QUANTITATIVE RISK ASSESSMENT (QRA) REPORT INDIAN OIL CORPORATION LIMITED

Transcription

1 QUANTITATIVE RISK ASSESSMENT (QRA) REPORT for LPG MOUNDED STORAGE of INDIAN OIL CORPORATION LIMITED at KONDAPALLI, ANDHRA PRADESH by VIMTA LABS LIMITED, HYDERABAD for ULTRATECH ENVIRONMENTAL CONSULTANCY AND LABORATORIES THANE REVISION 0 SEPTEMBER 2015 Page i

2 CONTENTS Chapter Description Page No. 1. INTRODUCTION 3 2. FACILITY DESCRIPTION 4 3. SCOPE, OBJECTIVE & METHODOLOGY 8 4. QUANTITATIVE RISK ANALYSIS CONCLUSIONS & RECOMMENDATIONS 33 ANNEXURE 1: PLANT LAYOUT DIAGRAM Page ii

3 ABBREVIATIONS ALARP BLEVE COMAH DNV EIV IOCL ISIR kg kw/m2 LPG LSIR MoEF MoP&NG MT OGP OISD psig QRA ROV SH&E UK-HSE VCE As Low As Reasonably Practicable Boiling Liquid Expanding Vapour Explosion Control of Major Accident Hazards Det Norske Veritas Emergency isolation valve Indian Oil Corporation Limited Individual-specific individual risk Kilogramme Kilowatt per square metre Liquefied Petroleum Gas Location-specific individual risk Ministry of Environment & Forests (Government of India) Ministry of Petroleum & Natural Gas (Government of India) Metric Tonne International Oil & Gas Producers Association Oil Industry Safety Directorate Pounds per square inch gauge Quantitative Risk Assessment Remote operated valve Safety, Health & Environment United Kingdom Health & safety Executive Vapour cloud explosion Page iii

4 1. INTRODUCTION Indian Oil Corporation Limited (IOCL) is a Government of India Enterprise with a Navratna Status, and a Fortune 500 and Forbes 2000 company. Incorporated as Indian Oil Corporation Ltd. on 1st September, 1964 Indian Oil and its subsidiaries account for approximately 48% petroleum products market share, 34% national refining capacity and 71% downstream sector pipelines capacity in India. It is India s flagship national oil company and downstream petroleum major thus being India s largest commercial enterprise. As the flagship national oil company in the downstream sector, Indian Oil reaches precious petroleum products to millions of people every day through a countrywide network of about 35,000 sales points. They are backed for supplies by 167 bulk storage terminals and depots, 101 aviation fuel stations and 89 Indane (LPG) bottling plants. IOCL plan to expand the LPG storage capacity in their existing LPG Bottling Plant at near Vijayawada in Andhra Pradesh by installing three mounded LPG bullets each with 600 MT capacity i e 3x600 MT. Being an organization with commitment to high standards of safety, health and environmental protection, IOCL wish to ensure that all hazards and risks due to the proposed additional mounded LPG storage in their LPG Bottling Plant at are properly identified and necessary risk reduction measures are implemented. Accordingly, IOCL invited e Tender for conducting EIA and RA from NABET accredited Consultants and awarded the Study to M/s UltraTech Environmental Consultancy & Laboratory, Thane (UT). UT has retained the engaged M/s services of Vimta Labs Limited, Hyderabad to carry out Quantitative Risk Assessment (QRA) Study for the proposed additional LPG storage in the LPG Bottling Plant at. UltraTech Environmental Consultancy and Laboratory

