proposed ane facility - orica mining services ane/final fire... · table 7.4: tnt equivalence ......
TRANSCRIPT
Document: J20210-007 Sherpa Consulting Pty Ltd (ABN 40 110 961 898) Revision: 0 Phone: 61 2 9412 4555 Revision Date: 24 February 2011 Fax: 61 2 9412 4556 Document ID: J20210-007 FHA Rev 0 Web: www.sherpaconsulting.com
PROPOSED ANE FACILITY
KURRI KURRI TECHNOLOGY CENTRE
FINAL HAZARD ANALYSIS
ORICA AUSTRALIA
PREPARED FOR: Richard Sheehan
Orica Australia
DOCUMENT NO: J20210-007
REVISION: 0
DATE: 24 February 2011
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DOCUMENT REVISION RECORD
REV DATE DESCRIPTION PREPARED CHECKED APPROVED METHOD OF ISSUE
A 17 February 2011 Draft for client comment J Polich - - PDF
0 24 February 2011 Final Revision J Polich P Johnson J Polich PDF
RELIANCE NOTICE
This report is issued pursuant to an Agreement between SHERPA CONSULTING PTY LTD („Sherpa Consulting‟) and Orica Australia which agreement sets forth the entire rights, obligations and liabilities of those parties with respect to the content and use of the report.
Reliance by any other party on the contents of the report shall be at its own risk. Sherpa Consulting makes no warranty or representation, expressed or implied, to any other party with respect to the accuracy, completeness, or usefulness of the information contained in this report and assumes no liabilities with respect to any other party‟s use of or damages resulting from such use of any information, conclusions or recommendations disclosed in this report.
Title:
Proposed ANE Facility
Kurri Kurri Technology Centre
Final Hazard Analysis
QA Verified:
P Johnson
Date: 24 February 2011
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CONTENTS
ABBREVIATIONS ...................................................................................................................................... 6
1 SUMMARY ........................................................................................................................................ 8
2 INTRODUCTION ............................................................................................................................. 13
2.1 Background .............................................................................................................................. 13
2.2 Objective .................................................................................................................................. 13
2.3 Scope ....................................................................................................................................... 13
2.4 Methodology ............................................................................................................................ 13
2.5 Risk Criteria ............................................................................................................................. 15
2.6 Limitations ................................................................................................................................ 17
2.7 Links to Other Studies ............................................................................................................. 17
3 SITE DESCRIPTION ....................................................................................................................... 18
3.1 Site Overview ........................................................................................................................... 18
3.2 ANE Project Overview ............................................................................................................. 18
3.3 Location and Surrounding Land Use ....................................................................................... 18
3.4 Site Security ............................................................................................................................. 19
3.5 Site Layout ............................................................................................................................... 19
3.6 Australian Standard Separation Distances .............................................................................. 19
3.7 ANE Plant Process Overview .................................................................................................. 25
3.8 Technology Centre Existing Facilities...................................................................................... 26
4 REVIEW OF QRA BASIS AND PROJECT SAFETYSTUDIES ....................................................... 27
4.1 Review of QRA Basis .............................................................................................................. 27
4.2 Review of HAZOP.................................................................................................................... 27
4.3 Review of FSS ......................................................................................................................... 27
4.4 Review of CSS ......................................................................................................................... 28
5 HAZARD IDENTIFICATION ............................................................................................................ 29
5.1 Hazardous Materials for Proposed ANE Plant ........................................................................ 29
5.2 Hazardous Materials at Existing Technical Centre Facilities .................................................. 31
5.3 External Events........................................................................................................................ 31
5.4 Bushfires .................................................................................................................................. 32
5.5 Potential Hazardous Incident Scenarios ................................................................................. 36
5.6 Scenarios for Quantitative Assessment .................................................................................. 36
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5.7 Rule Sets for Incident Inclusion ............................................................................................... 37
6 QRA BASIS ..................................................................................................................................... 46
7 CONSEQUENCE ANALYSIS .......................................................................................................... 48
7.1 Overview .................................................................................................................................. 48
7.2 Effect Levels of Interest ........................................................................................................... 48
7.3 Explosion Consequence Assessment Assumptions ............................................................... 50
7.4 Explosion Scenario Consequence Results ............................................................................. 53
7.5 Onsite Escalation ..................................................................................................................... 58
7.6 Toxic Effects Consequence Assessment ................................................................................ 67
8 FREQUENCY ANALYSIS AND RISK RESULTS ............................................................................ 70
8.1 Individual Fatality Risk ............................................................................................................. 70
9 RISK ASSESSMENT ....................................................................................................................... 72
9.1 Individual Fatality Risk ............................................................................................................. 72
9.2 Explosion Injury Risk ............................................................................................................... 72
9.3 Escalation Risk (Offsite Property) ............................................................................................ 73
9.4 Toxic Injury / Irritation Risk ...................................................................................................... 73
9.5 Risk to Biophysical Environment ............................................................................................. 75
10 CONCLUSIONS .............................................................................................................................. 78
APPENDICES
APPENDIX A. HAZARDOUS MATERIALS AND PROCESS DESCRIPTION
APPENDIX B. HIRAC INFORMATION
APPENDIX C. EXPLOSION OVERPRESSURES CONSEQUENCE MODELLING METHODOLOGY
APPENDIX D. QRA SCENARIOS
APPENDIX E. SUMMARY OF ASSUMPTIONS
APPENDIX F. REFERENCES
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TABLES
Table 1.1: Summary of Compliance with Risk Criteria ......................................................................... 12
Table 2.1: NSW Individual Risk Criteria, New Plants ........................................................................... 15
Table 2.2: NSW Escalation Risk Criteria, New Plants ......................................................................... 16
Table 2.3: NSW Risk Criteria, Existing Plants ...................................................................................... 16
Table 3.1: Existing Facilities Inventory Summary ................................................................................. 26
Table 5.1: NO2 Toxicity ......................................................................................................................... 31
Table 5.2: External Events ................................................................................................................... 31
Table 5.3: Proposed ANE Production Facility Hazardous Material Properties .................................... 34
Table 5.4: Rule Set for Scenarios Considered in QRA ........................................................................ 38
Table 5.5: Hazardous Scenarios Considered in FHA, Proposed ANE production facility ................... 39
Table 5.6: Hazardous Scenarios Considered in QRA, Existing Technical Center Facilities ................ 45
Table 6.1: QRA Basis, Proposed ANE PLant ....................................................................................... 46
Table 6.2: QRA Basis, Existing Kurri Facilities ..................................................................................... 47
Table 7.1: Fatality / Overpressure Correlation ..................................................................................... 48
Table 7.2: Impact Levels For Toxic Effects .......................................................................................... 50
Table 7.3: ANS and AN Explosion Efficency ........................................................................................ 51
Table 7.4: TNT Equivalence ................................................................................................................. 52
Table 7.5: Separation Distances Between Inventories ........................................................................ 53
Table 7.6: Consequence Analysis Results – Overpressures Proposed ANE PLant ............................ 63
Table 7.7: Consequence Analysis Results – AS2187.1 Separation Distances Proposed ANE Plant . 64
Table 7.8: Consequence Analysis Results – Overpressures for Existing TEchncial Centre Inventories65
Table 7.9: Consequence Analysis Results – AS2187.1 Separation Distances Existing Kurri Facilities66
Table 7.10: Consequence Analysis Results – NO2 Dispersion ............................................................. 69
Table 8.1: Orica Frequency Scale ........................................................................................................ 71
Table 9.1: Compliance with Individual Fatality Risk Criteria ................................................................ 72
Table 9.2: Compliance with Injury Risk Criteria .................................................................................... 73
Table 9.3: Compliance with Escalation Risk Criteria ............................................................................ 73
Table 9.4: Compliance with Toxic Injury / Irritation Risk Criteria .......................................................... 74
FIGURES
Figure 3.1: Site Location .................................................................................................................. 22
Figure 3.2: Kurri Kurri Technical Centre Site Layout ....................................................................... 23
Figure 3.3: Proposed ANE Plant Layout .......................................................................................... 24
Figure 7.1: Proposed ANE Plant Worst Case Explosion – Aggregate Inventory ............................ 55
Figure 7.2: Proposed ANE Production Facility - ANE (maximum storage) Explosion ..................... 56
Figure 7.3: Proposed ANE Plant – ANS Storage Tank (largest inventory) Explosion ..................... 57
Figure 7.4: Research Magazine and Quarry Services Explosion (Maximum NEQ) ........................ 59
Figure 7.5: Research Laboratory Explosion (Maximum NEQ) ........................................................ 60
Figure 7.6: Mixing Laboratory Explosion (Maximum NEQ) ............................................................. 61
Figure 7.7: Test Cell Explosion (Maximum NEQ) ............................................................................ 62
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ABBREVIATIONS
AEGL Acute Emergency Guideline Level
AEMSC Australian Explosive Manufacturers Safety Committee
AN Ammonium Nitrate
ANE Ammonium Nitrate Emulsion
ANS Ammonium Nitrate Solution
APZ Asset Protection Zone
AS Australian Standard
BOS (Orica) Basis of Safety
CSS
CoP
Construction Safety Study
Code of Practice
DG Dangerous Goods
DGRs (NSW DoP) Director General‟s Requirements
DoP (NSW) Department of Planning
EA Environmental Assessment
ERPG Emergency Response Planning Guideline
FHA
FRMP
Final Hazard Analysis
Fire Risk Management Plan
FSS
HAZOP
Fire Safety Study
Hazard and Operability study
HIPAP Hazard Industry Planning Advisory Paper
HIRAC Hazard Identification Risk Assessment and Control
KI Kooragang Island
MAE Major Accident Event
ML Mixing Laboratory
MMU Mobile Manufacturing Unit
MSDS Material Safety Datasheet
NEQ Net Explosive Quantity
NO Nitric Oxide
NO2 Nitrogen dioxide
NOx Oxides of nitrogen (includes NO, NO2 and others)
OXS Oxidiser Solution
PHA Preliminary Hazard Analysis
PW Protected Works
QRA Quantitative Risk Assessment
QS Quarry Services depot
RFS NSW Rural Fire Service
RL Research Laboratory
RM Research Magazine
SHE Safety Heath and Environment
TNT Trinitrotoluene
tpa Tonnes per annum
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UK HSE United Kingdom Health and Safety Executive
UN United Nations
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1 SUMMARY
Background
Orica Australia Pty Ltd (Orica) proposes to build a new Ammonium Nitrate Emulsion
(ANE) Production Facility at their existing Technology Centre site at Richmond Vale,
NSW to meet the projected regional ANE demand to 2020 and beyond. The
Technology Centre site currently undertakes research and commercial production of
various Class 1 explosives and Class 5 ANEs. The site is several kilometres away
from populated areas and the current explosives facilities are well separated from each
other and site boundaries, as the site complies with the quantity distance rules in
AS2187.1-1998 Explosives – Storage, Transport and Use Part 1: Storage.
The proposed ANE Production Facilities comprise the ANE Production Facility or Plant
and associated infrastructure such as offices and access roads. The proposed ANE
Production Facility will manufacture Class 5.1 ANEs classified as UN number 3375.
Materials meeting this classification are precursor materials which behave as
Dangerous Goods of Class 5 – Oxidisers, rather than as Class 1 – Explosives. These
materials undergo final processing at the point of use (eg at a mine site) and only
become explosives at that stage.
The NSW Department of Planning (DoP) Project Approval (09-0090, July 2010)
requires that a Final Hazard Analysis (FHA) be prepared in accordance with the DoP
Hazardous Industry Planning Advisory Papers No 6 Hazard Analysis Guidelines
(HIPAP 6) and No 4 Risk Criteria for Land Use Safety Planning (HIPAP 4).
Orica retained Sherpa Consulting Pty Ltd (Sherpa) to prepare the FHA.
Purpose and Scope
The overall objective of the FHA is to develop a comprehensive understanding of the
hazards and risks associated with the facility and the adequacy of the safeguards.
The FHA covers the proposed ANE Production Facilities and also potential interactions
with the existing facilities on the Technology Centre site. The FHA takes into account
the detailed design and outcomes of the Hazard and Operability study (HAZOP) and
Fire Safety Study (FSS) for the ANE plant.
Major Findings
The risk associated with the ANE plant area has been assessed and compared against
the DoP risk criteria.
There have been no changes to the project scope and design since the Preliminary
Hazard Analysis (PHA) was prepared which increase or otherwise alter predicted
offsite risk levels. Therefore the results of the FHA confirm the preliminary results
presented in the PHA. As per the PHA conclusions, the proposed facility complies with
all land use safety planning risk criteria.
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Hazardous Incidents
The potentially significant hazardous incidents identified were:
ANE Production Facility - explosions involving raw materials, ie ammonium
nitrate solutions (ANS) or ammonium nitrate, or emulsion products (ANE) due
to contamination or external heating.
ANE Production Facility – ANS decomposition and toxic decomposition product
(NOx) formation.
Existing Technology Centre facilities – explosion in existing Class 1 high
explosives, ANE or AN facilities. Note there are no significant toxicity impacts
associated with explosion of high explosives.
External factors were considered in the hazard identification. Bushfire was the only
identified external event of potential concern.
Methodology
The assessment followed the methodology given in HIPAP 6 and also the DoP
guideline Multi-Level Risk Assessment. For this study, sufficient quantitative analysis
was undertaken to identify the events with the potential to have an offsite impact on
people or property, including potential escalation effects from or to the existing site
facilities.
The ANE Production Facility assessment was prepared using maximum storage
inventories for individual scenarios, including an assessment of an aggregated Net
Explosive Quantity (NEQ) to cover an escalation scenario involving all susceptible
inventories in the ANE Production Facility. Assessment of the existing facilities was
also conservatively based on the maximum aggregate NEQ for each area.
Analysis of the consequences of these incidents on people or property was
undertaken using a TNT equivalent model for explosion effects and standard
air dispersion packages for toxic impacts (TNO Riskcurves, BP Cirrus and US
EPA ALOHA).
Evaluation of likelihood of the hazardous incidents occurring was based on the
order of magnitude frequency assessments from the qualitative frequency
rankings applied in Orica‟s hazard study workshops. Likelihood was assessed
only for those incidents where the consequence analysis showed offsite
impacts were possible.
Risk levels were compared with risk criteria given in HIPAP 4.
This is a level 2 risk assessment as defined in the Multi-Level Risk Assessment
guidelines. A level 2 approach was selected as the initial consequence assessment
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indicated only a small number of scenarios with the potential to have offsite impacts.
This approach was confirmed in the FHA.
