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RISK ANALYSIS REPORT

OF

LPG PLANT, DURGAPUR

OF

BHARAT PETROLEUM CORPORATION LTD

OCTOBER 2015

INDEX

Risk Analysis For BPCL LPG Bottling Plant at Durgapur, West Bengal

INDEX

SL NO

SECTION

SUBJECT

PAGE No

1 Section – 1

Introduction 1-1 to 1-2

2 Section -2

Executive summary 2-1 to 2-8

3 Section -3

Hazard Identification 3-1 to 3-4

4 Section -4

Description & Properties 4-1 to 4-5

5 Section -5

Maximum credible Accident analysis 5-1 to 5-14

6 Section -6

Hazard of LPG Spillage/ Escape from containment

6-1 to 6-3

7 Section -7

History of Past Accident 7-1 to 7-4

8 Section -8

Consequence Analysis 8-1 to 8-34

9 Section -9

Recommendation 9-1 to 9-10

1 Anx - 1 Material Safety Data sheet of LPG Attachment 1

INTRODUCTION

Page 1

Risk Analysis for BPCL LPG Bottling Plant at Durgapur, West Bengal

SECTION – I

INTRODUCTION

1.0 INTRODUCTION

M/s Bharat Petroleum Corporation Ltd., one of the leading oil marketing

companies in Public Sector is engaged in bottling of LPG Cylinders for

domestic as well as industrial purposes. Since the demand of LPG is

growing day by day, refineries are increasing their capacities for

production of more LPG along with other Oil products.

Since LPG is highly inflammable and is stored under pressure in

substantial quantities, there is potential for damage to property and injury

in the event of release of significant quantity of LPG.

Bharat Petroleum Corporation Limited,. Vide purchase order No

4505086925 dated 08.06.2015 entrusted Sonar Bharat Environment &

Ecology Pvt. Ltd., (SBEE) to carry out a ‘Comprehensive Risk Analysis’ of

the Durgapur LPG Plant. Our team of experts had visited Durgapur LPG

Plant to collect relevant data. For the purpose of obtaining specification of

different onsite facilities, pipe lines, pump Capacity as well as off site

facilities, a detailed questionnaire was prepared. During visit of our team

members, they had collected the required information’s in the format.

Pertinent documents like lay out plan., P&I diagram, were collected from

the Plant. Our team members along with the staffs of the station had gone

round the Plant. Besides operational aspect, the team was also apprised

of the organizational set up, existing system of handling Emergency

Situation, available fire fighting system

SBEE wants to put on record the excellent co operation they had received

from the respective In charge of the station and his team during entire

course of their study. We extend our thanks especially to Mr. Nirmalya

Chakraborty and Mr. Krishno Kanto Saaha for their excellent support in

preparation of the report.

INTRODUCTION

Page 2


Scope of work includes the following

Identification of vulnerable sections of the plant, which are likely to

cause damage to the plant, operating staff and the surrounding

communities due to accidental release of LPG from the LPG

Plant.

Assessment of overall damage potential of the hazardous events

in relation to Plant and environment.

Assessment of total individual risk for activities in the plant.

This is an expansion project for increasing the storage capacity by

installation of 2 nos of Mounded bullet of 300 mt each. Capacity of

existing storage of LPG Plant is 450 MT (150MT x 3) .After the

proposed enhancement of storage capacity by 600 MT. Aggregate

storage capacity of the LPG plant shall stand at 1050 MT.

EXECUTIVE SUMMARY

Page 1


SECTION –II

EXECUTIVE SUMMARY

2.0 INTRODUCTION

Durgapur LPG Bottling Plant of M/s Bharat Petroleum Corporation Limited

(BPCL) is located at Rajbandh Chatty, Durgapur, West Bengal. Durgapur

Rajbandh is located 11 km away from Durgapur City & 500 mtrs from NH-

2. The land area is 25 acres.

Nearest facilities are follows

SL,NO

FACILITIES

NAME

KM

1 Railway Station Rajbandh 6 km

2 Air Port Andal 20 km

3 Bus Stand Rajbandh 3 km

4 Police Station Kanksa 4 km

5 Fire Station Durgapur 5 km

6 Hospital D.S.P Hospital Durgapur 10 km

7 National Highway HH-2 0.5 km

The plant premise is bounded by the following

North BPCL Retail Installation, Small village,

South Vacant Land

East HPCL Rajbandh IRD

West Rajbandh station

EXECUTIVE SUMMARY

Page 2


2.1 PROCESS DESCRIPTION

Bulk LPG is received from Haldia Refinery. Road tankers are decanted at

Tank lorry Gantry. Four Nos. of tank Lorries can be unloaded

simultaneously. Proposed project envisages addition of two bays in the in

gantry. LPG from the tank Lorries is transferred to the storage vessels

through LPG Compressors by differential pressure method

LPG from bullets is transferred through a pipeline to filling manifolds of

carousal with the help of centrifugal pumps.

The empty LPG cylinders brought into premises by Lorries are received

and stored in the empty shed. They are fed to conveyor system after due

inspection and are carried to the filling machines in the filling shed. The

filling is cut off as soon as the weight of LPG in the cylinder reaches the

desired weight. . After filling these cylinders are counter checked for

correct weight, tested for leaks from valves and body, capped and sealed

before sending them to the filled cylinder shed. Any defective cylinder is

emptied for product LPG recovery. The filled cylinder are dispatched for

distribution .through distributors.

2.2 PLANT FACILITY

RECEIVING

Bulk petroleum LPG is received by Road tankers of 18 MT

capacity. About 8 Nos of Tankers per day supply bulk LPG to the

bottling Plant. There are 4 bays for unloading the tankers. 2 more

bays are proposed to be added for unloading.

Bulk LPG is received from Haldia Refinery by Road tankers is

decanted at Tank lorry Gantry. ,

LPG from the tank lorries is transferred to the storage vessels

through LPG Compressors by pressure differential method.

EXECUTIVE SUMMARY

Page 3


STORAGE

3 Nos. Bullets having a safe filling capacity of 3 x 150 MT and 2

nos of Mounded Bullet having capacity 2 x 300 MT are proposed to

be installed. On top of the Bullet two nos. of safety relief valves are

provided, one valve is set at 13.6kg/cm2 and other is set at 14.2

kg/cm2. All bullets are provided with two independent level

indicators and high level alarm. Remote operated valves are

provided in liquid and vapour lines of each storage vessels.

Technical details of the Bullets are as under :

BULLET NOS 1.2 & 3

SL,NO ITEM TECHNICAL DETAILS

1 Bullet no. 1,2 & 3 150 MT

2 Design Pressure 16 kg/cm2 at 550C

3 Operating Pressure 14.2 kg/cm2 at 550C

4 Hydro testing Pressure 20.93 kg/cm2

5 Corrosion Allowance 1.6 mm

BULLET NOS 4 & 5 (Mounded Bullet)

SL,NO ITEM TECHNICAL DETAILS

1 Bullet no. 4&5 300 MT

2 Design Pressure 16.5 kg/cm2 at 550C

3 Operating Pressure 14.2 kg/cm2 at 550C

4 Hydro testing Pressure 21 kg/cm2

5 Corrosion Allowance 1.5 mm

FILLING OPERATION

LPG from bullet is pumped to the filling plant for bottling through 24

station carousel. The system is capable of bottling various capacity

of cylinders. The filling system can turn out 50TMT per anum on

single shift of 8 hrs. The sequence of filling operation starts with the

receipts of empty cylinders and the fallowing operation are carried

out:

EXECUTIVE SUMMARY

Page 4


Visual checking for defects and tare weight

De-capping

Filling

Electronic weight checking

Correction of overfilled and under filled cylinder

Valve leak / ‘O’ ring checking

Cylinder body and bung leak checking

Capping and sealing

Loading in trucks

Empty cylinders are unloaded from Lorries and manually placed

over Telescopic chain conveyor. As they move on the conveyor, the

empty cylinder is to be checked visually for defects and markings.

Defective cylinders are to be segregated. There are provission for

storing about 76680 kg empty cylinders in the empty cylinders

storage shed.

The cylinders after de-capping are moved on to the filling machine

for filling and will be filled automatically at a rate of approximately

26 cylinders per minute. Filled cylinders automatically come out of

the carousel and continue to travel in the conveyor for weight

checking. The under / over filled cylinders are separated for weight

correction. Cylinders with correct weight are to be subjected to

valve leak check, O Ring leak and body and bung leak check as

they move on the conveyor. Cylinder found defective on the above

checks will be sent for replacement of Valve in online valve

changing machine and replacement of O Ring. Sound cylinder

move on for capping and sealing the valves. Cylinders will then be

loaded on to Lorries or will be stored in the storage shed which can

store about 5000 nos of filled cylinders.

EXECUTIVE SUMMARY

Page 5


AUTOMATIC FILLING PROCESS FUNCTIONAL DESCRIPTION LPG is pumped to the carousal from which the cylinders of different

sizes are filled under pressure

The system described is intended for filling standard domestic &

LPG cylinder for industrial use, with a minimum number of

operations, with process, production and monitoring function carried

out with the help of sophisticated equipment and control system.

VAPOUR EXTRACTION

The Vapour extraction system will facilitate extraction of any

leakage of LPG from around the carousel and other leak prone

areas and discharge the same at suitable elevation above the roof

level of shed. The system will be completed with exhaust fan and

necessary ducting

EVACAUTION AND VALVE CHANGE

Cylinder found defective in valves, bung or body will be evacuated

of their contents using a vapor compressor and the evacuated LPG

will be sent back to the bullets. Leaky valves will be removed and

fitted with new valves. Cylinders that require hot work will be sent to

the authorized repair shops

PURGING FACILITY

Purging will be required in the following cases: ● New cylinder received are required to be air evacuated and

LPG purged before the same are filled.

● Repaired cylinders which have been hydro tested with water

are subject to evacuation for removal of moisture and air

before refilling.

● An online purging system has been provided.

EXECUTIVE SUMMARY

Page 6


2.3 PLANT UTILITIES

Air compressor/ Receiver/ Dryer

Air compressor along with air receiver and dryer are provided to

cater to the requirement of instrument air for carousel, pneumatic

ROVs, fire protection system

Compressed air is required for the following purpose

Pneumatic actuation of different on-line instruments like ROV and control valve.

Instrument actuation in LPG filling system.

For compressed air requirement, 1 no. of 198 CFM 7.0 kg/sq cm

capacity and 2 no. 100 CFM 7.0 kg/sq cm capacity air compressors

have been installed.

