Quantitative Risk Assesment - 06_0160_appendix_d

8/8/2019 Quantitative Risk Assesment - 06_0160_appendix_d

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Quanti tat ive Risk Assessmentprepared by

ModuSpec Austral ia Pty Limited

A p p e n d i x D


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CALTEX REFINERIES (NSW) PTY LTD

Kurnell Refinery

Tank 632

Quantitative Risk Assessment


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Caltex Refineries (NSW) Pty Ltd ModuSpecTank 632 Quantitative Risk Assessment Abstract

Project Title Tank 632 Quantitative Risk Assessment

Client Name Caltex Refineries (NSW) Pty Ltd

Job No. AUS0352.8

Project Manager Lachlan Dreher

Project Analyst (s) Lachlan Dreher, Marian Magbiray, Patrick Walker

Report Author (s) Marian Magbiray, Patrick Walker

ABSTRACT

ModuSpec Australia Pty Ltd was engaged to undertake a quantitative risk assessment toanalyse the risks associated with the installation of the proposed new crude oil tank

(Tank 632).

This report details the results of the individual components of the risk assessment,including the hazard identification, frequency assessment and consequence assessment.

The individual risk was evaluated in terms of risk of fatality and risk of injury. Theseresults were compared with the applicable criteria to determine the acceptability of therisks associated with the proposed installation. In determining the acceptability of the

risks, the impact on the adjacent industrial facilities to the west of the refinery boundarywas assessed, with particular emphasis on the Serenity Cove Development.

Key Words: PETROL, QRA, BUNDFIRE, STOR

ReleaseNo.

Date ofIssue

Reviewed by Approved by Reason for Update

Draft A 19 April 2006 L. Dreher

S. Masterton

L. Dreher Client Review

Draft B 15 June 2006 L. DreherS. Masterton


Draft C 22 June 2006 L. DreherS. Masterton


Draft D 29 June 2006 L. DreherS Masterton



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Caltex Refineries (NSW) Pty Ltd ModuSpecTank 632 Quantitative Risk Assessment Table of Contents

TABLE OF CONTENTS

1. EXECUTIVE SUMMARY .............................................................................5

1.1. Fatality Risk ...........................................................................................51.2. Injury Risk ............................................................................................. 5

2. ACRONYMS & GLOSSARY .........................................................................8

3. INTRODUCTION.....................................................................................10

3.1. Project Scope ....................................................................................... 103.2. Locations ............................................................................................. 10

4. STUDY METHODOLOGY ..........................................................................12

5. RISK CRITERIA......................................................................................14

5.1. Individual Fatality Risk Criteria................................................................ 14

5.2. Individual Injury Risk Criteria.................................................................. 14

6. FACILITY AND OPERATION DESCRIPTION .............................................16

6.1. Facility Description ................................................................................ 166.2. Process Description ............................................................................... 166.3. Meteorological Conditions ....................................................................... 16

7. HAZARD IDENTIFICATION.....................................................................17

7.1. Hazardous Materials .............................................................................. 177.2. Hazardous Scenarios ............................................................................. 17

8. FAILURE FREQUENCY AND EVENT TREE ANALYSIS.................................18


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Caltex Refineries (NSW) Pty Ltd ModuSpecTank 632 Quantitative Risk Assessment Table of Contents

APPENDICES:

APPENDIX A PROJECT ASSUMPTIONS...........................................................A1APPENDIX B HAZARDOUS SCENARIOS AND PROCESS CONDITIONS..............B1APPENDIX C FAILURE FREQUENCY DATA ...................................................... C1APPENDIX D HAZARDOUS SCENARIOS AND FAILURE CONTRIBUTORS ..........D1

APPENDIX E EVENT TREE ANALYSIS ............................................................. E1APPENDIX F CONSEQUENCE LEVEL IMPACT CRITERIA .................................. F1APPENDIX G CONSEQUENCE RESULTS ..........................................................G1


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Caltex Refineries (NSW) Pty Ltd ModuSpecTank 632 Quantitative Risk Assessment Executive Summary

1. EXECUTIVE SUMMARY

Caltex Refineries (NSW) Pty Ltd has proposed the installation of an additional crude oil

storage tank (Tank 632), for the Kurnell Refinery. The proposed location for the tank isin the south crude storage area, immediately to the west of Tank 633. Several industrialfacilities, most notably the Serenity Cove Industrial Facility, are situated to the west ofthe refinery boundary, neighbouring the southern crude tank farm and the proposed

location of Tank 632. Hence, a quantitative risk assessment (QRA) was undertaken toassess the risk impacts associated with the new installation, and to establish whether

these risks comply with the applicable criteria.

The full range of potential hazardous scenarios and consequence events associated withthe installation and operation of the proposed tank was considered in the analysis. Theindividual risk was assessed in terms of risk of fatality and risk of injury to determine the

impact the proposed installation would have on the surrounding area.

1.1. Fatality Risk

The 5 x 10-6 per year risk criterion applied in the assessment was based on the guidelines

for risk acceptance levels to neighbouring commercial developments, as published by theNSW Department of Urban Resources and Planning (DUAP) [1]. The 5 x 10-6 per yearrisk contour is presented in Figure 1.1.

The 5 x 10-6 per year individual risk contour level is confined within the refineryboundary. This risk level represents the limit of acceptability for risk impact on the

neighbouring commercial area of the Serenity Cove Development and therefore with thisrisk level contained within Caltexs site, the risk criterion is satisfied.

A review of the consequence events that contribute to the western region of the 5 x 10

-6

per year individual risk contour indicated that a bund fire associated with the newinstallation constitutes a major contribution to the risk.

The risk assessment was based on whole crude oil service. The modelling of whole crude


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632

633

622

623

N

5 10-6


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632

633

622

623

N

50 10-6


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Caltex Refineries (NSW) Pty Ltd ModuSpecTank 632 Quantitative Risk Assessment Acronyms & Glossary

2. ACRONYMS & GLOSSARY

ACRONYMS

ADG Australian Dangerous Goods

ALARP As low as reasonably practicable

Caltex Caltex Refineries (NSW) Pty Ltd

CDU Crude Distillation Unit

DUAP Department of Urban Affairs and Planning

HUM Hold up massIR Individual risk

ModuSpec ModuSpec Australia Pty Ltd

MV Motorised valve

NSW New South Wales

PHA Preliminary hazard analysis

P&ID Piping and instrumentation diagram

QRA Quantitative risk assessment

GLOSSARY

Acceptance Criteria Defines the level of risk to which an individual is exposed,as either tolerable (negligible risk), intolerable or within

the ALARP region.

Bund An embankment or wall which may form part or all of theperimeter of a compound around a storage tank, intended

to contain any release of liquid.

Consequence This is the severity associated with an event in terms oftoxic doses, fire or explosion etc., i.e. the potential effectsof a hazardous event.

Frequency This is the number of occurrences of an event expressed


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Caltex Refineries (NSW) Pty Ltd ModuSpecTank 632 Quantitative Risk Assessment Acronyms & Glossary

GLOSSARY

Individual Risk Contours As IR (Individual Risk) is calculated at a point, calculatingthe IR at many points allows the plotting of IR contours,

these being lines that indicate constant levels of risk. Mostcommonly used are the 1 chance per million-year contourand the 10 chances per million-year contour.

Isolatable Section A system of pipes or vessels containing the hazardousmaterials that are bounded by specific isolation points.

Isolation Point A point in the process, which can be used to isolate one

part of the process from the rest of the system.Probability The expression for the likelihood of an occurrence of an

event or an event sequence or the likelihood of the

success or failure of an event on test or demand. Bydefinition, probability must be expressed as a numberbetween 0 and 1.

Quantitative RiskAssessment

A risk assessment undertaken by combining quantitativeevaluations of event frequency and consequence.

Risk The combination of frequency and consequences, thechance of an event happening that can cause specificconsequences.