5 2. SCOPE, OBJECTIVE & METHODOLOGY Scope of work The scope of work of this study covers the Quantitative Risk Assessment (QRA) for the proposed mounded LPG storage installation of IOCL at in Andhra Pradesh Objective of the Study The objectives of this study are as follows: Identifying the potential failure scenarios for release of flammable/ toxic material in the LPG storage installation. Carrying out consequence analysis for significant accident scenarios. Carrying out for Quantitative Risk Analysis Estimating the individual risk and societal risk due to the installation. Assessing the risk with respect to the risk tolerance criteria Identifying risk reduction measures wherever warranted to ensure that the risk is as low as reasonably practicable. Methodology Risk arises from hazards. Risk is defined as the product of severity of consequence and likelihood of occurrence. Risk may be to people, environment, assets or business reputation. This study is specifically concerned with risk of serious injury or fatality to people. The flow diagram of QRA is shown in Figure 2.1. The following steps are involved in quantitative risk assessment (QRA): Study of the plant facilities and systems. Identification of the hazards. Enumeration of the failure scenarios. Estimation of the consequences for the selected failure incidents. Risk analysis taking into account the failure frequency, extent of consequences and exposure of people to the hazards. Risk assessment to compare the calculated risk with risk tolerability criteria and review the risk management system to ensure that the risk is As Low As Reasonably Practicable (ALARP) UltraTech Environmental Consultancy and Laboratory

6 Figure 2.1 : Flow diagram of quantitative risk assessment (QRA) Consequence Analysis Consequence analysis for the selected failure scenarios is carried out using DNV Phast software. Consequence analysis provides results for the following: Dispersion of toxic clouds to defined concentrations Heat radiation intensity due to jet fire and pool fire Explosion overpressure The renowned DNV Phast software package is used worldwide for consequence modelling and quantitative risk analysis. Phast is based on Unified Dispersion Modelling to calculate the results of the release of material into the atmosphere. It can model both heavy gas dispersion and buoyant dispersion of lighter-than-air gases. Phast has extensive material database and provides for definition of mixtures Quantitative Risk Analysis (QRA) Page 6 of 38

7 The quantitative risk analysis is carried out using the renowned software package PHAST Risk Micro (also known as SAFETI Micro) version 6.6 developed and marketed by Det Norske Veritas (DNV) of Norway. The following input data are required for the risk calculation: Process data for release scenarios (material, inventory, pressure, temperature, type of release, leak size, location, etc.) Estimated frequency of each failure case Distribution of people in the plant/ adjoining area during the day and night time. Distribution of wind speed and direction (wind rose data). Ignition sources The failure frequencies for different types of equipment are estimated using generic failure rate databases published by organizations such as International Oil & Gas Producers Association (OGP). OGP Report No Process Release Frequencies for equipment & piping OGP Report No Storage Incident Frequencies For objective and comprehensive risk analysis, whole range of leak sizes is considered in each section containing large inventory of hazardous material Small leak (5 mm diameter) Medium leak (25 mm diameter) Large leak (100 mm diameter) Full bore leak. Extract of generic failure rates for equipment items relevant to this study from OGP database publication is shown in Table 2.1. Page 7 of 38

8 Table 2.2 : Generic Failure Rate Data for Equipment Items Leak size Equipment Item 5 mm 25 mm 100 mm 2" Pipe 1.80E E " Pipe 8.50E E E-07 2" Flange 7.60E E " Flange 1.10E E E-06 2" Valve (Manual) 7.70E E " Valve (Manual) 1.20E E E-06 2" Valve (Actuated) 7.30E E " Valve (Actuated) 6.60E E E-06 Instrument Connection 6.80E E-05 0 Pressure Vessel 2.00E E E-05 Centrifugal Pump 1.00E E E-05 Reciprocating Pump 1.20E E E-04 Reciprocating Compressor 8.00E E E-04 Note: Failure rate notation: 1.0E-05 per year means 1.0 x 10-5 per year The results of quantitative risk analysis are commonly represented by the following parameters: Individual Risk Societal Risk Individual risk is the risk that an individual remaining at a particular spot would face from the plant facility. The calculation of individual risk at a geographical location in and around a plant assumes that the contributions of all incident outcome cases are additive. Thus, the total individual risk at each point is equal to the sum of the individual risks, at that point, of all incident outcome cases associated with the plant. The individual risk value is a frequency of fatality, usually chances per million per year, and it is displayed as a two-dimensional plot over a locality plan as contours of equal risk in the form of iso-risk contours as shown in the following Figure 2.2. Page 8 of 38