ELECTRICAL SYSTEM

The total power demand of the LPG filling plant is in the region of 200

KVA. Client’s battery limit has been considered as the incoming HT supply

at 11 KV and through the two-pole structure / substation would be brought

into 11 KV transformers for further onward LT distribution. Incoming supply

is taken from the state electricity board at 11 KV

TRANSFORMER

500 KVA Air cooled transformer is installed in the plant.

STANDBY POWER SUPPLY

1X380 KVA , 1X250 KVA, 1X125 KVA & 1X7.5 KVA DG sets.

ELECTRICAL FITTINGS All electrical fitting in the sensitive area are of flameproof /

intrinsically safe type.

EXECUTIVE SUMMARY

Page 7


2.4 SAFETY RELATED TYPES OF UTILITIES

Some of the general safety features for the storage & handling of LPG

provided in the complex are discussed below

DESIGN The main feature of the plant is the safe design of the equipment &

pipelines .Equipment are designed, inspected stage wise tested & certified

by statutory authorities such as CCOE (Chief Controller of Explosives) &

third party in accordance with relevant codes & standards . The main

codes & standards used in the LPG bottling plant are ASME VUl or IS-

2825 or BS-5500 or equivalent duly approved by CCOE for pressure

vessels. Materials of Construction (MOC) used are SA 516 Gr. 70. Full

radiography, stress relieving & hydro-test is carried out for the vessels &

all critical drawings /documents are certified & approved by the competent

authority. All critical LPG piping is seamless carbon steel of 300 rating with

piping designed in accordance with ASTM, ANSI & equivalent codes &

standards within built margin of safety.

Intrinsic safety is largely built in into the design itself through use of time

tested standards & codes which inherently incorporate a good margin of

safety. Apart from the equipment design & selection (only well known

reputed vendors with proven safe & trouble free track record in similar

service are selected ) there are other features related to safety in the

layout .operation , shutdown systems etc

FIRE WATER STORAGE Two Above Ground Tanks having capacity 2 X 2700 KL (5400KL).

.

FIRE WATER PUMP & JOCKEY PUMP Diesel driven 3 nos. of 616Kl/Hr. 2X10Kl/Hr

EXECUTIVE SUMMARY

Page 8


LPG PUMP 2 nos. of 50 Kl/Hr.

FIRE HYDRANT SYSTEM Fire hydrants have been provided to be located as per requirements

specified in OISD-144 to cover the entire plant area and Tank Lorry

Parking area.

Double Headed Hydrants - 25 Nos

Single Headed Hydrants - 5 Nos.

Water Monitors - 16 Nos

SAFETY RELIEF SYSTEM Relief system adequately designed and provided as per OISD 144

guidelines. Two sets of safety relief valves are provided on each vessel,

each relief valve having the required design, relieving capacity. Other

routed locally but to safe location

There is a locking arrangement to prevent inadvertent closing of the

isolation valves, thus rendering the tank unprotected. Relief valves are

always kept locked in open position. Relief valves are tested once a year

and calibrated, if necessary.

HAZARD IDENTIFICATION

Sonar Bharat Environment & Ecology Pvt Ltd Page 1


SECTION –III


3.0 ENUMERATION & SELECTION OF INCIDENTS

Effective management of a Risk Analysis study requires enumeration &

selection of incidents or scenarios. Enumeration attempts to ensure that

no significant incidents are overlooked, selection tries to reduce the

incident outcome cases studied to a manageable number.

These incidents can be classified under either of two categories: loss of

containment of material or loss of containment of energy. Unfortunately,

there is an infinite number of ways (incidents) by which loss of

containment can occur in either category. For example, leaks of process

materials can be of any size, from a pinhole up to a severed pipeline or

ruptured vessel. An explosion can occur in either a small container or a

large container and in each case, can range from a small "puff" to a

catastrophic detonation.

A technique commonly used to generate an accident list is to identify

potential leaks & major releases from fractures of all process pipelines &

vessels. This complication should include all pipe work & vessels in direct

communication, as these may share a significant inventory that cannot be

isolated in an emergency. The data generated is as shown below.

Vessel number description & dimensions

Materials present

Vessel conditions ( phase, temperature & pressure)

Inventory & connecting pining dimensions

The goal of selection is to limit the total number of incident outcome cases

to be studied to a manageable size without introducing bias or losing

resolution through overlooking significant incidents or incident outcomes.

The purpose of incident selection is to construct an appropriate set of




incidents for study from the Initial List that has been generated by the

enumeration process. An appropriate set of incidents is the minimum

number of incidents needed to satisfy the requirements of the study &

adequately represent the spectrum of incidents enumerated.

3.1 CHARACTERISING THE FAILURE

Accidental release of flammable or toxic vapours can result in severe

consequences. Delayed ignition of flammable vapours can result in blast

overpressures covering large areas. This may lead to extensive loss of life

& property. Toxic clouds may cover yet larger distances due to the lower

threshold values in relation to those in case of explosive clouds (the lower

explosive limits). In contrast, fires have localized consequences. Fires can

be put out or contained in most cases; there are few mitigating actions one

can take once a vapor cloud gets released. Major accident hazards arise,

therefore, consequent upon the release of flammable or toxic vapors or

BLEVE in case of pressurized liquefied gases.

In an LPG bottling plant such as the plant in question the main hazard

arises due to the possibility of leakage of LPG during decanting (large

number of those connections etc), storage , cylinder filling & storage &

transportation. The various operations where leakage is more likely

include during compression. To formulate a structured approach to

identification of hazards and understanding of contributory factors is

essential.

3.2 BLAST OVER PRESSURES

Blast over Pressures depends upon the reactivity class of material & the

amount of gas between two explosive limits. LPG is expected to give rise

to a vapor cloud on release.




3.3 OPERATING PARAMETERS

Potential vapor release for the same materials depends significantly on

the operating conditions. Since LPG is being handled at atmospheric

temperature & in pressurized conditions, LPG releases have been

considered for release scenario based on their pressure & temperature

condition.

3.4 INVENTORY

Inventory analysis is commonly used in understanding the relative hazards

& short of release scenarios. Inventory plays an important role in regard to

the potential hazard. Larger the inventory of a vessel or a system, larger is

the quantity of potential release. A practice commonly used to generate an

accident list is to consider potential leaks & major releases from fractures

of pipelines & vessels containing sizable inventories. The potential vapor

release (source strength) depends upon the quantity of liquid release, the

properties of the materials & the operating conditions (pressure,

temperature)

3.5 LOSS OF CONTAINMENT

Plant inventory can get discharged to Environment due to loss of

containment. Various causes & modes for such an eventuality have been

described. Certain features of materials to be handled at the plant need to

the clearly understood to .Firstly list out all significant release cases & then

to short release scenarios for a detailed examination.

Liquid release can be either instantaneous or continuous. Failure of a

vessel to an instantaneous outflow assumes the sudden appearance of

such major crack that practically all of the contents above the crack shall

release in a very short time. The more likely event is the case of liquid

release from a hole in a pipe connected to the vessel. The flow rate will

depend on the size of the hole as well as on the pressure in front of the




hole, prior to the accident. Such pressure is basically dependent on the

pressure in the vessel.

Vaporization of released liquid depends on the vapour pressure & weather

conditions. Such consideration & others have been kept in mind both

during the initial listing as well as the short listing procedure. Initial listing

of all significant inventories in the process plants was carried out

This ensured no omission through inadvertence. Based on the

methodology discussed above a set of appropriate scenarios was

generated to carry out Risk Analysis calculation, as listed below

S.NO ITEM EVENT

1 Catastrophic Rupture of 150 MT Bullet Immediate Ignition, BLEVE

2 150 MT (each) LPG Bullets Vapour Side

rupture

VCE

3 Failure of bottom line of LPG Bullet Delayed Ignition, VCE

4 Failure of LPG Compressor Delayed Ignition, VCE

5 Failure of LPG Pump Delayed Ignition, VCE

6 Flange joint leakage in LPG Pipeline Delayed Ignition, VCE

7 Tank Truck Vessel Failure BLEVE

8 Electrical Fire

9 Hygiene Events

Earthquake, extreme Wind,

Aircraft Impact

10 Rupture of filled 5,14.2, 19, 35 & 47.5 kg

cylinder

Immediate ignition and

BLEVE

Civil Disorder, strikes etc can lead to any of these releases scenarios & it

would result in similar consequences. However, these events have been

considered in the probability estimation for the release scenarios,

wherever would have significant impact.

DESCRIPTION AND PROPERTIES

Page 1


SECTION –IV


4.0 INTRODUCTION

LPG is a mixture of commercial propane & commercial Butane which may

also contain small quantity of unsaturated hydrocarbons. LPG market in

India is governed by IS 4776 & Test methods by IS – 1148.

LPG being highly flammable may cause fire & explosion. It, therefore calls

for special attention during its handling.

PHYSICAL PROPERTIES DENSITY

LPG at atmospheric pressure & temperature is a gas which is 1.5 to

2.0 times heavier than air. It is easily liquefied under moderate

pressure. The density of liquid is approximately half that of water

and ranges from 0.507 to 0.58 m3.

Since LPG vapour pressure is heavier than air , it normally settle

down at ground level/low lying areas. This accumulation of LPG

vapour gives rise to potential fire and explosion.

VAPOUR PRESSURE

The pressure inside a LPG storage vessel is corresponding to the

temperature in storage vessel. This vapour pressure is dependent

on temperature as well as percentage composition of the mixture of

hydrocarbons present in LPG. Beyond liquid full condition in

cylinders any further expansion of the liquid will increase the

cylinder pressure by 7 – 8 kg/ m2. For each degree centigrade rise

in temperature. This clearly indicates the hazardous situation which

may arise due to overfilling of cylinder or any storage vessel.


Page 2


FLAMMABILITY

LPG has an explosive limit range or 1.8% to 9.5% by volume of the

gas in air. This is an considerably narrower than other common

gaseous fuel.

AUTO-IGNITION TEMPERATURE.

The auto ignition temperature of LPG is around 4100 – 5480 C & will

not ignite on its own at normal temperature.

COMBUSTION

Combustion of LPG increases the volume of products in addition to

generation of heat. LPG requires about 24 to 30 times its own for

complete combustion & yields 3 – 4 times of its own volume of Co2 .