Risk Reduction The process of risk assessment coupled to a systematicconsideration of potential control measures and a

judgement on whether they are reasonably practicable toimplement.


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Caltex Refineries (NSW) Pty Ltd ModuSpecTank 632 Quantitative Risk Assessment Introduction

3. INTRODUCTION

3.1. Project Scope

Caltex Refineries (NSW) Pty Ltd has proposed the installation of an additional crude oilstorage tank, to be designated as Tank 632, for the Kurnell Refinery. A PreliminaryHazard Analysis (PHA) was initially conducted to provide a semi-quantitative assessmentof the risks associated with the proposed new installation and the acceptability of these

risks [2]. The PHA was unable to conclusively demonstrate that the risk impact onto the

adjacent industrial facility complied with the adopted risk acceptance criterion.

The PHA was conducted as a semi-quantitative analysis, based on a series of simplifyingassumptions. In order to draw more definitive conclusions about the acceptability of theoffsite risk exposure, more detailed quantitative analysis was conducted, i.e. aquantitative risk assessment (QRA). The QRA involved the assessment of the likelihood

and consequence for scenarios associated with the process in a quantitative manner,based on data specific to the operation.

3.2. Locations

The proposed storage tank is to be located in the southern crude storage area, adjacentto the refinery's western boundary. The location of the tank and the bunded area within

which it is located was taken from information provided by Caltex [3], which indicatedtank size, tank location and the configuration of the bunded area. These specificationshave been reproduced in Figure 3.1.


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Caltex Refineries (NSW) Pty Ltd ModuSpecTank 632 Quantitative Risk Assessment Introduction


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Caltex Refineries (NSW) Pty Ltd ModuSpecTank 632 Quantitative Risk Assessment Study Methodology

4. STUDY METHODOLOGY

The study methodology followed the standard risk assessment steps outlined below.

Figure 4.1 presents a flow chart of the risk assessment steps followed.

Hazard identification

Hazard identification was carried out by a review of the proposed operations and

materials handled, in order to identify the equipment and pipelines containing potentiallyhazardous materials and to define representative hazardous scenarios.

Frequency assessment

The frequency assessment stage of the analysis involved defining the potential releasesources and subsequently determining the likelihood (frequency) of the various releases.The failure frequencies were determined using failure item counts for each of the failureitems identified and publicly available historical failure rate data. Details of the failurerate values used are provided in Appendix C. Ignition probability data was used toestimate the probability of a release subsequently being ignited.

Consequence assessment

The potential consequences from the hazardous scenarios were determined and theimpact zones modelled using appropriate software tools. Where possible, the effects of

existing mitigation measures at the facility were also taken into account in theconsequence assessment. The primary consequence type was a pool fire following a fuelspill.

Details of these steps are described in the appropriate sections of the report. A numberof assumptions were made during the analysis. Details of the assumptions are presentedin Appendix A.

Risk assessment:

The frequency and consequence assessments were combined to calculate individual riskfor both fatality and injury. The risk results have been presented as contours on a site


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Caltex Refineries (NSW) Pty Ltd ModuSpecTank 632 Quantitative Risk Assessment Study Methodology

HAZARD IDENTIFICATION

FREQUENCY ASSESSMENT

CONSEQUENCE ASSESSMENT

Detailed process

information including

plans, process flow

diagrams and

emergency detection

and shutdown systems

Identification ofHazardous Substance

Identification of

Failure Modes

Definition of Failure Case

Event Tree Analysis

End Event Identification

End Event Frequency

Determination

Failure Rate Data

Component Data

Specific System Data

Ignition Probabilities

Explosion Probabilities

Detection Strategies

Isolation Strategies

Chemical Data- Flammability

- Specific Properties

Meteorological Data

Equipment layout and

release control and

protection systems

Emergency Response

Capabilities

Consequence Modelling

- Fire

- Flammable Vapour Dispersion

Determination of Impact Zones

Select Appropriate

Risk Criteria

Identify Major Risk

Contributors and

propose risk

reduction measures

to achieve acceptable

risk levels


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Caltex Refineries (NSW) Pty Ltd ModuSpecTank 632 Quantitative Risk Assessment Risk Criteria

5. RISK CRITERIA

A comparison of the risk against an appropriate target or criterion is required in order to

assess the acceptability of that risk. The risk criterion applied for this assessment wasobtained from the criteria published by the NSW Department of Urban Affairs andPlanning (DUAP) [1].

5.1. Individual Fatality Risk Criteria

The NSW criteria are based on a principle that if the risk from a potentially hazardous

installation is less than most risks being experienced by the community (e.g. voluntaryrisks, transportation risks), then that risk may be tolerated. This principle is consistent

with the basis of risk criteria adopted by most authorities internationally. The individualrisk criteria are as follows:

Hospitals, schools, child-care facilities and old age housing development shouldnot be exposed to individual fatality risk levels in excess of half in one million per

year (0.5 x 10-6 per year) Residential developments and places of continuous occupancy, such as hotels and

tourist resorts, should not be exposed to individual fatality risk levels in excess of

one in a million per year (1 x 10-6

per year) Commercial developments, including offices, retail centres, warehouses with

showrooms, restaurants and entertainment centres, should not be exposed toindividual fatality risk levels in excess of five in a million per year (5 x 10 -6 peryear)

Sporting complexes and active open space areas should not be exposed toindividual fatality risk levels in excess of ten in a million per year (10 x 10-6 peryear).

These criteria apply to new industry and surrounding land use proposals. In theory, thecriteria should apply to existing facilities, however this may not be possible in practice.For existing facilities, an overall planning approach is necessary. In terms of criteria, thefollowing principles should apply [1]:

The 1 x 10-6 per year individual fatality risk level is an appropriate criterion within


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Caltex Refineries (NSW) Pty Ltd ModuSpecTank 632 Quantitative Risk Assessment Risk Criteria

Exposure to heat flux of greater than 4.7 kW/m2 is considered high enough to trigger the

possibility of injury for persons who are unable to be evacuated or seek shelter. Thisamount of heat radiation would cause injury after an exposure period of 30 seconds.

This criterion is applicable to residential areas. Injury risk criteria for neighbouringcommercial developments or industrial facilities have now been published. The land uses

along the site boundary in the area of interest in this study are commercial andindustrial. Similar to the relationship between individual fatality risk criteria forresidential, commercial and industrial land uses, higher acceptability criteria for injury

risk would be expected for commercial and industrial land uses, as compared to that forresidential areas. On this basis, for neighbouring commercial land uses, injury risk lessthan 250 chances in a million per year would be deemed acceptable.


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Caltex Refineries (NSW) Pty Ltd ModuSpecTank 632 Quantitative Risk Assessment Facility and Operation Description

6. FACILITY AND OPERATION DESCRIPTION

6.1. Facility Description

The location proposed for Tank 632 is the southern crude tank area, directly to the westof the existing Tank 633. There are several light industrial facilities neighbouring thesouthern crude tank area, including the Serenity Cove Development adjacent to theproposed location. The H.C.E Extractions Facility is located to the north of Serenity Cove.

6.2. Process Description

The product to be stored in Tank 632 would be whole crude oil. Tankers transportingcrude oil are unloaded at the Kurnell wharf and the oil is transferred via pipeline to thestorage tanks in the southern crude tank area. The crude oil in the storage tanks istransferred to the refinery Crude Distillation Units (CDU) for further processing. The

inventory of crude oil stored in Tank 632 will cycle up and down in line with the transferof the cargo from the ships and subsequent transfer for processing. Tank 632 would tie-in to the existing crude receiving and process plant suction lines.

The proposed design and operation of Tank 632 has been modelled on the existing Tank633. Therefore, the design and operating parameters associated with Tank 633 havebeen used in the QRA. Tank 633 is a floating roof tank in whole crude oil service.