9 Iso-Risk Contours on Site Plan (Typical) Figure 2.2: Risk tolerability criteria For the purpose of effective risk assessment, it is necessary to have established criteria for tolerable risk. The risk tolerability criteria defined by UK Health & Safety Executive (UK- HSE) are normally used for risk assessment in the absence of specific guidelines by Indian authorities. UK-HSE has, in the publications Reducing Risk and Protecting People and Guidance on ALARP decisions in control of major accident hazards (COMAH) enunciated the tolerability criteria for individual risk. The guidance on QRA also can be taken from MoEF, Gov. of India from its publication Technical EIA Guidance Manual for Offshore and Onshore Oil and Gas Exploration Development and Production, September and Bureau of Indian Standards Hazard Identification and Risk Analysis (IS 15656:2006). An individual risk of death of one in a million (1 x 10-6 ) per annum for both workers and the public corresponds to a very low level of risk and should be used as a guideline for the boundary between the risk acceptable and ALARP regions. An individual risk of death of one in a thousand (1 x 10-3 ) per annum should on its own represent the dividing line between what could be just tolerable for any substantial category of workers for any large part of a working life, and what is unacceptable. For members of the public who have a risk imposed on them in the wider interest of society this limit is judged to be an order of magnitude lower, at 1 in 10,000 (1 x 10-4 ) per annum. Page 9 of 38

10 The upper limit of tolerable risk to public, 1 x 10-4 per year is in the range of risk due to transport accidents. The upper limit of acceptable risk, 1 x 10-6 per year, is in the range of risk due to natural hazard such as lightning. The tolerability criteria for individual risk are shown in Figure 2.3. Figure 2.2 : Individual Risk Criteria Page 10 of 38

11 Societal Risk (or Group Risk) Criteria Societal Risk parameter considers the number of people who might be affected by hazardous incidents. Societal risk is represented as an F-N (frequency-number) curve, which is a logarithmic plot of cumulative frequency (F) at which events with N or more fatalities may occur, against N. Societal risk criteria indicate reduced tolerance to events involving multiple fatalities. For example a hazard may have an acceptable level of risk for one fatality, but may be at an unacceptable level for 10 fatalities. The tolerability criteria for societal risk as defined by UK-HSE are shown in the following Figure 2.4 below. Figure 2.3 : Societal Risk Criteria Risk Assessment Based on the results of QRA, necessary measures to reduce the risk to ALARP are to be formulated. For this purpose Phast Risk software provides the information regarding risk contribution from each leak scenario modelled. Page 11 of 38

12 3. FACILITIES DESCRIPTION 3.1 IOCL LPG Bottling Plant, Vijayawada LPG Plant was commissioned in the year 1990 with a total Area of 37 Acres. The plant is principally engaged in bottling of LPG. This plant is located about 3 kms from Railway station near Vijayawada in Andhra Pradesh. It is situated in an industrial area covered by major industries like HPCL, BPCL, GAIL, VTPS, LANCO and other industries. Map indicating location of the plant is shown in the Figure below. Figure: Site Location Map IOCL LPG Bottling Plant The layout drawing of IOCL LPG Plant is enclosed in Annexure 1. UltraTech Environmental Consultancy and Laboratory

13 3.2 Description of Facilities IOCL LPG Bottling Plant at consists of the following systems: Receipt of LPG from pipeline Storage of LPG in bullets/sphere. Receiving of empty LPG cylinders Filling of LPG into cylinders Dispatch of filled cylinders Filling of LPG in TTs to other plants / unloading of LPG from TTs. Receipt of LPG from pipeline: Liquefied Petroleum Gas (LPG) from IOCL Visakhapatnam Refinery is received through VSPL pipe line of M/s GAIL. The LPG from pipeline is transferred to storage vessels. About 450 MT of LPG is received daily. LPG Storage The existing facility contains three above-ground bullets of 150 MT capacity and three mounded bullets of 300 MT capacity for storage of LPG. The Storage vessels have been provided with all necessary fittings, for filling, emptying, vapour pressurization, draining facilities and measuring devices like pressure gauges temperature gauges, level indicators, High level alarm, safety relief valves etc. It is proposed to install three additional mounded bullets of 600 MT capacity. S. No. Product Vessel Capacity (MT) Existing Facility 1 LPG Mounded bullets 3x300 = 900 MT 2 LPG Above ground bullets 3x150 = 450MT Proposed Additional Facility 3 LPG Mounded bullets 3x600 = 1800 MT Total 3150 MT Page 13 of 38