The heat of combustion is about 10,900 kcal.kg

COLOUR

LPG is colorless both in liquid and vapour phase. During leakage

and vaporization of LPG cools the atmosphere & condenses the

water vapour contained in it forming a white fog. This makes

possible to see & escape of LPG

VISCOSITY

LPG has a low viscosity (around 0.3 at 450C) & can leak when other

petroleum products cannot. This properly demands a high degree of

integrity in the pressurized systems handling LPG to avoid

Leakage.

ODOUR

LPG has a very faint smell & as such for detecting leakage of LPG

ethyl mercaptan is generally added in the ratio approx 1 kg for

mercaptan per 100 ft 3 of Liquid LPG (20 ppm)


Page 3


TOXICITY LPG is slightly toxic. Although it is not poisonous in vapour phase, it

suffocates when present in large concentration due to displacement

of Oxygen. IDLH value of LPG is generally taken as 19000 PPM

PYROFORIC IRON

Highly inflammable pyroforic iron Sulphide is formed due to reaction

of loose iron / iron oxide with Sulphur or its compounds. Formation

of , Pyrophoric Iron Sulphide is prevented by totally eliminating

H2S, limiting the total volatile Sulphur to 0.2% by mass & reducing

loose iron oxide by thoroughly cleaning the storage vessels

internally during outage.

However, pyrophoric Iron Sulphide will spontaneously ignite in a

sphere or a cylinder due to high concentration of LPG which is

much above the upper flammable limit. When these vessels are

aired (during opening The saturation vapour pressure, flammability

range, toxicity data of Propane- Butane mixtures as well as pure

compounds are listed below

Propane (%)

Butane (%)

S.V. Process at 50C kg/Cm2

Flammability (Range (%)

Toxicity IDLH

(PPM)

Odour Threshold

(PPM)

100

- 21.12 2.1-9.5 19000 5000

70

30

19 1.9-9.5 N/A N/A

30

70 8.25 1.8-9.5 N/A N/A

20

80 7.31 1.8-9.5 N/A N/A

-

100 5.84 1.9-8.4 N/A -


Page 4


CHEMICAL PROPERTIES

Sl.No

1 Formula C3-C4 mixture

2 Molecular Weight 51.10 Kg/KMol

3 Boiling Temperature at 1 bar (0K) 251.80K

4 Critical Temperature (0K) 357.50K

5 Critical Pressure (bar) 40 bar

6 Density ( liquid) at 450C 50.75 E+01 Kg/M3

7 Boiling Temperature 58.89 E+01 Kg/M3

8 Density ( Gas) at 1 Bar & 450C 1.93 E + 00 Kg/M3

9 At Boiling Temperature 2.44 E + 00 Kg/M3

10 Heat capacity ( Gas) at 450C 17.59 E+ 02 J/Kg/k

11 Heat of Vapourisation at 450C (J/Kg) 31.78 E + 04 J/Kg/K

12 Boiling Temperature 40.00 E/ + 02 J/Kg/K

13 Heat Combustion (J/Kg) 45.94 E+06 J/ Kg/K

14 Vapour Pressure at 450C 9.74 bar

15 Ratio of Spec heats (cp/cv) 1.11

16 Thermal Conductivity ( Gas) at 450C 1.97E-02 W/M/K

17 Boiling Temperature 0.00 E-00 W/M/K

18 Thermal Conductivity ( Liquid) at 450C 8.33 E -02 W/M/K

19 At Boiling Temperature 12.17E -02 W/M/K

20 Stoichiometric Ratio 0.036M3/M3

21 Lower Flammability Limit (% V/V) 1.80

22 Upper Flammability Limit (% V/V) 9.5

23 IDLH Valve (PPM) 19000

E (+,- numerals) = Means Power of ten of the coefficients


Page 5


THE PHYSICAL CHEMICAL PROPERTIES OF LPG WHICH MAKE LPG

HAZARDOUS ARE AS FOLLOWS :

LPG liquid is lighter than water and hence floats on water and

evaporates

LPG vapor is heavier than Air

LPG can be stored at ambient temperatures only at higher that

atmospheric Pressure

Pressure and the actual pressure depends on the percentage of

propane in LPG

LPG is highly inflammable and forms explosive mixtures with air

LPG liquid expands to vapor phase by about 250 times

LPG has a fairly good burning velocity and explosive potential

The flame temperature is quite high and has a potential to endanger

steel structure.

With high moisture. LPG can form solid hydrates – which can Plug

pipelines, valves, regulators and other devices at lower temperatures.

Vapour pressure increases steeply with increasing temperature.

Frost bites, can occur when LPG in liquid phase comes into contact

with skin

MAXIMUM CREDIBLE ACCIDENT ANALYSIS (MCAA) APPROACH

Page 1


SECTION-V MAXIMUM CREDIBLE ACCIDENT ANALYSIS (MCAA)

APPROACH 5.1 INTRODUCTION

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

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

MCA analysis does not include quantification of probability of occurrence of an

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

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

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

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

of risk analysis studies, especially accident analysis.

Major hazards posed by flammable storage can be identified taking recourse to

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

calculate the consequent effects in terms of damage distances of heat radiation,

toxic releases, vapor cloud explosion etc. A host of probable or potential

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

handling of the hazardous materials are examined to establish their credibility.

Depending upon the effective hazardous attributes and their impact on the

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

damage caused can be assessed.

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

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

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

following factors have been taken into account:

Type of compound viz. flammable or toxic

Quantity of material present in a unit or involved in an activity and


Page 2


Process conditions such as temperature, pressure, flow, mixing and

presence of incompatible material

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

adjacent activities is taken into consideration to account for the potential

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

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

are summarized, accident scenarios are established in hazard identification

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

Credible Accident Analysis Studies.

5.2 METHODOLOGY

Following steps are employed for visualization of MCA scenarios: Chemical inventory analysis

Identification of chemical release and accident scenarios

Analysis of past accidents of similar nature to establish credibility to

identified scenarios; and

Short-listing of MCA scenarios

5.3 COMMON CAUSES OF ACCIDENTS

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

are identified as:

Poor house keeping

Improper use of tools, equipment, facilities

Unsafe or defective equipment facilities

Lack of proper procedures

Improvising unsafe procedures

Failure to follow prescribed procedures

Jobs not understood

Lack of awareness of hazards involved


Page 3


Lack of proper tools, equipment, facilities

Lack of guides and safety devices, and

Lack of protective equipment and clothing

5.4 FAILURES OF HUMAN SYSTEMS

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

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

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

Major causes of human failures reported are due to:

Stress induced by poor equipment design, unfavorable environmental

conditions, fatigue, etc.

Lack of training in safety and loss prevention

Indecision in critical situation; and

Inexperienced staff being employed in hazardous situation

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

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

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

systems and consequent damages.

5.5 MAXIMUM CREDIBLE ACCIDENT ANALYSIS (MCAA)

Hazardous substances may be released as a result of failures or catastrophes,

causing possible damage to the surrounding area. This section deals with the

question of how the consequences of release of such substances and the

damage to surrounding area can be determined by means of models.

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

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

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

injuries and damage to exposed population and environment. A disastrous


Page 4


situation in general is due to outcome of fire, Vapor Cloud explosion in addition

to other natural causes, which eventually lead to loss of life, property and

ecological imbalance.

Major hazards posed by flammable storage can be identified taking recourse to

MCA analysis. MCA analysis encompasses certain techniques to identity the

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

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

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

and handling of the hazardous materials are examined to establish their

credibility. Depending upon the effective hazardous attributes and their impact

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

respective damage caused can be assessed. The MCA analysis involves

ordering and ranking various sections in terms of potential vulnerability. 5.6 PHYSICAL EFFECTS AND CONSEQUENCES

Using the failure case data developed the program undertakes consequences

calculation for each indentified incident or failure case. The software initially

models the dispersion of the released material irrespective of whether it is

flammable or toxic. For flammable materials the software then proceeds to

determine the effect zones for the various possible outcomes of such release.

The risk analysis must account for all these possible outcomes. The possible

consequences include.

Fireball / BLEVE

Heavy Cloud Dispersion

Jet Fire

Vapor Cloud Explosion

The particular outcomes modeled depend on the behavior of the release and the

dilution regimes which exist. This can be quite complex. The program


Page 5


undertakes these calculations for the representative meteorological condition as

suitable for the meteorological condition in the area.

Consequential effects of the accidental release of a chemical are:

Intensity of heat radiation due to a fire or a fireball or BLEVE as a

function of the distance of source

Energy of vapor cloud explosion as a function of the distance of the

exploding cloud.

Concentration of gaseous material in the atmosphere due to the

dispersion of the evaporated material. The letter can be either an

explosive or a toxic material.

A release can ignite as the result of the event, which causes it, or can ignite

close to the source before the flammable cloud has travelled away from the

source. Immediate ignition can result in a fireball or a BLEVE or pool fire

depending on the nature and spread of release. A fireball can occur when there

is a specific type of fireball resulting raises the internal pressure and weakens

the vessel shell unit it bursts open and releases its entire contents as large and

very intense fireball.

If the material does not ignite immediately, allowing spill / release to form a liquid

pool a flammable gas cloud may be formed thorough evaporation of the pool due

to combination of solar heat, ground heat and heat from the neighbouring

environment and it can ignite at a number of points downwind if its path is such

that it goes across ( for example , a road an area where people are present or

other ignition sources). Delayed ignition can result in wide spread damaging

vapor cloud explosion of high energy or minor flash fire of limited energy

depending on the quantity of flammable vapor. The accident scenarios are

normally divided into the following categories of the chemicals according to their

physical state / phase, pattern of release , nature of dispersion, physical effects

and damage:


Page 6


a. Release of a gas ( Flammable or toxic or both )

b. Release of a liquid ( Flammable or toxic or both )

c. Release of a liquefied gas ( Flammable or toxic or both )

Event trees are the simplified schemes of consequence, which show the

possible evolution of effects after the release of the material. Such trees are very

effective in determining the possible consequences.

5.7 CONSEQUENCE MODELLING

Accidental release of' flammable or toxic vapors can result in severe

consequences. Delayed ignition of flammable vapors can result in blast

overpressures covering larger areas. This may lead to extensive loss of life &

property. Toxic clouds may cover yet a larger distance due to the lower threshold

values in relation to those in case of explosive clouds (the lower explosive

limits). In contrast, fires have localized consequences. Fires can be put out or

contained in most cases; there are few mitigating actions one can take once a

vapor cloud gets released

If LPG is released into the atmosphere, it may cause damage due to resulting

BLEVE, fires or vapor cloud explosion of the evaporated LPG. To formulate a

structured approach to identification of hazards and understanding of

contributory factors is essential. These factors have been described in detail.

