35, 47.5 kg)
Flashfire/ Jetfire
5.
Cylinder
degassing shed
5. Failure of Evacuation vessel
Flying projectiles
6.
Cylinders
6. Rupture of cylinder
Flying projectiles
Detailed consequence analyses have been carried out for cases of jetfire, vapor cloud
explosion/ flashfire and fireball. The events depicting the worst-case scenarios are
summarized in the following sections.
3.3
Consequence Modeling
Consequence Calculations were carried out based on models accepted within the
chemical industry and Indian standards (IS 15656: 2006 HAZARD IDENTIFICATION &
RISK ANALYSIS – CODE OF PRACTICE) and international guidelines.
The extent of the consequences of an accident in a hydrocarbon installation depends
on the type and quantity of the product stored and handled, mode of containment,
and external factors like location, density of population in the surrounding area, etc.
In many cases realisation of hazard and its potential also depend on prevailing
meteorological conditions and availability of ignition source.
Petroleum products such as LPG require interaction with air or oxygen and an ignition
source for the hazard from loss of containment to be realised. Under certain
circumstances, vapours of the product when mixed with air may be explosive,
especially in confined spaces.
Dense dispersion model was used to calculate the extent of dispersion up to lower
flammable limits (LFL). The most pessimistic meteorological conditions (wind speed
2.2 m/s, stability class F) and wind direction were taken for dispersion simulations.
The amount in flammable limits was considered for calculation of pressure effects.
3.4
Consequence Outputs
For the identified scenarios, computer simulations were carried out using data
collected from BPCL, Kappalur, Madurai.
Past accidents and engineering judgment concur that 100% leaks are credible for pipe
sizes of 6” and less. 20% leaks have also been considered to represent gasket/ flange
leaks.
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Risk Analysis Report
3.5
LPG Bottling Plant, BPCL Kappalur, Madurai
Quantification & Criteria employed
Hazardous situations identified in this section have been quantified using consequence
models. Quantification provides an estimate of the damage potential for each
individual scenario. The damage is expressed in terms of the area involved. The extent
of damage in turn depends on the composition, quantities involved, location and
conditions of release of LPG.
Fire damage estimates are based on correlation with recorded incident radiation flux
and damage levels. Explosion damage is estimated based on recorded peak
overpressures and corresponding potential damage effects.
3.5.1
Damage Criteria for heat radiation effects
The damage criteria give the relation between extent of the physical effects
(exposure) and the percentage of the people that are killed or injured due to those
effects.
Thermal radiation effects are used as damage criteria for fires. Damage criteria for
heat radiation used in the analysis are given and explained here
The consequence caused by exposure to heat radiation is a function of:

The radiation energy onto the human body [kW/m2]

The exposure duration [sec]

The protection of the skin tissue (clothed or naked body)
100% lethality may be assumed for all people suffering from direct contact with
flames. The effects due to relatively lesser incident radiation intensity are given in
the table below.
Table 3.2
Effects due to Incident Radiation Intensity
Incident Heat Flux
Type of Damage Caused
kW/m2
To Equipment
To People
1.2
Solar Heat at Noon
1.6
---
Minimum Level of pain
threshold
2.0
PVC insulated cables damaged
---
4.0
---
Causes pain if duration is
longer than 20 sec. Blistering
is unlikely.
6.4
---
Pain threshold reached after
8 sec. Second degree burns
after 20 sec.
12.5
Minimum energy to ignite
wood with a flame; Melts
plastic tubing
1% fatality in 30 sec
----
Severe burns after 5 sec.
16.0
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First degree burns in ten sec.
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Risk Analysis Report
LPG Bottling Plant, BPCL Kappalur, Madurai
Incident Heat Flux
kW/m2
Type of Damage Caused
To Equipment
To People
21.2
---
1% fatality in 10 sec. with
protection of clothing
25.0
Minimum energy to ignite
wood at indefinitely long
exposure without a flame
100 % fatality in 1 (one)
minute
37.5
Severe damage to plant
100 % Fatality
Heat radiation of 37.5Kw/m2 is considered as fatal heat radiation. It is also the
intensity at which structural damage can be expected to exposed units.
Evaluation of Severity for Thermal Radiation: The criteria used to evaluate the
severity of the consequence (Thermal radiation) is 12.5 kW/ m2 corresponding to 1%
fatality for exposures of 30 seconds
3.5.2
Damage Criteria for overpressure effects
A Vapour Cloud Explosion (VCE) is a deflagration accompanied by a blast effect that
occurs in the open air as a consequence of the ignition of a cloud containing flammable
vapour.
The estimate of the likely maximum value of overpressure that may be generated in
a VCE is of considerable importance for consequence analysis. If no immediate ignition
of a released material occurs, it can disperse into the atmosphere. Following ignition,
the vapour cloud will start to burn. It is assumed that fatality will be 100% in the
projected area of the vapour cloud.
The shock wave model, used for a wide range of flammable gas clouds, expresses
explosion overpressure as a function of distance from the center of the cloud. This
correlation uses a measure of distance from the cloud center, which is scaled to onethird the power of the available combustion energy. The damage criteria used to
assess VCEs are given in Table 3.3 below
Table 3.3
Over
pressure
(bar)
Overpressures and corresponding types of damage 1
Type of damage
To Equipment/ Property
To people
0.01
Crack of windows
0.02
10% window glass broken
0.03
Large & small windows usually shattered
People injured by flying glass
and debris
0.10
Repairable;
1% eardrum rupture
1% serious wounds from
flying objects
Moderate damage to houses (windows
and doors blown out and severe damage
to roofs)
1
Threshold Damage Limits September 2003 www.fireriskforum.com Page 27 Table 5.17: Explosion
Overpressure Damage Impacts
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Risk Analysis Report
LPG Bottling Plant, BPCL Kappalur, Madurai
Over
pressure
(bar)
0.20
0.20 to 0.27
0.30
Type of damage
To Equipment/ Property
To people
Steel frame constructions distorted and
pulled away from foundations;
Serious injuries are common,
fatalities may occur
Rupture of Oil storage tanks
Residential structures collapse
Heavy damage; Most buildings collapse
Injuries are universal,
fatalities are widespread
1% death from lung damage
>50% eardrum rupture
>50% serious wounds from
flying objects
Evaluation of Severity for Overpressures: The levels of interest in risk assessment
are those that can cause loss of life and damage to property (0.3 to 0.1 bar)
3.6
Worst Case Scenario & Damage Contour
It may be seen from the calculations that jet fires are the most credible scenarios as
the quantities available in flammable limits are too low for the development of vapor
cloud explosions. The complete results from the analysis have been given in Appendix
6.
Jet fires
The worst case scenario occurs on immediate ignition of LPG released from the leak
of pipe section after ROV on the MSV.
The calculated damage distances are given in Table 3.4 below for the representative
cases of maximum impact at various locations within the plant
Table 3.4
Event
Reference
No.
Damage distances from Jet fire (Worst case scenario)
Scenario
Thermal
radiation
inside jet
Length
Width
kW/m2
m
m
Damage distances (m)
37.5 kW/m2
12.5 kW/m2
4 kW/m2
DW
CW
DW
CW
DW
CW
2b
Leak
(20%) of
pipe
section
after
ROV
4.3
302.2
24.1
2.1
25.7
4.2
27.6
10.1
30.2
3a
Rupture
(100%) of
liquid
discharge
from
pump to
filling
station
line
299.4
32.5
2.8
34.6
5.6
37.1
13.4
40.5
25.4
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Risk Analysis Report
Event
Reference
No.
1a
Scenario
Release
from SRV
on tank
lorry
LPG Bottling Plant, BPCL Kappalur, Madurai
Thermal
radiation
inside jet
Length
Width
kW/m2
m
m
185.9
22.7
1.9
Damage distances (m)
37.5 kW/m2
12.5 kW/m2
4 kW/m2
DW
CW
DW
CW
DW
CW
23.6
2.5
25.1
6.7
27.1
13.6
The credible damage contours for jet fire scenarios at MSV, pump house and TLDG
were plotted on the layout of the plant in the probable wind direction and shown in
Fig. 3.2, 3.3 and 3.4
LEGEND for Figures
Code for Jet Fire
Thermal Radiation In kW/m2
Maximum radiation within the jet
37.5
12.5
4
Code for Overpressures
Overpressures in bar
0.3
0.1
0.03
Area of Flash Fire
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Risk Analysis Report
LPG Bottling Plant, BPCL Kappalur, Madurai
Fig 3.2 Damage contours due to Jet fire at MSV (Event no 2b)
Fig 3.3 Damage contours due to Jet fire at Pump house (Event no 3a/ 3b)
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Risk Analysis Report
LPG Bottling Plant, BPCL Kappalur, Madurai
Fig 3.4 Damage contours due to Jet fire at Gantry (Event no 1a/ 1b)
VCE
In the event of release of LPG in substantial amounts, a flashfire or VCE could result
if suitable ignition source is available. For such a case the damage distances at the
MSV (Event no 2a) have been calculated and given in Table 3.5
Table 3.5
Event
Reference
No.
2a
Damage distances from Flashfire/ VCE
Scenario
Leak (20%)
of pipe
section close
to vessel
(before ROV)
Wind
velocity
&
Stability
Cloud
radius/
Height
Amount in
Explosive
limits
LFL
distance
m
kg
m
Damage distances
(m)
0.3
bar
0.1
bar
0.03
bar
2F
25.1/
14.7
618
12
72.1
144.2
360.5
5D
18.2/
9.7
515
30
67.8
135.7
339.3
The events are mutually exclusive in that the occurrence of a flashfire precludes the
occurrence of a VCE. However the damage distances for both the events have been
plotted on the layout in the dominant wind direction (South west) and presented as
damage contours in Fig 3.5 below
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Risk Analysis Report
LPG Bottling Plant, BPCL Kappalur, Madurai
Fig 3.5 Damage contours due to Flashfire & VCE at the MSV (Event no 2a)
3.6.1
Secondary events and Cascade Effects
In the event of an external fire within the plant, exposed vessels such as filled tanker
lorries at the gantry/ parking area, or evacuation vessel in the filling area or filled
cylinders in the shed could overheat and give rise to events classified as Cascade or
Domino Effects.
BLEVE
A sustained fire at the TLDG could result in BLEVE of filled tanker lorry. The damage
arising from such an event is given in Appendix 6, Table 6.1.3. The damage contours
have been plotted on the layout and presented in Fig 3.6
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Risk Analysis Report
LPG Bottling Plant, BPCL Kappalur, Madurai
Fig 3.6 Damage contours from BLEVE of tanker lorry at the TLDG (Event no 1d)
Secondary events such as BLEVE/ Fireball can have impacts covering the whole plant
and on the areas external to the LPG bottling plant. Such events arise from primary
events and are of low probability.