Risk Results:
This study has found that there are no neighbouring hazardous inventories,
infrastructure or populations that may be affected by an explosion event. Due to the
large separation distances between the various hazardous inventories and the site
boundaries, very few events were identified with potential to cause injury or fatality
outside the site boundary. For those few events, the population potentially affected is
very low as the area within a one kilometre distance from the site boundary is largely
unpopulated. In summary:
No explosion events were identified associated with the ANE Production
Facilities or existing Technology Centre facilities with the potential to affect
offsite residential or industrial populations, or occupied buildings.
No explosion events were identified with the ANE Production facilities or
existing Technology Centre facilities with potential to damage offsite property or
infrastructure.
No explosion events were identified which would result in escalation incidents
between the proposed ANE Production Facilities and existing facilities at the
Technology Centre.
Dispersion modelling of toxic decomposition products (modelled as NO2) from a
worst case decomposition occurring in the largest ANE Production Facility
inventory demonstrated that there would be no offsite fatality effects. Injurious
concentrations would not be exceeded in any residential areas. Irritation effects
were possible in populated areas at a very low frequency (below the irritation
risk criterion).
The quantitative risk criteria are complied with as summarised in Table 1.1.
Safeguards:
The detail design stage for the project has been completed. Risk assessment activities
have occurred throughout the design process, including completion of a HAZOP and
FSS (which were reviewed to prepare the PHA and the FHA). In addition, quantitative
consequence explosion overpressure results were utilised early in the design process
to identify required separation distances between inventories and site boundaries,
determining the production facility location and layout.
Key safeguards include:
Minimisation of inventories to minimise offsite consequences of potential
explosion events.
Separation distances from site boundaries and existing facilities.
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Separation distances between any combustible material storages and Class
5.1 inventories.
Engineering controls such as automated control of ANE manufacture batch
process and high reliability low flow trips for emulsion pumps.
Asset protection zones to protect against bushfire impingement.
Recommendations
No recommendations in relation to additional engineering or layout safeguards are
made as part of the FHA.
It is recommended that the existing site (internal Orica) Fire Risk Management Plan
(FRMP) be updated to cover the proposed ANE Production Facilities. This should
specifically address extension of the existing site bushfire hazard reduction practices to
cover the ANE Production Facility area.
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TABLE 1.1: SUMMARY OF COMPLIANCE WITH RISK CRITERIA
Land Uses Max Risk (per year)
Comments Complies with HIPAP 4 Criteria?
Proposed ANE Prod Facility
Existing Tech Centre Facilities
Cumulative
Individual Fatality Risk
Sensitive uses 0.5 x 10-6
No fatality impacts in this land use
Y Y Y
Residential areas 1 x 10-6
No fatality impacts in this land use
Y Y Y
Commercial developments, retail centres, offices, entertainment centres
5 x 10-6
No fatality impacts in this land use
Y Y Y
Sporting complexes and active open space
10 x 10-6
No fatality impacts in this land use
Y Y Y
Remain within boundary of an industrial site
50 x 10-6
Event frequency does not exceed risk criterion.
Y Y Y
Injury Risk (Explosion) Risk
Fire / Explosion Injury risk - incident explosion overpressure at residential areas should not exceed 7 kPa at frequencies of more than 50 chances in a million per year
50 x 10-6
No injury impacts in this land use
Y Y Y
Escalation (Explosion) Risk
Overpressure at neighbouring potentially hazardous installations or the nearest public building should not exceed a risk of 50 per million per year for the 14 kPa overpressure contour.
50 x 10-6
No damage impacts in this land use
Y Y Y
Toxic Injury / Irritation Risk
Toxic Injury - Toxic concentrations in residential areas should not exceed a level which would be seriously injurious to sensitive members of the community following a relatively short period of exposure at a maximum frequency of 10 in a million per year
10 x 10-6
Injurious concentrations not experienced in residential areas
Y Y
Y
Toxic Irritation - Toxic concentrations in residential areas should not cause irritation to eyes, or throat, coughing or other acute physiological responses in sensitive members of the community over a maximum frequency of 50 in a million per year
50 x 10-6
Event frequency does not exceed risk criterion.
Y Y
Y
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2 INTRODUCTION
2.1 Background
Orica Australia Pty Ltd (Orica) currently operates an Ammonium Nitrate Emulsion
(ANE) Production Facility at their Liddell site. Liddell is the ANE manufacturing centre
for the South East Region, including the Hunter Valley, NSW and southern Australia.
To meet the projected regional demand for ANE to 2020 and beyond, the ANE
manufacturing capacity requires expansion. Orica proposes to meet this additional
demand by closing and decommissioning the current ANE manufacturing facility at
Liddell and constructing a new ANE manufacturing facility at their existing Technology
Centre site at Richmond Vale.
The NSW Department of Planning (DoP) Project Approval (09-0090, July 2010)
requires that a Final Hazard Analysis (FHA) be prepared in accordance with the DoP
Hazardous Industry Planning Advisory Papers Hazard Analysis Guidelines (HIPAP 6)
(Ref 1) and Risk Criteria for Land Use Safety Planning (HIPAP 4) (Ref 2).
Orica retained Sherpa Consulting Pty Ltd (Sherpa) to assist in completing the risk
assessment activities associated with the ANE Project, including preparing the FHA.
2.2 Objective
The objectives of the FHA were to:
Develop a comprehensive understanding of the hazards, risks and the
adequacy of the safeguards associated with the proposed ANE facility.
Establish the offsite risk levels from the proposed ANE facility and also
determine the cumulative offsite risk from all operations on the site and
compare these with the risk criteria given in HIPAP 4.
Prepare a report in accordance with HIPAP 6 for inclusion in the project EA that
satisfies the requirements of the NSW DoP.
2.3 Scope
The study covers:
the proposed ANE Plant and associated facilities (ANE Production Facilities);
and
the existing Technology Centre facilities at site, which will be unchanged by the
project.
2.4 Methodology
The assessment follows the methodology given in the NSW Department of Planning
(DoP) guideline Hazardous Industry Planning Advisory Paper (HIPAP) No. 6
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Guidelines for Hazard Analysis (HIPAP 6) (Ref 1) and is also consistent with the DoP
guideline Multi-Level Risk Assessment (Ref 3).
The main steps are:
Identification of hazards and description of potential incident scenarios. Hazard
identification and development of hazardous incident scenarios was conducted
using the Orica HIRAC (Hazard Identification Risk Assessment and Control)
process in a workshop attended by relevant site and engineering design
personnel. This included review of incidents known to have occurred at Orica‟s
sites and other similar facilities in the industry. Based on the HIRAC process,
scenarios with potential off-site impact were identified for further analysis. Refer
to Section 4 of this report for further details.
Analysis of the consequences of these incidents on people, property and the
biophysical environment. Consequences for explosion scenarios were
assessed using the TNT equivalence method. Toxic emission consequences
were assessed using information from the UK HSE to estimate quantities of
toxic gases formed in a fire leading to decomposition of AN solutions and a
Gaussian dispersion model in the BP Cirrus software to estimate toxic gas
effect distances (Refer to Section 7.3 of this report).
Evaluation of likelihood of the hazardous incidents occurring and the adequacy
of the safeguards provided. Likelihood was assessed using order of magnitude
estimates from the literature, supplemented by some information from the Orica
Ammonium Nitrate Draft Code of Practice (v8) available in Orica‟s SHE Risk
Register (Ref 4). Likelihood was assessed only for those incidents where the
consequence analysis showed offsite impacts were possible. (Refer to Section
8 of this report).
The resulting risk levels were obtained by combining the frequency and
consequence for each event of interest, which are then summed for all potential
recognised incidents. A separate summation is carried out for each
consequence of interest, eg injury, individual fatality etc.
Comparison of risk levels with appropriate risk criteria as detailed in HIPAP 4.
Safeguard Assessment: Using the information from the previous steps,
potential risk reduction measures were identified for further assessment as part
of the project process. (It is noted that recommendations generally related to
inventory reduction and were already included in the design covered by both
the PHA and this FHA, hence are not repeated as recommendations).
As suggested in the Multi-Level Risk Assessment guidelines, the frequency,
consequence and risk analysis can be carried out either qualitatively or quantitatively,
or using a combination of techniques.
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For this study, sufficient quantitative analysis was undertaken to identify the events
with the potential to have an offsite impact on people or property and also whether the
project will comply with the risk criteria published in HIPAP 4. This approach is known
as a Level 2 risk assessment. A level 2 assessment is appropriate as the initial
consequence modelling results were used to site the ANE Production Facilities (ie
contain effects within the site boundary), hence minimise the number of incidents that
could have offsite effects.
The major assumptions made to prepare the risk assessment are discussed in the
subsequent sections of this report and also summarised in APPENDIX E.
2.5 Risk Criteria
Individual risk represents the probability of a specified level of harm (usually fatality or
injury) occurring to a theoretical individual located permanently at a particular location,
assuming no mitigating action such as escape can be taken, hence it is considered to
cover vulnerable individuals such as the very young, sick or elderly.
NSW DoP quantitative individual risk criteria for new plants are given in HIPAP 4 and
are summarised inTable 2.1. These criteria are expressed in terms of individual fatality
risk or likelihood of exposure to threshold values of heat radiation, explosion
overpressure or toxicity.
Escalation criteria (ie likelihood of property damage to neighbouring facilities due to
exceeding specified overpressure or heat radiation levels) are also provided in HIPAP
4 and shown in Table 2.2.
TABLE 2.1: NSW INDIVIDUAL RISK CRITERIA, NEW PLANTS
Risks for Different Land Uses (New Plants) Maximum Risk (per year)
Individual Fatality Risk
Sensitive uses (hospitals, schools, childcare , old age) 0.5 x 10-6
Residential areas 1 x 10-6
Commercial developments, retail centres, offices, entertainment centres 5 x 10-6
Sporting complexes and active open space 10 x 10-6
Remain within boundary of an industrial site 50 x 10-6
Injury / Irritation - Fire / Explosion
Fire / Explosion Injury risk – incident heat flux radiation at residential areas should not exceed 4.7 kW/m
2 at frequencies of more than 50
chances in a million per year or incident explosion overpressure at residential areas should not exceed 7 kPa at frequencies of more than 50 chances in a million per year
50 x 10-6
Injury / Irritation - Toxic Impacts
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Risks for Different Land Uses (New Plants) Maximum Risk (per year)
Toxic Injury - Toxic concentrations in residential areas should not exceed a level which would be seriously injurious to sensitive members of the community following a relatively short period of exposure at a maximum frequency of 10 in a million per year
10 x 10-6
Toxic Irritation - Toxic concentrations in residential areas should not cause irritation to eyes, or throat, coughing or other acute physiological responses in sensitive members of the community over a maximum frequency of 50 in a million per year
50 x 10-6
TABLE 2.2: NSW ESCALATION RISK CRITERIA, NEW PLANTS
Description Risk Criteria (per year)
Escalation
Incident heat flux radiation at neighbouring potentially hazardous installations or land zoned to accommodate such use should not exceed a risk of 50 per million per year for the 23 kW/m
2 heat flux contour.
50 x 10-6
Overpressure at neighbouring potentially hazardous installations or the nearest public building should not exceed a risk of 50 per million per year for the 14 kPa overpressure contour.
50 x 10-6
Additionally HIPAP 4 states that the criteria apply to new industry and surrounding land
use proposals and in theory should apply to existing situations, however it recognises
that this may not be possible in practice. Individual fatality risk criteria for existing
plants are also available in HIPAP 4 and are given in Table 2.3.
TABLE 2.3: NSW RISK CRITERIA, EXISTING PLANTS
Description Risk from Existing Facility (per year)
note 1
Ongoing risk reduction and safety reviews of existing facility, no additional hazardous industry
≥ 10 x 10-6
No intensification of residential development ≥ 1 x 10-6
Notes:
1. Risk level within residential area
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2.6 Limitations
The study focuses on the offsite effects of potential accident scenarios. HIPAP 4 and 6
do not require quantification of, or provide criteria for, onsite risks to personnel /
employees, hence employee risk is not covered in this FHA.
The FHA does not assess any potential impacts from long-term or continuous
emissions, or occupational, health and safety issues that may arise from routine plant
operations. These are addressed via other mechanisms such as the Environmental
Assessment process and occupational health and safety management systems.
2.7 Links to Other Studies
Detail design for the project has been completed. Risk assessment activities have
occurred throughout the design process, including completion of a HAZOP in
accordance with Orica‟s internal project requirements. Related studies used to prepare
the FHA are listed below:
A Hazard Identification, Risk Assessment and Control (HIRAC) study for the
ANE Project, was undertaken. The HIRAC was used to develop the incident
scenarios included in the Preliminary Hazard Analysis (PHA, Ref 5). No
changes were found to be required to prepare the FHA.
A HAZOP study (Ref 6). The HAZOP study and action status were reviewed as
part of the FHA.
A Fire Safety Study (FSS) was undertaken to ensure the appropriateness of the
proposed fire prevention, detection and protection systems for potential fire
scenarios identified for the ANE plant. The FSS report also summarises the
existing fire prevention, detection and protection systems for the existing
facilities (Ref 7)
A Construction Safety Study (CSS) (Ref 8).
At the planning approval stage for the Technology Centre site, a hazard analysis for
the existing facilities was submitted to the NSW Department of Planning (1992, Ref 9).
The 1992 hazard study is no longer directly applicable as a number of the facilities
originally proposed for the site have not been installed. The 1992 report is superseded
by the information contained in this FHA report.
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3 SITE DESCRIPTION
3.1 Site Overview
The existing Technical Centre site is home to Orica‟s Mining Services Technical
Centre and undertakes research and development activities with some commercial
manufacturing. The existing facilities include:
Mixing Laboratory (ML)
Research Laboratory (including pilot scale manufacturing plant) (RL)
Research Magazine (RM)
Quarry Services Depot (QS)
Test Cell
There is also an existing office complex housing around 150 people.
The existing facilities will not be altered by the proposed ANE Production Facilities.
The number of people located permanently at the site would not increase significantly.
3.2 ANE Project Overview
The project will provide an ANE manufacturing facility together with associated
infrastructure at the Orica Technical Centre site. The new ANE manufacturing facility
will initially produce about 135,000 tonnes per annum (tpa) of ANE at the
commencement of operations in 2011. ANE production is forecast to increase to a
maximum production rate of 250,000 tpa over 10 to 15 years depending on customer
demand. The new ANE Production Facilities will be built using Orica Mining Services‟
global standard technology.
3.3 Location and Surrounding Land Use
The Orica Technology Centre site is located at George Booth Drive, Richmond Vale
NSW. The Technology Centre is located on Lot 2, DP 809377 and is approximately
292 hectares in area. The land is wholly owned by Orica. The surrounding area
encompasses a variety of land use activities including agriculture, bushland, rural
residential area, rural industrial activities and transport corridors.