6.3. Meteorological Conditions

The local meteorological data was taken from the 2001 and 2002 CALMET weather data

files, supplied by Caltex [4]. From this data, the probability of the various atmosphericstability conditions at the site, in addition to the average temperature and wind speed atthese stability classes were determined. These values are presented in Table 6.1. Theoverall average temperature was 18.1C and the average wind speed was 3.4 m/s. Thevalue for the average humidity used in the analysis (57%) was obtained from the nearbyweather station at Sydney Airport [5].


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Caltex Refineries (NSW) Pty Ltd ModuSpecTank 632 Quantitative Risk Assessment Failure Frequency and Event Tree Analysis

8. FAILURE FREQUENCY AND EVENT TREE ANALYSIS

8.1. Failure Frequency

The potential for the release of product is attributed to the potential for the failure of anyitem of equipment within the process.

The hazard identification phase involved the identification of specific isolation points

within the process under consideration. Any items of equipment and fittings located

between these isolation points were therefore assessed as items that could potentially failand cause a release. The frequency assessment step involved the calculation of the

likelihood (ie. frequency) of releases from each of these sources, based on the failurefrequency of the individual items within the isolatable section. The Caltex Kurnell CrudeSystem P&ID, inclusive of the proposed tank, was used to identify these isolation pointsand associated items of equipment and fittings.

The failure frequencies were estimated using generic failure frequency data obtainedfrom industry databases. The failure rate data for different types of failure items are

summarized in Appendix C. These values are dependent on the equipment/pipe sizes.The leak frequency applied for a mixer seal is detailed in Appendix A.

8.2. Equipment Failure Scenarios

The overall failure frequency represents the rate at which an item of equipment or pipewill fail, but provides no indication of the magnitude of the failure. Hence, a distributionof hole sizes was assigned to represent the full range of potential failure scenarios. A

representative selection of four hole sizes was modelled for each scenario.

The guidelines for selecting the sizes were: Select sizes that fall into the following categories:

Small hole up to 10 mmMedium hole 10 mm to 75 mmL h l 75 t 100


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Ignition sources

Consequence mitigation measures.

The event tree analysis includes the following factors: The probability of detection of a release (by personnel, the standard process

control system or via automatic release detection systems) Following detection of a release, the probability that the release can be

successfully isolated The probability of ignition both immediate ignition and delayed ignition.

The data used in the development of the event trees is presented in Appendix E. Anevent tree diagram depicting the frequency and probability values associated with thescenario involving a loss of containment of product from Tank 632 as a result of therupture of the tank is presented in Figure 8.1.


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The Singapore Study provided data taken from three studies covering storage tank

operations in the Netherlands, USA and Scotland, as well as from oil and petrochemicalcompanies operating terminals in Singapore from 1945. The full surface tank firefrequency derived from the USA/Europe and Singapore operations were 2.0 x 10-4 peryear and 9.3 x 10-4 per year respectively.

The LASTFIRE Project involved the largest study to date undertaken to determine the firefrequency for large floating roof storage tanks. It involved data obtained from 16companies, operating 2,420 tanks at 164 sites throughout 36 countries over a survey

period from 1981 to 1996. The study derived a full surface tank fire frequency of1.2 x 10-4 per year.

The frequency considered most applicable for the Kurnell refinery is 1.2 x 10-4 per year,

derived from the LASTFIRE project. This value has been selected because it has beenderived from the widest sample set of events and tank locations. Statistically, this canbe expected to provide a more appropriate representation of the true event frequency.

In addition, both data sources reviewed suggested that there is a correlation between thefrequency of storage tank fires and the number of thunderstorm days experienced in thearea. When compared with Singapore, the number of thunderstorm days experienced in

the Kurnell area is relatively low. This suggests that the expected frequency for a fullsurface tank fire in Singapore should be higher than at Kurnell. The selected frequency is

consistent in this respect, in that it is lower than the value determined solely foroperations in the Singapore area.

8.5. Bund Fire

A bund fire is generated by the ignition of a major release of flammable liquid from apipe or storage tank into a bunded area. The QRA assessed the frequency of a bund firebased on the release of product from a failure of the tanks or associated fittings in

conjunction with the likelihood of ignition. The intervention measures implemented arealso considered in the derivation of the consequence frequency values. The likelihood ofignition is dependent on the release rate of the product.


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these failures is 6.1 x 10-5 per year. This is comparable to the bund fire value

determined by the LASTFIRE Project.

The bund fire frequency calculated as part of the QRA were considered a morereasonable representation of the scenarios at the proposed facility, as they were derivedfrom a specific analysis of the proposed design. Specific design information was used in

the analysis, including equipment parts counts and the proposed failure detection andmitigation measures. This gives an assessment that is more specific to the system underconsideration, rather than a more generic frequency value that may be based on widely

differing systems.


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Caltex Refineries (NSW) Pty Ltd ModuSpecTank 632 Quantitative Risk Assessment Consequence Modelling

9. CONSEQUENCE MODELLING

The consequence scenarios associated with the installation of the proposed Tank 632

were modelled to determine their potential impact on the surrounding area. Themodelling took into account the chemical properties of the product released and themeteorological conditions, where applicable.

The consequences modelled were based on a release of whole crude oil from thefollowing:

Tank 632 or associated fittings Transfer piping or associated fittings.

The Bernoulli equation was used to determine the liquid release rate for the scenariosconsidered. The release rate provides a measure of the magnitude of the spill. For

releases that are bunded, the size of the liquid pool would be contained, thereby limitingthe magnitude of any subsequent pool fire. The effect of bunding has been accounted forin the consequence analysis.

The consequence types that could result from the scenarios under consideration

included: Pool fires Full surface tank fires.

Pool fires result from the ignition of a flammable liquid spill. The heat radiation emitted

by pool fires was modelled using the Mudan & Croce model [11].

The results of the analysis were used to determine the impact on personnel (fatalityrate). The probability of fatality from exposure to heat radiation from a pool fire was

determined using a probit equation. The heat flux exposure was calculated at 2 m aboveground level, to represent an upper limit of heat flux exposure to a person present nearthe flame. The heat radiation levels modelled, the resulting fatality probabilities, along

with a detailed description of the criteria, are presented in Appendix F.


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Caltex Refineries (NSW) Pty Ltd ModuSpecTank 632 Quantitative Risk Assessment Risk Results

10. RISK RESULTS

10.1. Individual Risk

The overall risk was determined by combining the frequency and consequence data forthe individual scenarios examined. The results of the analysis are presented as individualrisk contours. Contours were generated for individual risk of fatality and individual riskof injury. These are illustrated in Figure 1.1 and Figure 1.2 respectively.

10.2. Comparison with Risk Criterion

The quantified risk results were compared with the applicable risk criteria for land useestablished by DUAP. This provides the basis for determining the acceptability of therisk.

10.2.1.Fatality Risk

Focus was placed on the risk exposure on the Serenity Cove Development located tothe west of the refinery border, adjacent to the proposed Tank 632. The Serenity

Cove Development is an office building and hence the applicable risk criterion forindividual risk of fatality level is 5 chances in a million per year (5 x 10-6 per year).

The 5 x 10-6 per year individual risk contour is shown in Figure 1.1. This contour isconfined within the beyond the site boundary. Therefore, the risk criterion forindividual risk of fatality is satisfied.

An overall individual risk contour for the Caltex Refinery has not been developed atthis point and hence was not available to enable a risk contour to be developedrepresenting the cumulative risk, including the addition of the proposed tank. In the

absence of a risk contour for the existing activities, the cumulative risk exposure onneighbouring facilities from the addition of Tank 632 has been assessed qualitatively.

The existing refinery activities in the area where the proposed tank is to be installed


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Considering the lube oil shipping line, the risk exposure may considered lower again

for the following reasons: The pipeline is not in continuous use for lube oil transfers The ignition probability is very low due to the high flash point of the oils being

transferred.

The risk exposure to adjacent areas from the flare line may be considered low for thefollowing reasons:

The pressure in the flare line would normally be low The pipeline is separated from the boundary by a short distance.