Physical explosion
Secondary events such as explosion of the evacuation vessel or filled cylinders can
occur if sustained ignition sources (such as external fire) are available in the vicinity.
These explosions could give rise to projectiles from the explosion of the units and
further damage from the fragments. The damage distances from such events have
been given in Appendix 6 Table 6.1.4 & 6.1.5
3.7
Observations
Credible scenarios were constructed based on HAZID studies, past accidents, and
engineering judgment. Consequences were estimated and the worst case was plotted
on the site layout.
The damage zones from all primary events/ scenarios envisaged at the plant are seen
to be restricted within the plant boundary. Leaks within the plant and at the carousel
are small and the quantities expected to be released in such cases will be insufficient
to sustain vapor cloud explosion.
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Risk Analysis Report
CHAPTER IV.
4.1
LPG Bottling Plant, BPCL Kappalur, Madurai
Probability Assessment & Risk from the plant
Preamble
Several credible scenarios with potential to cause damage were considered and
assessed. The realization of these credible scenarios is prevented by the presence of
safety systems inbuilt in the design and operation of the facility. This chapter collates
all the safety systems, both preventive and mitigative and provides appropriate
linkage to the individual scenarios considered. In addition, the effectiveness of these
safety systems was evaluated using probability assessment.
4.2
Evaluation of the Safety System
As LPG can potentially leak from several locations, BPCL is introducing several
preventive and mitigative features across the site. The following safety systems have
been assumed to be available within the site.
SAFETY TRIPPING SYSTEM
1. Emergency Shut Down :
a. Shuts down all the LPG Operations
b. Trips EB Power
c. Indication at Control panel
2. Manual Call Point :
a. Shuts down all the LPG Operations
b. Operates Siren
c. Indication at Control panel
3. Quartzoid Bulb :
a. Shuts down all the LPG Operations
b. Trips EB Power
c. Indication at Control panel
d. Operates Medium Velocity spray sprinklers system in the affected area
as per OISD norms.
4. DV Remote Push Button :
a. Shuts down all the LPG Operations
b. Trips EB Power
c. Indication at Control panel
d. Operates Medium Velocity spray sprinklers system in the affected area
as per OISD norms.
Additional safety features to be introduced:
1)
2)
3)
4)
5)
6)
RCE Chennai
All electrical motors to be specified as IE 3 grade for maximum efficiency
and reduced energy costs.
Smart MCC, with fuseless feeders for safe and easy operation/
maintenance.
LED lighting.
Low drop compressed air header system.
Biometric access control for drivers.
HMT with LEP light fixtures shall be provided.
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Risk Analysis Report
LPG Bottling Plant, BPCL Kappalur, Madurai
In addition to the above, option for implementing the following shall be explored.
a)
b)
c)
d)
Automatic online correction Unit
Vision camera for automatic tare weight reading and encoding.
Automatic SQC.
Filling data to be uploaded to SAP.
Safety systems of other facilities within the plant
a. Fire hydrant system: - Fire hydrant ring main covering all facilities will be
provided as per the OISD requirements. Double hydrants (with hose boxes, hoses
& nozzles) and fire water monitors as per the stipulations in the OISD-144 will be
provided. Long range Fire Monitors shall be provided in critical areas with remote
operation.
b. MV Spray system: As per OISD norms for Fire Protection System.
c. Fire Extinguishers: Shall be provided as per OISD norms.
d. Deluge Valves: Auto reset type deluge valves having manual quick bypass system
as per OISD norms shall be provided with fire protection wall. Provision for
activation of DV shall be for auto and manual modes (local & remote panel) as
per OISD-144.
e. All the isolation valves used in firefighting system shall be of rising stem type.
f. Manual Calling Point (MCP): Manual Call Points at strategic locations as
enumerated in OISD-144 shall be provided to raise alarm (siren) and also shut
down LPG operations, in case of emergency with suitable hooter on annunciation
panel at fire water pump house.
g. Gas monitoring system: Gas monitoring system with infra-red / Catalytic type
sensors shall be provided as per revised OISD standard-144. Mimic & repeater
panels shall be provided at FWPH (Fire Water Pump House) /Control room and
security gate
h. Vapour extraction system: Shall be provided at the carousel and always ‘ON’
during filling operations
i. Vapour Seal: Suitable vapour seals to be provided in storm water drain at the
following areas
•
Drains around filling & filled cylinder sheds
•
Bulk storage
•
Boundary
j. Communication System: Intrinsically safe paging system, inter-com at all
working stations/points, Walkie-talkie for designated staff (VHF/UHF) and PA
system for announcement at gate shall be provided.
k. Cathodic protection system shall be provided for all MSVs and related piping.
l. Electrical fittings: All electrical fittings will be as per the area classification (refer
OISD-113) and prevalent IE Rules. All Motors to be of IE 3 Grade.
m. Main instrument control panel (MIC): Flame proof ROV control panel shall be
provided at LPG Pump House with parallel display at FWPH. /Control room.
Some of these systems are activated automatically, while some require manual
activation. The distinctive features of these systems have been evaluated in the
probability analysis.
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Risk Analysis Report
4.3
LPG Bottling Plant, BPCL Kappalur, Madurai
Probability Assessment
For each of the consequence scenarios identified in the previous section, a
probabilistic assessment was carried out based on the safety system listed above. The
effectiveness of these systems in preventing and or mitigating the effects of leak has
been assessed using probabilistic analysis through event-tree. This technique gives due
consideration to the element of time and sequence of activation. This is critical as
every leak of LPG has the potential to either ignite immediately or disperse and
accumulate in flammable concentration.
4.3.1
Events in the accident chain and safety features
An incident will occur only under the following chain of events.
1. Initiating event
o
Leak, spill, etc.
2. Failure of protective/ warning devices
o
Instruments, human action
3. Presence of ignition sources (fixed & mobile)
4. Failure of mitigation measures
o
Dykes, firefighting equipment, training
The risk of an accidental outcome can be contained if any of the systems identified in
the chain of events functions as designed. The analysis was based on the Layer of
Protection Analysis (LoPA2) and hierarchy of the safety systems is given in Appendix 8.
4.3.2
Estimation of Probability
The probabilities of failure of the components that make the accident chain were
combined to arrive at the probability of occurrence, i.e., whether it is fire, explosion,
toxic dispersion or any combination of consequences within the site. The probability
of each event was estimated considering the number and type of units and sequence
of operation at each location.
Factors such as the equipment layout, availability of ignition source, proposed safety
systems and the surrounding topography have been considered for the assessment.
These are further described in Appendix 1.
Estimation was carried out for both primary and secondary events. Primary events
assume generic failure of pipes and failure of instruments and interlocks. Secondary
events involve vessel failures caused by primary events.
Generic failure data collated from published industrial databases such as Risk
Assessment Data Directory of the International Association of Oil & Gas Producers3, UK
Health Safety Executive (UK HSE) database, etc. was used to generate the
probabilities at each location. Ignition probabilities given in OGP Risk Assessment Data
Directory – Ignition Probabilities4 were used in the analysis.
2
Layer of Protection Analysis – Simplified Process Risk Assessment’ published by Center for Chemical
Process Safety of the American Institute of Chemical Engineers, New, York, New York, 2001
3
OGP RADD – Storage Incident Frequencies Report No. 434 – 3, March 2010
4
OGP RADD – Ignition Probabilities Report No.: 434-6.1 March 2010
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Risk Analysis Report
LPG Bottling Plant, BPCL Kappalur, Madurai
The table below gives the probability of occurrence per year of an incident of fire or
explosion arising at each location.
Table 4.1
Frequency estimation at different locations within the plant (primary &
secondary events
S
no.
Location/
Equipment/
Activity
Scenario
Frequency
of
occurrence/
yr of Jetfire
Frequency
of
occurrence/
yr
of
Flashfire or
VCE
1
LPG road tanker
(18MT) ( filled)
1a. Safety relief valve
malfunctioning
1.00E-09
5.00E-10
1b. Level/temperature
gauge leak
7.00E-10
3.50E-10
1c. Leak from drain valve
7.00E-09
3.50E-09
1d. Catastrophic Failure*
LPG road tanker
(18MT)
(during
unloading)
2
New
Mounded
storage
vessel
(900MT)Case 1: no filling
Case 2: filling of
MSV
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Frequency
of
occurrence/
yr of Fireball
1.00E-12
1e. Rupture (100%) of
unloading arm- liquid line
9.00E-15
4.50E-15
1f. Rupture (100%) of
unloading arm- vapor line
2.10E-14
1.05E-14
1g. Rupture in transfer
pipe line from LPG road
tanker to bullet
2.25E-14
1.13E-14
1h. Rupture of the vapor
line from LPG road tanker
to bullet
5.25E-14
2.63E-14
2a. Leak (20%) of pipe
section close to vessel
(before ROV)
4.50E-12
2b. Leak (20%) of pipe
section away from vessel
(after ROV)
9.00E-12
4.50E-12
2c. Leak of drain pipe
9.00E-12
4.50E-12
2d. Leak (20%) of vapor
line
2.80E-11
2e. Release through
Stack 10-m above ground
level
7.00E-10
2f. Overfilling - release
through the SRV
3.00E-09
1.50E-09
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Risk Analysis Report
LPG Bottling Plant, BPCL Kappalur, Madurai
S
no.
Location/
Equipment/
Activity
Scenario
Frequency
of
occurrence/
yr of Jetfire
Frequency
of
occurrence/
yr
of
Flashfire or
VCE
3
Transfer
from
bullet/MSV/Sphere
via pump to filling
station (Discharge
line)
3a. Rupture of liquid pipe
line
9.00E-13
4.50E-13
3b. Rupture (100%) of
liquid return pipe line
1.50E-12
7.50E-13
Filling Shed
4a. Leak at filling point
(14.2, 19 kg)
3.50E-14
1.75E-14
4b. Leak at filling point
(35, 47.5 kg)
3.50E-14
1.75E-14
4
Frequency
of
occurrence/
yr of Fireball
5
Cylinder degassing
shed
5. Failure of Evacuation
vessel*
1.00E-12
6
Cylinders
6. Rupture of cylinder *
9.00E-17
*These are secondary events that require primary events such as direct impingement of
flame/ external fire as initiators
4.4
Observations
The highest frequency of occurrence of an unwanted event is of the order of 10-9 per
year, i.e., the chance of occurrence is once in thousand million years.