14 Receipt of Empty LPG Cylinders Four Telescopic type unloading bays are provided for unloading of empty cylinders received in trucks at plant. All necessary inspections are carried out after unloading at telescopic conveyor before going for filling. The segregated cylinders are stacked separately and the same undergoes testing/repair. Filling of LPG in cylinders Two each with 24 point electronic filling machines and cylinder conveyor have been installed in filling shed for filling of 14.2 kg and 19 kg cylinders. Besides the above this shed also have electronic check scales for weight checking filled cylinders, weight correction unit machines, Automatic valve testing machines, test bath for checking any leakage from cylinder bung and body. Hot air sealing machine for sealing of cylinders prior to despatch and SQC machine for quality checks of cylinders facilities are there in the filling shed. Processed cylinders directly go to loading bays and failed cylinders during testing go to repair/servicing. Despatch of Filled Cylinders After passing of all tests, the filled cylinders are laded in Cylinder trucks by using four Telescopic type loading bays. Tank Lorry Filling Shed A four bay Tank Lorry Decantation/Filling Shed (TLD) has been provided to load LPG from Storage Vessels to Tank Trucks (or) to load LPG from Storage Vessels to Tank Trucks. LPG Pumps and Compressor House Two vertical can type pumps and one centrifugal pump have been installed to pump liquid LPG from storage vessels to carousel. These pumps have been provided with pop-action valves on discharge lines and are coupled to flame proof motors. Three LPG vapour compressors each coupled to a flame-proof motor have been installed for loading/unloading of LPG based differential pressure mechanism. The maximum discharge pressure of these compressors is 11.5 kg/cm 2 (gauge). Page 14 of 38

15 LPG Pumps LPG Pump Capacity (M 3 /Hr) Pump Type Motor Capacity (KW) Year in Service 48 Horizontal Vertical Vertical Fire Protection & Safety Measures Purpose (Bottling/ TT Loading) Cylinder Filling & bullets loading Cylinder Filling & bullets loading Cylinder Filling & bullets loading Size of Suction Pipe (inch) Size of Discharge Pipe (inch) Storage and handling of LPG involves the following hazards: Fire hazard due to ignition of leaking LPG liquid/ vapour Explosion due to delayed ignition of vapour cloud in flammable range formed by large quantity of LPG mixed with air Cold burn due to contact with flashing liquid LPG at very low temperature Fire protection measures provided in the LPG installation include the following: Fire water system Fire water storage tanks 3 Nos. each 2500 KL capacity Fire water pumps with diesel engine drives - 5 Nos. each 410 M 3 /hr capacity Fire water jockey pumps with motor drive - 2 Nos. each 288 M 3 /hr capacity Fire water distribution network Fire hydrants 44 Nos. Monitors 25 Nos. Water spray systems with deluge valves 13 Nos. LPG received in road tankers or GAIL pipeline is odorized with ethyl mercaptan to alert the people in the area in case of any leaks. Gas detectors are provided in areas around bullets, pumps & tanker loading stations. Ignition sources are strictly controlled by the following measures: Use of flame-proof electrical equipment & fittings Strict implementation of No Smoking rule Page 15 of 38