The pressure in the flare line would normally be low as the there would be minimaltransfer through the line unless a process upset was in progress. Therefore, if therewere a failure of the line, the release rate of vapour from the leak would be low andhave a very limited impact zone. The separation distance between the flare line and

the Caltex boundary would reduce the likelihood of offsite impacts even further.

Based on the discussions above, the existing risk exposure to the Serenity Cove

Development and the HCE site from operations in the vicinity of the proposedstorage tank is expected to be well within the risk acceptance criteria applicable for

these land uses.

Given that the existing operations on the Caltex site are not expected to impose highlevels of risk to the neighbouring areas, and the risk associated with the addition ofTank 632 does not exceed the criteria, it can reasonably be assumed that thecumulative individual fatality risk from the existing and proposed operations does notexceed the acceptance criteria. For the Serenity Cove Development, the individual

risk of fatality from Caltexs operations considering the addition of the proposedstorage tank would be less than 5 x 10-6 per year, and the cumulative individual riskof fatality risk imposed from Caltex on HCE site would be less than 50 x 10-6 per year

(i.e. the applicable criteria for neighbouring industrial sites).

10.2.2.Injury Risk

6


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10.3.1.Fatality Risk

The major risk contributor to the western sector of the 5 x 10-6 per year fatality riskcontour is a major release from Tank 632, resulting in a large bund fire. As the bundsurrounding Tank 632 has a very large surface area, the heat radiation from a full

bund fire will extend well beyond the western boundary of the refinery into theneighbouring area. The heat radiation impact from smaller fires will typically notextend a sufficient distance to contribute to the risk at this location.

The events that contribute the most to the risk in the eastern sector of the 5 x 10-6

per year risk contour are releases from the transfer piping. These risks impact the

adjacent Tanks 622, 623 and 633, however are limited to the bunded areas throughwhich they pass.

10.3.2.Injury Risk

The major risk contributor to the 50 x 10-6 per year injury risk contour is a fullsurface tank fire. The 4.7 kW/m2 heat flux associated with this event has thepotential to extend a distance of 83.6 m downwind from the tank centre. Another

significant risk contributor is a pool fires resulting from the ignition of significantreleases (representative a range in hole sizes starting from 100 mm).

10.4. Maximum Consequence Impact

Based on the heat radiation impact distances, the installation of the proposed crude tank

at the location nominated will have the potential to generate offsite heat radiationimpacts. The major consequence event with the potential to generate offsite impact is afull bund fire resulting from a major release of whole crude oil from Tank 632. This eventalso represents the maximum extent of heat flux to the west of the refinery boundary.

Although this worst-case event will produce large impact zones, the frequency of the

event is low (calculated to be in the order of 1 x 10-7

per year). The low event frequencyleads to a low contribution to the overall individual risk from this event. Consequently,the impacts of a bund fire can be considered acceptable from a risk perspective.


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Caltex Refineries (NSW) Pty Ltd ModuSpecTank 632 Quantitative Risk Assessment References

11. REFERENCES

1 Department of Urban Affairs and Planning Planning NSW, Risk Criteria for LandUse Safety Planning, Hazardous Industry Planning Advisory Paper No. 4,March 2002.

2 ModuSpec Australia Pty Ltd, Caltex Refineries (NSW) Pty Ltd Preliminary HazardAnalysis, Storage Tank 632, Reference: AUS 0352.1, August 31 2005.

3 Email from Kevin Houlihan (Caltex RPIP Project Engineer (Kurnell) Shedden UhdePty Ltd), Lachlan Dreher to (General Manager, ModuSpec Australia Pty Ltd)

Caltex Crude Tank QRA, 4th May 2006.

4 Email from Ramez Aziz (Senior Risk Engineer, Caltex Refineries (NSW) Pty Ltd), to

Marian Magbiray (Risk Engineer, ModuSpec Australia Pty Ltd) MET Data forKurnell (AUSPLUME files for Caltex Kurnell site), 2nd June 2005.

5 Bureau of Meteorology, Climate Averages for Australian Sites;

http://www.bom.gov.au/climate/averages/tables/cw_066037.shtml,June 14 2005.

6 LASTFIRE PROJECT, Large Atmospheric Storage Tank Fire Project LASTFIRETechnical Working Group, June 1997.

7 Offshore Hydrocarbon Release Statistics, Offshore Technology Report OTO 97950, UK Health and Safety Executive, December 1997

8 Guidelines for Process Equipment Reliability Data, Center for Chemical ProcessSafety of the American Institute of Chemical Engineers, 1989, Vessels Atmospheric-Metallic, page 203, Lower Value.

9 Q i i Ri k A D h Di E&P F R N


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Caltex Refineries (NSW) Pty Ltd ModuSpecTank 632 Quantitative Risk Assessment Appendix A: Project Assumptions

APPENDIX A: PROJECT ASSUMPTIONS

TABLE OF CONTENTS

1. INTRODUCTION........................................................................................2

2. ASSUMPTIONS .........................................................................................3

Assumption 1: Modelling Boundaries.................................................................... 3Assumption 2: Scenario 1 Crude Receiving......................................................... 3Assumption 3: Scenario 2 Transfer of Crude Oil from Tank 632 ............................. 3

Assumption 4: Scenario 3 Static Tank 632 .........................................................4Assumption 5: Pipelines .....................................................................................4Assumption 6: Frequency Assessment Tank and Piping Utilisation.......................... 4Assumption 7: Frequency Assessment Full Surface Tank Fires............................... 4

Assumption 8: Frequency Assessment Tank Mixers............................................. 5Assumption 9: Meteorological Data ...................................................................... 6

3. REFERENCES ............................................................................................7


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1. INTRODUCTIONThis appendix documents the assumptions made during the risk analysis. The

assumptions have been based on information provided by Caltex. The justification forthe assumptions has been included where applicable.


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2. ASSUMPTIONS

Assumption 1: Modelling Boundaries

The analysis is bounded by the proposed Tank 632 and the associated crudereceiving and discharge piping to the eastern bund wall of Tank 633.

ModuSpec Analyst: Marian Magbiray Date: 21/09/05

Assumption 2: Scenario 1 Crude Receiving

Isolation section: Crude Receiving Line Pipe 9-P610-KA1-650 at the boundary of theeastern bund wall of Tank 633 to the motorised valve (MV) at the inlet of Tank 632.

Product: Whole Crude OilTemperature: 30CPressure: 88 kPa(g)Flowrate: 4000 m3/hr [1].

Utilisation: See Assumption 6.

Justification

Due to the significant distance from the ship pump, the pressure in the pipeline wasassumed to be the same as the hydrostatic head in the tank.


Assumption 3: Scenario 2 Transfer of Crude Oil from Tank 632

Crude Suction Line 9-P611-KA1-450Isolation section: MV at Tank 632 outlet along the suction piping 9-P611-KA1-450 tothe eastern bund wall of Tank 633.Product: Whole Crude Oil


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Assumption 4: Scenario 3 Static Tank 632

Tank 632 was modelled at 85% level [2]Product: Whole Crude OilTemperature: 30CPressure: atmosphericUtilisation: See Assumptions 6

ModuSpec Analyst: Patrick Walker Date: 09/06/06

Assumption 5: Pipelines

The pipe lengths were estimated from the site plan provided [3]. The largestpipe diameter in each isolatable section was used to represent the pipe sizing

during the modelling.


Assumption 6: Frequency Assessment Tank and Piping Utilisation

The tank utilisation was assumed to be 100%.

Based on the frequency and duration of the tank filling and emptying operations, theutilisation for the crude receiving pipeline was estimated to be 10%. The transferpiping for the delivery of crude to the CDU was assumed to be 90%.