As the plant is located in the industrial area, and there are no pockets of habitation
in the vicinity, the risk is evaluated on the basis of effect on personnel in the plant.
4.5
Evaluation of Risk
Risk numbers are based on the probability of occurrence and the severity of the
consequences of a particular outcome and provide a relative measure of the risk
associated with the operation.
Risk is calculated as the product of the consequence and probability for each individual
event.
The scenarios shortlisted are those that can cause potential fatalities/ serious injuries
to personnel and represent the maximum credible events. This included worst damage
from an occurrence of jet fire/ VCE/ BLEVE/ physical explosion within the plant.
The following criteria equivalent to 1% fatality was employed for risk assessment
Table 4.2
Risk Criteria considered for individual risk evaluation
Effects
Level of interest (equivalent to 1% fatality)
Thermal radiation
12.5 kW/m2
Overpressures
0.1 bar
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Risk Analysis Report
LPG Bottling Plant, BPCL Kappalur, Madurai
Based on the projection of damage contours on the site layout for these levels the
effects of all significant events were evaluated.
It was assumed that the primary events are pipe leaks which have higher failure rates
than vessel rupture. These primary events can lead to secondary events such as vessel
failure/ rupture resulting in BLEVE/ Fire ball situations.
4.6
Risk criteria
To provide a relative ranking of the outcomes, the risk criteria as described below was
adopted.
The individual frequency values used in the analysis are given in Table 4.2. These are
classified in terms ranging from ‘Extremely remote’ to ‘Frequent’ based on industrial
experience worldwide5. Severity values used in risk matrix are based on the effects
within the site that are likely to occur when a hazardous event takes place.
The magnitude and category of risk at the plant was assigned based on the following
Matrix.
Table 4.3
Qualitative Risk Matrix for Potential effects on human life
Frequency of occurrence
Extremely
Remote
(< 10-9)
Severity of occurrence
Remote
(10-6 to 10-9)
Occasional
(10-3 to 10-6)
Frequent
(10-1 to 10-3)
1
2
3
4
No significant effect
1
Low
Low
Low
Low
Injury or serious health
effects/
Repairable
Property
damage
2
Low
Low
Medium
Medium
Fatality/
disability/
damage
3
Low
Medium
Medium
High
4.7
permanent
Structural
Risk to personnel inside and outside the plant
The plant is proposed to be run on two shifts, during which operation personnel are
to be stationed at the various locations within the plant.
It may be noted that the severe damage effects corresponding to 1% fatality from the
jet fire and flashfires are localized and the risk is restricted to within the plant.
However in the event of VCEs the vulnerable zone extends over the plant area. These
effects extend outside the plant boundary along the north and west.
5
Values of failure frequencies given in Table 5.1 (pg 71) & Table 6.4 (pg 96), ‘Layer of Protection Analysis
– Simplified Process Risk Assessment’ published by Center for Chemical Process Safety of the American
Institute of Chemical Engineers, New, York, New York, 2001
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Risk Analysis Report
LPG Bottling Plant, BPCL Kappalur, Madurai
The following table gives the category of risk of each event scenario identified at the
plant.
Table 4.4
Risk levels from various credible scenarios at different locations
inside the LPG bottling plant
S
no.
1
Location/
Equipment/
Activity
Frequency
rating
Severity
rating
Risk
Rating
LPG
road 1a. Safety relief Jet fire
tanker (18MT) valve
Flashfire
( filled)
malfunctioning
1
3
Low
1
3
Low
1b.
Level/ Jet fire
temperature
Flashfire
gauge leak
1
3
Low
1
3
Low
1c. Leak from drain Jet fire
valve
Flashfire
1
3
Low
1
3
Low
1
3
Low
1e.
Rupture Jet fire
(100%)
of
unloading
armFlashfire
liquid line
1
3
Low
1
3
Low
1f. Rupture (100%) Jet fire
of unloading armFlashfire
vapor line
1
3
Low
1
3
Low
1g. Rupture in Jet fire
transfer pipe line
from LPG road Flash fire
tanker to bullet
1
3
Low
1
3
1h. Rupture of the Jet fire
vapor line from
LPG road tanker to Flashfire
bullet
1
3
Low
1
3
Low
1
1
Low
1
3
Low
Scenario
Hazardous
outcome
1d. Catastrophic BLEVE/
Failure*
fireball
LPG
road
tanker (18MT)
(during
unloading )
2
New Mounded 2a. Leak (20%) of Flashfire
storage vessel pipe section close
(900MT)to vessel (before
ROV)
Case 1: no
filling
Jet fire
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Low
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Risk Analysis Report
S
no.
Location/
Equipment/
Activity
LPG Bottling Plant, BPCL Kappalur, Madurai
Frequency
rating
Severity
rating
Risk
Rating
1
3
Low
1
3
Low
1
3
Low
2d. Leak(20%) of Jet fire
vapor line
1
3
Low
2e.
Release Jet fire
through Stack 10m above ground
level
1
3
Low
Case 2: filling 2f. Overfilling - Jet fire
of MSV
release through
Flashfire/
the SRV
VCE
1
3
Low
1
3
Low
Transfer from
bullet/MSV/Sp
here via pump
to
filling
station
(Discharge
line)
3a. Rupture of Jet fire
liquid pipe line
Flash fire
1
2
Low
1
1
Low
3b.
Rupture Jet fire
(100%) of liquid
Flash fire
return pipe line
1
2
Low
1
1
Low
Filling Shed
4a. Leak at filling Jet fire
point (14.2, 19 kg)
1
3
4b. Leak at filling Jet fire
point (35, 47.5 kg)
1
3
1
3
1
3
Scenario
Hazardous
outcome
2b. Leak (20%) of Flashfire
pipe section away
from vessel (after
ROV)
2c. Leak of drain Jet fire
pipe
Flashfire
3
4
5
Cylinder
5.
Failure
of Physical
degassing shed Evacuation vessel* explosion
6
Cylinders
6. Rupture
cylinder*
of Physical
explosion
Low
Low
Low
Low
*Secondary events
The risk to personnel within the plant is qualitatively categorized as low.
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Risk Analysis Report
4.7.1
LPG Bottling Plant, BPCL Kappalur, Madurai
Risk from Secondary Events
The effects of secondary events will be experienced at manned locations within the
plant. Personnel in the open areas will be vulnerable within a radius of 140 to 425 m
from exploding cylinders at the cylinder filling area. The damaging effects from a
BLEVE at the TLDG will extend over a radius of 164 m. The pumphouse, MSVs, filling
shed, filled cylinder shed lorry parking area, planning & control room, change room
and toilet main gate, security cabin, part of Admin building fall within this zone.
Radiation levels ranging from 12 to 4 kW/m2 may be experienced outside the boundary
along the western, northern and eastern boundary.
4.8
Summary
Credible accident scenarios were initially constructed followed by consequence
estimation using mathematical modeling and probability analysis. The maximum risk
for the proposed operation for areas inside and outside the plant has been estimated.
It needs to be mentioned that the plant is located within an industrial area and no
major population settlements are expected in the vicinity of the plant.
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Risk Analysis Report
CHAPTER V.
5.1
LPG Bottling Plant, BPCL Kappalur, Madurai
Major Findings & Recommendations
Preamble
A risk assessment (RA) study was carried out for BPCL’s proposed LPG bottling plant
at Kappalur, Madurai. The process of the RA study included a series of steps, viz.,
hazard identification, consequence estimation, probability assessment and risk
evaluation.
The main findings are reported in three stages viz., consequence assessment,
probability assessment and risk classification.
Measures for reduction of risk have been suggested for events with potential to cause
significant damage to life and property.
5.2
Main Findings of Consequence Assessment
The results of consequence analysis conducted at several locations for potential
release of LPG within the bottling plant are summarized below. These sections include
receipt at gantry, storage in mounded storage vessels, filling of cylinders at the
carousel and storage of filled cylinders in shed prior to dispatch.
The findings include potential impacts of credible accidents on personnel inside and
outside the plant. The potential outcomes from these scenarios include jet fire, flash
fire, VCE, physical explosion and fireball.
Two categories of events have been considered in the analysis: primary and secondary
events. While primary events occur due to generic failures (aging, corrosion, etc.) and
operational deviations during activities, secondary events are the result of cascade
potential of primary events such as heat radiation, overpressures, etc.
5.2.1
Primary events
The primary events include jet fires and VCEs at the MSV, pumphouse/ compressor
room and gantry. The individual events and impacts are discussed below
A. Jet fire at MSV:
1. Thermal radiation resulting in severe damages and fatality may affect the
LPG pump house.
2. Jet fire from one MSV may impinge on the projections like relief valve of
neighbouring MSV leading to further damages.
3. Thermal radiation from jet fire (up to 4kW/m2) may extend beyond the
western boundary.
B. Jet fire in LPG pump house:
1. Thermal radiation from jet fire emanating from the pump house may affect
the MSVs.
2. Effects will be contained within the plant boundaries.
C. Jet fire in unloading gantry:
1. Jet fire in unloading gantry will be localised and will not affect the
neighbouring facilities.
2. Effects will be contained within the plant boundaries.
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Risk Analysis Report
LPG Bottling Plant, BPCL Kappalur, Madurai
D. VCE in Mounded Storage Vessel (MSV):
1. Damage zone from 0.3 bar overpressures will be contained within the plant
boundaries in the north, south and east directions and extend to upto 40m
outside the western boundary (HPCL Depot). Within the plant, the pump
house and MSVs fall within this zone.
2. Damage zone of overpressure of 0.1 bar extends beyond the northern
boundary to a distance of about 45 m, and 115m from the western boundary.
Areas falling within this zone in the plant include the TLDG, cylinder filling
shed, filled cylinder shed, weighbridge and part of the lorry parking area.
5.2.2
Secondary event
These events require a primary event for realization.
E. BLEVE in LPG tanker at the gantry
1. In the event of BLEVE of a tanker at the gantry, severe damage and 100%
fatality from thermal radiation of 37.5 kW/m2 extends to the pump house,
the MSVs and about 47m beyond the northern boundary.
2. Thermal radiation accounting for 1% fatality (12.5 kW/m2) will be
experienced at the filling shed, filled cylinder shed lorry parking area,
planning & control room, change room and toilet main gate, security cabin,
part of Admin building within the plant. Effects will also be experienced
about 90m beyond the eastern boundary, 130m beyond the northern
boundary and about 62m beyond the western boundary.