DAMAGE CRITERIA

In consequence analysis, use is made of a number of calculation models to

estimate the physical effects of an accident (spill of hazardous material) & to

predict the damage (lethality, injury, material destruction) of the effects. The

calculations can roughly be divided in three major groups:


Page 7


a) Determination of the source strength parameters.

b) Determination of the consequential effects.

c) Determination of the damage or damage distances.

The basic physical effect models consist of the following

SOURCE STRENGTH PARAMETERS

Calculation of the outflow of liquid, vapors or gas out of a vessel or

a pipe, in case of rupture. Also two-phase outflow can be

calculated

Calculation, in case of liquid outflow, of the instantaneous flash evaporation & of the dimensions of the remaining liquid pool.

Calculation of the evaporation rate, as a function of volatility of the material, pool dimensions & wind velocity

Source strength equals pumps capacities, etc in came cases.

CONSEQUENTIAL EFFECTS

Dispersion of gaseous material in the atmosphere as a function of source

strength, relative density of the gas, weather conditions & topographical

situation of the surrounding area.

Intensity of heat radiation ( KW/M2) due to fire or a BLEVE, as a function

of distance of the source

Energy of vapor cloud explosions [in N/M2], as a function of the distance

to the distance of the exploding cloud

Concentration of gaseous material in the atmosphere, due to the

dispersion of evaporated chemical. The tatter can be either explosive or

toxic.


Page 8


It may be obvious, that the types of models that must be used in a specific risk

study strongly depend upon the type of material involved

Gas, vapor, liquid, solid?

Inflammable, explosive, toxic combustion products?

Stored at high /low temperatures or pressure?

Controlled outflow (Pump Capacity) or catastrophic failure ?

SELECTION OF DAMAGE CRITERIA

The damage criteria give the relation between extent of the physical effects

(exposure) & the percentage of the people that will be killed or injured due to

those effects. The knowledge about these relations depends strongly on the

nature of the exposure. For instance, much more is known about the damage

caused by heat radiation, than about the damage due to toxic exposure, & for

these toxic effects, the knowledge differs strongly between different materials. In

consequences Analysis studies, in principle three types of exposure to hazardous

effects are distinguished:

Effects are distinguished

I. Heat radiation from a jet, pool fire, a flash or a BLEVE

II. Explosion

III. Toxic effects, from toxic material or toxic combustion products

In a LPG bottling plant as there are no toxic chemicals handled. In the next two

paragraphs, the chosen damage catena are given & explained for heat radiation

& vapor cloud explosion

HEAT RADIATION

The consequences of exposure to heat radiation are a function of:

The radiation energy into the human body ( KW/M2)

The exposure duration [sec]

The protection of the skin tissue ( clothed or naked body)


Page 9


The limits for 1% of the exposed people to be killed due to heat radiation & for

second degree bums are given in the table below

DAMAGES TO HUMAN LIFE DUE TO HEAT RADIATION

Since in practical situations, only the own employees will be exposed to heat

radiation in cases of a fire, it is reasonable to assume the protection by clothing. It

can be assumed that people would be able to find a cover or a shield against

thermal radiation 10 sec time. Furthermore, 100% lethality may be assumed for

all people suffering from direct contact with flames, such as the pool fire, a flash

fire or a jet flame. The effects relatively lesser incident radiation intensity is given

below:

EFFECTS DUE TO INCIDENT RADIATION INTENSITY

THERMAL RADIATION (KW/M2)

TYPE OF DAMAGE

0.7

EQUIVALENT TO SOLAR RADIATION

1.6

NO DISCOMFORT FOR LONG EXPOSURE

4.0

SUFFICIENT TO CAUSE PAIN WITHIN 20 SEC BLISTERING OF SKIN (1ST DEGREE BURNS ARE LIKELY)

9.5

PAIN THRESHOLD REACHED AFTER 8 SEC 2ND DEGREE BURN AFTER 20 SEC

12.5 MINIMUM ENERGY REQUIRED FOR PILOTED IGNITION OF WOOD, MELTING PLASTIC TUBING ETC

The actual results would be less severe due to the various assumptions made in

the models arising out of the flame geometry, emissivity, angle of incidence,

view factor & others. Upon ignition , a spilled liquid hydrocarbon would be burn in


Page 10


the form of a large turbulent diffusion flame the size of the flame would be

depend upon the spill surface & the thermo - chemical properties of the spilled

liquid. In particular, the diameter of the fire (if not confined to a dyke), the visible

height of the flame, the tilt & drag of the flame due to wind can be correlated to

the burning velocity of the liquid. The radiative output, of the flame would be

dependent upon the fire size, extent of mixing with air & the flame temperature.

Some fraction of the radiation is absorbed by carbon dioxide & water vapor in

the intervening atmosphere. In addition, large hydrocarbon pool fires produce

thick smoke, which can significantly obscure flame radiation. Finally the incident

flux at an observer location would depend upon the radiation view factor .which

is a function of the distance from the flame surface, the observer's orientation &

the flame geometry Estimation of the thermal radiation hazards from the pool

fires essentially involves 3 steps; characterization of flame geometry,

approximation of the radiative properties of the fire & calculation of safe

separation distances to specified levels of thermal radiation

EXPLOSION In case of vapor cloud explosion, two physical effects may occur

A flash fire over the whole length of the explosive gas cloud.

A blast wave , with typical peak overpressures circular around ignition

source

As explained above, 100% lethality is assumed for all people who are present

within the cloud proper.

For the blast wave the lethality criterion is based on

A peak overpressure of 0.1 bar will cause serious damage to 10% of the

housing / structures

Falling fragments will kill one of each eight persons in the destroyed

buildings

The following damage criteria may be distinguished with respect to the peak

overpressures resulting from the blast wave:


Page 11


DAMAGE DUE TO OVERPRESSURES

PEAK OVERPRESSURE

DAMAGE TYPE

0.83 BAR

TOTAL DESTRUCTION

0.30 BAR

HEAVY DAMAGE

0.10 BAR

MODERATE DAMAGE

0.03 BAR

SIGNIFICANT DAMAGE

0.01 BAR

MINOR DAMAGE

From this it may be concluded that p=0.17 E+5 pa corresponds approximately

with 1% lethality. Furthermore it is assumed that everyone inside an area in

which the peak overpressure is greater than 0.17 E+5 pa will be wounded by

mechanical damage. For the gas cloud explosion this will be inside a circle with

the ignition source as its center

EXTERNAL EVENTS

External events can initiate & contribute to potential incidents considered in a

Risk Analysis. Although the frequency of such events is generally low, they may

result in a major incident. They also have the potential to initiate common cause

failures that can lead to escalation of the incident. External events can be

subdivided into two main categories.

Natural hazards : Earthquakes , Floods, Tornadoes, extreme temperature,

lightening etc

Man induced events : Aircraft crash, missile, nearby industrial activity,

sabotage etc


Page 12


TECHNOLOGY

Normal design codes for gas/chemical plants have sufficient safety factors to

allow the plant to withstand major external events to a particular level (e.g.

intense loading of say 120 mph). Quantitative design rules usually used for

seismic events, flooding, tornadoes & extreme wind hazards as follows

SEISMIC –The design should withstand critical ground motion with an

annual

Probability of 10-4 or less

FLOODING – The design should withstand the efforts of worst

flooding occurrence in 100 year period

WINDS - The design should withstand the most critical combination

of Wind velocity & duration having a probability of 0.005 or less in a 50

year period (annual probability of 10-4 or less).

DAMAGE DUE TO INCIDENT RADIATION INTENSITY

INCIDENT RADIATION

(KW/M2)

TYPE OF DAMAGE

62.0

Spontaneous Ignition Of Wood & Sufficient To Cause Damage To Process Equipments

37.5

Minimum energy required to ignite wood at infinitely long exposure ( Non plastic )

12.5

Minimum energy required for piloted ignition if wood, melting plastic tubing, etc

4.5

Sufficient to cause pain to personal if unable to reach cover within the 20 seconds. However blistering of skin ( 1st degree burn is likely)

1.6 Will cause no discomfort to long exposure.

0.7

Equipment to solar radiation.


Page 13


PHYSIOLOGICAL EFFECTS OF THRESHOLD THERMAL DOSES

DOSE THRESOLD (KW/M2)

EFFECT CONSEQUENCES

37.5 3RD DEGREE BURN INVOLVE WHOLE OF DPIDERMIS AND DERMIS; SUB- CUTANEOUS TISSUES MAY ALSO BEDAMAGED.

12.5 2ND DEGREE BURN INVOLE WHOLE OF EPIDERMIS OVER THE AREA OF THE BURN PLUS SOME PORTION OF DERMIS.

4.0 1ST DEGREE BURN INVOLE ONLY EPIDERMES, BLISTER MAY OCCUR, EXAMPLE SUNBURNS.

DAMAGE EFFECTS OF BLAST OVERPRESSURE

BLAST OVER PRESSURE

(Bar)

DAMAGE LEVEL

0.3 Major structure damage ( assumed fatal to people inside building or within the other structures

0.1 Storage failure

0.01 Eardrum Rupture

0.03 Repairable damage, pressure Vessels light structure collapse


Page 14


POSSIBLE RELEASE SCENARIO OF LPG

PIPELINE RELEASE RUPTURE OF VESSEL

VAPOR LIQUID

OUTFLOW

JET FIRE DISPERSION

DELAYED IGNITION

NO IGNITION

VCE/ FLASH FIRE

SAFE DISPERSION

BLEVE

OUTFLOW MODEL

TWO PHASE OUTFLOW

JET FIRE LIQUID SPREADING AND EVAPORATION

DISPERSION

POOL FIRE

DELAYED IGNITION

NO IGNITION

VCE/ FLASH FIRE

SAFE DISPERSION

HAZARDS OF LPG SPILLAGE / ESCAPE FROM CONTAINMENT

1


SECTION-VI HAZARDS OF LPG SPILLAGE / ESCAPE FROM

CONTAINMENT 6.0 General

When LPG is released from a storage vessel or a pipeline , a fraction of LPG

vaporizes immediately and the other portion forms a pool if the released liquid

quantity is more. LPG from the pool vaporizes rapidly entrapping some liquid as

droplets as well as considerable amount of air forming a gas cloud. The gas

cloud is relatively heavier than air and forms a thin layer on the ground. The

cloud flows into trenches and depressions and in this way travels a considerable

distance.