There are aboveground power lines in an electrical easement running northwest to
south east across the front of the Orica site. An underground gas pipeline is proposed
to run within the electricity easement.
The land to the south, west and east of the site is predominantly bushland (Crown
land). An electrical easement runs east-west through this land around 500 m south of
the Orica site. There are fire trails throughout the area surrounding the Orica site and it
is possible that occasional recreational activities such as bushwalking or 4WD
activities occur in this area.
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The nearest industrial population or industrial infrastructure is Tasman Underground
Mine which is located approximately 2.5 km to the south-east of the Technology
Centre on George Booth Drive. The Sydney-Newcastle Freeway is around 4.5 km to
the south east.
The nearest residential area (rural residential rather than suburban) is to the north. The
nearest residence is a single house located 250 m north west of the northern site
boundary, ie around 1.8 km from the proposed ANE Plant location. Various farms
(chicken farm, flower farm) are also located in this area. The nearest residential areas
are Seahampton, which is around 6 km to the southeast of the site and Kurri Kurri,
which is around 7 km to the northwest.
The lots to the west of the Orica site have also been subdivided to large blocks (rural
residential) though are not yet occupied.
The site location is shown in Figure 3.1 with the approximate site boundary also
shown.
3.4 Site Security
As the site already handles security sensitive materials such as AN and Class 1
explosives, a site security plan is in place in accordance with the relevant regulations.
This includes personnel security checks, security fencing and access control, alarms
and security monitoring. These arrangements are unchanged by the proposed ANE
Plant.
The ANE Plant will also be provided with its own security fence.
3.5 Site Layout
The overall site layout is shown in Figure 3.2 (including the location of existing facilities
and the proposed ANE Plant). The proposed ANE Plant will be located in the south
part of the site, around 250m from the nearest site boundary. Figure 3.3 shows the
ANE Plant layout.
3.6 Australian Standard Separation Distances
Explosives facilities are generally sited and designed in accordance with AS2187.1-
1998 Explosives – Storage, Transport and Use Part 1: Storage and ANEs in
accordance with a Code of Practice (Ref 10) which has been developed by the
Australian Explosives Manufacturers Safety Committee (AEMSC), Code of Good
Practice Precursors For Explosives Edition 1 – 1999. Separation distance
requirements are explained in the following sections.
The quantity distance rules in AS2187.1 have been based on UK standards which
were in turn based on the observed effects of damage occurring in accidental
explosions that have occurred throughout the world up until the mid 20th century. It is
generally accepted by the explosives industry and regulators that compliance with
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AS2187.1 and the AEMSC Code will ensure that there will be minimal offsite
consequences or escalation effects from explosion events, ie the risk is negligible.
3.6.1 Class 1 Explosives
AS2187.1 contains quantity distance rules which specify separation distances to
various activities or occupied areas based on the Net Explosive Quantity (NEQ) at the
magazine or works. The separation distances are based on consequence (ie
overpressure level or impulse) developed by explosions of NEQs. The distances are
set to:
Prevent propagation between explosives storages and associated works.
Reduce risk to acceptable level for people associated with the site.
Minimise risk at protected works (PW) and vulnerable facilities. (Vulnerable
facilities are generally large populations who would be difficult to evacuate).
Protected works are defined as follows:
(a) Class A: Public street, road or thoroughfare, railway, navigable waterway, dock,
wharf, pier or jetty, market place, public recreation and sports ground or other open
place where the public are accustomed to assemble, open place of work in another
occupancy, river-wall, seawall, reservoir, above ground water main, radio or television
transmitter or main electrical substation, a private road which is a principal means of
access to a church, chapel, college, school, hospital or factory. (Known as PWA
distance).
(b) Class B: A dwelling house, public building church, chapel, college, school, hospital,
theatre, cinema or other building or structure where the public are accustomed to
assemble; a shop, factory, warehouse, store or building in which any person is
employed in any trade or business; a depot for the keeping of flammable or dangerous
goods; major dam. (Known as PWB distance)
Separation distances to „vulnerable facilities‟ (including but not restricted to schools,
hospitals, major places of transport, significant public infrastructure) are also defined.
Vulnerable facilities require the largest separation distances, with PWB the next largest
distance and PWA the smallest distance. There are no vulnerable facilities within 5 km
of the Technical Centre site. The nearest PWB is a single dwelling located 1.8 km
north west of the proposed ANE facility.
The existing Technical Centre site layout complies with the separation distances
required by AS2187.1. It is arranged so that the PWB distances are generally within
the site boundary.
3.6.2 Precursors
Since they are not explosives UN3375 ANEs are outside the scope of AS2187.
However a code of good practice (the AEMSC Precursor Code) covering explosives
precursors has been accepted by the majority of Australian jurisdictions, including
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NSW. Under the AEMSC Code, storages of ANE either adopt the same quantity
distances as explosives as per AS2187.1, or must be able to be evacuated in the
event of an emergency which could potentially lead to an explosion.
3.6.3 Oxidisers
Minimum separation distances for Class 5 materials such as ANS are given in AS4326
(2008) “The storage and handling of oxidising agents”. These are much smaller (of the
order of several metres) than the AS2187.1 distances adopted by the AEMSC Code.
The AS4326 distances generally are to provide separation between incompatible
materials, as well as personnel and site boundaries. For Class 5 ANEs the AS4326
distances would be the minimum requirement if there were no populations or other
explosives, AN or ANE inventories in the vicinity. Any installation meeting the AEMSC
Code will also comply with AS4326 separation distances.
3.6.4 Proposed ANE Plant
The proposed ANE Plant will be located such that all separation distances that would
apply to an equivalent amount of explosives under AS2187.1 Table 3.2.3.2 will be met
(ie the design adopts the guidance in the AEMSC Code). In this proposal there is no
reliance on evacuation for any offsite populations.
The FHA compares the predicted consequences for identified events with the required
distances as noted in subsequent sections of this report. This is to confirm that the
AS2187.1 distances are adequate to minimise risk associated with the proposed ANE
Plant.
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FIGURE 3.1: SITE LOCATION
Note: Figure reproduced from EA
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FIGURE 3.2: KURRI KURRI TECHNICAL CENTRE SITE LAYOUT
Note: Figure reproduced from EA
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FIGURE 3.3: PROPOSED ANE PLANT LAYOUT
ANE (4 tanks)
Dry oxidiser store
Combustibles
ANS and oxidising solutions
Dwg ref: 0516-G-1005 Rev B
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3.7 ANE Plant Process Overview
The proposed ANE Plant will make explosives precursors. All of the precursors to be
manufactured at the proposed ANE Plant will fall under the UN3375 classification for
Ammonium Nitrate Emulsions (collectively referred to as ANEs), ie will behave as
Dangerous Goods of Class 5 – Oxidisers, rather than Class 1 – Explosives. These
materials undergo final processing at the point of use and only become explosives at
that stage.
ANE is made up of a fuel blend and an oxidiser solution (predominantly ammonium
nitrate, AN). At the point of use (a mine site, not at the ANE Plant), the ANE is
processed into an explosive by sensitising it, usually by the introduction of gas
bubbles, microballoons or polystyrene. The gas bubbles may be generated by mixing
ANE with various “gasser” and /or “companion” solutions.
Companion and gasser solutions (which are weak solutions of Ammonium Nitrate or
Sodium Nitrite and water) will also be made up in the new ANE Plant area. These
solutions are not Dangerous Goods and will be kept separated from ANE to avoid any
potential contamination issues.
The emulsion products and companion/gasser solutions will be loaded onto tankers in
the ANE Plant. These tankers supply various Depot Plants situated close to customer
sites. The Depot Plants supply Mobile Manufacturing Units (MMUs), which deliver
products to customers.
The maximum ANE inventory in the ANE Plant is 120 tonnes (including all storage).
The ANE Plant is logically divided into the following sections:
Raw materials, comprising:
Ammonium Nitrate Solution (ANS) and other oxidiser solution raw materials
unloading and storage.
Fuel Blend Raw Material unloading and storage.
Oxidiser Solution (OXS) Batch Preparation (recipe based + development
mode).
Emulsion Manufacture (recipe based + development mode)
Emulsion Storage and Loading
Companion Solution Manufacture
Gasser solution Manufacture
Services, including power, process water, instrument air and hot water system.
Information for each of these sections has been summarised from the process
description (Ref 11) and is contained in APPENDIX A.
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3.8 Technology Centre Existing Facilities
The existing Technology Centre site undertakes various research and manufacturing
activities in four main areas on the site. Table 3.1 summarises these, including the
maximum inventories and types of explosive for each area to arrive at a Net Explosive
Quantity (NEQ) for each area.
The information shown in Table 3.1 reflects the most recent update of the site
Dangerous Good notification (August 2008). The quantity figures shown include all
process and storage inventories. The combined Quarry Services / Research Magazine
area has the largest NEQ (around 50 tonnes).
TABLE 3.1: EXISTING FACILITIES INVENTORY SUMMARY
Area Activities
(Includes process
inventory and storage)
(kg) (kg)
Research Magazine (RM) Storage - magazines Mag 5 4000 1 4000
and Mag 5A 3300 1 3300
Quarry Service Depot (QS) Mag 5B 2700 1 2700
Mag 9 + dets 220 1 220
TOTAL Magazines 10220
Storage - QS depot EP1 40000 0.68 27200
AN1 40000 0.32 12800
TOTAL QS Depot 40000
TOTAL RM and QS 50220
Research Laboratory (RL) Research activities
(processing)
RL1 process 2000 0.91 1820
Depot 4 (ANE) 5000 0.68 3400
Depot 2 (Nitrates - AN) 20000 0.32 6400
RL1 TOTAL 11620
Mixing Laboratory (ML) Research and
commercial activities
Mag 10 20 1 20
ML process 40 1 40
ML Exist Building aggregated 60
Depot 1 - AN 500 0.32 160
Depot 1 - ANE 500 0.68 340
ML New Building total aggregated 560
Test Cell Research activities
(processing)Test Cell 50 1 50
Explosives / precursors
used
Inventory TNT Equiv.
Factor
TNT
Equiv.
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4 REVIEW OF QRA BASIS AND PROJECT SAFETYSTUDIES
4.1 Review of QRA Basis
No major changes have been made to the layout, inventories or process technology
proposed for the ANE Plant. The following updates have been made to the design
compared to the PHA basis:
Minor layout changes. Updated layout provided in Figure 3.3.
Minor changes to proposed storage tank sizes for canola and paraffin. No
change in total combustible inventory. Updated quantities are given in
APPENDIX A.
Potential deletion of ANE chiller. This would result in a very small reduction in
the ANE inventory in the ANE plant. No changes have been made to modelling
to account for this (i.e. maximum inventories remain unchanged as shown in
Table 6.1).
4.2 Review of HAZOP
The HAZOP studies carried out for the ANE Plant have been reviewed with the aim of
identifying additional hazardous events or their causes, or additional safeguards or
systems proposed that would significantly change the basis and / or results of the
hazard and risk analysis presented in the FHA.
As stated in the HAZOP Report page 6 “The majority of actions arising from the
HAZOP fall into the “improved operability class”, i.e. minor or negligible risk issues, or
refer to updating of procedures etc”. None of the changes identified during the HAZOP
studies significantly alter the assumptions made in the FHA, hence will not change
offsite risk estimates.
It is noted that remote activation water injection will be provided to enable quenching in
ANS storage if a thermal excursion occurs (HAZOP Action ref 1124). This may reduce
th likelihood of a decomposition event. This safeguard has been added to the Hazard
ID table in Section 5.5.
4.3 Review of FSS
A review of the FSS was undertaken as part of this FHA. The FSS has been submitted
to the NSW Fire Brigades and the DoP. No comments have been received at the time
of preparing the FHA.
The FSS concluded that the ANE Plant presents a low fire risk, due to the minimal
quantities of flammables or combustible materials associated with the plant. It was also
concluded that the prevention, detection and fire fighting measures proposed for the
plant were adequate to respond to identified fire scenarios.
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4.4 Review of CSS
A CSS has been completed for the project and submitted to DoP. This has been
reviewed for the purposes of the FHA.
The CSS explicitly covers the particular hazards associated with the construction
period of the project and the measures proposed to control these hazards. The control
measures are largely based on existing Orica systems and procedures such as Permit
to Work, Emergency Procedures, Incident Reporting, Site Induction etc.
No issues that would alter the risk levels were identified. Due to the large separation
distance between the proposed ANE Plant and the existing site facilities, no potential
interactions were identified.
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5 HAZARD IDENTIFICATION
5.1 Hazardous Materials for Proposed ANE Plant
The hazardous materials associated with the proposed ANE Plant considered in this
risk assessment are listed below. Table 5.3 summarises their main hazards from the
Orica Material Safety Data Sheets and Basis of Safety (BOS) documents.
Ammonium nitrate solution (ANS) / Oxidiser solution (OXS)
Ammonium Nitrate Emulsion (ANE)
Ammonium Nitrate (AN)
Combustibles
Sodium Nitrite
5.1.1 AN and Oxidiser solutions
ANS is a class 5.1 oxidiser. The main hazard associated with handling AN solution
materials (ie ANS, OXS) is decomposition due to excessive heating and/or
contamination and eventually explosion if the decomposition gases are sufficiently
confined (eg in an inadequately vented storage tank, pump, process vessel etc).
Additionally, most of the gaseous decomposition products are toxic. These gases can
include ammonia (NH3), nitrous oxide (N2O), nitric oxide (NO), nitrogen dioxide (NO2)
and nitric acid vapour (HNO3). NO2 is the most toxic of these.
In general, assuming they are uncontaminated, ANS and OXS are highly insensitive to
friction and impact and essentially insensitive to sparks (ie low explosion risk).
5.1.2 Ammonium Nitrate Emulsions
ANEs are class 5.1. Most emulsions do not contain any self explosive ingredients but
once ANE has been produced, the main hazard is decomposition due to excessive
heating and/or contamination which can cause accelerating decomposition to the point
where explosion or detonation can occur especially if the decomposition gases are
sufficiently confined (eg in an inadequately vented storage tank, pump, process vessel
etc).
Sensitivity to accidental decomposition/detonation is increased by the presence of
energetic sensitising materials or chemical contaminants (eg excess sodium nitrite).
ANEs are insensitive to friction and impact and also insensitive to sparks.
5.1.3 Ammonium Nitrate
Although it is not combustible, Ammonium Nitrate (AN) is a Class 5 oxidiser and will
support combustion of other materials as it produces oxygen as one of its
decomposition products. If the decomposition gases are confined (eg in a storage tank,
process vessel etc) AN may explode. Most of the gaseous decomposition products are
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toxic (various NOx compounds, N2O etc), with nitrogen dioxide (NO2) the most toxic of
these.