3. Thermal radiation of 4kW/m2 extends to a radius of 312m from the tanker
5.3
Findings from Probability Analysis for individual events
The scenarios quantified in the consequence assessment were analysed to determine
the frequency of occurrence per year of the hazardous event. The analysis took into
consideration the sequence of development of the event and the preventive and
mitigation measures based on the safety systems proposed within the plant.
The probability of hazardous outcomes for each scenario was calculated using the
failure rates of pipes, instruments and vessels along with the failure rates of available
measures for detection and control. The risk numbers are summarised below
Table 5.1
Order of magnitude of risk from primary and secondary events
Hazardous Outcome
Frequency of occurrence per year (range)
Primary events
Jet fire
1.00E-09 to 1.00E-15
Flash fire
1.00E-09 to 1.00E-15
VCE
1.00E-09 to 1.00E-15
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Risk Analysis Report
LPG Bottling Plant, BPCL Kappalur, Madurai
Hazardous Outcome
Frequency of occurrence per year (range)
Secondary events
BLEVE
1.00E-12
Cylinder explosion
1.00E-17
a) The risk of primary events may be considered extremely low due to the
provision of several safety features, interlocks and redundancy.
b) Frequencies of secondary events are also extremely low as each hazard
requires a primary event for initiation.
5.4
Risk classification of credible events
Individual events which are credible were rated based on a three level risk
classification viz., ’High’, ‘Medium’ and ‘Low’.
It can be seen that all the events fall in the ‘Low’ category.
Events that relatively represent the highest hazard potential in the plant are the
following outcomes:
a) Jet fire & flash fire from leak on the drain line of the tanker lorry (event no:
1c)
b) Flash fire/ VCE from Leak(20%) of pipe section close to vessel (before ROV)
(Event no 2a)
c) Jet fire from the safety relief valve of the tanker lorry (event no: 1a).
5.4.1
Estimation of Individual risk
In addition to the above risk classification of individual events, Individual Risk levels
inside the installation were evaluated at locations where people are stationed.
The maximum individual risk (IR) is the cumulative effect of several primary events
that may have impact on specific locations. The criteria used for the IR is 1% fatality
i.e., extent of thermal radiations upto 12.5 kW/m2 or overpressures of up to 0.1 bar,
The Individual Risk levels at manned locations are summarised below.
Table 5.2
Individual Risk at manned locations
Ref no. in Layout
Manned locations
Individual Risk per yr
18
Filling shed
1.46E-11
19
Filled cylinder shed
1.35E-11
22
Unloading gantry
1.04E-07
24
LPG pump house
1.58E-08
26
TRU room
1.58E-08
Beyond north boundary
1.35E-11
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Risk Analysis Report
Ref no. in Layout
LPG Bottling Plant, BPCL Kappalur, Madurai
Manned locations
Individual Risk per yr
Beyond west boundary
1.35E-11
Risk from primary events is highest at the gantry, followed by the pumphouse, and the
filling shed, valve changing shed, degassing shed, and filled cylinder shed and other
manned locations within the plant as well as outside the boundary.
To compare the evaluated risk posed by the plant, risk acceptance criteria was
adopted from Hazard Identification & Risk Analysis – Code of Practice IS 15656 : 2006;
ANNEX E. A selection was made from the code of practice based on the type of
industry, current stage of the project and surrounding environment, and the criteria
are mentioned in Table 5.3.
Table 5.3
Criteria adopted for Individual Risk of a new plant6
Authority and application
Maximum Tolerable Risk
(per year)
Negligible
(per year)
VROM, The Netherlands (New)
1.0E-6
1.0E-8
Risk
On comparison to adopted criteria the maximum individual risk of the order of
1.0E-7/yr lies between the maximum tolerable risk and negligible risk levels for a new
plant. While this level is within the ALARP7 region, it can be brought down further
through the following risk reduction measures.
5.5
Risk Reduction Measures
The risk estimation and categorization for the scenarios within the plant should be
considered in relative terms as BPCL has not adopted risk criteria of its own. BPCL
should therefore continue its risk reduction programs to bring down the risk levels
further.
5.5.1
Safety Measures at Tanker Lorry Decanting Gantry
Events involving the tanker lorry at the gantry represent the relatively highest risk
levels within the plant. Hence risk reduction measures directed at eliminating or
mitigating risk at this location are listed.
1) PSV rating on LPG tankers should be designed for fire engulfment. It is
assumed that regular servicing and maintenance of the PSV on the lorry
tanker is carried out.
5.5.2
Measures at Mounded Storage Vessel (MSV)
Jetfires and VCEs may be generated by leaks from the MSVs. While the vessels
themselves may not be impacted by these events, they can result in damaging effects
in the vicinity. Measures to prevent and attenuate these effects are given below
6
ANNEX E – Risk Criteria in some countries – Extract from IS 15656-2006
7
ALARP – As Low As Reasonably Practicable
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Risk Analysis Report
LPG Bottling Plant, BPCL Kappalur, Madurai
i) Jetfire at MSV
Distances upto LFL limits from source of release should be considered as hazardous
areas within which sources of ignition should be avoided or protected as per codes.
1. All electrical equipment falling within LFL limits shall be intrinsically safe.
2. All projections on top of MSV (PSV stem, vapour lines, etc.) need to be fire
proof.
ii) VCE at MSV
As noted from the consequence assessment, over pressures from VCE corresponding to
0.3bar falls on the western boundary and the effects may be experienced upto 70m
outside the plant.

The MSV cluster may be shifted by 70m away from the western boundary to
ensure effects of 0.3bar overpressures are contained within the plant site.
In addition, overpressure of 0.1 bar extends beyond the northern boundary to a
distance of about 45 m, and 130m from the western boundary. The following
recommendations may be considered.



5.5.3
No permanent manned activities should be allowed in these areas outside the
plant and communication in this regard must be made to the neighbouring
industries.
An offsite emergency plan must be prepared with industries sharing
boundaries with the BPCL LPG bottling plant.
Since the project is in the construction stage, inclusion of intrinsic safety
devices to prevent leak and reduction of liquid pipe sizes to mitigate leak
incidents may be considered, if viable.
Prevention of leaks & fires in filling/ carousel area.
While small leaks of LPG are common in the carousel and filling area (due to manual
errors in handling of cylinders, O-ring leak in over-filled cylinders, tipping of cylinders
from conveyors, etc.), these areas are generally well ventilated and provided with
exhaust blower to vent out leaked LPG.
Despite many types of protection to be provided within the licensed areas (anti-static
flooring, earthing, etc.) there are several means through which ignition may still
occur. These include
a) Switches & fixtures, cables connection joints that may deteriorate due to
moisture or aging and cause sparks and become potential source of ignition.
b) Sparks arising when the operator attempts to shut off valves or switches in
filling areas.
c) Sparks caused by metallic impact between cylinder base and metal structure
of the carousel line or between filling clamp and cylinder.
Hence a program needs to be initiated to identify sources of various static electricity
generation and measures to eliminate.
The following risk reduction measures aimed at potential areas of LPG leaks and on
elimination and control on the ignition sources may be considered for implementation
before commissioning of the plant.
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Risk Analysis Report
i.
LPG Bottling Plant, BPCL Kappalur, Madurai
SOP should be developed for all manual and semi-automatic activities being
conducted in the carousel and filling area (listing all individual steps and
tasks).
Gas sensors to be installed for identifying minor/major leaks at various
sources of LPG and operating sprinklers.
SOP should include operator’s actions (do’s and don’ts) during leak situation
especially in preventing static electricity generation
Shutdown of valves required as part of the operation/ operator action should
also be reviewed as these have potential for generation of static charges. The
review should also include shut-off logic for automatic valves in the carousel
section.
Training in employing these SOPs should be imparted to operators prior to
commissioning.
ii.
iii.
iv.
v.
5.5.4
Layout consideration
Obstacles such as building, boundary walls in the path of leaked LPG may delay the
dilution of leaked LPG and result in buildup of flammable concentration and increasing
the chance of an explosion.
The following factors should be considered in the layout design
a) Upwind and downwind direction surrounding the gantry and filling plant
should be free of obstacles and buildings to ensure quick dispersal of leaks
and prevent build-up of LPG vapours in flammable concentrations
b) Boundary wall should not be very high and be made porous to ensure
dispersal of leaked LPG
c) Fire water pipeline and monitors/hydrants are to be installed outside the
fire/ explosion zone.
5.5.5
Vapour cloud dispersal
Leaked LPG if not diluted or dispersed immediately, may increase the chance of an
explosion due to its high density and tendency to crawl along the ground. BPCL may
consider an effective vapor cloud dispersal of leaked LPG along the following lines
a) Activation of the sprinkler systems directly by gas detectors to disperse and
dilute the escaping LPG.
b) Such activation may be provided at MSV, pump house, carousel and gantry.
5.5.6
Reliability of critical instruments:
Overfilling of the MSV can occur due to faulty indicators or malfunctioning of the level
indicator or transmitter systems (LI/LT). Hence BPCL may consider fault-diagnostic
tools to be included as part of its preventive maintenance for level indicators and
transmitters.
5.5.7
Limitation of Activities beyond the plant
Based on the risk analysis, it is recommended that a NO-ACTIVITY ZONE of a minimum
of 40m be demarcated along the boundary walls along the northern and western
boundaries of the plant. Communication to the neighboring industries and the
appropriate authorities should be initiated.
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Risk Analysis Report
5.6
LPG Bottling Plant, BPCL Kappalur, Madurai
Site specific emergency planning
Several secondary events identified in the study (e.g., fireball, projectiles, etc.) which
are of low probability, need to be addressed in the development of site specific
emergency plans. The success of the plan will depends on the efficacy of mitigation
measures and evacuation protocols.
1) BPCL is requested to prepare emergency evacuation plan considering damage
distances from BLEVE and fire ball radiation upto 300 m.
2) Evacuation route should be planned to avoid thermal radiation zones up to
4kW/m2 arising from jet fires within the plant.
3) Leak of LPG shall be immediately intimated to the neighbouring IOCL
Terminal, HPCL POL Depot and HPCL LPG plant and to industries under SIDCO
Industrial Estate
4) Mutual aid scheme should be set up for emergency actions and efficient use
of resources
5.7
Conclusion
Hazard and risk analysis studies were carried out for the LPG bottling plant in
Kappalur, Madurai covering the proposed facilities, operations and activities at the
site. The main findings include:
I.
II.
III.