As the cloud formed in the area of spill moves downwind under influence of

wind, it gets diluted. A small spark, when the vapour cloud is within the

flammability limit can cause flash fire, explosion and if the liquid pool still exist

and remains in touch of cloud under fire it can ignite the whole mass of liquid.

However in case of non existence of any source of ignition there will be no

occurrence of hazardous event and the cloud may get diluted to such a level that

the mixture is no longer explosive. However , it can cause asphyxiation due to

displacement of oxygen . Different types of combustion reactions . associated in

case of. release of LPG from the containment are listed in the following sections.

JET FIRE

Escaping jet of LPG from pressure vessels / piping, if ignited cause a jet flame.

The jet flame direction and tilt depend on prevailing wind direction and velocity.

Damage, in case of such type of jet fires, is restricted to within the- plant

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

equipment carrying LPG and cause domino effect.


2


POOL FIRE

The liquid pool, if ignited , causes a "Pool Fire" . In the pool fire, LPG burns with

long smoky flame throughout the pool diameter radiating intense heat which

creates severe damage to the adjoining buildings, structures , other vessels and

equipment causing secondary fires. The flame .may tilt under influence of wind

and may get propagated / brown several pool diameters down wind. Damage, in

case of such fires ,is restricted within the plant area and near the source of

generation.

UNCONFINED VAPOUR CLOUD EXPLOSION (UVCE)

Clouds of LPG vapour mixed with air (within flammability limit) may cause

propagating flames when ignited. In certain cases flame take place within

seconds the thermal radiation intensity is severe depending on the total mass of

LPG in the cloud and may cause secondary fires. When the flame travels very

fast it explodes high over pressures or blast effects causing heavy damage at

considerable distance from the release point. Such explosions are called

unconfined vapour cloud explosion.

BOILING LIQUID EXPANDING VAPOUR EXPLOSION (BLEVE)

This phenomenon occurs when pressure inside a storage vessel increases

above the design pressure due to a fire in the adjacent area. Due to

impingement of flame or due to radiant heat, temperature in the vapour portion

of the storage vessel increases rapidly compared to the portion filled with liquid.

Increase in temperatures softens and weakens the metal wall of the shell. With

the rise in vapour pressure and inadequate vapour space for expansion , the

shell of storage tanks bursts causing fragments of the shell flying like projectiles

with release of whole mass of pressurized boiling liquid. The released liquid

flashes and atomies immediately often resulting a large fire ball in contact with


3


an ignited source. Although the fire ball lasts only a few seconds , its effect is

devastating due to flame contact and intense thermal radiation. This

phenomenon is called BLEVE. The effect of BLEVE extends beyond the plant

boundary in case of catastrophic failure of large pressurized storage vessels.

PAST LPG INCIDENTS IN INDIA



SECTION –VII

HISTORY OF PAST ACCIDENTS IN LPG PLANTS IN INDIA

A. HARYANA, 1973

Road accident: A truck carrying 300 LPG cylinders on National Highway 20

miles away from Delhi .capsized 8. LPG cylinders tumbled down. Suspected

cause of fire is friction between the cylinders which might have leaked due to

rolling down . 1 person died & 3 others were injured

B. MADRAS , 04.04.1981

Fire Accident at LPG Filling Plant at Madras Refineries Limited . On the

day of the fire no filling operation was planned . However it was planned to

do some housekeeping & cleanup operations & interacting of cylinders &

stacking . A truck was also engaged to remove defective cylinders. Prior to

the removal of defective cylinders , reported that about 4500 cylinders

were lying there . Till the truck arrived the contract workmen were engaged

in shifting cylinders by rolling to the new stacking location & they removed

about 400 cylinders & had been stacking them . The truck also made one

trip , of intercarting of 265 cylinders to the new location. , The truck made a

second trip , picked up about 230cylinders & came to the stacking location

& stood by , ready to unload the cylinders . At this time the fire broke out

from the middle of the new stack of defective cylinders & spread fast to the

entire stack of cylinders . In a matter of minutes cylinders had started to

burst with a loud noise due to exposure to intense heat of fire & several

cylinders gave way due to over pressuring . Sudden bursting of cylinders

led the splinters / metal pieces to fly off in all odd directions quite far away

from the accident spot. Due to bursting of cylinders & spreading of fire, the

truck also caught fire & with its full load of cylinders was gulfed in fire &

was totally destroyed. Smoking is believed to be the cause of this accident

B. DELHI, 15.05.1983




A large fire occurred in LPG Bottling Plant filling 9000 cylinders per day , in two shift operation . LPG was supplied to the plant in tank wagons

The fire originated from the cylinder repair area . Leaked LPG got ignited by the lighted beedi, which one of the workers, in the repair area ,was smoking while he was carrying decanting operations 4 persons died & 25 were injured. About 80665 cylinders were damaged.

D. MADRAS, 1985

Fire accident occurred in one of the restaurants when one of the untrained

workers attempted to disconnect an empty cylinder from the pigtail

connection for fixing a filled LPG cylinder. 7 people died & 10 others were

injured

E. SALEM

LPG gas leak was observed through the improperly closed gate valve near

the top manhole, in a railway wagon . Due to timely action a big fire

accident could be averted.

F. NELLORE 1988

Tanker carrying LPG cylinders burst into flames right under the Nellore

railway bridge, melting the electric traction wire to a span of 45 m &

completely twisting the track over the bridge. 1 person died & 2 others

were injured

G. CHANDIGARH, 1989

An accident occurred in a LPG Plant , when some employees of LPG

agency were trying to pilfer LPG from one cylinder to another when the

leaking gas got ignited from the open fire nearby . Two people died & no

one was reported injured.

H. RAJKOT.1989




Indian Oil Corporation LPG bottling Plant: A LPG leakage incident

involving a LPG road tanker took place at the IOCL .The locking pin of the

shut off valve of the liquid line of the tanker was broken . Since the valve

after being opened, could not be closed, LPG started leaking . 2 people

were injured.

I. RONALI, BARODA, 1989

Another LPG leakage incident involving a road tanker occurred because the gasket used in the liquid line of the tanker had worn out & gave way leading to leakage of LPG.

J. DHULE, MAHARASHTRA, 1990

Another LPG incident involving road tankers took place when the driver of

the tanker lost control & the vehicle fell into a ditch leading to the shearing

of excess flow check valve & safety valve of the tank resulting in the

leakage of LPG. The cloud traveled a distance of 100 m away & met with a

source of ignition resulting in flash fire. 12 people died in this accident.

K. HOWRAH, BRIDHE, CALCUTTA, 1990

A road tanker carrying 12.45 MT of LPG overturned on Howrah bridge &

the roto gauge was damaged & the gas leak occurred. Due to prompt

safety measures taken by the fire brigade, an explosion was averted. Two

people were injured in this incident.

L. BONTHAPALLY ,AP,1990




There was a gas leak from a faulty valve. At the same time static charge

accumulated on the tanker during unloading. Since the tanker was not

"earthed" electrostatic arcing occurred & resulted in an explosion & the

entire vehicle was burnt. Nobody was hurt.

M. GANAURSI, PUNJAB, 1990

Yet another LPG road tanker incident, a tanker overturned & the safety

valve got damaged resulting in a gas leak which enveloped an entire

village. The gas got ignited on coming in contact with some flame &

resulted in a massive fire. 31 People died & 30 others were injured.

N. JAMSHEDPUR, 1991

Due to damage in the terflon packing around the thermowell connecting

the nozzle to the Horton sphere thermoweli was displaced resulting in a

leak. One person was injured

O. PUNE, 1992

Since the liquid discharge valve was not closed properly after the

unloading of LPG from the tanker, liquid LPG leaked out. The vapors from

the leak, reached the workers quarters, & got ignited. The flames reached

the tanker, which caught fire. One person died & two others were injured.

CONSEQUENCE ANALYSIS

Page 1

Risk Analysis For BPCL LPG Bottling Plant Durgapur, West Bengal

SECTION –VIII


8.0 BASIC ASSUMPTION FOR CALCULATING EFFECT ZONE

PRODUCT : LPG ( 60% Butane and 37.4% Propane by weight ),

Molecular Weight : 52, Vapour pressure: 7.72 Bar at 448 K, LEL: 1.8%,

UEL: 9.5%, Boiling Point: -17Deg C at 1 Bar, Liquid Density : 0.521 Kg/

M3, Heat Capacity : 2736 J/KG/K,

PROPANE:- Heat of Combustion: 4.65 E+07 J/ KG, Heat of Evaporation

at Boiling Temp ( 231 K at 1 Bar) : 2.22 E +03 J/KG. K

Butane:- Heat of Combustion : 4.59E + 07 J/ KG, Heat of Evaporation at

Boiling Temperature ( 273 K at 1 Bar ): 3.84 E + 05 J/KG

METEOROLOGICAL DATA

A. Temperature

Summer (0 c) 26 – 37.4 Winter (0 c) 12 – 17.5 Humidity: 44%- 70%

Tanker Bullet Size : 18 Tons Bullet Capacity : 150 MT x 3

300 MT x 2 (Proposed)

Pipeline Data

Liquid Line dia from tanker to bullet : 150mm

Liquid Line dia from bullet to pump : 100mm

Liquid Line dia from pump to carousal : 100mm

Return vapour line dia : 100mm

Dia of return pipeline from carousal : 100mm

Dia of vapour return line from carousal : 50mm


Page 2


Pump Capacity :

LPG Pump Capacity : 50 M3/Hr x2

Jockey Pump Capacity : 10 M3/Hr x2

Fire water Pump Capacity : 616 Kl/Hr x2

Compressor Capacity

Air Compressor Capacity : 100 CFM x 2

198 CFM x 2 LPG Compressor Capacity : 150 CFM x 1

65 CFM x 2

CONSEQUENCE CALCULATION: Please consider; Storage Temperature : 293 K; Storage Pressure : 5.5 Kg/ Cm2,

Discharge Coeff: 0.6, Wind Speed: 1.3 M/ sec, Atm Stability : F

BLEVE:

Source : a) 18 MT Bullet Truck

b) 150 MT Bullet ( Vessel- in open pedestal)- full capacity

HEAVY CLOUD DISPERSION (dispersion LEL distance considering

Release Time of 1800 Sec )