Solid AN may explode under confinement and high temperature, but is not readily
detonated. High temperature, confinement and contamination are the main factors
which affect the likelihood and severity of an AN explosion. AN explosions can be
caused by a fire involving AN if there is sufficient confinement and/or contamination, or
by contamination without a fire if the decomposition rate is sufficiently high (with
sufficient confinement).
If none of these factors are present, solid AN requires a high energy shock wave (eg
from high explosive) to detonate. When molten it may decompose violently due to
pressure or shock.
5.1.4 Combustibles
C1 and C2 combustibles will be used at the ANE Plant. There will be no Class 3
(flammable) materials and all combustibles will be stored in bunded areas complying
with AS1940 Storage and Handling of Flammable and Combustible Liquids separated
from the ANE and ANS storage tanks by at least 30m.
Combustibles are difficult to ignite in the absence of a direct flame. Pool fires are
possible if a strong ignition source is present and a spill occurs, however the impact
area is local to the pool fire and will not extend offsite (given the distances of at least
several hundred metres from the combustible storage areas and site access road to
the site boundary).
Therefore the study considers combustible fires as a possible source of external heat
to the AN, ANE and ANS inventories only.
5.1.5 Sodium Nitrite
Similarly to AN, sodium nitrite is a strong oxidiser and will support combustion of other
materials. Heat, shock, or contact with other materials may cause fire or explosive
decomposition. It is incompatible with AN. It is also extremely toxic if ingested,
however it has no wider toxicity impacts except to the immediately affected individual.
For the assessment, sodium nitrite is treated as having the same hazards as AN.
5.1.6 Toxic Combustion / Decomposition Products
As noted above, nitrogen dioxide (NO2) is the most toxic of the decomposition products
formed in an AN / ANS / ANE decomposition reaction. NO2 is a respiratory irritant,
however its main danger lies in the delay before its full effects upon the lungs are
shown by feelings of weakness and coldness, headache, nausea, dizziness,
abdominal pain and cyanosis. In severe cases, convulsions and death by asphyxia
may follow exposure.
Effects on people are summarised in Table 5.1, reproduced from the Acute Emergency
Guideline Level (AEGL) documentation for NO2 (Ref 12).
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TABLE 5.1: NO2 TOXICITY
Table 2: Effects of acute exposure to high NO2 concentrations (from Ref 12)
NO2 Concentration (ppm) Effect
0.4 approximate odour threshold
15-25 respiratory and nasal irritation
25-75 reversible pneumonia and bronchiolitis
150-300+ fatal bronchiolitis and bronchopneumonia
5.2 Hazardous Materials at Existing Technical Centre Facilities
The existing facilities handle various high explosives of DG Class 1.1, Class 1.4 and
Class 1.5, as well as AN and ANE. The main hazard associated with Class 1 high
explosives is explosion with consequent overpressure and shrapnel / missile impacts.
There are no significant toxicity hazards associated with the explosives at the site.
5.3 External Events
As part of the hazard identification process, the potential for external events to affect
the proposed ANE Plant was considered as summarised in Table 5.2. Given the site is
surrounded by heavily vegetated Crown Land, bushfires were the only external event
identified as a potential concern and are discussed in more detail in Section 5.4.
TABLE 5.2: EXTERNAL EVENTS
Issue Discussion Summary
External Flooding Site is not considered a flood prone area.
Earthquakes According to GSHAP this area is classified as a low to moderate earthquake hazard.
Land slip/ subsidence
Mining in the area (nearest mine about 2 km away). Civil design has not indentified any potential subsidence issues.
Cyclones Not a high wind risk area. Facility structures designed in accordance with relevant codes.
Lightning Systems complying with relevant Australian Standards to be installed to manage the risks associated with lightning.
Plane crash Not in flight path. Risk not considered significant.
Vehicle crash Not exposed to outside traffic. Site speed limits and plant protection for structures installed to prevent vehicle impact on critical plant. Considered as an external fire source only.
Sabotage/ vandalism
Secure site as required by AN security sensitive regulations.
Utilities failure Loss of power results in “fail safe” condition. ANE Plant operation not possible. No other significant utilities on the ANE Plant site.
Bushfire Credible risk due to surrounding environment. Safeguards discussed in further detail in Section 5.4.
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5.4 Bushfires
5.4.1 Existing facilities
A comprehensive bushfire hazard reduction programme is in place for the existing
facilities at the Technology Centre site. This includes:
Cleared areas around all facilities, with further low fuel asset protection zones
(APZ) in accordance with the relevant NSW Rural Fire Service (RFS) Planning
for Bushfire Protection (PBP) 2006 guidelines.
Provision of leafguards and appropriate windows (non-openable) for all
buildings.
Provision of fire trails within and surrounding the site.
Regular programme of inspections by the RFS.
Yearly controlled hazard reduction and backburning operations undertaken by
the RFS (timing and location as advised by RFS).
Manual hazard reduction (ie clearing of vegetation within designated APZ).
Regular maintenance is also carried out as follows:
Low fuel zones up to 60 m from facilities including lawns, planted garden strips,
roads and pathways.
Fire trails checked regularly by trained site personnel with frequency increasing
during fire season.
Water levels checked daily, minimum of 200,000 litres retained for fire fighting.
Fire pumps, fire hoses and equipment checked monthly by site personnel.
Bushfires would normally approach the Kurri site from the west (as has historically
been the case). Fires can approach from the east but this is rare due to the terrain of
the site. The last serious bushfires experienced at the site were in 1996. These
approached the Kurri site on a 44oC day with westerly winds assisting the fire. The
fires were extinguished as they reached cleared areas such as roads and lawns, which
form part of the site‟s fuel reduced zones but kept burning to the west of the site.
Bushfire brigades and on-site crew remained onsite and no damage to facilities
occurred.
However it must be recognised that, if involved in a fire, the rate of decomposition and
confinement conditions, hence time to explosion is extremely unpredictable with all
explosives and ammonium nitrate compounds1 (including ANE, ANS, AN). Therefore
Orica have a policy of shutting down all operations and evacuation of all non-essential
personnel if an AN manufacturing, research or bulk storage site is threatened by fire.
1 Historical incidents (globally) have shown that AN compounds engulfed in flames often decompose
without explosion, but the fire response policy treats these as if they were explosives.
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The existing site Fire Risk Management Plan (FRMP) and Emergency Response Plan
(ERP) covers bushfire in this context. It would be extremely rare that a bushfire could
approach with no warning. There are several pre-planned safe egress routes available
depending on the location of the fire.
In the first instance a small crew of site personnel and security guards may remain
onsite to carry out certain functions providing they are safe and competent to do so.
5.4.2 Proposed ANE Production Facility
The approach to bushfire protection for the ANE Production Facility will be similar to
the approach for existing facilities and will be covered in the Emergency Response
Plan (ERP) and Fire Risk Management Plan (FRMP which is an Orica internal
requirement). The existing site FRMP and ERP will be updated to cover the ANE
Production Facility.
As required by the DGRs, a bushfire assessment (Ref 13) for the ANE Production
Facility has been undertaken in accordance with the NSW Rural Fire Service (RFS)
Planning for Bushfire Protection (PBP) 2006 guidelines. The proposed location of the
ANE Production Facility complies with the Asset Protection Zones (APZs) (ie
separation distances) required based on the slope, Fire Danger Index (FDI) rating and
the structure of surrounding vegetation. The required APZ around the ANE Production
Facility is shown in Figure 3.2. The APZ is 20 m on the northern, southern and eastern
sides of the proposed facility and 25 m from the western edge of the proposed facility.
As the ANE Plant is surrounded by a perimeter road plus an area cleared of vegetation
(the APZ), sustained direct impingement by a bushfire on an ANE or ANS inventory is
unlikely.
A 10,000 litre rainwater tank (non-combustible materials of construction) dedicated to
bushfire fighting purposes, fitted with suitable connections for the RFS tankers to refill,
will be provided adjacent to the front perimeter gate of the ANE Production Facility.
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TABLE 5.3: PROPOSED ANE PRODUCTION FACILITY HAZARDOUS MATERIAL PROPERTIES
Material Description State DG Class UN no Hazards Refs: Orica MSDS, BOS documents
Ammonium Nitrate Solution (ANS)
Ammonium Nitrate solution approx 80-90% AN, balance water
Solution normally at 90 – 100 oC
Liquid 5.1 PGII 2426 The main hazard associated with strong (>80 wt%) ANS is decomposition due to excessive heating or contamination and eventually explosion if decomposition gases are confined. Contaminants that increase the risk of decomposition include acids, chlorides, organics, alkali metals, nitrites. Most of the gaseous products of ANS decomposition are toxic (NOx gases).
ANS does not burn, but as an oxidising agent, will support fire, even in the absence of an external source of oxygen. ANS is insensitive to friction and impact and also insensitive to sparks.
Oxidiser Solution (OXS)
Ammonium Nitrate solution 70% AN with balance pH adjustment materials such as caustic, acetic acid, ammonia and water.
Liquid 5.1 PGII 2426 As per ANS
Ammonium Nitrate Emulsion (ANE)
A mixture of around 70% AN, 15% water and balance combustible liquids. All bulk emulsions at the proposed ANE Production Facility at Kurri will fall within the UN definition of Ammonium Nitrate Emulsion (ANE), intermediate for blasting explosives, UN number 3375.
Liquid 5.1 PGII 3375 None of the ANE to be manufactured at the proposed site will contain any self-explosive ingredients but once the ANE has been produced, excessive heating can cause accelerating decomposition to the point where thermal explosion or detonation can occur. Sensitivity to accidental decomposition/detonation is increased by the presence of energetic sensitising materials or chemical contaminants (eg excess sodium nitrite). ANEs are insensitive to friction and impact and also insensitive to sparks
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Material Description State DG Class UN no Hazards Refs: Orica MSDS, BOS documents
Ammonium Nitrate (AN)
Technical grade AN. > 98% AN, other materials < 2%
Solid (prill)
5.1 PGIII 1942 Ammonium Nitrate (AN) is a strong oxidising agent that will sustain combustion as it produces oxygen as one of its decomposition products. May explode under confinement and high temperature, but not readily detonated. When molten may decompose violently due to shock or pressure. Contaminants that increase the risk of decomposition / explosion include combustibles, hypochlorite, organics, alkali metals, nitrites. Most of the gaseous products of AN decomposition are toxic (various NOx gases).
Combustible liquids
Various – diesel, paraffin, canola etc
Liquid C1 or C2 various Combustible, ie will ignite if sustained strong ignition source is present.
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5.5 Potential Hazardous Incident Scenarios
The potential hazardous incidents associated with the ANE Production Facility were
identified by:
Review and consolidation of hazardous scenarios identified in the Orica Hazard
Study 2 for the ANE Production Facility Project, the HIRAC for the existing Liddell
ANE Production Facility, HIRACs for generic ANE Plants and HIRACs for other
similar Orica plants.
A two day workshop to review the consolidated HIRACs for the ANE Production
Facility Project, which was attended by relevant Orica personnel.
The HIRAC is a study undertaken in a workshop attended by relevant operations and
design personnel. It included discussion of incidents known to have occurred at Orica
sites and other similar facilities in the industry. Hazardous incidents and safeguards
are identified and discussed and a qualitative risk ranking applied using the Orica
corporate risk matrix. The consolidated HIRAC minutes for the ANE Upgrade Project
are available in the SHE Risk Register.
Detailed scenarios have not been provided in the FHA due to potential security
concerns. However a brief description of the HIRAC process and a list of HIRAC
scenarios are included in APPENDIX B. It should be noted that some scenarios were
considered to have local rather than off-site consequences. These were not carried
forward for quantitative analysis in this study.
5.5.1 Proposed ANE Plant
The significant hazardous incidents identified were consolidated into discrete scenarios
to allow a quantitative model to be developed. The hazardous incidents (referred to as
major accident events or MAEs) included in the FHA are listed in Table 5.5 for
proposed ANE Production Facility.
The MAEs are all very similar in terms of the physical scenario, but have been set up
separately in the quantitative models as they are applicable to different production
facility areas and inventories.
5.5.2 Existing Technical Centre Facilities
An upper limit scenario for each existing area at the site was defined. This scenario is
the explosion of the maximum NEQ in each operational area as summarised in Table
5.6. The inventories used to define the potential explosion scenarios are given in Table
3.1.
5.6 Scenarios for Quantitative Assessment
APPENDIX D tabulates the input to the quantitative model for each scenario. The
assumptions made to develop the consequence and frequency for the QRA scenarios
are discussed in Sections 6 and 8 of this report.
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5.7 Rule Sets for Incident Inclusion
A rule set for inclusion in the risk assessment was developed based on the properties
of the materials and the results of the HIRAC study. The rule set:
Identifies the causes which can result in an explosion in Class 1, ANS, ANE or
AN materials.
Distinguishes between a scenario which develops over time (ie a “with warning”
explosion where evacuation is possible) and a “no warning explosion” (where
evacuation would not be possible).
Identifies which materials are susceptible to knock-on (ie sympathetic initiation)
from an explosion event.
Essentially:
External fire or contamination could cause explosion in Class1 explosives, AN,
ANE or ANE inventories.
Class 1 explosives, AN and ANE are susceptible to sympathetic detonation,
ANS is not.
This is summarised in Table 5.4. This is a generic rule set, hence covers some items
not applicable to the proposed ANE Production Facility. AN will be handled in bags
only (ie AN Stacked), there is no bulk AN.
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TABLE 5.4: RULE SET FOR SCENARIOS CONSIDERED IN QRA
Rev Date Prepared By Checked By
A 10-Nov-08 J Polich
(Sherpa)
Ian Dennison
(Orica)
Project: Proposed ANE Plant Kurri Kurri, QRA
Objective: Rule set for determining which explosion scenarios to include in consequence modelling / QRA
Applicability: Explosives / AN/ ANE / ANS Storage and Handling.
Not manufacturing / processing of any Explosives on the ANE plant.
KEY:
Yes Credible (even if very low likelihood)
No Not possible
n/a not applicable - physical configuration not relevant
Without warning explosion (evacuation not possible)
Warning (evacuation possible)
Material (Note 1) Cause of explosion Escalation potential - from another source event
Fire engulfment Contamination Other (undefined
miscellaneous)
Explosion (blast)(Note 3)
Projectile(Note 3)
Propagation from
pump explosion
(connected)
Class 1 Yes Yes Yes Yes Yes Yes
ANE Yes Yes No Yes Yes Yes (Note 2)
ANS Yes Yes No No No No
AN bulk Yes Yes No Yes Yes n/a
AN stacked Yes Yes No Yes Yes n/a
Notes:
1. Material is on spec and uncontaminated (except for "contamination" cause)
2. Except for case where diaphragm pump is used. Knock on from diaphragm pump not possible.
3. Distances required to avoid risk of knock on are specified in AS2187 for AN. The same distances apply to ANE as per AEMSC code.