The impact zones of the most credible hazardous scenarios will be confined
within the plant site and will have limited effects outside the plant.
All the credible events for which risk rating was assigned were seen to fall in
‘Low’ category. This is mainly due to the inherent safety of mounded type of
vessel for LPG storage and several safety features provided in the system.
The evaluation of individual risk at manned locations were shown to fall
within the range between 10-7 to 10-8 times per year. This is extremely low,
when compared with criteria for hazardous industries given in IS 15656: 2006,
where risk numbers below 10-06/ yr is considered negligible.
Implementation of the risk reduction measures and programs recommended will
further reduce the risk levels as the estimated risk levels should be seen in a relative
manner.
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Risk Analysis Report
LPG Bottling Plant, BPCL Kappalur, Madurai
Appendix 1 Description of units and operations at an LPG Bottling facility
- receipt, storage and filling systems
The units and operations proposed to be carried out in BPCL, Kappalur, Madurai plant
premises are described here in detail.
A. Description of Mounded Storage Vessels
Mounded storage vessels for LPG, designed as per OISD 150, are located in a single
cluster of three units of 900 MT capacity each. Each MSV is 56 m long with diameter
of 7 m. The vessels have a shell thickness of 305-mm. Each storage vessel is connected
with 200 - mm liquid and 150 – mm vapor lines. The MSV has 25 mm water draw off
line.
LPG is stored in the MSVs at a pressure of 5-7-kgf/ sq. cm
Cathodic protection is provided for each MSV to guard against corrosion.
The MSV is laid on a compacted sand bed with no raised support. This design protects
the storage vessel from any source of fire impinging on it from any direction and
virtually eliminates the possibility of failure of vessel and occurrence of fireball
(BLEVE) scenario.
A retaining wall of reinforced concrete in front of the vessel protects it from effects
of overpressure from blast waves and explosion.
Level, pressure and temperature are monitored and the instruments provided with
redundancy. The level in the MSV is monitored during filling. The inlet to the vessel is
provided with an ROV which closes on reaching 84% capacity.
The presence of Remote Operated Valves (ROV) on the pipeline connected to the MSV
ensures that transfer operation to and from the bulk storage can be stopped from a
remote location.
B. Operations/ Activities carried out at the plant
a)
LPG receipt: The plant proposes to receive LPG stock via road tankers from
Palakkad LPG Storage Terminal.
b)
Filling of cylinders from MSV at LPG filling station: Filling operation is done
only from a MSV which is not engaged in loading operation. Hence LPG receiving and
filling will be carried out from different MSVs.
The LPG stored in the mounded storage vessels is drawn and pumped into cylinders of
5, 14.2-kg, 19-kg, 35 and 47.5 kg capacities. New cylinders are purged with LPG vapor
before filling. Filling machines are housed in the cylinder filling shed. Empty cylinders
are loaded on the conveyor system and the filled cylinders stacked in the demarcated
areas in the cylinder storage shed.
The filling points are as follows
a. 24 point carousel which caters to 5 Kg/14.2 kg/19 kg/35 Kg/47.5 Kg
b. Conveyor line shall be provided for filling of 19, 35 and 47.5 Kg cylinders for
manual filling
c)
Quality check: Quality check is conducted on filled cylinders
d)
Dispatch:
1. Loading of packed cylinders in trucks.
2. Supply & distribution to markets.
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Risk Analysis Report
LPG Bottling Plant, BPCL Kappalur, Madurai
The work flow at the site is schematically given in Fig A1
Fig A1 Product Flow for Kappalur LPG Plant
LPG unloading from tank
truck
Empty cylinder unloading
Checked for damages (valve leaks)
Mounted Storage Vessel
(3 X 900 MT)
LPG cylinder filling
shed (1 X 24 station)
Final QC
OK cylinders
diverted to
filling carousel
Valves
refitted for
leaky
cylinders
Damaged
cylinders
sold as
scrap
Dispatched through
road
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Risk Analysis Report
LPG Bottling Plant, BPCL Kappalur, Madurai
A schematic diagram depicting the carousel operation is shown in Figure A2
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Risk Analysis Report
LPG Bottling Plant, BPCL Kappalur, Madurai
Fig A2 Flow Chart for Carousel & Cylinder Filling Operation
UNLOADING
DECAPPING
SEGREGATION
WASHING UNIT
TARE WT. PUNCHING
FILLING
INCORRECT WEIGHT
CHEC
K
CORRECTION UNIT
CORRECT
WEIGHT
VALVE CHANGE
UNIT
VALVE LEAK
GD
UNIT
NO LEAK
O-RING LEAK
PI
UNIT
O-RING CHANGE
NO LEAK
CAP PLACEMENT
TAPPING
TEST BATH
SEAL PLACEMENT
HOT AIR SEALING
STATISTICAL QUALITY
CHECK
HAND SEALING
LOADING
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Risk Analysis Report
LPG Bottling Plant, BPCL Kappalur, Madurai
C. General facility description
I.CHAIN CONVEYOR SYSTEM:
As per the requirement of Electronic carousel, the speed of chain conveyor system
shall be between 12 – 22 M/Min. On the Introduction line and Ejection line, the speed
should be minimum 22 M/Min and 18M/Min up to the test bath. A layout has been
developed showing the position of OLD/VLD and the location of test bath and HAS.
The ratings & numbers of Drive Units will be provided commensurate with the new
electronic carousel.
One Telescopic Chain Conveyor and one Manual Chain Conveyor each for loading and
unloading Fingers shall be provided. This is adequate to cater to the requirement of
24 Station Electronic Carousel.
Careful design shall be done on floor keeping operational and aesthetics aspects in
mind. Further, conveyors shall be designed to offer high efficiency at designed load
with help of high efficiency motors/helical or direct mount gear boxes etc.
Auto on-off operation of loop conveyers at correction, valve & O-ring change and
evacuation conveyors to be provided.
Telescopic conveyors to be provided for unloading/loading of empty/filled cylinders
to and from box lorry with photoelectrical type auto sensing/tripping system.
All electric motors shall be of high efficiency “IE 3” grade.
II. ELECTRICAL SYSTEM:
Incoming supply will be taken from State Electricity Board preferably through an
independent feeder to ensure uninterrupted power supply from grid. At present
Maximum demand expected is 350 KVA and connected load shall be 500KVA.
III. PLANT SECURITY SYSTEM:
Provision of following facilities shall be ensured;
1.
Handheld metal detector for frisking
2.
Door Frame Metal detector
3.
Mirror trolley
4.
Integrated Biometric Access Control System
5.
Digital Surveillance through CCTV cameras with memory back-up for 30 days.
All critical areas i.e. Admin Bldg, Filling shed, LPG Pump House, Tank Farm, TLD
Gantry , Parking and Gate areas to be covered under constant surveillance.
6.
Perimeter surveillance
7.
Sufficient High mast illumination in parking as well as for plant.
IV. COMMUNICATION SYSTEM:
Following systems to be provided;
•
Intrinsically Safe Paging System
•
Inter-com at all working stations/points
•
Display of carousel performance at TC cabin & Planning
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Risk Analysis Report
LPG Bottling Plant, BPCL Kappalur, Madurai
•
Walkie-talkie for designated staff (VHF/UHF)
•
PA system for announcement at gate.
C. Personnel distribution within the plant:
Table A1 Table showing personnel distribution within the plant
Sl. No
Location
Number of operating
personnel
Number of operating
personnel
Shift 1
Shift 2
1.
Pump house
1
1
2.
Filling shed
15
15
3.
Drivers & cleaners
80
80
4.
Loading Bay
3
3
5.
Firewater Pump
2
2
6.
Administration (canteen)
5
5
7.
Security
5
5
8.
Maintenance
6
6
9.
Electrical shed
4
4
Total
121
121
D. Neighboring Facilities :

North: SIDCO industrial estate industries

South: HPCL LPG bottling plant

East: Barren land

West: HPCL POL Terminal
E. Potential Ignition Sources and Protection
The following locations were identified as probable ignition sources and the
available safeguards were noted
Table A2
Sl no
1.
Location of Sources of Ignition within the BPCL plant
Location Inside the Plant
Safeguards
Pump house/ LPG Compressor
Flameproof motors & junction boxes
Sprinkler system, Gas monitoring system, Fire
extinguisher, DV system
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Risk Analysis Report
Sl no
LPG Bottling Plant, BPCL Kappalur, Madurai
Location Inside the Plant
Safeguards
2.
Filled Cylinder Shed Empty/
Filling Shed
Flameproof equipment
3.
Tank lorry
loading Bays
Spark arrestors, TL engine turned off during
loading/ unloading operations, electrical fittings of
the TL are checked for proper insulation before
induction of the TL
4.
MCC room
Fenced; Earthing; located in de-licensed area
5.
DG Set room
Acoustic enclosure; all electrical armored cables
underground, earthed
6.
Static Electricity
Earthing of tankers, MSVs, pipelines, Carousel, etc.
7.
Maintenance
Non-sparking tools to be used
8.
Hot work
Work Permit system to be practiced
movement
at
External to plant area
9.
1.
General facility area
Personnel entering the depot will be checked for
matchboxes, cigarette lighters, mobiles, etc., before
allowing entry.
Restricted entry
10.
Traffic on SIDCO internal roads
along southern and eastern
boundaries
Green belt surrounding the plant
11.
Railway line along northern
boundary
Min 20m distance from northern boundary
HPCL Depot
boundary
Green belt
12.
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on
western
Green belt
Maintenance of minimum safe distances of all nits
within the plant
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Risk Analysis Report
LPG Bottling Plant, BPCL Kappalur, Madurai
Table
A3 Safety Systems and sequence of activation at various locations in plant
S
no.
Location/Activities
1. Mounded storage vessel
Safety Systems & sequence of Location/
number
activation
Activation details
a. SRV
2 on each MSV
b. ESD
1
& Outcome of activation
ESD will activate the following
All ROV close
All pump trip
c. MCP
1
d. Level Indicator
3 on each MSV
1-radar gauge
ROV close & hooter sound &
beacon glow
1—servo level gauge
1-HLS
e. Gas detectors
3 on each MSV
f. ROV
3 on each MSV
g. EFCV
2 on each
h. Sprinkler/ Water curtain
1
i. Deluge system
j. Firefighting system
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OISD 144
45
Risk Analysis Report
S
no.