Source : a) 150 mm liquid line rupture (100%) from bullet truck

b) 100 mm liquid line rupture (100%) to carousal

c) 100 mm vapour line rupture (25%) from bullet truck

d) 100 mm liquid line rupture (25%) to carousal

e) 100 mm liquid line rupture (100%) from bullet trucl to pump

f) 100 mm liquid line rupture (25%) from bullet suction

g) 100 mm vapour line rupture (100%) from bullet truck

h) 100 mm vapour return hrader under compression

i) 100 mm carousal return line (liquid)

j) 50 mm carousal return line (vapour)


Page 3


VAPOUR CLOUD EXPLOSION

Source : a) 150 mm liquid line rupture from bullet truck (100%)

b) 100 mm liquid line rupture to carousal (100%)

c) 150 mm liquid line rupture from bullet truck (25%)

d) 100 mm liquid line rupture to carousal (25%)

e) 100 mm liquid line rupture (100%) from bullet suction

f) 100 mm liquid line rupture from bullet suction (25%)

g) 100 mm carousal return line liquid

JET FIRE ( if ignited) ,

Source : a) 150 mm liquid line rupture from bullet truck (100%)

b) 100 mm liquid line rupture to carousal

c) 100 mm vapour line rupture from bullet truck (100%)

d) 100 mm liquid line rupture from bullet suction (100%)

e) 100 mm vapour return header under compressor

f) 100 mm carousal return line (liquid)

g) 50 mm unloading arm rupture (liquid)

GASKET FAILURE :

Source : a) 100 mm Gasket failure in LPG pump discharge

b) 100 mm Gasket Failure in LPG pump discharge (25%)


Page 4


SCENARIO -1

BLEVE - 5 KG CYLINDER

ASSUMPTION 1. AMBIENT TEMPERATURE : 37.4 (0C)

2. AMOUNT OF GAS : 5 (KG)

3. DIAMETER CLOUD : Nil

4. DURATION OF FIRE BALL : Nil

5. INTENSITY OF RADIATION : Nil

6. RELATIVE HUMIDITY : 44%

THE THERMAL LOAD IS CALCULATED FROM THE CENTRE OF THE FIRE BALL

SL.NO THERMAL RADIATION DISTANCE (M)

1 1st Degree Burn ( 4KW/M2) Quantity insufficient for BLEVE

2 50% LETHALITY ( 12.5KW/M2) Quantity insufficient for BLEVE

3 100% LETHALITY ( 37.5KW/M2) Quantity Insufficient for BLEVE


Page 5


SCENARIO -2

BLEVE - 14.2 KG CYLINDER

ASSUMPTION

1. AMBIENT TEMPERATURE : 37.4 (0C)

2. AMOUNT OF GAS : 14.2 (KG)







1 1st Degree Burn ( 4KW/M2) Quantity insufficient for BLEVE

2 50% LETHALITY ( 12.5KW/M2) Quantity insufficient for BLEVE

3 100% LETHALITY ( 37.5KW/M2) Quantity Insufficient for BLEVE

SL.NO Cylinder Capacity

(kg)

Failure During Overheating

Total Energy

(KL)

Max. Fragment

range (m)

Fragment

Velocity (m/s)

1 14.2

12.5 162.2 39.8


Page 6


SCENARIO -3

BLEVE -- 19 KG CYLINDER









1 1st Degree Burn ( 4KW/M2) Quantity In sufficient for BLEVE

2 50% LETHALITY ( 12.5KW/M2) Quantity In sufficient for BLEVE



Page 7


SCENARIO -4

BLEVE -- 35 KG CYLINDERS












SL.NO Cylinder

Capacity (kg)


Total Energy

(KL)

Max. Fragment

range (m)

Fragment Velocity

(m/s)

1 35

31.4 131.2 43.3


Page 8


SCENARIO -5

BLEVE – 47.5 KG CYLINDERS


2. AMOUNT OF GAS : 47.5 (KG)









3 100% LETHALITY (37.5KW/M2) Quantity In sufficient for BLEVE

SL.NO Cylinder Capacity

(kg)


Total Energy

(KL)

Max. Fragment

range (m)

Fragment Velocity

(m/s)

1 47.5

42.4 199.2 44.2


Page 9


SCENARIO -6

BLEVE - 18 MT BULLET TRUCK


2. AMOUNT OF GAS : 18 MT

3. RADIUS OF FIRE BALL : 62.5 (M)

4. DURATION OF FIRE BALL : 8.8 (S)

5. INTENSITY OF RADIATION : 191.9 (KW/M2)




1 1st Degree Burn ( 4KW/M2) 318.3

2 50% LETHALITY ( 12.5KW/M2) 195.2

3 100% LETHALITY ( 37.5KW/M2) 115.3


Page 10


SCENARIO - 7

BLEVE -150 MT BULLET



3. RADIUS OF FIRE BALL : 124.4(M)


5. INTENSITY OF RADIATION : 232.3(KW/M2)




1 1st Degree Burn ( 4KW/M2) 673.4

2 50% LETHALITY ( 12.5KW/M2) 413.6

3 100% LETHALITY ( 37.5KW/M2) 244.6


Page 11


SCENARIO – 8

BLEVE -300 MT MSV



3. RADIUS OF FIRE BALL : 187.2(M)


5. INTENSITY OF RADIATION : 232.3(KW/M2)




1 1st Degree Burn ( 4KW/M2) BLEVE is not possible

2 50% LETHALITY ( 12.5KW/M2) BLEVE is not possible

3 100% LETHALITY ( 37.5KW/M2) BLEVE is not possible


Page 12


SCENARIO – 9

HEAVY CLOUD DISPERSION – 150 MM LIQUID LINE RUPTURE (100% )

FROM BULLET TRUCK

ASSUMPTION 1. AMBIENT TEMPERATURE : 12 (0C)

2. PIPE DIA : 150MM

3. FLOW RATE : 380.4 (Kg/Sec)

4. RELEASE TIME : 1800 SEC

5. PUMPING PRESSURE : 12 Kg/CM2


DISTANCES FOR DISPERSION OF HEAVY CLOUD

Event No

Distance LEL (M) Distance UEL (M)

DW

CW

DW CW

1. 42 78.7 10 31.3


Page 13


SCENARIO - 10

HEAVY CLOUD DISPERSION – 100 MM LIQUID LINE RUPTURE (100%) TO CAROUSAL

ASSUMPTION

1. AMBIENT TEMPERATURE : 12 (0C)

2. PIPE DIA : 100MM



5. PUMPING PRESSURE : @ 55 kl/hr at 14 Kg/CM2



Event No


DW

CW

DW CW

1. 12 9.8 2 4.8


Page 14


SCENARIO -11

HEAVY CLOUD DISPERSION – 100 MM VAPOUR LINE RUPTURE (25% ) FROM BULLET TRUCK


2. PIPE DIA : 100MM




6. RELATIVE HUMIDITY : 70 %


Event No


DW

CW

DW CW

1. 32 38.4 6 13.1


Page 15


SCENARIO -12

HEAVY CLOUD DISPERSION – 100 MM LIQUID LINE RUPTURE (25% ) TO CAROUSAL

ASSUMPTION


2. PIPE DIA : 100 MM






Event No


DW CW

DW CW

1. 4 3.01 1 1.95


Page 16


SCENARIO -13

HEAVY CLOUD DISPERSION –100 MM LIQUID LINE RUPTURE (100% ) FROM BULLET TRUCK TO PUMP


2. PIPE DIA : 100 MM






Event No


DW

CW

DW CW

1. 10 8.7 1.8 4.4


Page 17


SCENARIO -14

HEAVY CLOUD DISPERSION – 100 MM VAPOUR LINE RUPTURE (100%) FROM BULLET TRUCK


2. PIPELINE DIA : 100mm






Event No


DW CW

DW CW

1. 44 21.5 10 8.3


Page 18


SCENARIO -15

HEAVY CLOUD DISPERSION – 100 MM CAROUSAL RETURN LINE (LIQUID)






6. COMPRESSION : 93 CFM



Event No


DW CW

DW CW

1. 14.7 11.9 2.4 5.1


Page 19


SCENARIO -16

HEAVY CLOUD DISPERSION – 50 MM CAROUSAL RETURN LINE (VAPOUR)









Event No


DW CW

DW CW

1. 26 11.3 6 4.4


Page 20


SCENARIO -17

HEAVY CLOUD DISPERSION – 50 MM UNLOADING ARM RUPTURE (LIQUID)









Event No


DW CW

DW CW

1. 12 9.8 2 4.8


Page 21


SCENARIO -18

VAPOUR CLOUD EXPLOSION -150 MM LIQUIDLINE RUPTURE FROM BULLET TRUCK ( 100% )


2. PIPE DIA : 150mm



5. WIND VELOCITY & STABILITY : 2/F

6. SOURCE STREMGTH FOR DISPERSION : 380.4 Kg/S

7 VAPOUR CLOUD RADIUS : 78.7 M

8 VAPOUR CLOUD HEIGHT : 15.4 M

9 AMOUNT IN EXPLOSIVE LIMITS : 5700 Kg

10 LEL DISTANCE : 42 M


DAMAGE DISTANCES FOR VAPOUR CLOUD EXPLOSION


1 0.3 bar 151.1

2 0.1 bar 442.2

3 0.03 bar 755.5


Page 22


SCENARIO -19

VAPOUR CLOUD EXPLOSION -100 MM LIQUID LINE TO CAROUSAL (100%)


2. PIPE DIA : 100MM







9 AMOUNT IN EXPLOSIVE LIMITS : 44.5 Kg





1 0.3 bar Explosion unlikely Qty low




Page 23


SCENARIO - 20

VAPOUR CLOUD EXPLOSION -150 MM LIQUIDLINE RUPTURE FROM BULLET TRUCK ( 25% )

ASSUMPTION


2. PIPE DIA : 150MM












1 0.3 bar 82.1

2 0.1 bar 164.3

3 0.03 bar 410.7


Page 24


SCENARIO -21

VAPOUR CLOUD EXPLOSION -100 mm LIQUID LINE RUPTURE (25%) TO CAROUSAL

ASSUMPTION


2. PIPE DIA : 100mm


4. WIND VELOCITY & STABILITY : 1.3/F













Page 25


SCENARIO -22

VAPOUR CLOUD EXPLOSION -100 MM LIQUID LINE RUPTURE (100%) FROM BULLET SUCTION

ASSUMPTION


2. PIPE DIA : 100mm











1 0.3 bar 82.5

2 0.1 bar 165.3

3 0.03 bar 408.5


Page 26


SCENARIO -23

VAPOUR CLOUD EXPLOSION -100 MM CAROUSAL RETURN LINE (LIQUID)