16 The LPG installation and fire protection measures conform to relevant OISD standards. Page 16 of 38

17 4. QUANTITATIVE RISK ANALYSIS Input Data for QRA S.No. The failure scenarios and the relevant input data for QRA of IOCL LPG bottling plant at are shown in Table 4.1. Description Table 4.1 : Failure scenarios and the relevant input data Material & Phase Temp. (C) Mounded LPG Bullets (Existing & Proposed) 1 LPG Mounded Bullet Liquid Inlet Line 2 LPG Mounded Bullet Liquid Outlet Line 3 LPG Mounded Bullet Vapour Line Above-Ground LPG Bullets (Existing) 4 LPG Above-ground Bullet Liquid Inlet Line 5 LPG Above-ground Bullet Liquid Outlet Line 6 LPG Above-ground Bullet Vapour Line Pressure (kg/cm 2 g) Leak Size (mm) Leak Frequency (per year) LPG Liquid E E E-05 LPG Liquid Liq. Head 5 3.0E E E-05 LPG Vapour E E E-05 LPG Liquid E E E-05 LPG Vapour Liq. Head 5 3.0E E E-05 LPG Vapour E E E-05 7 LPG Above-ground Bullet Failure LPG Liquid Rupture 1.0E-06 LPG Transfer Pumps 8 LPG Transfer Pump LPG Liquid E E E-05 LPG Compressor 9 LPG Compressor LPG Vapour E E E-04 LPG Road Tanker & Unloading Arm 10 LPG Tanker & LPG Liquid E-05 Unloading Arm E-05 Note: Failure rate 1.0E-05 per year means 1.0 x 10-5 per year Page 17 of 38

18 Population Data Plant operations are carried out only during day time in general shift. The distribution of personnel in the IOCL LPG bottling plant is shown in Table 4.2. Table 4.2 : Distribution of People in LPG Bottling Plant, S.No Responsibility 1 st shift 2 nd shift 3 rd shift General shift Total 1 Officers 1 2 1* Employees * Contract workers PMCC contract 4 workers Loading unloading 5 contract workers Security Total shift wise Ignition Sources Ignition sources are strictly controlled in the LPG bottling plant area. All electrical equipment and fittings are flame-proof type. No vehicle is allowed inside the premises without approved spark arrestor in the engine exhaust. The following sources of ignition are considered in the risk analysis. Transformer MCC/ Electrical Room Canteen Weather parameters Weather parameters play a significant role in dispersion analysis. The notable parameters for assessing the atmosphere are wind speed, atmospheric stability, ambient temperature, humidity and topographic parameters. Atmospheric stability represents the vertical turbulence in the air due to temperature differentials caused by heating of the earth by solar radiation. Atmospheric stability effects are represented through Pasquill parameters as follows shown in Table 4.3. Page 18 of 38

19 Stability Class A B C D E F Table 4.3 : Pasquill parameters Atmospheric Condition Very Unstable Unstable Slightly Unstable Neutral Stable Very Stable The relationship between wind speed and atmospheric stability is shown in Table 4.4. Table 4.4 : Relationship between wind speed and atmospheric stability Wind speed Day-Time: Solar Radiation Night-Time Cloud Cover (m/s) Strong Medium Slight Thin <3/8 Medium >3/8 Overcast >4/5 <2 A A-B B - - D 2-3 A-B B C E F D 3-5 B B-C C D E D 5-6 C C-D D D D D >6 C D D D D D Category D (neutral) is the most probable at sites in moderate climates and may occur for up to 80 % of the time at relevant sites. Stability F (very stable) represents the most adverse condition in which dispersion extends over longer distances horizontally. Normally, stability F occurs for short periods in the year, mainly during winter nights. Weather data (monthly average maximum & minimum temperature and rain fall) for Vijayawada are indicated in Figure 4.1. Figure 4.1 : Weather Data for Vijayawada Month Temperature, 0 C Temperature 0 C Temperature 0 C Rainfall, mm Normal Max. Min. January February March April May June July August September October November December Page 19 of 38