Ref: Scenario Rule Sets Excel 2003 ID Rev 2.xls
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TABLE 5.5: HAZARDOUS SCENARIOS CONSIDERED IN FHA, PROPOSED ANE PRODUCTION FACILITY
ID Major Accident Event (MAE) Description
Causes Controls and Safeguards Incorporated in FHA?
External Events
All Bushfire threatens ANS / ANE / AN inventory. Decomposition, toxic fume emission and eventual explosion
1. Bushfire in surrounding environment.
Asset protection zones (APZ) maintained around all facilities as per RFS guidelines
Firewater tank for RFS use
Evacuation of non-essential personnel
Firefighting to protect inventory (spot fire extinguishment etc)
Y
Raw Materials Storage and Handling
ANS-01 External fire causes decomposition in ANS storage. Toxic fume emission and eventual explosion.
1. Electrical fire 2. Vehicle fire 3. Human failure
followed by failure to control fire.
Minimal fuel / combustible material in the area – sustained fire extremely unlikely
Vehicles separated by kerbing and bollards from storage areas - Vehicle fire impingement extremely unlikely
Quench water injection facilities (manual, remote activation)
Y
ANS-02 Contamination causes decomposition in ANS storage. Toxic fume emission and eventual explosion.
1. Human error followed by failure to control decomp reaction.
Density measurement of incoming product, Option to adjust pH.
Temperature monitoring and high temp alarms in storage tanks
Tanks are well vented (increases available time for evacuation)
Quench water injection facilities (manual, remote activation)
Y
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ID Major Accident Event (MAE) Description
Causes Controls and Safeguards Incorporated in FHA?
ANS-03 Heating or contamination causes decomposition in ANS unloading pump. Pump explosion.
1. Dry running or dead heading 2. Friction or impact 3. Contamination or compositional change
Initial explosion would not have off-site impact, given the limited inventory in the pump.
Propagation to ANS bulk storage not credible (where there is no contamination and concentration is below 92%).
N
ANS-04 Fire on board ANS delivery tanker causes decomposition of ANS. Toxic fume emission and eventual explosion.
1. Tyre fire 2. Engine fire followed by failure to control decomposition reaction
Vehicle maintenance
Tyre fire more likely en-route (not parked)
Fire extinguishers on tanker
Driver trained in emergency procedures
Y
DSL-01 External fire impinges on fuels storage area. Failure of fuel storage tank and progression to significant fire.
1. Electrical fire 2. Vehicle fire 3. Fuel transfer pump fire. 4. Human failure 5. Chemical decomposition
No offsite effects from pool fire heat radiation as site boundaries several hundred metres away. Separation distance (around 30m) means escalation to ANE / ANS storage very unlikely. Pool fire consequences not covered in QRA, however fire considered as a cause of explosion in ANE / ANS storage as per ANS-01, OXS-01, ANE-01
N
DSL-02 Combustible delivery tanker fire while onsite
1. Electrical fire 2. Vehicle fire
No offsite effects from pool fire heat radiation as site boundaries several hundred metres away from delivery road and tanker delivery location. Separation distance (around 30m) means escalation to ANE / ANS storage very unlikely.
N
OXS-01 External fire causes decomposition in OXS batch tank. Toxic fume emission and eventual explosion.
1. Electrical fire followed by failure to control fire.
Minimal fuel / combustible material in the area – sustained fire extremely unlikely
Y
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ID Major Accident Event (MAE) Description
Causes Controls and Safeguards Incorporated in FHA?
OXS-02 Contamination causes decomposition in OXS batch tank. Toxic fume emission and eventual explosion.
1. Impurities 2. Incorrect batch sequence or quantities followed by failure to control decomposition reaction.
Raw material QA
Operating procedures
Y
OXS-03 Heating or contamination causes decomposition in oxidiser solution pump. Pump explosion.
1. Dry running or dead heading 2. Friction or impact 3. Contamination or compositional change
Pumps trip in the event of low flow or elevated temperatures.
Initial explosion would not have off-site impact, given the limited inventory in the pump. However, missiles from the explosion may knock-on to the ANE tank. Propagation to ANS bulk storage not credible (where there is no contamination and concentration is below 92%).
Y
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ID Major Accident Event (MAE) Description
Causes Controls and Safeguards Incorporated in FHA ?
ANE Manufacture
ELK-01 External fire causes decomposition in ELK. Toxic fume emission and eventual explosion.
1. Electrical fire 2. Vehicle fire 3. Human failure followed by failure to control fire.
Minimal fuel / combustible material in the area – sustained fire extremely unlikely
Y
ELK-02 Heating or contamination causes decomposition in ANE transfer pump. Pump explosion.
1. Dry running or dead heading 2. Friction or impact 3. Contamination or compositional change
Pumps trip in the event of low flow or elevated temperatures.
Initial explosion would not have off-site impact, given the limited inventory in the pump. However, missiles from the explosion may knock-on to the ELK. Propagation to main ANE inventory may also occur. This is one cause of explosion of ANE inventory, not covered as a separate scenario.
N
ANE-01 External fire causes decomposition in ANE storage. Toxic fume emission and eventual explosion.
1. Electrical fire 2. Vehicle fire 3. Human failure 4. Chemical decomposition followed by failure to control fire.
Minimal fuel / combustible material in the area – sustained fire extremely unlikely
An explosion can only be produced if there is some degree of confinement – for example, storage in a sealed container. Tanks are well vented (increases available time for evacuation)
Y
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ID Major Accident Event (MAE) Description
Causes Controls and Safeguards Incorporated in FHA ?
ANE-02 Heating or contamination causes decomposition in NAPCO gear pump. Pump explosion.
1. Dry running or dead heading 2. Contamination or compositional change
Initial explosion would not have off-site impact, given the limited inventory in the pump. Note: Trials have shown that propagation to main ANE inventory not credible for gear pumps due to the relatively low energy input and high heat dissipation from the pump casing.
N
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ID Major Accident Event (MAE) Description
Causes Controls and Safeguards Incorporated in FHA?
AN Store
AN-01 Fire in Dry Oxidiser store results in explosion in store
1. Electrical faults 2. Vehicle fire 3. External fire
Minimal fuel/combustible kept in the store.
Y
AN-02 Contaminated AN results in decomposition and store explosion
1. Fuel spill 2. Contaminated product delivered
Product quality tested at point of manufacture. Fuel minimised in area?
Y
Escalation Scenarios
Esc-01 Explosion in ANE Plant area results in sympathetic detonation of ANE Plant aggregated inventory
All causes except ANS storage explosion
Propagation to ANS not possible, rupture of ANS storage tanks may occur, however this will result in a spill, not a net increase in NEQ as ANS is not susceptible to shock detonation
Y
Esc-02 Explosion in ANS storage area results in sympathetic detonation of ANE Plant aggregated inventory including ANS initiating storage inventory.
ANS storage Y
Esc-03 Explosion results in hot shrapnel, initiating a bushfire
All causes Refer to Biophysical Risk, Section 9.5.1 Y
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TABLE 5.6: HAZARDOUS SCENARIOS CONSIDERED IN QRA, EXISTING TECHNICAL CENTER FACILITIES
ID Major Accident Event (MAE) Description
Causes Controls and Safeguards Incorporated in FHA?
RM/QS-01
Explosion in Research Magazine or Quarry Services Depot which propagates to involve entire inventory in this plant location
All causes Located and designed in accordance with AS 2187 series.
Y
ML-01 Explosion in Mixing Lab which propagates to involve entire inventory in this plant location
All causes Located and designed in accordance with AS 2187 series
Y
RL-01 Explosion in Research Laboratory which propagates to involve entire inventory in this plant location
All causes Located and designed in accordance with AS 2187 series
Y
TC-01 Explosion in Test Cell which involves entire inventory in this plant location
All causes Located and designed in accordance with AS 2187 series
Y
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6 QRA BASIS
To carry out the QRA, a number of assumptions were made with respect to the
quantities of material stored. For this study, the proposed ANE Plant is assessed as
per the inventory basis given in Table 6.1. The maximum storage inventories have
been adopted as the basis for the plant, with a worst case scenario represented by an
aggregate NEQ including all relevant inventories in the proposed ANE Plant. This is a
conservative approach to the assessment, but is considered to be appropriate for a
QRA conducted for land use planning purposes. The assumptions used to estimate the
NEQ shown in the last column of the table are explained in Section 7.3. It is assumed
that no changes to the oxidiser inventories.
TABLE 6.1: QRA BASIS, PROPOSED ANE PLANT
Plant Area as used in QRA scenarios
Proposed ANE Plant Comments
Inventory (t) Proportion of Time (%)
NEQ (note 1)
(t)
ANS Storage Tank
330 100 30.2 Maximum inventory of largest ANS Tank (250kL is approximately equivalent to 330t at 88.5 wt% concentration). 100% full is conservative
(note 2)
ANS Tanker 26 Single
38 B-Double
n/a 4.8 Loads expected to be delivered in single Tankers or B-Doubles.
OXS Batch Tank
80 100 6.4 Maximum inventory of largest Batch Tank
ELK unit 2 100 1.4 Estimate. 100% usage is conservative.
ANE Storage Tank
120 100 81.6 4 adjacent tanks, each 30t (note 3).
100% full is conservative as tanks are operated as surge capacity and total quantity will be limited to 100t procedurally.
Dry Oxidiser Stores
20 100 6.4 Rarely used ingredients for OXS. AN less than 9.6t, calcium nitrate 8t. Separate store for 8t sodium nitrite A total of 20t AN is assumed for the risk assessment to cover all dry oxidiser materials.
ANE Plant aggregate
470 n/a 118 1 x largest ANS tank (330t), ANE inventory, 4 x 30t plus Dry Oxidiser store max inventory of 20t AN (equivalent)
Notes: 1. Refer to Section 7.3 for assumptions used to calculate NEQ.
2. ANS is not susceptible to sympathetic detonation (where there is no contamination and concentration is below 92%) hence the single largest inventory rather than the aggregate inventory is considered (refer to Section 5.7).
3. ANE is susceptible to sympathetic detonation hence the aggregate inventory is considered (refer to Section 5.7).
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Assessment of the existing plant is also conservatively based on the maximum NEQ
for each area. The NEQs are summarised in Table 6.2. Also see Table 3.1 for further
details as to how the NEQs were calculated.
TABLE 6.2: QRA BASIS, EXISTING KURRI FACILITIES
Existing Area NEQ (t) (note 1)
Proportion of Time (%)
Comments
Research Magazine (RM) and Quarry Services Depot (QS)
50.2 100 Combined inventory due to proximity of RM and QS. Conservative to assume all inventories are 100% full
Research Laboratory (RL) 11.6 100 Conservative to assume all inventories are 100% full
Mixing Laboratory (ML) 0.56 100 Conservative to assume all inventories are 100% full
Test Cell 0.05 100 Conservative to assume all inventories are 100% full
Notes: 1. Refer to Table 3.1 for assumptions used to calculate NEQ.
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7 CONSEQUENCE ANALYSIS
7.1 Overview
For this study, consequence analysis involves qualitative and / or quantitative review of
the identified hazardous scenarios to estimate the potential to cause injury/fatality. The
events of interest in the study are explosions and toxic emissions due to
decomposition of AN or AN solutions, ANE or Class 1 explosives that may result in
injury or fatality. Explosions may be caused by a thermal event (eg external fire) or
contamination.
7.2 Effect Levels of Interest
7.2.1 Overpressure
Overpressure levels are equated to different impacts (ie injury or probabilities of
fatality) as summarised in Table 7.1. These criteria are based on the levels given in
HIPAP 4.
TABLE 7.1: FATALITY / OVERPRESSURE CORRELATION
Overpressure (kPa)
HIPAP 4 description Probability of Fatality assumed in QRA
Inside Building Outside
7 Damage to internal partitions and joinery but can be repaired. Probability of injury is 10%. No fatality.
- -
14 Houses uninhabitable and badly cracked.
1% 0.1%
21 Reinforced structures distort. Storage tanks fail. 20% chance of fatality for a person in a building.
20% 1%
35 House uninhabitable. Wagons and plant items overturned. Threshold of eardrum damage. 50% chance of fatality for a person in buildings and 15% chance of fatality for a person in open.
50% 15%
70 Threshold of lung damage. 100% chance of fatality for a person in a building or in the open. Complete demolition of houses.
100% 100%
7.2.2 Toxicity Effects
The toxic decomposition products of AN (as NO2) have the potential to cause acute
toxic effects. The values used to assess toxicity impacts are summarised in Table 7.2.
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Fatality
Probability of fatality is usually estimated using probit equations of the form:
Pr = A + b ln(cnt)
Pr Probit value
A, b Constants specific to each material.
c concentration (ppm)
t time exposed to concentration (min)
erf error function (mathematical)
These can then be converted to a probability of fatality using the error function
transform:
Probability = 0.5(1 + erf(2
5Pr))
Injury / Irritation
HIPAP 4 injury and irritation risk criteria for toxic gas exposure were given in Table 2.1.
The PHA makes the following interpretations:
Serious Injury: occurs due to toxic exposure to the lower of the Acute Exposure
Guideline Level 2 (AEGL-2) and Emergency Response Planning Guideline Level 2
(ERPG-2) concentrations. AEGL-2 is the airborne concentration of a substance above
which it is predicted that the general population, including susceptible individuals, could
experience irreversible or other serious, long-lasting adverse health effects or an
impaired ability to escape. ERPG-2 is defined as the maximum airborne concentration
below which nearly all individuals could be exposed for up to 1 hour without
experiencing or developing irreversible or other serious health effects or symptoms that
could impair an individual's ability to take protective action.
Irritation: occurs due to toxic exposure to the lower of the AEGL-1 and ERPG-1
concentrations. AEGL-1 is the airborne concentration of a substance above which it is
predicted that the general population, including susceptible individuals, could
experience notable discomfort, irritation, or certain asymptomatic, non-sensory effects.
However, the effects are not disabling and are transient and reversible upon cessation
of exposure. ERPG-1 is defined as the maximum airborne concentration below which
nearly all individuals could be exposed for up to 1 hour without experiencing more than
mild, transient adverse health effects or without perceiving a clearly defined
objectionable odour.