2. PIPE DIA : 100 mm















Page 27


SCENARIO -24

JET FIRE -150MM LIQUID LINE RUPTURE FROM BULLET TRUCK (100%)


2. PIPELINE DIA : 150 MM



5 THERMAL RADIATION INSIDE JET : 154.5 KW/M2

6. LENGTH : 205.2 M

7 WIDTH : 17.7 M


DAMAGE DISTANCES FOR JET FIRE


1

1st Degree Burn ( 4KW/M2)

DW 238.0

CW 97.8

2

50% LETHALITY ( 12.5KW/M2) DW 22.2

CW 35.7

3

100% LETHALITY ( 37.5KW/M2) DW 209.3

CW 15.1


Page 28


SCENARIO -25

JET FIRE -100 MM LIQUID LINE RUPTURE TO CAROUSAL






6. LENGTH : 34.1 M

7 WIDTH : 2.9 M




1


DW 42.6

CW 26.9

2


CW 14.2

3


CW 5.9


Page 29


SCENARIO -26

JET FIRE -100 MM VAPOUR LINE RUPTURE FROM BULLET TRUCK (100%)






6. LENGTH : 36.2 M

7 WIDTH : 3.1 M




1


DW 44.3

CW 25.9

2


CW 13.3

3


CW 5.5


Page 30


SCENARIO -27

JET FIRE -100 MM LIQUIDLINE RUPTURE FROM (100%) FROM BULLET

SUCTION

ASSUMPTION

1. AMBIENT TEMPERATURE : 37.4 (0C)





6. LENGTH : 171.2 M

7 WIDTH : 14.8 M




1


DW 130.5

CW 60.4

2


CW 28.4

3

100% LETHALITY ( 37.5KW/M2) DW 114.3

CW 10.8


Page 31


SCENARIO -28

JET FIRE -100 MM VAPOUR RETURN HEADER UNDER COMPRESSOR






6. LENGTH : 43.2 M

7 WIDTH : 3.7 M




1


DW 52.2

CW 29.1

2


CW 14.7

3


CW 5.8


Page 32


SCENARIO -29

JET FIRE -100 MM CAROUSAL RETURN LINE (LIQUID)






6. LENGTH : 34.1 M

7 WIDTH : 2.9 M




1


DW 50.8

CW 33.5

2


CW 17.6

3


CW 6.9


Page 33


SCENARIO -30

JET FIRE -50 MM UNLOADING ARM RUPTURE (LIQUID)


2. HOSE DIA : 50 MM




6. LENGTH : 34.1 M

7 WIDTH : 2.9 M




1


DW 38.7

CW 25.1

2


CW 13.3

3


CW 5.7


Page 34


SCENARIO -31

VAPOUR CLOUD EXPLOSION -100 MM GASKET FAILURE IN LPG PUMP DISCHARGE (25%)

ASSUMPTION


2. PIPE DIA : 100mm











1 0.3 bar Explosion Unlikely Qty Low



RECOMMENDATION



SECTION –IX

RECOMMENDATION 9.0 SUGGESTION

Handling And Storage of Liquid Petroleum Gas is a Hazardous process as the

chemical properties of L.P.G indicates that the material is explosive. Leakage

from any point and getting a source ignition may cause disaster..

Based on M.C.A analysis, different probable accident scenarios were

identified and its consequences have been identified.

Risk contours have been plotted on the layout to show the possibilities of

damage on the onsite/offsite facilities.

Fallowing Scenarios were considered

BLEVE

5 kg cylinders

14.2 kg cylinders

19 kg cylinders

35 kg cylinders

47.5 kg cylinders

18 MT bullet truck

150 MT bullet

300 MT MSV

PIPE LINE DIA :

150 mm liquid line - Tanker to Bullet

100 MM liquid line - Bullet to pump

100 mm liquid line - Pump to carousal

100 mm pipeline - Vapour Return line

100 mm pipeline - Return line from carousal

50 mm return line - Unloading Arm

50 mm line - Vapour return line from carousal

RECOMMENDATION



BLEVE

Maximum Damage from Fireball

S no.

Failure Scenarios

Source Strength

Radius of fireball

Duration of Fireball

Intensity of Radiation inside fireball

Damage distances from the center of the fireball

m

T m s kW/m2 37.5 kW/m2

12.5 kW/m2

4 kW/m2

a) 18 MT Bullet Truck- full capacity

9 62.5 8.8 191.9 115.3 195.3 318.4

b) 150 MT Bullet ( Vessel- in open pedestal)- full capacity

75 115 15.3 217 244.6 413.6 673.4

c) 300 MT MSV - Bleve

101

187.2

20.4 252.7 BLEVE is not possible

In the above cases thermal radiation zone will spread beyond the boundary and cause

off site risk. These will also cause damage to on site facilities like unloading bay etc.

RECOMMENDATION



HEAVY CLOUD DISPERSION (dispersion LEL distance considering Release Time of 1800 sec)

S no. Scenario Pipe size

Flow rate LEL (m) UEL (m)

mm (kg/s) DW CW DW CW

a)150 mm liquid line rupture (100%)

1. from bullet truck under pressure of 12Kg/ cm2

150 380.4 (rupture assumed to be

at vessel-pipe joint)

42 78.7 10 31.3

2 liquid line . to Carousal @ 55 Kl/ Hr at 14Kg/ cm2)

100 2.2 4 3.01 1 1.95

b)100 mm vapour line rupture (25%) (from Bullet truck)

100 10.06 32 38.4 6 13.1

c)100 mm liquid line ruptures to Carousal (suction @ 14Kg/ cm2)

100 8.9

12 9.8 2 4.8

d)100 mm liquid line ruptures (Bullet to Pump

100 260.2 10 8.7 1.8 4.4

e)100 mm vapour line rupture (100%) (from Bullet truck)

100 14.6 44 21.5 10 8.3

f) 100 mm Carousel return line( liquid)

100 8.9 14.7 11.9 2.4 5.1

100 mm Carousel return line( Vapour)

50 6.4 16 11.3 6 4.4

g)50 mm unloading arm rupture 50 8.9 12 9.8 2 4.8

In case a source of ignition this may cause damage to the onsite facilities Mitigative Measures:-

1. Elimination of ground level ignition source 2. Nozzle for vapour cloud dispersion is to be put into operation 3. Provision for vapour dilution system

RECOMMENDATION



VAPOUR CLOUD EXPLOSION (DELAYED IGNITION considering Release time of 1800 Sec)

Damage distances due to VCE

S no.

Scenario Pipe size

Release rate

Wind velocit

y & Stabilit

y

Source strengt

h for dispersi

on

Cloud radius/ Height

Amount in

Explosive

limits

LEL distanc

e

Damage distances (m)

mm kg/s kg/s m kg m 0.3 bar 0.1 bar 0.03 bar

a) 150 mm liquid line rupture 1. from bullet truck under pressure of 12 Kg/ cm2) (100%)

150 380.4 2/ F 380.4 78.7/15.4

5700 28 151.1 442.2 755.5

2. from bullet truck under pressure of 12 Kg/ cm2) (25%)

150 76.4 2/F 76.4 38.4/6.5 912 32 82.1 164.3 410.7

b) 100 mm liquid line rupture

1. . to Carousal @ 50 Kl/ Hr at 14 Kg/ cm2) (100%)

100 8.9 2/ F 8.9 9.8/2.7 44.5 12 Explosion unlikely Qty low

2. to Carousal @ 50 Kl/ Hr at 14 Kg/ cm2) (25%)

100 2.2 2/ F 8.92.2 3.01/1.9 4.4 4 Explosion unlikely Qty low

c) 100 mm liquid line rupture (100%) (from Bullet suction @ 6 Kg/ cm2)

100 260.2 2/ F 260.2 58.4/ 9.5 3120 44 82.5 165.3 408.5

d) 100 mm Carousel return line (liquid)

100 8.9 2/ F 8.9 9.8/2.7 44.5 12 Explosion unlikely Qty low

Effect of explosion will spread beyond the boundary wall and will cause off site risk

RECOMMENDATION



JET FIRE (If ignited)

S no.

Scenario Pipe size

Discharge rate

Thermal radiation inside jet

Length Width Damage distances (m)

mm kg/s kW/m2 m m 37.5 kW/m2

12.5 kW/m2

4 kW/m2

DW

CW

DW

CW

DW

CW

a) 150 mm liquid line rupture (100%) 1. from bullet truck under pressure of 12 Kg/ cm2

150 380.4 154.5 205.2 17.7 29.3

15.1

22.1

35.7

238 97.8

b) 100 mm liquid line rupture to carousal

100 8.9 444.9 34.1 2.9 36.3

5.9 38.9

14.2

42.6

26.9

c) 100 mm vapour line rupture (100%) (from Bullet truck @ 12 KG/ cm2)

100 10.06 259.4 36.2 3.1 38.1

5.5 37.4

13.3

44.3

25.9

d) 100 mm liquid line rupture from bullet suction

100 260.2 184.9 171.2 14.8 114.3

10.8

125.5

28.4

130.5

60.4

e) 100 mm vapour return header under compression

100 14.6 236 43.2 3.7 45.3

5.8 48.4

14.7

52.2

29.2

2. 50mm hose rupture (liquid)

50 7.2 321.5 30.8 2.6 32.9

5.7 35.2

13.3

38.7

25.1

These will cause damage to the onsite facilities Mitigative Measures:- Activation of sprinkler system for cooling down the facilities

RECOMMENDATION



VAPOUR CLOUD EXPLOSION (DELAYED IGNITION considering Release time of 1800 Sec)

RECOMMENDATION

1. Periodic cleaning of filter element to reduce probability of rupture line due to

blockage of filter.

2. Over filling of cylinder due to reverse flow from the bullet can lead to rupture

of cylinder which are disastrous. Hence NRV in between evacuation unit and

tank to recommended.