20 Wind rose diagram for distribution of wind direction and wind speed is shown in Figure 4.2. Figure 4.2 : Wind Rose Diagram for Vijayawada N 6.5% NE 13.4% 6.6% NW 9.5% SW 0% WNW 0% WSW 0% NNW 18.9% W C-10.5% SSE 0% 0% SSW NNE 0% 10.5% S ENE 0% ESE 0% SE 7.3% E 16.8% ANNUAL 08:30 hr 8.1% NW 0% WNW 0% WSW 6.0% SW 0% NNW N 4.6% 12.1% W C-5.4% SSE 0% 0% SSW NNE 0% NE 4.2% ENE 0% ESE 0% E 13.2% 21.2% S ANNUAL 17:30 hr SE 25.2% SCALE 5% SPEED CALM >19 Km/hr Page 20 of 38

21 The following representative combinations of weather parameters for the site are considered in this study. Table 4.5 : Weather Parameters for Risk Analysis Description #1 #2 #3 Temperature (C) Wind speed (m/s) Atmospheric Stability E D D Ignition Sources In case of gas leakage, ignition of the gas will result in damage due to fire or explosion. Therefore, identification of ignition sources is important in risk analysis. The electrical and instrument items in the installation conform to the electrical hazardous area classification. Flame-proof electrical items will be installed in the classified areas, and these will not be ignition sources. Vehicles inside the plant are provided with spark arrestors in the exhaust. There is no overhead HT electrical line in the plant area which may act as ignition source. The following ignition sources are identified for input to Phast Risk software. Vehicles moving in the road Electrical switchgear room and transformer area Diesel generator. Hazardous Properties of LPG The flammable consequences of LPG release from equipment are mainly the following: Jet fire/ pool fire/ flash fire Vapour cloud explosion Properties of LPG relevant to this QRA study are as follows. Composition: Normal Boiling Point: Lower Flammable Limit (LFL): Upper Flammable Limit (UFL): Auto ignition temperature: Mixture of Propane and Butane (-)6 C 1.8 % (vol) 9.5 % (vol) C (approx.) LPG is stored as liquid under pressure. LPG vapours are heavier than air and disperse close to ground level. LPG odorized with ethyl mercaptan is received in the plant so as to provide warning in case of leakage. Page 21 of 38

22 Consequence Analysis Jet/ Pool Fire Radiation The effect from jet fire and pool fire is thermal radiation intensity on the receptor surface as shown in Table 4.6. Table 4.6 : Damage Effects due to Jet/ Pool Fire Radiation Heat Observed Effect Radiation Intensity (kw/m 2 ) 4 Sufficient to cause pain to personnel if unable to reach cover within 20 seconds; however blistering of the skin (second-degree burn) is likely; 0% lethality Minimum energy required for piloted ignition of wood, melting of plastic tubing Sufficient to cause damage to process equipment. Thermal radiation intensity exceeding 37.5 kw/m² may cause escalation due to damage of other equipment. Thermal radiation intensity exceeding 12.5 kw/m² may cause ignition of combustibles on buildings and impairment of escape route. Thermal radiation intensity exceeding 4 kw/m² may cause burn injury on personnel injury Vapour cloud explosion (VCE) When a large quantity of flammable vapour or gas is released, mixes with air to produce sufficient mass in the flammable range and is then ignited, the result is a vapour cloud explosion (VCE). In the LPG installation large release of LPG from equipment or piping has potential for vapour cloud explosion. The damage effect of vapour cloud explosion is due to overpressure as shown in Table 4.7. Table 4.7 : VCE over pressure limit and Observed Effect Over-pressure Effect bar(g) psig Observed Damage Safe distance (probability 0.95 of no serious damage below this value); projectile limit; some damage to house ceilings; 10% of window glass broken Repairable damage; partial demolition of houses; steel frame of clad building slightly distorted Partial collapse of walls of houses Heavy machines in industrial buildings suffered little damage; steel frame building distorted and pulled away from foundations. Page 22 of 38