Assumption 7: Frequency Assessment Full Surface Tank Fires

Based on a review of several sources that have published the frequency values for a

full surface tank fire, the frequency considered most applicable for the Kurnellrefinery is 8.9 x 10-5 per year, derived from the LASTFIRE project [4]. This valuehas been selected because it has been derived from the widest sample set of eventsand tank locations. Statistically, this can be expected to provide a more appropriate


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Assumption 8: Frequency Assessment Tank MixersAssumption

Failure of a tank mixer was considered in terms of the failure of the mixer seal and aleak from that seal. It was assumed that a mixer seal is comparable to a pump sealand that external leaks are considered to be the only reasonable foreseeable failuremode. Referring to OREDA-97 [5], the mean failure rate for pumps and the pump

seal failure percentage of the overall failure rate is as follows:

Critical Failure Mode Failure Rate(per 10-6 hrs) Seal Failure ModePercentage Total FailureMode Percentage

External Leakage 3.64 9.02% 22.92%

Significant ExternalLeakage

0.63 0.26% 0.26%

Degraded Failure Mode

External Leakage 9.61 9.02% 22.92%

Significant External

Leakage 0.63 0.26% 0.26%

Applying the seal failure and total failure mode percentages presented above to the meanfailure rate gives the following failure rates that have been applied for seal failures for

each failure mode:

Failure Mode (Seal) Critical Failure Degraded Failure

External Leakage 1.19 x 10-2 per year 3.31 x 10-2 per year

Significant External Leakage 5.52 x 10-3 per year 5.52 x 10-3 per year

This corresponds to a total seal mean failure frequency of 5 61 x 10-2 per year It is


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Assumption 9: Meteorological DataThe local meteorological data, extracted from the 2001 and 2002 CALMET files weresupplied by Caltex Kurnell. [6].

The average temperature is 18.1C and the average humidity is 57%. Humidity datawas taken from the nearby weather station at Sydney Airport [7].

A total of 16 wind directions and 6 stability classes were used in the analysis. The

values used are listed below.

StabilityB C D D E F Average

of all

Stabilities

Wind Speed

(m/s)2.4 3.7 7.2 3.5 4.0 1.9 3.4

Probability ofAtmospheric

Conditions

0.140 0.182 0.126 0.126 0.134 0.292 1.0

Wind

Direction Probability of wind direction

N 0.031 0.029 0.012 0.021 0.051 0.072 0.042

NNE 0.050 0.085 0.062 0.058 0.108 0.078 0.075

NE 0.128 0.113 0.077 0.079 0.069 0.062 0.085

ENE 0.128 0.094 0.031 0.067 0.025 0.038 0.062

E 0.078 0.051 0.002 0.048 0.024 0.038 0.041

ESE 0.094 0.044 0.005 0.072 0.025 0.045 0.047

SE 0.084 0.065 0.035 0.111 0.059 0.044 0.063

SSE 0.052 0.064 0.082 0.127 0.045 0.030 0.060

S 0.071 0.116 0.221 0.135 0.090 0.046 0.102

SSW 0.025 0.056 0.101 0.064 0.059 0.049 0.057

SW 0.020 0.027 0.053 0.019 0.041 0.060 0.040

WSW 0 025 0 051 0 123 0 041 0 107 0 081 0 071


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3. REFERENCES

1 Caltex Refineries (NSW) Pty Ltd, Additional Crude Storage Project, Process Datafor Phase 2 Preliminary Hazard Analysis.

2 Email from Tracey Hyland (Environmental Engineer, Kurnell, Caltex Refineries

(NSW) Pty Ltd), Lachlan Dreher to (General Manager, ModuSpec Australia Pty Ltd)Fw: Tank 632 QRA Report, 9th June 2006.

3 Caltex Kurnell Refinery Neighbourhood Layout for Risk Assessment, Drawingnumber 127103, Revision 0.

4 LASTFIRE Technical Working Group, LASTFIRE PROJECT, Large AtmosphericStorage Tank Fire Project June 1997.

5 Sintef Industrial Management, OREDA Offshore Reliability Data Handbook,

OREDA Participants, 3rd Edition, 1997.

6 Email from Ramez Aziz (Senior Risk Engineer, Caltex Refineries (NSW) Pty Ltd), toMarian Magbiray (Risk Engineer, ModuSpec Australia Pty Ltd), MET data for

Kurnell (AUSPLUME files for Caltex Kurnell site), 2nd June 2005.

7 Bureau of Meteorology, Climate Averages for Australian Sites;http://www.bom.gov.au/climate/averages/tables/cw_066037.shtml, 14th June

2005.


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Caltex Refineries (NSW) Pty Ltd ModuSpecTank 632 Quantitative Risk Assessment Appendix B: Hazardous Scenarios and

Process Conditions

APPENDIX B: HAZARDOUS SCENARIOS AND PROCESSCONDITIONS

TABLE OF CONTENTS

1. INTRODUCTION........................................................................................2

2. HAZARDOUS SCENARIOS AND PROCESS CONDITIONS..............................3


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Process Conditions

1. INTRODUCTION

This appendix provides details of the hazardous scenarios identified in the analysis and

the process conditions relating to them. The definition of the data presented in thetables is outlined below:

Scenario Name The name of the isolatable section or specific equipmentconsidered as the scenario

Product The product representing the material in the scenarioUtilisation (%) The percentage of time the scenario is in use

Temperature (C) Temperature in the processPressure (kPa) Pressure in the processDiameter (mm or m) Diameter of pipeline or vesselLength (m) Approximate length of pipelineHeight (m) Height of the vesselLiquid Level (%) Liquid level in vessel

Total HUM The hold up mass for the isolatable sectionVessel Capacity (t) The capacity of the vessel


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Process Conditions

Ref: AUS0352.8, Release 01 Page B.3 of 37 July 2006

2. HAZARDOUS SCENARIOS AND PROCESS CONDITIONS

Table 2.1 details the tank scenario modelled. Table 2.2 presents the process conditions for the transfer pipelines (crude receiving line andtransfer lines to CDU for further processing).

Table 2.1: Summary of Vessel Scenario

Scenario Name Product Diameter(m)

Height(m)

VesselCapacity

(t)

Utilisation(%)

Temperature(C)

Pressure(kPa)

LiquidLevel (%)

Tank 632 Wholecrude oil

77.5 20.5 5.4 x 104 100 30 101 85

Table 2.2: Summary of Representative Pipeline Scenarios

Scenario Name Product Diameter(mm)

Length(m)

Total HUM(kg)

Utilisation(%)

Temperature(C)

Pressure(kPa)

Crude receiving(Pipe 9-P610-KA1-650)

Whole crudeoil

650 240 55,748 10 30 189

Crude suction to CDU(Pipe 9-P611-KA1-450)

Whole crudeoil

450 220 24,493 45 30 189

Crude suction to CDU(Pipe 9-P962-B4-250)

Whole crudeoil

450 220 24,493 45 30 189


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Caltex Refineries (NSW) Pty Ltd ModuSpecTank 632 Quantitative Risk Assessment Appendix C: Failure Frequency Data

APPENDIX C: FAILURE FREQUENCY DATA

TABLE OF CONTENTS

1. INTRODUCTION........................................................................................2

2. FAILURE FREQUENCY DATA ......................................................................3

2.1. Process Pipes...........................................................................................32.2. Valves ....................................................................................................42.3. Flanges...................................................................................................6

2.4. Small Bore Fittings ...................................................................................72.5. Tank Mixers.............................................................................................72.6. Storage Tanks ......................................................................................... 72.7. Full Surface Tank Fires..............................................................................7

3. REFERENCES ............................................................................................8


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1. INTRODUCTIONFor each of the hazardous scenarios examined, items such as tanks, pipework, valves,

flanges and fittings termed failure items associated with the scenario were identified.Failure modes of each failure item were represented as a range of hole size releases.Frequencies of hole size releases of each failure item were obtained using historicalindustry data.

This appendix presents the failure frequency values applied in the analysis.