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TABLE 7.2: IMPACT LEVELS FOR TOXIC EFFECTS
Material Concentration
1% Fatality at 30mins exposure
Serious Injury (AEGL-2 Ref. 12 or
ERPG-2 Ref. 14)
Irritation (AEGL-1 Ref 12 or
ERPG-1 Ref 14)
Probit (Ref 15 (ppm
n min)
ppm ppm Ppm
Nitrogen dioxide (NO2) -16.19+ ln(c3.7
t) 65 12 0.5
7.2.3 Escalation
Two types of escalation are considered, consequence results for both levels of interest
have been generated as follows:
Third party property damage. As per the criteria in HIPAP 4 shown in Table 2.2,
NSW DoP suggest 14kPa as a criterion for assessing property damage
potential due to explosion overpressure.
Detonation of another explosives or ANE inventory. In this case the escalation
event of concern onsite would be explosion in one area generating high energy
projectiles or an impulse that then initiates an explosion in other areas with
larger effects than the initial explosion. The AS2187.1 (1998) Table 3.2.3.2
separation distances (and associated formulas) are used as the threshold
where shock or projectiles from an event in the ANE Plant could cause a
detonation in another onsite explosives or ANE facility or vice versa, ie whether
the existing facilities could impact the proposed ANE Plant and vice versa.
7.3 Explosion Consequence Assessment Assumptions
The TNT equivalent model is used to estimate explosion overpressure effects. This
method involves:
1. Equating the explosive or oxidiser of interest into an equivalent mass of TNT.
This is known as the Net Explosive Quantity (NEQ).
2. Estimating the distance to the overpressure levels of interest using a scaling
law known as the TNT overpressure vs. scaled distance relationship.
7.3.1 TNT Equivalent Mass for AN or ANS
To equate AN or ANS to an equivalent mass of TNT, three factors are considered as
follows:
NEQ = x α e MassAN
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Proportion of material present that is sensitised to explosion (x):
This is set at 100% for this study for AN. High temperature, confinement and
contaminants sensitise Ammonium Nitrate to explosion however are not
expected to extend uniformly to the entire AN inventory (particularly for a bulk
store). Therefore setting this factor to 100% for AN and ANS is considered a
conservative assumption.
(Note that this factor is not relevant for ANE or Class 1 explosives as an
explosion will always propagate through the whole inventory, ie always 100%
involvement).
Efficiency (α): The proportion of the sensitised material that actually detonates
in the explosion. Orica‟s AN Draft Code of Practice (CoP) (Ref 4) has been
based on a review of published effects of AN and ANS explosion events that
have occurred. The values suggested in the CoP for AN or ANS have been
adopted for this study and are summarised in Table 7.3.
TNT equivalence (e): Essentially a ratio of the blast energy produced by the
explosive of interest to the blast energy produced by the same quantity of TNT.
Refer to Section 7.3.2 for details for ANS and AN and Section 7.3.3 for ANE.
TABLE 7.3: ANS AND AN EXPLOSION EFFICENCY
Materials Explosion initiator Efficiency (α) Comments
Strong (>80%) ANS
Unconfined decomposition
0.3 A storage tank well vented /
frangible roof etc, reactor etc
that allows decomposition
products to freely vent
Confined decomposition
0.6 Road tanker, storage with small
vents, PSV
AN Fire 0.16 AN Draft Code of Practice
Contamination 0.5 AN Draft Code of Practice
High energy projectile
1 AN Draft Code of Practice
7.3.2 TNT Equivalence for AN and ANS (e)
The literature has a range of values for AN (solid) equivalence, ranging from around
0.32 to 0.57. Orica‟s draft AN Code of Practice (CoP) has been based on a review of
published data and the equivalence values suggested in the CoP have been adopted
for this study as shown in Table 7.4. (This is the value used for “e” in the equation in
Section 7.3.1).
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7.3.3 TNT Equivalence for ANE
Estimates for TNT equivalence of ANEs range from 0.10 to 0.70. For the types of
ANEs to be produced at the new ANE Production Facility, a value of 0.68 has been
selected as shown in Table 7.4.
This is derived from Orica's proprietary "Ideal Detonation" modelling software IdeX.
The IDeX software derives TNT equivalence from the isentropic expansion energy for
the chosen explosive relative to the same energy for TNT. This software is well-
validated as it is in routine use as the basis on which Orica conducts blast modelling
and blast design on a commercial basis.
TABLE 7.4: TNT EQUIVALENCE
Material Equivalence
(e) Comments
ANS 0.353 Specified in Orica Draft AN Code of practice
AN 0.32 Specified in Orica Draft AN Code of practice
ANE 0.68 Orica's Ideal Detonation code IDeX
7.3.4 TNT Equivalence for Class 1 Explosives
TNT equivalence for Class 1 explosives is generally 1. However there are some
materials in the existing facilities with a lower TNT equivalence. This has already been
accounted for in the NEQ calculations as shown in Table 3.1.
7.3.5 Scaled Overpressure
Overpressure versus scaled distance relationships are presented as equations or
graphs. In this case the Kingery and Bulmash correlation is used to estimate the
scaled distance (Z) from the overpressure of interest (Ref 16). The Kingery and
Bulmash correlation is as follows:
P = exp(A + B.Xo + C.Xo2 + D.Xo
3 + E.Xo4)
Xo = ln(Zo)
Zo = d / NEQ0.333
Where:
Zo scaled distance (m/kg0.333)
d distance at particular overpressure level (m)
P overpressure (kPa)
NEQ Net Explosive Quantity (kg)
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Refer to APPENDIX C for the Kingery and Bulmash coefficients (A,B,C,D,E), the
overpressure (P) levels of interest and solutions to the equation, as these coefficients
vary depending on Zo.
7.4 Explosion Scenario Consequence Results
Consequence modelling results for all potential explosion scenarios included in the risk
assessment are detailed in APPENDIX C for both the proposed ANE Production
Facility and existing facilities. The results include estimated distances to the
overpressure levels of interest (as per the rule sets in Table 7.1) and identification of
the events which cause overpressures sufficient to cause injury or fatality offsite.
The separation distances between the existing explosive inventories and the proposed
ANE Production Facility, have been estimated from the site layout (see Figure 3.2 and
Figure 3.3) and are summarised in Table 7.5.
As noted in Section 3.3, the nearest residence is around 1.8 km from the proposed
ANE Production Facility location, the nearest industrial population and infrastructure is
around 2.5 km away and the nearest major road (F3 freeway) is around 4.5 km away
from the site boundary.
TABLE 7.5: SEPARATION DISTANCES BETWEEN INVENTORIES
7.4.1 Proposed ANE Production Facility
Overpressure results for the proposed ANE Plant are summarised in Table 7.6. The
required separation distances to other inventories based on AS2187.1 Table 3.2.3.2
are shown in Table 7.7.
The following conclusions can be made:
Distances to the 21 kPa level (capable of causing fatality to individuals located
outside – ie not in a building) remain within the site boundary which is a
minimum of 260 m away for all scenarios except for an escalated event
resulting in sympathetic detonation of the maximum aggregated NEQ in the
ANE Production Facility. The escalated event 21 kPa consequence distance
Separation Distance (m) Receptor
Source Proposed ANE Plant
(ANS areas)
Proposed ANE Plant
(Dry Oxidiser store)
Nearest Site
Boundary
Direction of Nearest
Site Boundary
Proposed ANE Plant (ANS
areas)
- 30 260 South
Proposed ANE Plant (Dry
Oxidiser store)
30 - 280 South
Research Magazine (RM) and
Quarry Service Depot (QS)
355 325 635 East
Research Laboratory (RL) 555 525 715 North east
Mixing Laboratory (ML) 850 820 480 North
Test Cell 215 185 450 South
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extends around 100 m beyond the southern boundary into the unpopulated and
undeveloped Crown Land. It is contained within the site boundary in all other
directions.
Distances to the 14 kPa level (capable of causing fatality to individuals located
inside a building) range from approximately 100 – 340 m for individual inventory
explosions and up to around 520 m for an escalated event involving the
aggregated ANE Production Facility inventory (extending around 250m beyond
the site boundary to the south and contained within the boundary in all other
directions). However the overpressure effects do not extend to any buildings or
populations (industrial or residential) as the land to the South of the site is
undeveloped Crown land with no buildings for at least 2 km. The nearest
residence (to the north) is more than 1800 m away from the proposed ANE
Production Facility, the rural subdivision (potential occupied buildings) to the
west is at least 1000 m from the proposed ANE Production Facility area.
An overpressure of 14 kPa is also capable of causing property damage,
however this overpressure level does not extend to any offsite infrastructure
(industrial, busy roads etc). The electrical easement to the south of the site and
the power lines and (not yet installed) underground gas lines running through
the Technical Centre site, are also more than 700 m away from the proposed
ANE Production Facility area. The maximum overpressure at the easement
area in a worst case event is around 7-8 kPa, hence infrastructure will not be
significantly affected by an explosion in the proposed ANE Production Facility.
Distances to an overpressure of 7 kPa (capable of causing injury) for a number
of scenarios including explosion in largest inventory ANS tank, an ANS tanker,
OXS batch tank or ANE tank, or the escalated event involving the aggregate
ANE Production Facility inventory extend offsite up to 600m beyond the
southern boundary (contained within site boundary in all other directions)
however do not extend to any offsite populations (industrial, busy roads or
residential).
Figure 7.1 to Figure 7.3 show the results for some representative scenarios, including
the worst case scenarios (ie aggregate inventory of proposed ANE Production Facility
including all the ANE and the largest ANS inventory in Figure 7.1 and, in Figure 7.2 the
aggregate inventory of proposed ANE Production Facility including the only the ANE
inventory).
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FIGURE 7.1: PROPOSED ANE PLANT WORST CASE EXPLOSION – AGGREGATE INVENTORY
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FIGURE 7.2: PROPOSED ANE PRODUCTION FACILITY - ANE (MAXIMUM STORAGE)
EXPLOSION
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FIGURE 7.3: PROPOSED ANE PLANT – ANS STORAGE TANK (LARGEST INVENTORY)
EXPLOSION
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7.4.2 Existing Facilities
Overpressure results for the maximum explosives inventories in the existing facilities
are summarised in Table 7.8, with AS2187.1 separation distances given in Table 7.9.
The results are shown graphically in Figure 7.4 to Figure 7.7. The following
conclusions can be made:
No events with potential offsite fatality effects to outdoor populations (21 kPa
overpressure) were identified.
No events with potential offsite damage potential or fatality effects to
populations inside buildings (14kPa overpressure) were identified.
One event with potential offsite injury impact was identified (Research
Magazine/ Quarry Store Depot 7 kPa overpressure contour extends around
20m across the southern boundary in Crown Land). However the impact does
not extend to any offsite populations (industrial, busy roads or residential).
Escalation to the proposed ANE Production Facility / AN storage area is
extremely unlikely given the separation distances comply with AS2187.1.
These results confirm that compliance with the AS2187.1 quantity distance rules
minimises offsite risks associated with explosion events.
7.5 Onsite Escalation
Based on the separation distance rules in AS2187.1 it can be concluded from the
consequence results presented in Table 7.9, that there is no risk of escalation from the
existing facilities to the proposed ANE Production Facilities.
The worst case event defined for the proposed ANE Production Facilities (ie
sympathetic detonation of all inventories due to a decomposition in the largest ANS
tank as shown in Figure 7.1) may result in a knock-on to the Test Cell area as shown
in Table 7.7.
The Test Cell does not have a permanent inventory and even if in use, the maximum
Test Cell NEQ is 50 kg (compared to an NEQ of more than 120,000 kg for the worst
case ANE Production Facility event). Hence including this additional inventory would
have minimal impact on the worst case predicted consequence distances and not alter
the conclusions of the consequence and risk assessment.
This is also a “with warning” event as defined in Table 5.4 hence the Test Cell area
would be evacuated if it were being used at the time an ANS decomposition occurred
(protecting onsite personnel).
It can therefore be concluded that the worst case event in the ANE Production
Facilities does not have the potential to cause an escalated event with additive
consequences between the existing and proposed facilities, ie the proposed ANE Plant
is sufficiently separated from the existing facilities with any significant explosive
inventories to ensure that there is minimal risk of escalation between the proposed and
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existing facilities. This conclusion remains true for all initiating causes (including
bushfire).
FIGURE 7.4: RESEARCH MAGAZINE AND QUARRY SERVICES EXPLOSION (MAXIMUM NEQ)
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FIGURE 7.5: RESEARCH LABORATORY EXPLOSION (MAXIMUM NEQ)
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FIGURE 7.6: MIXING LABORATORY EXPLOSION (MAXIMUM NEQ)
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FIGURE 7.7: TEST CELL EXPLOSION (MAXIMUM NEQ)
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TABLE 7.6: CONSEQUENCE ANALYSIS RESULTS – OVERPRESSURES PROPOSED ANE PLANT
QRA Scenario Consequence Model Parameters Distance to Overpressure (kPa)
(m)
Distance to
nearest
boundary (m)
Potential
Offsite fatality
effect (i.e.
>21kPa at
boundary)
Potential Offsite
fatality effect
(i.e. >14kPa at
boundary)
Potential
Offsite injury
effect (i.e.
>7kPa at
boundary)
Discuss in
QRA?