Location/Activities
2. Filling line
LPG Bottling Plant, BPCL Kappalur, Madurai
Safety Systems & sequence of Location/
number
activation
Activation details
k. Other features
3M X 3M size of room to be provided for Cathodic protection of
the MSV’s & related piping
a. Manned Operation
Automated operation
Transfer from MSV via pump to b. ESD
filling station
c. Gas detectors
3. Filling station/ Carousel
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Bottling pump suction/ discharge
pressure low will trip
1
1
d. Fire fighting
OISD 144
a. Manned Operation
Automated operation
b. Vapour extraction system
1
c. Gas detectors
1
d. ROV
-
e. Sprinkler/ Water curtain
1
f. Deluge system
4. Filled cylinder shed
& Outcome of activation
1
g. Fire fighting
OISD 144
a. Gas detectors
1
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Risk Analysis Report
S
no.
Location/Activities
5. Parked Tankers (filled/ empty)
6. Valve changing Shed
7. Pump house
LPG Bottling Plant, BPCL Kappalur, Madurai
Safety Systems & sequence of Location/
number
activation
Activation details
b. MCP
1
c. Sprinkler/ Water curtain/
deluge system
1
d. Fire fighting
OISD 144
e. ESD
1
a. Fire fighting
OISD 144
b. MCP
1
a. ESD
1
b. Gas detectors
1
c. MCP
1
d. Deluge System
1
a. Gas detectors
3
b. MCP
1
c. ESD
1
& Outcome of activation
ESD will activate the following
All ROV close
All pump trip
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Risk Analysis Report
S
no.
Location/Activities
LPG Bottling Plant, BPCL Kappalur, Madurai
Safety Systems & sequence of Location/
number
activation
Activation details
d. Deluge System
1
8. Compressor Area
a. Gas detector
1
9. Admin Building
a) ESD
1
b) MCP
1
& Outcome of activation
10. Security Cabin
11. Fire Water Pump House
12. MCC Room
13. Others
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Risk Analysis Report
LPG Bottling Plant, BPCL Kappalur, Madurai
Appendix 2 Material Safety Data Sheet
pg 1
Chemical Name: Liquefied Petroleum Gas
Formula: C3H6 - C3H6 - C4H10
Alternate names:
CAS No.: 68476-85-7
UN No.: 1075
LP Gas; Mix of Propane/ Butane; Bottled gas; Cooking gas
PHYSICAL & CHEMICAL PROPERTIES
Molecular Weight
44.00
Physical State (at 20C)
Gas
Boiling Point (C)
Melting Point (C)
– 40.0
Specific Gravity (liq)
0.5620
Vapor Pressure (bar)
– 46.0
Specific Gravity (vap) (air = 1)
NA
1.5
Heat of Combustion
46013000.00
Heat of Vaporization
NA
General Characteristics
Colorless gas at room temperature, it can have odor like natural gas. Mercaptans added for odor
warning
NFPA Ratings
NH (Health) 1
NF (Flammability) 4
NR (Reactivity) 0
FIRE & EXPLOSION HAZARDS
Flash Point (C)
-104.44
Flammable/ Explosive Limits
Auto Ignition Point (C)
466.11
Lower 2
Higher 10
Flammability
Explosivity
Combustion Products
Highly flammable material. It is
a dangerous fire hazard when
released in air as it will
flashback along vapor trail
Sensitive to shock & static
electricity
Emits CO & CO2
REACTIVITY DATA
Incompatible Material
Thermochemical Data
Avoid contact with oxidizing agents
HEALTH HAZARD DATA
TLV/ MAC (ppm) 1000
IDLH (ppm) 19000
LD50 (g/kg) na
TOXICITY
An Asphyxiant. High concentrations cause rapid respiration, mental dullness, poor
judgment, in-coordination, nausea & unconsciousness. Contact with liquid causes
frostbite
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Risk Analysis Report
LPG Bottling Plant, BPCL Kappalur, Madurai
Chemical Name: Liquefied Petroleum Gas
pg 2 (cont’d)
PREVENTIVE MEASURES
EMERGENCY
Fire
Extinguishing agents
Keep vessels/ cylinders closed. Do not allow
gas to leak out. Keep away from heat, sparks &
flame.
Stop flow of gas. Do not use flame to detect
leak. Use dry powder or CO2 to extinguish
small fires. Allow gas to burn under control
Explosion
First aid
Keep containers cool with water spray
Inhalation: Remove victim to fresh air; restore
breathing/ give oxygen if necessary. Get
medical help
Do not allow the gas to leak out.
Contact: Remove contaminate clothing; wash
exposed areas with plenty of water; keep
victim warm, covered with clean cloth/
bandage; get medical attention
Use gas mask, full protective clothing
Eyes: Flush with water; seek medical attention
PPE
ENVIRONMENTAL IMPACTS
Air
Water
Land
Mammals
Marine life
Others
HANDLING & STORAGE
Disposal
Evacuate
area,
eliminate
sources of ignition. Supply
maximum air ventilation. Stop
leak or remove leaky vessel to
open, remote area. Disperse
or dilute vapors with water
spray
Packing
Cylinders
Storage
Store in tightly closed
cylinders
in cool,
well
ventilated area away from
heat, sparks
ANY OTHER INFORMATION
Enforce strict observance of safety procedures. Periodic inspection/ testing of controls
recommended.
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Risk Analysis Report
LPG Bottling Plant, BPCL Kappalur, Madurai
Appendix 3 Past Accident Analysis
While no major incidents involving MSVs have been reported, incidents involving transfer
operations and transport vehicles have been recorded. An analysis of past accidents involving
LPG tank lorries during filling operations was carried out based on published literature.
i
Past LPG Accidents
Numerous accidents involving LPG have been reported. More than 1000 people have received
injuries of varied intensity and several hundreds of people died due to these accidents. Table
A3.1 gives the data obtained by an analysis of 45 LPG accidents.
Table A3.1
Sl no:
Analysis of past Accidents involving LPG
Type of incident
No
1
Fires, overpressures, explosions in LPG storage vessels
19
2
Overfilling, loading/ unloading and pipeline ruptures
5
3
Collision and impact of rail/ road tank lorries during transportation
21
Total
45
It can be seen that the storage areas and transportation vehicles for LPG are most vulnerable
to accidents. More than 10 out of the 45 accidents examined have ended in BLEVE (Boiling
Liquid Expanding Vapour Explosion) situations. The rest of them have caused fires and
explosions.
BLEVEs occur when a pressure vessel is heated so that the metal loses its strength and bursts.
Damage can occur in four different ways.
1. The pressure vessel may explode with great force and shatter, releasing projectiles
that can kill or injure people who are 300 m or more away.
2. The overpressure of the escaping gas can injure people and cause damage to buildings
and structures.
3. The escaping gas or liquid burns and the resulting heat radiation may injure people or
set fire to buildings.
4. The escaping gas or liquid may mix with the air and explode to produce a second
pressure wave that does further damage
One of the earliest recorded BLEVEs occurred at France in 1966 but many others were reported
later. BLEVEs probably occur more often and cause Unconfined Vapour Cloud Explosions
(UVCEs). All efforts have to be made to prevent them and the associated UVCEs.
The consequences of BLEVE have been most severe near the accident site. A major disaster
occurred in the LPG storage and distribution centre in San Juan in Mexico City. An extensive
fire and a series of explosions resulted in an almost complete destruction of the storage
facility.
It may also be noted that the analysis based on the past accident data has certain limitations.
First, there is the possibility that new operations/ processes may have created new hazards
that have not yet produced accidents. Secondly, it is possible that the lessons of the past
accidents have been learnt and they may not recur. Despite these limitations, the analysis
provides sufficient clues to the physics and mechanics of accidents of similar nature.
ii
Explosion as an Initiator of Cascade Effects
A BLEVE is usually accompanied by blast waves and missiles. The range of fragments from
unprotected vessels storing LPG, have been found to travel an average distance of 0.75 kms.
at a velocity of 275 m/ sec. These fragments will penetrate other storage equipment falling
within a radius of 750 m, like tankers and other equipment. This will cause further BLEVEs and/
or jet fires. Several accidents involving BLEVEs of LPG tankers have resulted in secondary
BLEVEs.
RCE Chennai
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Risk Analysis Report
LPG Bottling Plant, BPCL Kappalur, Madurai
Both fire and explosion as initiators release locked up energy. The values of energy release/
unit volume are of the same order. For example, methane flames and explosion contribute
3.3x106 joules per cubic meter each, although the velocities of a typical pressure wave (330
m/s) and flame front (0.5m/s) are different.
A list of recent occurrences at LPG bottling plants and LPG tank lorries is given in here
Table A3.2
Date
1974
Sept 16
Accidents at LPG Bottling Plants
Location
Hauconcourt –
[Moselle]
France
Consequences
3 employees injured by burns (body, face).
Part of the hall's roof and siding had been blown out.
Description: At 4.55 pm, a 13 kg (propane) cylinder tipped over upon exiting the carousel, spraying
liquid propane upward toward the hall's ceiling. The person in charge of connecting the clamps stopped
the carousel's rotation. The foreman was attempting to place the cylinder upright when the "flash"
occurred (the cylinder's valve had remained open): the foreman and 2 other employees were burned
on the face and body. Another employee then actuated the site's emergency stop which activated the
sirens, disconnection of the electricity (except for the lights), the closure of the valves on the spheres
and the gas valves supplying the carousel and the 35 kg station, as well as the air compressors and
ventilators. When the air supply was disconnected, the filling clamps began to "open" slowly while the
gas supply valves were closing slowly, thus creating new propane leaks in the workshop. The cloud
thus continued to ignite, and the fire spread to the paint booth nearby.
Extinguishing operations were in progress when the same phenomenon began at the 35 kg station:
there also, the clamps began to open due to a lack of air pressure. In this case, the gas caught fire
also.
Finally, the fire was extinguished at 5.20 pm.
1986
May 17,
Yokkaichi, Mie,
Japan
Two workers received severe burns, more than 100 cylinders
were destroyed, and nine buildings and 23 automobiles were
destroyed by fire. One fireman was injured.
A LPG filling station including an office and a warehouse was
destroyed by fire. Twenty-five cylinders of 500 kg LPG,
441cylinders of 50 kg LPG and other containers were
destroyed by fire. A tank lorry and trucks, etc. at the gas
station inside the site were damaged by fire
About 2km of the traffic on the national road No.1 stopped
until the next morning.
A large explosion occurred at a LPG filling station. In the filling process, a cylinder was over-filled
beyond the regulated limit weight of 20 kg. To decrease the filled weight, a worker pushed the cylinder
down sideways and opened the valve to release liquefied propane onto the concrete floor. The
released gas suddenly ignited, the worker panicked and evacuated. As the valve could not be closed,
the spouting gas kept burning. By heating other filled cylinders, the fire became very large with
sequential ruptures and ignitions of cylinders
1999
August 19
Marignane,
France
An operator was slightly injured.