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2. FAILURE FREQUENCY DATA

2.1. Process Pipes

Table 2.1: Process Piping Failure Frequency [1]

Pipe Size

(mm)

Hole Size

(mm)

Failure Frequency

(x10-6 /year per 10 mlength)

25 5 317.26

25 25 58.74

40 5 178.88

40 25 50.81

40 40 5.31

50 5 135.40

50 25 45.39

50 50 7.21

60 5 107.58

60 25 40.44

60 60 8.65

75 5 80.98

75 25 34.23

75 50 7.74

75 75 2.39

80 5 74.56

80 25 32 48


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Pipe Size

(mm)

Hole Size

(mm)

Failure Frequency

(x10

-6

/year per 10 mlength)

200 25 13.07

200 100 9.42

200 200 1.80

250 5 16.94

250 25 10.14

250 75 6.96

250 250 3.56

300 5 13.33

300 25 8.19

300 100 7.29

300 300 2.53

350 5 10.88

350 25 6.81

350 100 6.45

350 350 2.72

400 5 9.12

400 50 8.77

400 200 4.71

400 400 0.90

450 5 7.81450 50 7.64

450 200 4.42


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Valve Size

(mm)

Hole Size

(mm)

Failure Frequency

(x10

-6

/year)400 5 25.29

400 25 19.12

400 200 11.06

400 400 0.03

450 5 24.10

450 25 18.90

450 200 12.44

450 450 0.06

500 5 23.08

500 25 18.64

500 200 13.68

500 500 0.10

2.3. Flanges

Table 2.3: Flange Failure Frequency [2]

Flange

Size(mm)

Hole Size

(mm)

Failure Frequency

(x10-6 /year)

25 5 108.38

25 12 2.61

40 5 106.7040 12 4.26

50 5 110.06

50 12 0 94


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Flange

Size(mm)

Hole Size

(mm)

Failure Frequency

(x10

-6

/year)

400 5 54.00

400 12 1.49

450 5 54.36

450 12 1.13

500 5 54.00

500 12 1.49

600 5 53.49

600 12 1.99

2.4. Small Bore Fittings

The failure frequency value used for small bore fittings is 7.19 X 10-4 [3]. This has beenapplied for fittings having a diameter less than 25 mm.

2.5. Tank Mixers

Failure of a tank mixer was considered in terms of the failure of the mixer seal and a leak

from that seal. The total seal mean failure frequency used was 5.61 x 10-2 per year.Refer to Appendix A for further details.

2.6. Storage Tanks

Table 2.4: Storage Tank Failure Frequency Data [4].

Hole Size(mm)

Failure Frequency

(x10-6 /year)

10 1543.7575 617.50

100 302.75

Rupture 6.00


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3. REFERENCES

1 Hydrocarbon Leak and Ignition Data Base, E&P Forum, February 1992,N658/Final Report, Section III.3, Appendix III, page 2.

2 Classification of Hazardous Locations, A.W. Cox, F.P. Lees and M.L. Ang,

IChemE, 1993, Table 18.1, page 68.

3 Geometric mean of data obtained from source 2 and Hydrocarbon Leak and

Ignition Data Base, E&P Forum, February 1992, N658/Final Report, page 25.

4 Offshore Hydrocarbon Release Statistics, Offshore Technology Report OTO 97950, UK Health and Safety Executive, December 1997.

5 LASTFIRE PROJECT, Large Atmospheric Storage Tank Fire Project LASTFIRETechnical Working Group, June 1997.


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Caltex Refineries (NSW) Pty Ltd ModuSpecTank 632 Quantitative Risk Assessment Appendix D: Hazardous Scenarios and

Failure Frequency

APPENDIX D: HAZARDOUS SCENARIO AND FAILUREFREQUENCY

TABLE OF CONTENTS

1. INTRODUCTION........................................................................................2

2. HAZARDOUS SCENARIOS AND FAILURE CONTRIBUTORS ..........................32.1. Tank 632 ................................................................................................32.2. Crude Receiving.......................................................................................42.3. Crude Suction to CDU ...............................................................................5


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Caltex Refineries (NSW) Pty Ltd ModuSpecTank 632 Quantitative Risk Assessment Appendix D: Hazardous Scenarios and

Failure Frequency

1. INTRODUCTION

This appendix contains a listing of the hazardous scenarios identified and the process

failure items and overall failure frequency relating to them. The definitions for each ofthe headings presented are detailed below:

Item Failure item or specific equipment included in the isolatablesection.

Count The number of failure items associated with the isolatable section.

Diameter Diameter of failure item (mm).Hole Size 1 Representative hole size for a small release.FFreq. 1 Failure Frequency of pipeline release for hole size 1 (x 10-6 per

year).Hole Size 2 Representative hole size for a medium release.FFreq. 2 Failure Frequency of liquid release for hole size 2 (x 10-6 per

year).Hole Size 3 Representative hole size for a large release.FFreq. 3 Failure Frequency of liquid release for hole size 3 (x 10-6 per

year).Hole Size 4 Representative hole size for a rupture scenario. This equates to

the maximum size of the equipment, or 1000 mm for vessels.FFreq. 4 Failure Frequency of liquid release for hole size 4 (x 10-6 per

year).Frequency total Sum of frequencies at individual hole sizes.

The rupture case for storage tanks was represented by a hole size of 1000 mm. The

rupture cases for the pipelines were represented by the hole size equivalent to the pipediameter.


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Caltex Refineries (NSW) Pty Ltd ModuSpecTank 632 Quantitative Risk Assessment Appendix D: Hazardous Scenarios and Failure Contributors

Ref: AUS0352.8, Release 01 Page D.3 of 67 July 2006

2. HAZARDOUS SCENARIOS AND FAILURE CONTRIBUTORS

The following section lists the failure item parts count within each respective isolatable section.

2.1. Tank 632

Table 2.1: Failure Items for Tank 632

Item CountDiameter

(mm)

HoleSize 1(mm)

FFreq 1(x10-6/y)

HoleSize 2(mm)

FFreq 2(x10-6/y)

HoleSize 3(mm)

FFreq 3(x10-6/y)

HoleSize 4(mm)

FFreq 4(x10-6/y)

Associated pipework 60 m 350 25 106.14 100 38.7 350 16.32 1,000 0

Associated pipework 40 m 500 25 27.16 100 27 350 16.56 1,000 4.4800Flange 2 25 25 221.98 100 0 350 0 1,000 0

Flange 1 100 25 110.98 100 0 350 0 1,000 0

Flange 4 350 25 221.96 100 0 350 0 1,000 0

Flange 1 500 25 55.49 100 0 350 0 1,000 0

Flange 1 600 25 55.48 100 0 350 0 1,000 0

Small bore fitting 6 N/A 25 4,314.18 100 0 350 0 1,000 0

Tank Mixer Seal 5 N/A 25 280,500.00 100 0 350 0 1,000 0

Valve 2 25 25 222.00 100 0 350 0 1,000 0

Valve 1 100 25 109.57 100 1.43 350 0 1,000 0

Valve 3 350 25 137.85 100 27.33 350 1.32 1,000 0Valve 1 500 25 41.72 100 0 350 13.68 1,000 0.1

Process Vessel -floating roof 1 77.5 m 25 1,543.75 100 920.25 350 0 1,000 6

Frequency Total 287,668.26 1,014.71 47.88 10.58


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2.2. Crude Receiving

Table 2.2: Failure Items for the Crude Receiving Line (Pipe 9-P610-KA1-650)

Item CountDiameter

(mm)Hole Size1 (mm)

FFreq 1(x10-6/y)

Hole Size2

(mm)

FFreq 2(x10-6/y)

Hole Size3

(mm)

FFreq 3(x10-6/y)

Hole Size4

(mm)

FFreq 4(x10-6/y)