RECOMMENDATION



9.2 FIRE FIGHTING FACILITY

Details of Fire fighting arrangements within the factory and similar additional

services that can be obtained at a short notice are as under:

ITEM DESCRIPTION. Nos. Remarks Fire Water Tanks 1x2700 KL +

1 X 2700 KL

Fire Engines 3 x 616 kL/hr Fire Extinguisher -DCP Type-75 kg 04 -DCP Type-50 kg NIL -DCP Type-10 kg 65 -CO2 Type-4.5 kg 10 -CO2 Type-2 kg NIL Dry Chemical Powder (DCP) 550kg spare Foam (AFFF) NA Foam compound Trolly-250 ltrs NA Foam compound stalls (at vulnerable points) NA Water Sprinkler for MS Tank NA Sand Buckets 8 Double Headed Water Hydrants 25 Single Headed Water Hydrants 5 Water Monitors 16 Fire Hose Reels including spares 43 Fire Hose Boxes 13 Jet Nozzles including Spares 17 Foam cum water Nozzles(FB 10X) NA FB 5X Nozzle NA Fog Nozzle 4 Triple Purpose Nozzles (Diffuser) 3 Safety Shoes 27 Safety Helmets 30 Safety Belts 5 Flame Proof Torch 2 Breathing Apparatus 1 Fire Proximity suit, Boot , Helmet, Gloves 1 Water Jel Blanket 2 Electric Siren (2 Km) 1 Hand Operated Siren 6 Public Addressing System 1 First Aid Boxes 4 Stretcher 2 Wind Socks 3 Electrical Gloves 2

RECOMMENDATION



FIRE PROTECTION FACILITIES

Fire Fighting facility at LPG Bottling Plant, Durgapur has been designed

to cover all hazardous areas in the Plant. The system comprises of:

i) Fire Water Pump House

ii) Hydrant and Water Monitor Network

iii) Medium Velocity Sprinkler System (MVSS)

FIRE WATER PUMP HOUSE

A water pumping arrangement has been provided exclusively for fire fighting

purpose. This arrangement keeps all water outlets (monitors, hydrants and

deluge valves) pressurized at 7 kg/cm2 and fire pumps are designed to start

automatically on sensing any drop in pressure below desired level.

Three Nos. diesel driven (Two Working and one Standby ) of 616KL/Hr

Capacity fire water pump and Two Nos. electric driven ( 1Nos. Working

and One Standby) of 10Kl/Hr Jockey Pump have been installed.

All the pumps are centrifugal type. The first pump is preset to start when

the line pressure drops to 6.0 kg/cm2. The second pump starts at 5.5

kg/cm2 , Jockey Pump which has been provided to maintain line pressure,

starts at 7 kg/cm2 and stop at 9 kg/cm2. Other fire engines are stand by.

All the pumps are connected to ring main which is further connected to

various monitors, hydrants and deluge valves.

All diesel driven pumps are controlled by separate control panels,

automatic engine- starting is done through the panel connected to

pressure switch in delivery mains. Engine control panel gives audio visual

alarm to indicate fault in any operating area of engine.

Arrangement has been made for self priming of all the pumps because of

aboveground water tank facility.

RECOMMENDATION



The system uses compressed air for fire detection in hazardous areas,

Supply of this air is from two air compressors provided inside the F/W

pump house.

HYDRANT & WATER MONITORING NETWORK

Fire hydrant & monitors network has been designed to cover entire plant

area & T/L Parking area. The system consists of following:

Double headed Hydrant 25 Nos.

Single headed Hydrant 5 Nos

Water Monitors 16 Nos.

DELUGE VALVE / MEDIUM VELOCITY SPRINKLER SYSTEM

Total 12 nos. of deluge valves have been designed to cover the

following areas

Position No

Storage Vessels 3 1

Filled Shed 1

Filling Shed 5

PT shed 1

Tank lorry gantry 1

LPG Pump house 1

System operation in all above areas is automatic. It uses compressed air

networks for fire detection. Quartzoid bulb type detectors are fixed at fire

sensitive positions on the air network in the hazardous area. These bulbs are

heat sensitive and burst at preset temperature (79° C). Bulb breakage causes air

pressure in the network to drop very rapidly.

RECOMMENDATION



Water spray networks in these hazards are connected to mains through control

valves, automatic in operation, named deluge valves. These deluge valves

operate when the air pressure falls below 0.7 kg/cm2

SOURCE OF WATER : 2 X2700 KL = 5400 KL

Two Above Ground Tanks have been provided for fire fighting, which is located

outside the licensed area of plant.

Material Safety Data Sheet of LPG

1. Chemical Identification

Chemical Name : LPG Synonyms : Liquefied Petroleum Gas. Chemical classification : Flammable Gas - Category 1, Gases under Pressure - liquefied gas, Carcinogenicity - Category 1B, Mutagen city - Category 1B Specific Target Organ Toxcity (Single Exposure) - Category 3 Trade name : LPG U.N.No. : 1203 Formula : Mixture MAINLY Propane & Butane, Component C.A.S No. Weight Propane (C3 H8) 74-98-6 60-90% Butane (C4 H10) 106-97-8 10-30% Propane Propylene 115-07-1 1-5% Isobutene (C4 H10) 75-28-5 1-5% 1,3- Butadiene (C4 H6) 106-99-0 0-02% Shipping name : Liquified Petroleum gas. Regulated identification : LPG. Hazardous waste ID No. : NA. Hazchem No. : Class2.1

Hazardous Ingredients:-

Hazardous Approximate C.A.S. No. LD 50/LC 50 Exposures Ingredients. Concentration(%) specify species Limits. & Route.

a) Butane 50-60 106-97-8 Not available/inh 4hrs 1000 lpm.(OEL) & 658 g/m3. 1000 lpm(TLV1)

b) Ethane <5 74-84-0 Not available. 1000 lpm(TLV1) c) Propane 40-50 74-98-6 Not available 1000 lpm.

(OEL,TLV1) [ OEL= 8 hr Alberta Occupational Exposure Limit ] [ TLV = Threshold Limit Value ( 8 hrs) ] 1 As Aliphatic Hydrocarbon Gases

2. Physical & Chemical data

Physical state Liquefied Gas Boiling Range / points (-)270c Melting / freezing points (-) 170OC to (-) 187Oc Appearance & Odour Colorless, Odorless ( or may have

Mercaptan odour) Vapour Pressure(KPA) 1100 @ 200

C Vapour Density (Air-1) 1.6 - 2.0 Solubility in water Negligible Specific Gravity water 0.53 PH Not applicable. Evaporation rate Not available. Percent Volatiles, by volume 100 Odour Threshold (PPM) Range from 2500 to 5000. Coefficient of water / Oil Distribution <0.1

Initial Boiling point & range -0.50c (31.1F) at 1,013.25 hPa Relative density 0.56 at 150c

3. Fire and Explosion Hazards Data: Appearance Flammability Yes LEL by volume 1.8% to 5.3% UEL by volume 8.5% to 15% Flash Point (-)560c to (-)600c Auto ignition 4100c-5400c TDG Flammability classification Class 2.1 Sensitivity to impact Na. Sensitivity to Static discharge Yes, May ignite Means of extinction Foam, CO2, dry chemical Powder, Explosive

accumulations can build up in areas of poor ventilation.

Special Procedure Use water spray to cool fire exposed containers and disperse Gas if Leak has not ignited. If safe To do, cut off fuel and allow flame to burn out.

Hazardous Ploymerisation :

Combustible Liquid : Yes Explosive material : Yes Corrosive material : No Flammable material : Yes Oxidizer : NA Other : NA Pyrophoric material : NA Organic peroxide : NA

4. Reactivity Data

Chemical stability : Stable Condition : Not applicable Incompatibility with other material : Chlorine and other strong oxidizing agents. Reactivity : Yes Conditions : heat, strong sunlight Hazardous Reaction Product : On fire it will liberate some amount carbon monoxide, and Carbon-di-oxide.

5. Health Hazards Data

Routes of Entry : Inhalation , eye contact. Effects of Exposure symptoms : Inhalation can cause head ache, disorientation, dizziness

drossiness and possibly unconsciousness. Evidence exists that butane and propane can cause these effects at concentrations for below those require for oxygen deficiency, for example 10% LEL and above. As concentration increases, oxygen deficiency and asphyxiation may occur. Rapidly expanding gas are vaporized liquid may cause frostbite to skin and eyes.

Emergency Treatment : in case of contact with Skin flush with fresh with fresh water ,

remove containment clothing, in case of excessive inhalation move the victim to fresh air, obtain medical assistance.

Sensitization to Product : No Exposure limit of Product : 1000 lpm(OEL,TLV) Irritancy : Not available. Synergistic materials : None reported. Chronic exposure : Weakness, coughing, labored breathing, headache confusion

nausea/vomiting convulsions heart rate and pulse variations coma respiratory failure.

NFPA Hazards Health Flammability Instability Special Signals 2 4 0 none HMIS ratings Health Flammability physical hazards 1 4 2

6. Preventive measures: Personal Protective equipment : use Positive pressure self contained breathing apparatus

Or supplied air breathing apparatus when entering areas where high concentration may be presents.

a) Gloves: Insulated gloves. b) Respiratory Protection: SCBA ar SABA. c) Eye: splash goggles and face shield if SCBA or SABA not warn.

Handling and storage Precautions : Aroid contact with liquid cooled equipment, Avoid inhalation, avoid sparking condition store in a cool, dry, well ventilated area away from heat, strong sunlight and ignition source.

Keep away from fire, sparks & heated surfaces no smoking near

areas where material is stared or handled. The product should only be stored and handled in areas with intrinsically safe electrical classification.

7. Emergency and First aid measures:

Suitable Fire Extinguishing media : Foam, dry chemical powder, co2, containers which are not cooled with water spray

Extinguishing media to avoid : water Caution about specific danger in case of : Danger of violent reaction or explosion, vapors Fire and fire fighting procedures may travel considerable distances and cause

subsequent ignition. Vapors are heavier than air, may cumulate along the round in enclosed spaces – danger of explosion when burning; it emits carbon monoxide & CO2 and irritant fumes.

Fire Special procedures : Shut off leak, if safe to do so,. Keep non –involved

people away from spill site. Issue warning “ FLAMMABLE” . Eliminate all sources of ignition.

Unusual Hazards : Vapor heavier than Air it will spread along the the ground and collect in sewer. Exposure First Aid measures : Skin contact ; in freeze burn occurs, gently Bathe affected area in warm water (38-43)0C. Do not rub get medical attention Eye : Immediately flash with large amounts of Luke warm water for 15 minutes, lifting upper & lower lids at intervals. Seek medical attention If irritation persists.

Inhalation: Remove to fresh air, give oxygen, artificial respiration or CPR needed seek medical attention Ingestion : Usually no effect by this Route

Antidotes/Dosages : NA

Spills Steps to be taken : Shut off leak , if safe to do so, Keep non – Involved people away from spillage site.

Eliminate all sources of ignition. Prevent spill entering in to sewers, for Major spillage contact emergency services.

Waste disposal Method : NA

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