23 Page 23 of 38

24 Consequence Analysis Results for LPG Storage & Handling System Results of consequence analysis by Phast software for significant leak scenarios relevant to the LPG bottling plant are shown in the Table 4.8. Graphical results plotted on the site map drawings are shown in Figure 4.3 to Table 4.8 : Results of Consequence Analysis for LPG Bottling Plant S.No. Description Parameter 1. LPG Bullet Liquid Line Leak Pool Fire Radiation Intensity Downwind Distance (metres) Weather (Wind speed & Stability) 2 m/s; E 3 m/s; D 5 m/s; D 4 kw/m kw/m kw/m VCE Overpressure 0.02 bar LPG Pump Discharge Line Leak Pool Fire Radiation Intensity 0.07 bar bar kw/m kw/m kw/m VCE Overpressure 0.02 bar LPG Vapour Compressor Discharge Line Leak 0.07 bar bar Jet Fire Radiation Intensity 4 kw/m LPG Road Tanker Failure 12.5 kw/m kw/m VCE Overpressure 0.02 bar BLEVE/ Fire Ball Radiation 0.07 bar bar kw/m kw/m kw/m 2 Not reached Not reached Not reached Page 24 of 38

25 (1) New Mounded LPG Bullet Liquid Line Leak Figure 4.3 : New Mounded LPG Bullet Liquid Line Leak - Pool Fire Radiation Intensity UltraTech Environmental Consultancy and Laboratory

26 Figure 4.4 : New Mounded LPG Bullet Liquid Line Leak VCE Overpressure Page 26 of 38

27 (2) LPG Pump Discharge Line Leak Figure 4.5 : LPG Pump Discharge Line Leak - Pool Fire Radiation Intensity Page 27 of 38

28 Figure 4.6 : LPG Pump Discharge Line Leak VCE Overpressure Page 28 of 38

29 (3) LPG Vapour Compressor Discharge Line Leak Figure 4.7 : LPG Compressor Discharge Line Leak Jet Fire Radiation Intensity Page 29 of 38

30 (4) LPG Road Tanker Failure Figure 4.8 : Road Tanker Failure VCE Overpressure Page 30 of 38

31 Figure 4.9 : Road Tanker Failure BLEVE/ Fire Ball Page 31 of 38

32 Review of Consequence Analysis Results for LPG Storage & Handling System Based on the results of consequence analysis, the following observations are made: In case of maximum credible scenario represented by 25 mm leak in liquid and vapour lines connected to mounded LPG bullets, pumps and compressor, the effect distances for pool fire, jet fire and vapour cloud explosion are contained within the plant boundary. In case of worst case scenario such as catastrophic failure of tanker, effect distances for vapour cloud explosion overpressure and fire ball radiation will extend outside plant boundary. However, all necessary measures for prevention of such failures are provided in the IOCL LPG plant system. Mounded LPG bullets are not susceptible to catastrophic failure and BLEVE/ fire ball hazard. UltraTech Environmental Consultancy and Laboratory

33 QRA Results for LPG Storage & Handling The detailed results of QRA for IOCL LPG bottling plant in provided as outputs from Phast Risk software are presented in this section Individual risk The iso-risk contours for LPG bottling plant are shown in Figure Enlarged diagram of iso-risk contours diagram is shown in Figure x 10-6 per year 1 x 10-5 per year Figure 4.10 : Iso-Risk Contours on Plot Plan Page 33 of 38

34 1 x 10-6 per year Figure 4.11 : Iso-Risk Contours (Enlarged Diagram) 1 x 10-5 per year Individual Risk to Public Risk contour of 1 x 10-6 per year is mostly within the plant boundary. Therefore the maximum individual risk to members of the public outside the plant boundary is 1 x 10-6 per year. Individual Risk to Plant Personnel The highest iso-risk contour inside the plant area is 1 x 10-5 per year. Therefore the individual risk at any location in the plant does not exceed 1 x 10-4 per year. By taking risk transect at different locations, it is found that the maximum location-specific individual risk (LSIR) in the plant area is 6 x 10-5 per year. However, any individual person is present in the plant location only for a limited period in a year. The individual-specific individual risk (ISIR) is calculated taking into account the fraction of time the individual stays at the location. Normally the plant personnel work in daily shift of 8hours. Therefore the maximum individual-specific individual risk, ISIR = LSIR x (8/24) per year. = (6 x 10-5 ) x (1/3) per year = 2 x 10-5 per year The maximum value of individual risk to plant personnel in the IOCL LPG storage & bottling plant is 2 x 10-5 per year. Page 34 of 38