A propane leak caught fire in a gas storage facility. The leak was caused by the impact between a
filling clamp and an upright.
2003
September 12
Rognac,
France
Property damage was limited: the station's compressed air
line was damaged, plastic protection burned, roof damaged
locally
Fire broke out in a gas cylinder filling centre on the automated carousel used to fill 13 kg propane
cylinders. The cylinder was being filled when a leak occurred on the junction between the filling clamp
and the cylinder's valve. The shut-down device allowing a "connection fault" to be detected at the
station and stop the release was not activated: the gas jet was not oriented toward this device and
RCE Chennai
52
Risk Analysis Report
Date
LPG Bottling Plant, BPCL Kappalur, Madurai
Location
Consequences
could not activate it. The product leaked for 12 seconds. A flash occurred when the operator was able
to activate the supply shutoff valve. The alarm was activated and the personnel, except for the
intervention crew (3 to 4 people), made their way to the rendezvous locations. The accident was
brought under control by fire extinguishers in less than 2 minutes.
Table A3.3
Date
Accidents during road transportation of LPG
Location
Origin of accident
1974,
April 26
USA, Eagle Pass
Leakage of LPG during
road transport
LPG
17 dead, 34 injured.
1979,
Oct 1
GREECE, Suda Bay
Explosion during
transportation of
propane
Propane.
7 died, 140 injured
1990
Sept 25
THAILAND,
Bangkok
Crash of a tank lorry
carrying liquefied
petroleum gas
LPG
63 died, more than 90
injured
1990,
Sept 29
THAILAND,
Bangkok
Accident during
transportation of LPG
LPG
More than 51 died,
more than 54 injured
1994
July 27
USA, New York
Propane truck
collision and fire tank
fractured, releasing
the propane.
Propane
1 died, 23 injured, 400
feet radius area
engulfed by fire
1994
Dec 14
MOZAMBIQUE
Palmeira
Transportation
accident
Gas
36 died
2012
July 26
Surajpur Dadri,
NOIDA, UP
The incident took
place when the driver
noticed leakage in gas
tanker's capsule and
lost control over the
vehicle, ramming it
into a bridge divider,
at which the tanker
exploded
LPG
2009
Aug 27
Pune,
Maharashtra, India
A tanker collided with
a container truck
LPG
2009
December 31
Karunagapally in
Kollam district,
Kerala
An LPG tanker caught
fire after colliding
with a car
LPG
2012
Aug 27
Kannur, Kerala
An LPG tanker
exploded on the
national highway in
LPG
RCE Chennai
Material
Involved
Consequences
2 persons died and 20
others in the vicinity
critically injured,
early morning on
Friday. Fourteen fire
tenders took over
three hours to douse
the fire, as nearby
jhuggis and vehicles
were also burnt after
burning splinters fell
on them
Two persons were
charred to death. Five
other vehicles have
been burnt in the fire
The accident claimed
12 lives, including
those of two
policemen and a
fireman. The others
were good samaritans
who tried to evacuate
residents from the
accident site.
14 persons were killed
and 35 people were
injured. Forty-five
53
Risk Analysis Report
Date
LPG Bottling Plant, BPCL Kappalur, Madurai
Location
Origin of accident
Material
Involved
the Chala area by 9
pm Monday. The
incident occurred
when the lorry
carrying liquefied
petroleum gas (LPG)
overturned after
hitting a divider
2012
Nov 21,
Madhukoth near
Chakkarkal,
Kannur, Kerala
LPG tanker accident
on the wee hours of
Wednesday, when it
overturned
Consequences
houses, 40 shops and
11 vehicles were
gutted in the huge
resulting fire.
LPG
A mishap was averted
as gas was not leaked,
the accident
happened due to the
steep curve in the
road and also due to
the overspeed of the
vehicle.
2013, April 9
Table A3.4
Uppinangady,
Mangalore,
Karnataka
The driver of the
tanker lost control
while negotiating a
curve at Perne near
Uppinangady. Seconds
later, the tanker
carrying 16,000 litres
of LPG overturned,
leading to leakage
LPG
Fatalities: 8
Serious injuries: 6
Damage: a four-acre
arecanut plantation,
six houses, two shops
a garage, a van and a
car
Incident at Tank Lorry Filling Gantry (TLFG)
Date
Location
Origin of accident
Type of
fire
May 28, 2012
LPG Tank Truck
Loading Gantry,
IOCL LPG Bottling
plant, Sitapur
As per SOP, the loading arm
must be depressurized to
remove the residual LPG
content by cold flaring after
completion of every loading
operation. This step of SOP was
not followed.
Flash Fire
Consequences
Fatality - 1
driver
Minor burn
injuries – 1
driver
• This coupled with the failure
of the interlock of the quick
release coupling, the arm
content of LPG leaked in open.
The consequent recoil of the
arm / coupling caused metal to
metal contact with the
structure and created spark
that led to flash fire.
• The operation was done by a
driver instead of plant operator
which was a deviation of SOP
RCE Chennai
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Risk Analysis Report
LPG Bottling Plant, BPCL Kappalur, Madurai
Appendix 4 Fire and Explosion Index Worksheet
Name of Plant
Manufacturing Unit:
Material in Unit
Location
Bharat Petroleum Corporation Limited (BPCL)
Proposed LPG bottling Plant
LPG
Kappalur, Madurai dist. TN
State of Operation
Normal operation
Storage Unit
Mounded
Storage Vessel
Material Factor
General Process Hazards
Base Factor
Date
06/04/17
LPG Road
Tanker
21
21
Penalty Factor Range
Penalty Factor
Used
Penalty Factor
Used
1.00
1.00
1.00
A)
Exothermic Chemical Reactions
0.30 – 1.25
0.00
0.00
B)
Endothermic Processes
0.20 – 0.40
0.00
0.00
C)
Material Handling and transfer
0.25 – 1.05
0.50
0.50
D)
Enclosed or Indoor process units
0.25 – 0.90
0.00
0.00
E)
Access
0.20 – 0.35
0.00
0.00
F)
Drainage and spill control
0.25 – 0.50
0.00
0.00
1.50
1.50
Penalty Factor Range
Penalty Factor
Used
Penalty Factor
Used
General Process Hazards Factor (F1)
Special Process Hazards
Base Factor
1.00
1.00
1.00
0.20 – 0.80
0.20
0.20
0.50
0.00
0.00
1. Tank Farms Storage Flammable Goods
0.50
0.50
0.50
2. Process Upset or Purge Failure
0.30
0.00
0.00
3. Always in Flammable Range
0.80
0.00
0.00
A)
Toxic Material(s)
B)
Sub-Atmospheric Pressure
C)
Operation in or near Flammable Range
D)
Dust Explosion
0.25 – 2.00
0.00
0.00
E)
Relief Pressure
0.00
0.00
0.00
F)
Low Pressure
0.20 – 0.30
0.00
0.00
G)
Quantity of Flammable/ Unstable Material
1. Liquids or Gases in Process
0.10 – 10.00
0.00
0.00
2. Liquids or Gases in Storage
0.10 – 10.00
1.44
0.44
3. Combustible Solids in Storage, Dust in
Process
0.10 – 10.00
0.00
0.00
H)
Corrosion and Erosion
0.10 – 0.75
0.10
0.20
I)
Leakage - Joints and Packing
0.10 – 1.50
0.00
0.00
J)
Use of Fired Equipment
0.10 – 1.00
0.00
0.00
K)
Hot Oil Heat Exchange System
0.15 – 1.15
0.00
0.00
L)
Rotating Equipment
0.50
0.00
0.00
3.24
2.24
Special Process Hazards Factor (F2)
Process Unit Hazards Factor F3 = (F1 x F2)
4.86
3.51
Fire and Explosion Index (F3 x MF)
102.06
73.71
Intermediate
Moderate
Degree of Hazard
RCE Chennai
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Risk Analysis Report
LPG Bottling Plant, BPCL Kappalur, Madurai
Appendix 5 Meteorological data
Wind rose for Madurai district
The climate is moderate with no extremes. There are two dominant wind directions:


strong southwest winds from June to September
dominant north east winds from October to December
RCE Chennai
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Risk Analysis Report
LPG Bottling Plant, BPCL Kappalur, Madurai
Appendix 6 Models used in Consequence Analysis
Consequence analysis was conducted based on the following models and equations,
mentioned in the IS 15656: 2006. The most appropriate model(s) applicable for the
project have been used.
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 Engineers8 , 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
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
8
Cited by Environmental Protection Agency, US in its 1996 Document “Off-Site Consequence” Analysis Guidance
RCE Chennai
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Risk Analysis Report
LPG Bottling Plant, BPCL Kappalur, Madurai
Appendix 7 Outputs from Consequence Calculations
1.
Jetfires
Table 7.1.1
Event
Reference
No.
Scenario
Pipe size
Discharge
Phase
mm
Thermal radiation effects due to Jet fires
Discharge
rate
Thermal
radiation
inside jet
Length
Width
Damage distances (m)
kg/s
kW/m2
m
m
37.5 kW/m2
12.5 kW/m2
4
kW/m2
DW
CW
DW
CW
DW
CW
1. LPG TANK LORRY (Filled)
1a
Release from SRV
40
Vapor
3.8
185.9
22.7
1.9
23.6
2.5
25.1
6.7
27.1
13.6
1b
Level/temperature gauge
leak
50
Liquid
16
162.5
45.2
3.9
46.4
4.2
49.3
11.4
53.1
24.1
1c
Drain valve leak
50
Liquid
16
162.5
45.2
3.9
46.4
4.2
49.3
11.4
53.1
24.1
LPG TANK LORRY (Unloading)
1g
Rupture (100%) of liquid
line close to the tank lorry
50
Liquid
16
162.5
45.2
3.9
46.4
4.2
49.3
11.4
53.1
24.1
1h
Rupture (100%) of vapor
line close to the tank lorry
50
Vapor
1.1
256.1
12.5
1.1
13.3
1.5
14.3
3.8
15.5
7.8
2.