Flange 1 25 10 10.84 25 0.26 100 0 650 0

Flange 4 100 10 43.14 25 1.26 100 0 650 0

Flange 4 500 10 21.60 25 0.60 100 0 650 0

Flange 4 600 10 21.40 25 0.80 100 0 650 0

Process Pipe 240 m 650 10 9.53 25 0 100 9.91 650 9.50

Small bore fitting 11 N/A 10 158.19 25 632.74 100 0 650 0

Valve 1 25 10 10.82 25 0.28 100 0 650 0

Valve 4 100 10 33.37 25 10.46 100 0.57 650 0

Frequency Total 308.89 646.40 10.48 9.50


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2.3. Crude Suction to CDU

Table 2.3: Failure Items for the Crude Suction Line to CDU (Pipe 9-P611-KA1-450)

Item CountDiameter

(mm)

Hole Size1

(mm)

FFreq 1(x10-6/y)

Hole Size2

(mm)

FFreq 2(x10-6/y)

Hole Size3

(mm)

FFreq 3(x10-6/y)

Hole Size4

(mm)

FFreq 4(x10-6/y)

Flange 2 300 25 49.94 100 0 250 0 450 0

Flange 1 350 25 24.97 100 0 250 0 450 0

Flange 1 350 25 24.97 100 0 250 0 450 0

Flange 3 450 25 74.91 100 0 250 0 450 0

Process Pipe 220 m 450 25 77.32 100 75.64 250 43.76 450 10.1

Small bore fitting 6 N/A 25 1,941.38 100 0 250 0 450 0Valve 2 300 25 42.87 100 6.87 250 0 450 0.22

Valve 1 350 25 20.68 100 4.10 250 0 450 0.2

Frequency Total 2,257.04 86.61 43.76 10.52


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Table 2.4: Failure Items for Crude Suction Line to CDU (Pipe 9-P962-B4-250)

Item CountDiameter

(mm)

Hole Size1

(mm)

FFreq 1(x10-6/y)

Hole Size2

(mm)

FFreq 2(x10-6/y)

Hole Size3

(mm)

FFreq 3(x10-6/y)

Hole Size4

(mm)

FFreq 4(x10-6/y)

Flange 1 25 25 49.95 100 0 250 0 450 0

Flange 1 250 25 49.95 100 0 250 0 450 0

Flange 2 250 25 99.89 100 0 250 0 450 0

Flange 1 300 25 24.97 100 0 250 0 450 0

Flange 1 350 25 24.97 100 0 250 0 450 0

Process Pipe 220 m 450 25 77.32 100 75.64 250 43.76 450 10.10

Small bore fitting 2 N/A 25 647.13 100 0 250 0 450 0

Valve 1 25 25 49.95 100 0 250 0 450 0Valve 2 250 25 89.00 100 10.24 250 0.66 450 0

Valve 1 300 25 21.43 100 3.43 250 0 450 0.11

Frequency Total 1,134.56 89.31 44.42 10.21


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Caltex Refineries (NSW) Pty Ltd ModuSpecTank 632 Quantitative Risk Assessment Appendix E: Event Tree Analysis

1. INTRODUCTIONData acquired for the event tree considered the following for both a release and fire:

Probability of detection Probability of isolation Time to detect a release Isolation time.

The assumptions relating to leak detection and intervention measures for the proposedTank 632 were based on previous analysis for the gasoline storage tanks at the Kurnell

Refinery. The inlet and outlet lines of Tank 632 are to be fitted with motorised valves,whereas the event tree data for the gasoline tanks was based on the absence of remoteisolation. Therefore, the isolation strategies for Tank 632 were modified accordingly toincorporate the provision for remote isolation. This is reflected in the time allowed for

1st isolation. The event tree input data was collected by Caltex, based on discussions

with relevant Kurnell Refinery operations personnel [1].


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2. EVENT TREE DATADescriptions of the main headings on the event tree table are provided below.

% chance of seeing or % time person near unit - This is related to detection of therelease or fire. There are two options for detecting a release or fire. The first is

Process which is the chance that the basic process control system (e.g. an alarm or

other indication) will alert a process operator to an anomaly. The second is Person,which is the chance that a person will detect the release or fire if they are in or near theunit. The % time is the percentage of time that a person will be in or near the unit.

Note that for the case where the probability of detection is quoted as 100%, the valueused in the calculation was 99.5%, to allow for human error.

% chance of achieving isolation/time taken (min) This is the probability of

achieving isolation within a specific time frame. This occurs only once the release or firehas been detected. There are two chances for isolation (1st isol and 2nd isol) and eachhas an associated time. The 1st isolation time is typically associated with the automated

isolation of the release or fire. The 2nd isolation time is related to the manual isolation, inthe absence or failure of any automatic isolation.

Worse case time to detect - This is the maximum time that the leak could proceed

undetected. Generally this is for a release occurring in the middle of the night, when thelikelihood of detection is low.

2.1. Operator Nearby

The proportion of time that an operator / personnel are within the vicinity of the relevantunit was estimated based on weekday and weekend operations. Table 2.1 presents the

number of hours that different personnel are in the vicinity of the particular plant areas.

The average value, based on weekday and weekend operation is listed in the final row.

The data acquired for the gasoline tank farm quantitative risk assessment was applied to

the south crude tank farm, the area where Tank 632 is to be located.


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Table 2.1: Typical Presence of Personnel in the Crude Tank Farm.

Number of Hours

WEEKDAYS Crude Tank Farm

Operator 3.6

Security 0.5

General maintenance 1

Maintenance, vessel maint. routine 0

Personnel drive pass 1.5

Public 0

Total 6.6

% time a person at or nearby unit 27.5

WEEKEND Crude Tank Farm

Operator 3.6

Security 0.5

General maintenance 0

Maintenance, vessel maint. routine 0

Personnel drive pass 1

Public 0

Total 5.1

% time a person at or nearby unit 21.25

Average % time a person at or nearby theunit

25.71

2.2. General Assumptions

The following general assumptions associated with detection and isolation of a release


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Table 2.2: Event Tree Data (probability of detection and successful isolation fora release or fire at each section)

No. 1 1 1 2 2 2

Name Tank 633Tank 633Tank 633PipelinesPipelinesPipelines

Hole Size s m r s m r

Operatoron/near

unit

% time

26 26 26 26 26 26

Detector 0 0 0 0 0 0

Process 10 15 80 0 15 80Release

Person 20 60 90 20 60 100

Detector 0 0 0 0 0 0

Process 10 15 80 0 20 80%

chanceofseeing

Fire

Person 80 90 100 80 100 100

Detect Time min 727.5 67.5 17.5 247.5 122.5 17.5

Time R/FNote 1440/15 120/15 30/5 480/15 240/5 30/5

1st isol. 90 90 90 90 90 90

Time min 1 1 1 2 2 2

Releasetmeta

en


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3. REFERENCES

1 E-mail from Ramez Aziz (Senior Risk Engineer, Caltex Refineries NSW, Pty Ltd) toKate Filippin (Principal Risk Engineer, ModuSpec Australia) and Marian Magbiray(Risk Engineer, ModuSpec Australia), Event Tree Data (again), 12th July 2005.


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Caltex Refineries (NSW) Pty Ltd ModuSpecTank 632 Quantitative Risk Assessment Appendix F: Consequence Impact Level Criteria

APPENDIX F: CONSEQUENCE LEVEL IMPACT CRITERIA

TABLE OF CONTENTS

1. INTRODUCTION........................................................................................2

2. HEAT FLUX CRITERIA ...............................................................................3

3. REFERENCES ............................................................................................4


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2. HEAT FLUX CRITERIAThe effect of human exposure to a fire is a function of both the intensity of heat radiation

and the duration of exposure. The harmful effect can be characterised by a thermal dosethat is defined by the function (tI4/3), where I is the heat radiation intensity and t is theexposure duration.

A probit function has been used to evaluate the likelihood of fatality for different heat fluxexposures. The probit equation utilised is the Eisenberg equation [2]:

Equation 2.1:

Y 14.9 2.56 ln tI4

3

where: Y= probit valuet = exposure time (seconds)I = radiation intensity from fire (kW/m2)

In terms of human exposure, it is generally accepted that an exposure of 12.6 kW/m2 willresult in a 50% chance of fatality. Based on Equation 2.1, the required exposure timewould be 81 seconds.