Area MAE Ref MAE Description Material Max storage
quantity (te)
proportion
AN
Theoretical
Mass Avail
for Explosion
(te)
Equivalence Efficiency NEQ
(kg)
70 35 21 14 7 2
ANS Storage ANS-01
ANS-02
ANS-03
Explosion in ANS storage tank due to contamination or
external fire
ANS 330 0.885 292.05 0.353 0.3 30928 121 178 247 329 564 1415 260 N Y Y Y
ANS Storage ANS-04 Explosion in ANS tanker ANS 26 0.885 23.01 0.353 0.6 4874 65 96 133 178 305 764 260 N N Y Y
OXS Batch Tank OXS-01
OXS-02
OXS-03
Explosion in OXS batch tank due to contamination or
external fire
ANS 80 0.83 66.4 0.353 0.3 7032 74 109 151 201 344 863 260 N N Y Y
ELK Area ELK-01
ELK-02
Explosion in ELK ANE 2 1 2 0.68 1 1360 43 63 87 116 199 499 260 N N N N
ANE Storage ANE-01
ANE-02
Explosion in single ANE storage tank due to contamination
or external fire
ANE 30 1 30 0.68 1 20400 105 155 215 287 491 1231 260 N Y Y Y
ANE Storage ANE-01
ANE-02
Explosion in all (4) ANE storage tanks due to
contamination or external fire
ANE 120 1 120 0.68 1 81600 167 246 341 455 780 1955 260 Y Y Y Y
AN Storage AN-01 Explosion in Dry Oxidiser store due to contamination AN 20 1 20 0.32 0.5 3200 57 84 116 155 265 664 280 N N N N
AN Storage AN-02 Explosion in Dry Oxidiser store due to fire AN 20 1 20 0.32 0.16 1024 39 57 79 106 181 454 280 N N N N
AN Storage AN-03 Explosion in Dry Oxidiser store due to missile / high
energy shock wave
AN 20 1 20 0.32 1 6400 72 105 146 195 334 837 280 N N Y Y
AN Storage
(offspec)
Explosion in Dry Oxidiser store due to contamination AN (off
spec)
0 1 0 0.32 0.5 0 0 0 0 0 0 0 280 N N N N
ANE Plant all
inventory
ESC-01 ANE plant - ANS storage tank explosion and sympathetic
detonation, aggregate inventory including largest ANS (1 x
350 te ANS, 4 x 30te ANE and 20 te AN)
ANS+ANE+A
N
470 as per
individual
scenarios
as per
individual
scenarios
as per
individual
scenarios
as per
individual
scenarios
118928 190 279 387 516 884 2216 280 Y Y Y Y
ANE Plant all
inventory
ESC-02 ANE plant - knock on (any causes except ANS explosion)
and sympathetic detonation, aggregate inventory (4 x
30te ANE and 20 te AN)
ANE + AN 140 as per
individual
scenarios
as per
individual
scenarios
as per
individual
scenarios
as per
individual
scenarios
88000 171 252 350 467 800 2005 280 Y Y Y Y
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TABLE 7.7: CONSEQUENCE ANALYSIS RESULTS – AS2187.1 SEPARATION DISTANCES PROPOSED ANE PLANT
QRA Scenario Consequence Model Parameters Separation distances as per AS2187.1 1998 Table 3.2.3.2
(m)
Escalation
Area MAE Ref MAE Description Material Max storage
quantity (te)
proportion
AN
Theoretical
Mass Avail
for Explosion
(te)
Equivalence Efficiency NEQ
(kg)
Explosives
(unmounded)
D = 4.8 NEQ1/3
Explosives
(mounded)
D = 2. 4NEQ1/3
Process
building
D = 8 NEQ1/3
AN
(unmounded)
D = 1.8 NEQ1/3
Class A PW
Note 1
Class B PW
(unmounded)
Note 2
Class B PW
(mounded)
Note 2
Distance to
Nearest Existing
Explosives
Inventory (Test
Cell)
Potential onsite
escalation effect
(AS2187)
ANS Storage ANS-01
ANS-02
ANS-03
Explosion in ANS storage tank due to contamination or
external fire
ANS 330 0.885 292.05 0.353 0.3 30928 151 75 251 57 465 697 697 215 N
ANS Storage ANS-04 Explosion in ANS tanker ANS 26 0.885 23.01 0.353 0.6 4874 81 41 136 31 251 376 376 215 N
OXS Batch Tank OXS-01
OXS-02
OXS-03
Explosion in OXS batch tank due to contamination or
external fire
ANS 80 0.83 66.4 0.353 0.3 7032 92 46 153 34 284 425 425 215 N
ELK Area ELK-01
ELK-02
Explosion in ELK ANE 2 1 2 0.68 1 1360 53 27 89 20 123 180 184 215 N
ANE Storage ANE-01
ANE-02
Explosion in single ANE storage tank due to contamination
or external fire
ANE 30 1 30 0.68 1 20400 131 66 219 49 404 607 607 215 N
ANE Storage ANE-01
ANE-02
Explosion in all (4) ANE storage tanks due to
contamination or external fire
ANE 120 1 120 0.68 1 81600 208 104 347 78 642 963 963 215 N
AN Storage AN-01 Explosion in Dry Oxidiser store due to contamination AN 20 1 20 0.32 0.5 3200 71 35 118 27 204 311 311 185 N
AN Storage AN-02 Explosion in Dry Oxidiser store due to fire AN 20 1 20 0.32 0.16 1024 48 24 81 18 102 180 152 185 N
AN Storage AN-03 Explosion in Dry Oxidiser store due to missile / high
energy shock wave
AN 20 1 20 0.32 1 6400 89 45 149 33 275 412 412 185 N
AN Storage
(offspec)
Explosion in Dry Oxidiser store due to contamination AN (off
spec)
0 1 0 0.32 0.5 0 0 0 0 0 0 0 0 n/a N
ANE Plant all
inventory
ESC-01 ANE plant - ANS storage tank explosion and sympathetic
detonation, aggregate inventory including largest ANS (1 x
350 te ANS, 4 x 30te ANE and 20 te AN)
ANS+ANE+A
N
470 as per
individual
scenarios
as per
individual
scenarios
as per
individual
scenarios
as per
individual
scenarios
118928 236 118 393 89 728 1092 1092 215 Y
ANE Plant all
inventory
ESC-02 ANE plant - knock on (any causes except ANS explosion)
and sympathetic detonation, aggregate inventory (4 x
30te ANE and 20 te AN)
ANE + AN 140 as per
individual
scenarios
as per
individual
scenarios
as per
individual
scenarios
as per
individual
scenarios
88000 214 107 356 80 658 987 987 215 N
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TABLE 7.8: CONSEQUENCE ANALYSIS RESULTS – OVERPRESSURES FOR EXISTING TECHNCIAL CENTRE INVENTORIES
QRA Scenario Consequence Model Parameters Distance to Overpressure (kPa)
(m)
Distance to
nearest
boundary
(m)
Potential
Offsite
fatality
effect (i.e.
>14kPa at
boundary)
Potential
Offsite
injury effect
(i.e. >7kPa
at
boundary)
Discuss in
QRA?
Area MAE Ref MAE Description Material Max storage
(te)
NEQ
(kg)
70 35 21 14 7
Research Magazine
(RM) and Quarry
Service Depot (QS)
RM/QS-01 Explosion in Research
Magazine or Quarry
Services Depot which
propagates to involve
entire inventory in this
plant location
Explosive n/a 50220 142 209 290 387 663 635 N Y Y
Research
Laboratory (RL)
ML-01 Explosion in Mixing Lab
which propagates to
involve entire inventory
in this plant location
Explosive n/a 11620 87 129 178 238 407 715 N N N
Mixing Laboratory
(ML)
RL-01 Explosion in Research
Laboratory which
propagates to involve
entire inventory in this
plant location
Explosive n/a 560 32 47 65 86 148 480 N N N
Test Cell TC-01 Explosion in Test Cell
which involves entire
inventory in this plant
location
Explosive n/a 50 14 21 29 39 66 450 N N N
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TABLE 7.9: CONSEQUENCE ANALYSIS RESULTS – AS2187.1 SEPARATION DISTANCES EXISTING KURRI FACILITIES
QRA Scenario Consequence Model
Parameters
Separation distances as per AS2187.1 1998 Table 3.2.3.2
(m)
Escalation
Area MAE Ref MAE Description Material NEQ
(kg)
Explosives
(unmounded)
D = 4.8 NEQ1/3
Explosives
(mounded)
D = 2.
4NEQ1/3
Process
building
D = 8 NEQ1/3
AN
(unmounded)
D = 1.8 NEQ1/3
Distance to
Proposed
ANE Plant /
AN Store
Potential onsite
escalation effect (i.e.
less than AS2187
process building sep
distance to ANE Plant /
AN Store inventory)
Research Magazine
(RM) and Quarry
Service Depot (QS)
RM/QS-01 Explosion in Research
Magazine or Quarry
Services Depot which
propagates to involve
entire inventory in this
plant location
Explosive 50220 177 89 295 66 325 N
Research
Laboratory (RL)
ML-01 Explosion in Mixing Lab
which propagates to
involve entire inventory
in this plant location
Explosive 11620 109 54 181 41 525 N
Mixing Laboratory
(ML)
RL-01 Explosion in Research
Laboratory which
propagates to involve
entire inventory in this
plant location
Explosive 560 40 20 66 15 820 N
Test Cell TC-01 Explosion in Test Cell
which involves entire
inventory in this plant
location
Explosive 50 18 9 29 7 185 N
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7.6 Toxic Effects Consequence Assessment
The impact of toxic releases was assessed using the following methodology:
1. Estimating the amount of toxic material released
2. Estimating the distances to the toxic levels of interest (as defined in Section
7.2.2) using dispersion models.
Dispersion modelling assumed:
Ambient temperature: 25 oC
Typical stability / windspeeds: D 5 m/s and F 2 m/s
Surface roughness: 0.1 m
7.6.1 NOx Source Term Estimation
The amount of NO2 likely to be released from a fire involving AN solution materials
(ANS, OXS, ANE) was estimated by extrapolating the experimental results from
measurements of toxic emission from fires involving solid AN conducted by the UK
HSE (Ref 17). Although the results are for solid AN in a fire, there does not appear to
be a similar model for ANS in the public domain. The UK HSE work has been used as
the results are likely to be broadly conservative, given that the event could only occur if
a sustained fire occurred as water would have to be driven off the ANS before
decomposition to liberate NO2 can occur.
Two AN fire scenarios were considered by the UK HSE:
Scenario A: A large fire in combustible goods co-stored with AN. In this case, the
decomposition of the AN is driven by thermal radiation from the fire. The highest
emission of NO2 recorded in the experiments for this scenario was 3 g/s (for a 1 m2
molten pool of AN). It was also noted that in radiant fires large enough and hot
enough to initiate significant decomposition of co-stored AN, the decomposition
products will become entrained into the fire combustion products. These will be hot
and will generally lead to the decomposition of the NO2, with the result that NO will
be the dominant emission.
Scenario B: A self-sustaining combustion reaction between AN and timber palleting
on which it is stored. The experimental work indicated that 10 g/s of NO2 was
produced for a wooden pallet consumed in a fire. A correlation between the NO2
emission rate and the number of wooden pallets involved in the fire is provided in
the paper.
Scenario A was considered to be more representative of the fire scenarios modelled in
this QRA, ie there is no direct fire impingement and decomposition is the result of
radiant heat from external fires. The NO2 emission rate for this QRA was estimated
from the UK HSE results by assuming that the NO2 emission rate is related to source
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area, ie the NO2 flux is constant. Based on a surface area of 50 m2 for the largest
ANS/ANE tank, the NO2 emission rate modelled in this study is 151 g/s.
Again this is thought to be very conservative as radiant heat impact from an external
fire will be uneven ie from one side only and a constant mass emission rate from the
whole liquid surface is very unlikely.
7.6.2 Dispersion Modelling Results
Dispersion of NO2 was modelled using the BP Cirrus passive release dispersion
model. Although NO2 is denser than air at ambient conditions, NO2 emissions in this
study are likely to be buoyant due to the radiant heat effects from the fire. NO2
temperature was assumed to be 150 oC (as it decomposes to NO at 160 oC).
Consequence modelling results for the toxic scenarios considered in the QRA are
summarised in Table 7.10.
The results show:
Toxic releases do not result in concentrations offsite capable of causing fatality
Injurious levels (ERPG2 or AEGL2) are not exceeded in residential areas
Irritating levels of toxic decomposition gases (evolved during extended
exposure of a large ANS / ANE tank to heat radiation) may be experienced
several kilometres from the site and may extend to residential areas. However
it should be noted that the AEGL1 endpoint of 0.5 ppm is very low and large
dispersion distances (> 10 km) are estimated for F2 conditions. Dispersion
models such as those used in this study cannot accurately model behaviour
over more than a few kilometres as they do not take into account changing
terrain (slope, obstacles, channelling etc) or changes in meteorological
conditions, hence tend to over-predict effect distances.
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TABLE 7.10: CONSEQUENCE ANALYSIS RESULTS – NO2 DISPERSION
Scenario Distance to Following Ground Level Concentrations – F2 (m)
Distance to Following Ground Level Concentrations – D5 (m)
1% fatality Probit
AEGL-2 12ppm
AEGL-1 0.5ppm
1% fatality Probit
AEGL-2 12ppm
AEGL-1 0.5ppm
Toxic NOx emission from ANS decomposition in storage tank (0.151 kg/s)
Not found 1400 > 10,000 (Note 1)
Not found 100 2600
NOTES: 1. Dispersion distances over 10 km are highly unreliable as atmospheric conditions and terrain would not remain constant.
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8 FREQUENCY ANALYSIS AND RISK RESULTS
The frequency of an event is defined as the number of occurrences of the event over a
specified time period; with the period in risk analysis generally taken as one year.
Ideally statistical data would be used to estimate the likelihood of the identified
hazardous events occurring. However for rare events there is often insufficient data to
estimate a statistically valid frequency hence “best estimates” based on industry
knowledge can be made as described below.
The main focus of this QRA is to compare the offsite risk levels from the proposed
ANE Production Facilty with the criteria given in HIPAP4. Therefore estimation of
frequency is only carried out for the small number of events identified in the
consequence analysis in Section 6 where an offsite impact was identified.
8.1 Individual Fatality Risk
As per Section 6, only one event (in the proposed or existing facilities), an escalated
event involving the aggregated inventory in the proposed ANE Plant, was identified
with a potential offsite fatality impact (ie overpressure exceeding 21 kPa in outdoor
areas). However this impact did not extend to any residential, sensitive, recreational or
commercial areas.
In addition, the nearest (potentially) occupied building to the proposed ANE Production
Facility is in subdivided area to the west of the Orica site more than 1100 m away, with
the nearest (actually) occupied building to the north west 1800 m away from the
proposed ANE Production Facility.
No events (in the proposed or existing facilities) were identified with a potential offsite
fatality impact (ie overpressure exceeding 14 kPa) in any offsite buildings.
It can therefore be concluded that (regardless of the event frequencies) the offsite
fatality risk in the land uses where risk criteria are defined is minimal and fatality risk
contours have not been prepared.
8.1.1 Boundary Risk
The boundary risk criterion is 50 x 10-6 per year. This criterion is primarily aimed at
minimising risk to neighbouring hazardous industries (of which there are none adjacent
to the Technical Centre site). There is only one event with a fatality effect (ie 21 kPa
overpressure) at the site boundary, an escalated event involving the aggregated
inventory in the proposed ANE Production Facility.
8.1.2 Escalated Event Frequency
To provide a comparison with the criterion a frequency estimate needs to be made for
this event. The HIRAC process included ranking of each event using the Orica
frequency scale (shown in Table 8.1) and also identified any known events similar to
the hazardous incident scenario under discussion.
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Orica has stored and manufactured ANEs for over 30 years (as have other
companies). Orica currently has several thousand ANE tanks at around 500 sites
globally (and estimates a similar number operated by other companies). Across this
large number of sites there are no known occurrences of an escalated event of this
nature for sites with similar levels of control.
The two potential causes of explosion in any individual inventory (hence source of a
sympathetic detonation) are contamination and sustained heat source. External fires
are extremely unlikely as the combustible materials are located in a separate bund at
least 30m away from the ANE Production Facility area. ANS delivery and ANE
collection vehicles are also in a separate sealed area and separated from the tanks by
a least a few metres. Similarly to the existing facilities, bushfire risks will be controlled
primarily through maintenance of an APZ around the facility.