MOUNDED STORAGE VESSEL
2b
Leak (20%) of
section after ROV
pipe
200
Two phase
4.3
302.2
24.1
2.1
25.7
4.2
27.6
10.1
30.2
19.2
2c
Leak (100%) of drain pipe
25
Two phase
0.34
271.5
7.2
0.6
7.6
1.3
8.2
3.01
8.9
5.7
2d
Leak (20%) of vapor line
150
Vapor
4.2
240.1
23.8
2.1
25.1
3.4
26.8
8.5
29.1
16.6
RCE Chennai
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Risk Analysis Report
Event
Reference
No.
Scenario
LPG Bottling Plant, BPCL Kappalur, Madurai
Pipe size
Discharge
Phase
mm
2e
Release from SRV on
stack 10-m above ground
level
100
Vapor
Discharge
rate
Thermal
radiation
inside jet
Length
Width
Damage distances (m)
kg/s
kW/m2
m
m
37.5 kW/m2
12.5 kW/m2
4
kW/m2
DW
CW
DW
CW
DW
CW
23.9
200.7
54.7
4.7
56.9
6.3
60.5
16.3
65.4
32.9
3. TRANSFER FROM STORAGE VIA PUMP TO FILLING STATION (DISCHARGE LINE)
3a
Rupture (100%) of liquid
pipe line
100
Liquid
8.05
299.4
32.5
2.8
34.6
5.6
37.1
13.4
40.5
25.4
3b
Rupture (100%) of liquid
return line
80
Two-phase
8.05
210.55
32.5
2.8
34.0
4.0
36.2
10.3
39.2
20.7
4. FILLING SHED/ CAROUSEL
4a
Leak at filling point (14.2
kg)
80
Liquid
6.2
288.8
28.7
2.5
30.5
4.8
32.7
11.5
35.7
22.1
4b
Leak at filling point (35
kg)
80
Liquid
0.2
234.7
5.5
0.5
5.6
0.9
6.4
2.1
6.9
4.1
RCE Chennai
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Risk Analysis Report
2.
LPG Bottling Plant, BPCL Kappalur, Madurai
Flashfires and Vapour Cloud Explosions (VCE)
Damage distances due to VCE 9
Table 7.1.2
Event
Reference
No.
Scenario
Pipe
size
Discharge
Phase
mm
Releas
e rate
Wind
velocity &
Stability
kg/s
Source
strength
for
dispersion
Cloud
radius/
Height
Amount in
Explosive
limits
LFL
distance
kg/s
m
kg
m
Damage distances (m)
0.3 bar
0.1 bar
0.03
bar
1.LPG TANK LORRY (Filled)
1a
1b
Release from SRV
Level/
temperature
gauge leak
40
40
Vapor
Liquid
3.8
20.7
2F
3.8
Concentration at ground level below LFL
5D
3.8
Concentration at ground level below LFL
2F
20.7
19.2/ 3.6
207
26.4
Qty small
Explosion unlikely
5D
20.7
19.2/ 3.6
207
26.4
Qty small
Explosion unlikely
1c
Rupture (100%)
of liquid drain
line
40
Liquid
20.7
2F
20.7
19.2/ 3.6
207
26.4
Qty small
Explosion unlikely
5D
20.7
9.3/ 3.2
125
30
Qty small
Explosion unlikely
18 MT LPG TANK LORRY During unloading
1e
9
50
Liquid
16
2F
No activity during night
(Rupture = 100%, leak 20 % of pipe area) Source strength for dispersion -- 52 % of discharge rate
RCE Chennai
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Risk Analysis Report
Event
Reference
No.
LPG Bottling Plant, BPCL Kappalur, Madurai
Scenario
Pipe
size
Discharge
Phase
mm
Releas
e rate
Wind
velocity &
Stability
Cloud
radius/
Height
Amount in
Explosive
limits
LFL
distance
kg/s
m
kg
m
6.2/ 3.7
48
15
kg/s
Rupture (100%)
of unloading armliquid
5D
16
Damage distances (m)
0.3 bar
0.1 bar
0.03
bar
Qty small
Explosion unlikely
1f
Rupture (100%)
of unloading armvapor
2.
MOUNDED STORAGE VESSEL
Case 1 – no filling
Leak (20%) of
2a
pipe section
close to vessel
(before ROV)
Leak (20%) of
2b
pipe section
away from vessel
(after ROV)
Source
strength
for
dispersion
40
200
200
Vapor
1.1
Liquid
103.6
Two
phase
4.3
2F
No activity during night
2F
103.6
25.1/ 14.7
618
12
72.1
144.2
360.5
5D
103.6
18.2/ 9.7
515
30
67.8
135.7
339.3
2F
4.3
5.4/ 2.9
13
6
Qty small
Explosion unlikely
5D
4.3
3.1/ 1.2
9
10
Qty small
Explosion unlikely
2d
2e
RCE Chennai
Leak (20%)
pipe section
Stack 10-m
above ground
level
of
150
100
Vapor
Vapor
4.2
23.9
2F
4.2
Concentration at ground level below LFL
5D
4.2
Concentration at ground level below LFL
2F
23.9
Concentration at ground level below LFL
5D
23.9
Concentration at ground level below LFL
61
Risk Analysis Report
Event
Reference
No.
LPG Bottling Plant, BPCL Kappalur, Madurai
Scenario
Pipe
size
Discharge
Phase
mm
Releas
e rate
Wind
velocity &
Stability
Source
strength
for
dispersion
Cloud
radius/
Height
Amount in
Explosive
limits
LFL
distance
kg/s
m
kg
m
kg/s
Damage distances (m)
0.3 bar
0.1 bar
0.03
bar
73.9
147.8
369.6
Case 2 -during filling
2f
3.
Overfilling
release through
the SRV
200
Liquid
11.1
2F
No activity during night
5D
11.1
11.9/ 3.03
666 (50% of
1332 - amt for
2
min
accumulation)
17.6
TRANSFER FROM MSV VIA PUMP TO FILLING STATION (DISCHARGE LINE)
3a
Rupture (100%)
of liquid pipe line
3b
Rupture (100%)
of liquid return
pipe line
100
Liquid
8.1
2F
5D
80
Liquid
8.1
No activity during night
8.1
13.3/
8.2
32.4
Qty small
Explosion unlikely
2F
5D
20
No activity during night
8.1
13.3/ 8.2
32.4
20
Qty small
Explosion unlikely
3.
Fireball/ BLEVE
Table 7.1.3
Event
Ref. no
RCE Chennai
Failure Scenarios
Maximum Damage from Fireball
Source
Strength
Cloud
Radius.
Duration
Fireball
T
M
s
of
Intensity
Radiation
fireball
kW/m2
of
inside
Damage distances from the center of the fireball
m
37.5 kW/m2
12.5 kW/m2
4 kW/m2
62
Risk Analysis Report
1d
RCE Chennai
Failure of tank lorry (18T)
LPG Bottling Plant, BPCL Kappalur, Madurai
8.5
61.3
8.6
190.9
113.02
191.3
312.02
63
Risk Analysis Report
4.
LPG Bottling Plant, BPCL Kappalur, Madurai
Pressurization and Physical explosion of Evacuation unit:
Scenarios was considered under conditions of external heating
Table 7.1.4
Consequence outputs for release of LPG
due to physical explosion of the Evacuation Unit
S no.
Volume
LPG (Kl)
of
Failure during overheating
Total
(KJ)
5
0.4
5.
energy
248.3
Max. Fragment
range (m)
Fragment velocity (m/s)
423.4
64.4
Physical Explosion of LPG cylinder - Projectiles of LPG cylinders
Scenarios were considered under conditions of external heating
Table 7.1.5
S no.
Consequence outputs for release of LPG due to physical explosion of a filled cylinder
Cylinder Capacity
(kg)
Failure during overheating
Total energy
(KJ)
Max. Fragment range
(m)
Fragment velocity
(m/s)
1
5
4.2
142.3
37.4
2
14.2
12.5
162.2
39.8
3
19
16.7
184.6
42.5
4
35
31.4
191.2
43.3
5
47.5
42.4
199.2
44.2
During physical explosion of LPG cylinders about 60% of the expansion energy is absorbed by
fragments of the vessel while the rest goes into blast energy. Both the number of fragments
and fragment range were evaluated from the correlation between kinetic energy with pressure
and vessel volume.
RCE Chennai
64
Risk Analysis Report
Appendix 8
LPG Bottling Plant, BPCL Kappalur, Madurai
Identifying Independent Protection layers (IPLs) –
Layers for Defense against a Possible Accident
Safeguards or Independent Protection Layers (IPL) have been classified as active or passive
and preventive (pre-release) or mitigating (post-release) depending on how and when they
act and their efficacy in reducing the frequency or consequence of an initiating event.
The classification of layers of safeguards is given in Table below.
Table A8.1 Types of Safeguards / IPLs used in the analysis10
Layer no.
Type
Description
1.
Process design
Inherently safe designs are implemented to eliminate possible
scenarios.
2.
Basic
Process
Control Systems
(BPCS)
Including normal manual controls is the first level of protection
during normal operation and is designed to maintain the process
within the safe operating region.
3.
Critical
alarms
and
human
intervention
Systems that are normally activated by the BPCS form the second
level of protection during normal operation.
4.
Safety
Instrumented
Systems (SIF)
A combination of sensors, logic solvers and final elements with a
specified integrity level that detects an out-of-limit or abnormal
condition independent of the BPCS and brings the process to a
functionally safe state.
5.
Physical
protection
Can be provided to a high degree by devices such as relief valves,
rupture disks, etc. These however require appropriate design and
maintenance, and their effectiveness can be impaired in
fouling/corrosive conditions.
6.
Post-release
protection
Afforded by passive devices such as dykes, blast walls, etc. These
provide a high degree of protection if designed and maintained
correctly.
7.
Installation
community
emergency
responses
and
Features such as fire brigades, manual deluge systems, facility and
community evacuation, shelters, etc., are activated after an initial
release. These are not normally considered IPL as there are too many
variables affecting their effectiveness in mitigating scenarios, and in
the case of Community Emergency Responses, they provide no
protection for installation personnel.
In order to be considered an IPL, a device, system or action must be

Effective in preventing the consequence, when it functions as designed;

Independent of the initiating event and the components of any other IPL already
claimed for the same scenario;

Auditable or capable of validation by documentation, review, testing, etc.
The efficiency of an IPL is quantified in terms of its probability of failure on demand (PFD).
This is the probability that a system will fail to perform a specified function on demand.
The smaller the value of the PFD, the larger the reduction in frequency of the consequence
for a given initiating event.
10
Layer of Protection Analysis – Simplified Process Risk Assessment’ published by Center for Chemical
Process Safety of the American Institute of Chemical Engineers, New, York, New York, 2001
RCE Chennai
65