To account for all the possible means that adverse outcomes can occur, a range of heatflux levels need to be assessed. The values used in the analysis were based on anexposure time of 81 seconds and are presented in Table 2.1.

Table 2.1: Heat Flux Levels and Corresponding Fatality Probability

Heat Flux (kW/m2) 8.7 9.7 11.7 13.6 16.1

% Fatality 10 20 40 60 80


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3. REFERENCES

1 NSW Department of Urban Affairs and Planning; Risk Criteria for Land Use SafetyPlanning, Hazardous Industry Planning Advisory Paper No. 4, Sydney, 1990.

2 Lees, F.P., "Loss Prevention in the Process Industries, Hazard Identification

Assessment and Control", Butterworth & Heinemann, 1996, 2nd Edition,Volume 1, p9/64.


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Caltex Refineries (NSW) Pty Ltd ModuSpecTank 632 Quantitative Risk Assessment Appendix G: Consequence Results

APPENDIX G: CONSEQUENCE RESULTS

TABLE OF CONTENTS

1. INTRODUCTION........................................................................................2

2. CONSEQUENCES .......................................................................................3

2.1. Pool Fires................................................................................................ 32.2. Full Surface Tank Fires..............................................................................9


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1. INTRODUCTIONThis appendix contains the consequence results. The results are presented in table

format. The following list provides a definition for each of the headings presented.

Scenario Name The name of the isolatable section or specific equipmentconsidered as the scenario.

Hole Size (mm) The specific hole size considered for the consequencescenario.

Release Rate (kg/s) The rate at which the product is expected to be released.

Duration (s) The time taken for the product to be released.Frequency (x10-6 /y) Failure frequency for the scenario.Distance (m) to HeatCriteria (kW/m2)

The maximum distance at which the consequence isexperienced for the given heat flux level from the centreof the pool.


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Ref: AUS0352.8, Release 01 Page G.3 of 97 July 2006

2. CONSEQUENCES

2.1. Pool Fires

Table 2.1: Consequence Modelling Results for Pool Fires.

Distance (m) to Heat Criteria (kW/m2)Scenario

Holesize

(mm)

ReleaseRate Used

(kg/s)

Duration (s)Frequency(x10-6/y) 8.70 9.70 11.70 13.60 16.10

Crude Receiving 10 0.57 113352 0.3 14 13 13 12 12

Crude Receiving 10 0.57 114402 0.03 14 13 13 12 12

Crude Receiving 10 0.57 128352 2.25 14 13 13 12 12

Crude Receiving 25 3.5 30711 1.28 28 27 26 25 24

Crude Receiving 25 3.5 31761 0.12 28 27 26 25 24

Crude Receiving 25 3.5 45711 0.02 28 27 26 25 24

Crude Receiving 25 3.5 45711 9.67 28 27 26 25 24

Crude Receiving 100 57 8454 0.16 65 62 57 52 46

Crude Receiving 100 57 9504 0.02 65 62 57 52 46

Crude Receiving 100 57 16554 0.35 65 62 57 52 46

Crude Receiving 650 778 1193 0.55 128 121 110 103 100

Crude Receiving 650 778 2243 0.08 128 121 110 103 100

Crude Receiving 650 778 2993 0.01 128 121 110 103 100

Crude Receiving 650 778 2993 0.11 128 121 110 103 100Crude Suction (Line 9-P962-B4-250) 25 3.5 21886 2.25 28 27 26 25 24

Crude Suction (Line 9-P962-B4-250) 25 3.5 22936 0.22 28 27 26 25 24



Crude Suction (Line 9-P962-B4-250) 100 57 7902 1.33 65 62 57 52 46



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Holesize

(mm)

ReleaseRate Used

(kg/s)












Crude Suction (Line 9-P611-KA1-450) 25 3.54 21886 4.48 28 27 26 25 24




Crude Suction (Line 9-P611-KA1-450) 100 57 7902 1.29 65 62 57 52 46








Crude Suction (Line 9-P611-KA1-450) 450 78 1191 0.61 128 121 110 103 100Crude Suction (Line 9-P611-KA1-450) 450 78 2241 0.09 128 121 110 103 100



Tank 632 25 4.4 12442307 926.11 30 29 28 27 26

Tank 632 25 4.4 12443657 127.34 30 29 28 27 26


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Holesize

(mm)

ReleaseRate Used

(kg/s)


Tank 632 25 4.4 12486407 104.19 30 29 28 27 26

Tank 632 25 4.4 12486407 4208.88 30 29 28 27 26

Tank 632 100 70.1 779050 13.23 70 67 61 55 48

Tank 632 100 70.1 780400 2.43 70 67 61 55 48

Tank 632 100 70.1 783550 1.98 70 67 61 55 48

Tank 632 100 70.1 783550 38.56 70 67 61 55 48

Tank 632 350 64,041 953 0.14 177 168 155 150 149

Tank 632 350 64,041 954 2.63 177 168 155 150 149

Tank 632 350 60,891 963 0.17 177 168 155 150 149

Tank 632 350 59,541 967 0.90 177 168 155 150 149Tank 632 Rupture N/A Instantaneous 0.10 209 198 176 176 176

Tank 632 Rupture N/A Instantaneous 0.12 209 198 176 176 176




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Table 2.2: Consequence Modelling Results for the 4.7 kW/m2 Heat Criteria for Pool Fires

ScenarioHole size

(mm)Release RateUsed (kg/s)

Duration (s)Frequency(x10-6 / y)

Distance (m) to 4.7kW/m2 HeatCriteria

Crude Receiving 10 0.6 113352 0.30 16

10 0.6 114402 0.03 16

10 0.6 114402 0.00 16

10 0.6 128352 2.25 16

25 3.5 30711 1.28 32

25 3.5 31761 0.12 32

25 3.6 45711 0.02 32

25 3.6 45711 9.67 32

100 56.7 8453 0.16 78

100 56.7 9503 0.02 78

100 56.7 16553 0.00 78

100 56.7 16553 0.35 78

650 778 1193 0.55 159

650 778 2243 0.08 159

650 778 2993 0.01 159

650 778 2993 0.11 159

PLT 2 Suction 25 3.5 21885 2.25 32

25 3.5 22935 0.22 32

25 3.6 36885 0.03 32

25 3.6 36885 16.96 32

100 56.7 7902 1.33 78

100 56.7 8952 0.21 78

100 56.7 16002 0.03 78


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ScenarioHole size

(mm)

Release Rate

Used (kg/s)

Duration (s)Frequency

(x10

-6

/ y)

Distance (m) to 4.7kW/m2 Heat

Criteria

100 56.7 16002 2.98 78

250 78 7539 1.04 159

250 78 8589 0.16 159

250 78 15639 0.02 159

250 78 15639 2.33 159

450 78 1191 0.59 159

450 78 2241 0.09 159

450 78 2991 0.01 159

450 78 2991 0.12 159

PLT 45 Suction 25 3.5 21885 4.48 32

25 3.5 22935 0.44 32

25 3.6 36885 0.06 32

25 3.6 36885 33.75 32

100 56.7 7902 1.29 78

100 56.7 8952 0.20 78

100 56.7 16002 0.03 78

100 56.7 16002 2.89 78

250 78 7539 1.02 159

250 78 8589 0.16 159250 78 15639 0.02 159

250 78 15639 2.30 159

450 78 1191 0.61 159

450 78 2241 0.09 159

450 78 2991 0.01 159


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2.2. Full Surface Tank Fires

Table 2.3: Consequence Modelling Results for Full Surface Tank Fires

Downwind Distance (m) to Heat Criteria (kW/m2)Scenario Frequency (x10-6/y)

4.7 8.7 9.7 11.7 13.6 16.1

Tank 632 Full Surface Tank Fire 120 81 81 81 81 81 81

Documents

Quantitative Risk Assesment - 06_0160_appendix_d