35 The values of maximum individual risk to public and plant personnel in IOCL LPG storage & bottling plant in comparison with the risk tolerance criteria are shown in Figure Risk to Personnel Risk to Public 10-3 per year Intolerable Risk 10-4 per year Max. Individual Risk to Personnel: 2 x 10-5 per year 10-6 per year Risk Tolerable if ALARP Acceptable Risk Max. Individual Risk to Public: 1 x 10-6 per year 10-6 per year Figure 4.12 : Max. Individual Risk at IOCL LPG Storage & Bottling Plant, Societal Risk The FN Curves for societal risk due to IOCL LPG storage & bottling plant at is shown in Figure Page 35 of 38

36 Figure 4.13 : Societal Risk due to IOCL LPG Storage & Bottling Plalnt, It is seen that the societal risks due to IOCL LPG storage & bottling plant is in the Acceptable (Negligible) Risk region. Page 36 of 38

37 5. CONCLUSIONS & RECOMMENDATIONS Conclusions The conclusions of QRA study for the proposed mounded LPG storage system at IOCL are as follows. Individual risk to the public is within Acceptable level of 1E-06 per year. Maximum individual risk to personnel working in the LPG storage & bottling plant is 2.0E-05 per year, which is in the lower part of ALARP region. Societal risk due to LPG bottling plant is in Acceptable region. Based on the above results it is concluded that the LPG storage & bottling plant of IOCL at conform to the specified risk tolerance criteria. In case of maximum credible scenario represented by 25 mm leak in liquid and vapour lines connected to mounded LPG bullets, pumps and compressor, the effect distances for pool fire, jet fire and vapour cloud explosion are contained within the plant boundary. In case of worst case scenario such as catastrophic failure of tanker, effect distances for vapour cloud explosion overpressure and fire ball radiation will extend outside plant boundary. However, all necessary measures for prevention of such failures are provided in the IOCL LPG plant system. Mounded LPG bullets are not susceptible to catastrophic failure and BLEVE/ fire ball hazard. IOCL has responsibility to maintain the risk within the ALARP region by ensuring effective safety management system and adopting the best industry practices applicable to operation and maintenance of LPG storage and bottling plant. The LPG storage & bottling plant of IOCL at conforms to the requirements of OISD standards 144, 150 and 158. The proposed addition of LPG storage capacity in the form of mounded bullets represents the industry best practice with regard to safety. Fire protection system has been provided conforming to the requirement of OISD standards. This includes the following: Fire/ gas detectors with alarms Fire water storage and distribution system with hydrants, monitors and sprinklers Remote operated emergency isolation valves, non-return valves and excess flow check valves have been provided as per the requirement of OISD standards. Emergency response/ disaster management plan has been implemented for the existing LPG storage and bottling plant. This will be updated for the proposed additional LPG storage. Page 37 of 38

38 Recommendations The following recommendations are made in order to ensure that the risks at IOCL LPG storage & bottling plant are maintained at low level. 1. Emergency push buttons to close the remote-operated isolation valves (EIVs) and stop LPG pumps/ compressors are also to be provided in the plant area at appropriate locations neat bullets, pumps and tanker loading bays. 2. Raised face flanges with metallic spiral wound gaskets or tongue & groove type flanges should be used in LPG service. 3. Fire water system (hydrants, monitors and sprinklers) are to be extended to cover the new mounded LPG bullets. 4. Gas detectors are to be provided near LPG bullets, pumps, tanker loading bays and compressor. 5. Prevention of ignition The flame-proof electrical equipment should be properly maintained by competent and trained personnel to ensure their integrity. The spark arrestors used for vehicles should be maintained by regular checking. Use of cell phones should not be allowed in the LPG installation. *************** Page 38 of 38