Contamination of incoming ANS is highly unlikely since it is controlled via strict
manufacturing and quality assurance procedures at Orica‟s Kooragang Island siteand
any serious contamination would become evident during the journey as it would cause
emission of visible NOx fumes.
Taking into account the safeguards included (as per the HIRACs and as summarised
in Table 5.5), all large or sustained decomposition events were rated as “very unlikely”,
corresponding to a frequency of around 1x10-5 per annum per event, with a
subsequent explosion at least a factor of 10 lower or “extremely unlikely”.
Therefore in the absence of any sound historical frequency data, a frequency of 1x10-6
per year is judged to be applicable to an escalated explosion event. Note that a fault
tree approach is also possible however would also only arrive at an order of magnitude
judgement at best. It is therefore concluded that the frequency of the escalated event
is well below the boundary risk criterion of 50x10-6 per year.
TABLE 8.1: ORICA FREQUENCY SCALE
Likelihood Qualitative Description Range (per annum)
Almost Certain Will occur at least once a year > 1
Very Likely Very likely to occur at least once during a 10 year period of operation of the facility/business
10-1
to 1
Likely (possible)
Has occurred at least once during the operating life of the facility/business
10-2
to 10-1
Unlikely Known to have happened within the industry: periodically in small industries and more often in large industries
10-4
to 10-2
Very Unlikely Has occurred somewhere in the world in all related industries
10-6
to 10-4
Extremely Unlikely
Could theoretically occur but not aware of any instances
< 10-6
(around 10-7
)
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9 RISK ASSESSMENT
9.1 Individual Fatality Risk
Due to the large separation distances to populated areas and the large buffer zones
between operational areas and the site boundary, very few (worst case) events have
potential offsite impact. In addition, given the safeguards in place, event frequencies
for worst case events are low hence the individual fatality risk criteria are complied
with.
Table 9.1 gives a summary of compliance with the HIPAP4 individual fatality risk
criteria.
TABLE 9.1: COMPLIANCE WITH INDIVIDUAL FATALITY RISK CRITERIA
Land Uses Max Risk Comments Complies with HIPAP 4 Criteria?
(per year) Proposed ANE Plant
Existing Kurri Facilities
Cumulative
Sensitive uses 0.5 x 10-6
No fatality impacts in this land use
Y Y Y
Residential areas 1 x 10-6
No fatality impacts in this land use
Y Y Y
Commercial developments, retail centres, offices, entertainment centres
5 x 10-6
No fatality impacts in this land use
Y Y Y
Sporting complexes and active open space
10 x 10-6
No fatality impacts in this land use
Y Y Y
Remain within boundary of an industrial site
50 x 10-6
Event frequency does not exceed risk criterion.
Y Y Y
9.2 Explosion Injury Risk
Overpressure injury criteria are defined only for residential areas. As noted in the
results in Section 6 there were no events identified where injurious overpressures
would be experienced in residential areas.
Hence (regardless of frequency) the overpressure injury risk criterion (10x10-6 per year
in residential areas) is satisfied as summarised in Table 9.2.
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TABLE 9.2: COMPLIANCE WITH INJURY RISK CRITERIA
Land Uses Max Risk Comments Complies with HIPAP 4 Criteria?
(per year) Proposed ANE Plant
Existing Kurri Facilities
Cumulative
Fire / Explosion Injury risk –incident explosion overpressure at residential areas should not exceed 7 kPa at frequencies of more than 50 chances in a million per year
50 x 10-6
No injury impacts in residential land use
Y Y Y
9.3 Escalation Risk (Offsite Property)
Escalation criteria are defined for public buildings or neighbouring hazardous industry,
(rather than general or onsite infrastructure). As noted in the results in Section 6, there
were no events identified where overpressures capable of causing property damage
would be experienced in neighbouring installations (which are many kilometres away).
Hence the overpressure damage risk criterion (50x10-6 per year) is automatically
satisfied (regardless of frequency) as summarised in Table 9.3.
TABLE 9.3: COMPLIANCE WITH ESCALATION RISK CRITERIA
Land Uses Max Risk Comments Complies with HIPAP 4 Criteria?
(per year) Proposed ANE Plant
Existing Kurri Facilities
Cumulative
Overpressure at neighbouring potentially hazardous installations or the nearest public building should not exceed a risk of 50 per million per year for the 14 kPa overpressure contour.
50 x 10-6
No damage impacts outside the site boundary
Y Y Y
9.4 Toxic Injury / Irritation Risk
Toxic injury and irritation criteria are defined only for residential areas. Potential toxicity
effects were assessed only for the proposed ANE Production Facility as there are no
significant toxicity effects associated with Class 1 explosives and existing inventories
of AN and ANE are relatively small in comparison to the proposed ANE Production
Facility.
Assessment results compared against the risk criteria are summarised in Table 9.4
with further discussion in Sections 9.4.1 and 9.4.2.
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TABLE 9.4: COMPLIANCE WITH TOXIC INJURY / IRRITATION RISK CRITERIA
Land Uses Max Risk Comments Complies with HIPAP 4 Criteria?
(per year) Proposed ANE Plant
Existing Kurri Facilities
Cumulative
Toxic Injury - Toxic concentrations in residential areas should not exceed a level which would be seriously injurious to sensitive members of the community following a relatively short period of exposure at a maximum frequency of 10 in a million per year
10 x 10-6
Injurious concentrations not experienced in residential areas
Y n/a Y
Toxic Irritation - Toxic concentrations in residential areas should not cause irritation to eyes, or throat, coughing or other acute physiological responses in sensitive members of the community over a maximum frequency of 50 in a million per year
50 x 10-6
Event frequency does not exceed risk criterion.
Y n/a Y
9.4.1 Injury Risk
As noted in the results in Section 7.6, there were no events identified where injurious
toxicity impacts due to NOx formed during ANS decomposition events would be
experienced in residential areas (which are many kilometres away). Hence the toxic
injury risk criterion (10x10-6 per year in residential areas) is automatically satisfied.
9.4.2 Irritation Risk
As noted in the results in Section 7.6, emission of toxic decomposition products from a
large ANS/ ANE storage tank due to an external fire or contamination may result in
irritation due to toxic decomposition products being experienced in residential areas
under some wind weather conditions (F2).
To allow a comparison to the risk criteria, an estimate of frequency of decomposition
(not explosion) in ANS storage is required. There are very few reported events of this
nature involving ANS and ANE. The HIRAC process included ranking of each event
using the Orica frequency scale (shown in Table 8.1) and also identified any known
events similar to the hazardous incident scenario under discussion.
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As discussed in Section 8.1.1, the two potential causes of decomposition are
contamination and sustained heat source, both of which are very unlikely due to the
safeguards in place.
Taking into account the safeguards included (as per the HIRAC‟s and as summarised
in Table 5.5), all large or sustained decomposition events were rated as “very unlikely”,
corresponding to a frequency of around 1 x 10-5 per annum per event. Therefore in the
absence of any sound historical frequency data, a frequency of 1 x10-5 per year is
judged to be applicable to ANS / ANE decomposition events with a potential offsite
impact.
The total ANS decomposition event frequency was estimated at 50 x10-6 per year (This
is based on all 5 ANS scenarios with a decomposition frequency of 1x10-5 per year
each).
Adjusting for wind direction (a factor of 8 – 12 in any particular direction) and
probability of occurrence of F2 stability conditions (typically 20% of time or less), the
likelihood of offsite irritation effects is around 1x10-6 per year. It should also be
reiterated that the consequence model was conservatively developed and would be an
overestimate of effect distances from most decomposition events.
Hence the irritation risk criterion (50x10-6 per year in residential areas) is also satisfied.
9.5 Risk to Biophysical Environment
The main concern relating to environmental risk from accident events is generally with
effects on whole systems or populations. HIPAP 4 provides the following qualitative
guidance for assessment of environmental risk due to accident events:
Industrial developments should not be sited in proximity to sensitive natural
environmental areas where the effects (consequences) of the more likely
accidental emission may threaten the long-term viability of the ecosystem or
any species within it.
Industrial developments should not be sited in proximity to sensitive natural
environmental areas where the likelihood (probability) of impacts that may
threaten the long-term viability of the ecosystem or any species within it is not
substantially lower than the background level of threat to the ecosystem.
Whereas any adverse effect on the environment is obviously undesirable, there were
no accidental emissions identified for the ANE Production Facilities or existing
Technology Centre facilities with the potential to damage an ecosystem, or to result in
any environmental effect other than a localised impact.
Overpressures associated with a worst case explosion event may damage some
vegetation and fauna in the vicinity, however are unlikely to affect the long-term
viability of the ecosystem or any species within it. However as identified in Table 5.5 it
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is possible that an explosion could result in a bushfire with resulting adverse effects on
the environment. This is discussed in Section 9.5.1.
For completeness, potential risks to the biophysical environment due to loss of
containment events and control measures in place to prevent or reduce any impacts
are also briefly summarised in the following sections.
9.5.1 Explosion events resulting in bushfire
It is possible that hot shrapnel or fragments generated in an explosion could act as an
ignition source, initiating a bushfire. Any bushfire could result in significant impacts to
the biophysical environment (flora and fauna). As the ANE Production Facility will be
surrounded by an APZ, the fuel load will be low and fire development should be slow,
however the scenario cannot be entirely discounted as the ultimate effects would be
heavily dependent on the environmental conditions at the time.
As noted in Section 5.4, a serious bushfire was last experienced close to the site
around 1996. Even with active vegetation management, bushfires are always a
potential threat in the summer season, with the main causes of Australian bushfires
being lightning and human initiation (either malicious or accidental, Refs 18, 19). Given
past history, the background likelihood of a serious bushfire in the area would appear
to be of the order of 1 in 10 to 20 years (ie approximately 1x 10-1 per year).
The likelihood of an escalated explosion event in the ANE Production Facility is
estimated at around 1x10-6 per year (as per Section 8.1). The likelihood that an
explosion would also initiate a bushfire is not 100%. It can therefore be inferred that
the frequency of an explosion in the ANE Production Facility initiating a bushfire is less
than 1x10-6 per year.
Based on the history of bushfires in the area, it is concluded that the likelihood of an
explosion in the ANE Plant that then initiates a bushfire is substantially lower (at least
several orders of magnitude lower) than the background risk of a bushfire (and any
associated impact on the environment) occurring and that the location of the proposed
development is therefore consistent with the HIPAP4 biophysical risk criterion that:
Industrial developments should not be sited in proximity to sensitive natural
environmental areas where the likelihood (probability) of impacts that may
threaten the long-term viability of the ecosystem or any species within it is not
substantially lower than the background level of threat to the ecosystem.
9.5.2 Escape of Liquid Materials
Chemicals Stored in Bunded Areas:
Chemicals stored include various oxidisers and corrosives (ANS, acetic acid, caustic
soda etc as per APPENDIX A). These chemical are water soluble and would affect pH
if released into groundwater or surface waters. ANS contains significant amounts of
nitrogen so would add to nutrient loads if released into a waterway.
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All chemicals are stored within concrete bunded areas which are designed to hold up
to 110% of the capacity of the largest tank and 25% of the capacity of all the tanks
where there are multiple tanks in a bund. All tanker deliveries occur over sealed areas
with kerbing and a drainage design preventing any runoff to the environment if a spill
occurs.
Various combustible fuels (hydrocarbon or vegetable oils) are also stored. These are
stored in self-bunded tanks and the unloading area has a drainage design to prevent
any runoff to the environment if a spill occurs.
Drainage systems for the combustible materials delivery areas and ANS delivery areas
are separate to ensure cross contamination cannot occur in drains.
Spill kits are provided to areas identified via risk assessment, enabling recovery of
small quantities of spilt materials. A spill of any of these chemicals would have very
localised impacts. The likelihood of any spill reaching the environment is also very low
due to the onsite containment devices and sealed surfaces.
Drainage systems and site grades:
The plant, associated roadway and chemical storage areas are all sealed and where
appropriate, bunded. Water collected in process areas and chemical storage areas is
recycled within the plant.
The site grades have been designed to minimise stormwater flowing onto the site from
up gradient. Rainwater collected from sealed road surfaces will be treated to remove
sediment and hydrocarbons. The treated rainwater will be harvested for reuse within
the process where possible. Surplus rainwater will be discharged to the environment.
9.5.3 Escape of Gaseous Materials
There are no highly volatile materials handled at the ANE Plant.
Acetic acid may generate odours during transfer however this would have very
localised impact.
The only gaseous emission would be the NOx emitted if an AN decomposition occurs.
NOx compounds can contribute to air pollution/smog. However the likelihood of a
decomposition event is very low due to the controls in place and the total quantities of
NOx emitted in such a decomposition event would be very small in comparison to total
NOx from other sources such as power stations in the Hunter area.
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10 CONCLUSIONS
A hazard analysis for the proposed ANE Plant has been completed. The final hazard
analysis (FHA) takes into account the results of safety studies including the HAZOP
and FSS.
The area directly around the site is largely unpopulated and there are no offsite
hazardous inventories, vulnerable infrastructure or populations that may be affected by
an explosion event. The nearest residential property is located approximately 1.8 km
from the proposed new plant. Due to the large separation distances between the
explosives, ANE or ANS inventories and the site boundaries, very few events were
identified with potential to cause injury or fatality outside the site boundary.
The results demonstrate that the existing site facilities and proposed ANE Plant
individually comply with all NSW land use planning risk criteria for new plants as
published in HIPAP 4. There are very few scenarios with any offsite fatality, injury or
irritation effect for either the existing or proposed facilities when measured against the
relevant screening thresholds, hence cumulative risk will also be within the HIPAP 4
criteria.
The ANE project has advanced to the detail design stage. Risk assessment activities
have occurred throughout the design process; including completion of a HAZOP and
HIRACs. Quantitative consequence explosion overpressure results were used to
identify required separation distances between inventories and site boundaries, hence
determine plant location and layout. Key safeguards include:
Minimisation of inventories to minimise offsite consequences of potential
explosion events.
Separation distances from site boundaries and existing facilities.
Separation distances between any combustible material storages and Class
5.1 inventories.
Engineering controls such as automated control of ANE manufacture batch
process and high reliability low flow trips for emulsion pumps.
Asset protection zones and associated maintenance to protect against bushfire
impingement.
The results of the FHA confirm the results of the PHA. No recommendations in relation
to additional engineering or layout safeguards are made as part of the FHA.
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APPENDIX A. HAZARDOUS MATERIALS AND PROCESS DESCRIPTION
This Appendix summarises the logical division of the ANE Plant.
A1. Raw Materials
Ammonium Nitrate Solution (ANS) is delivered to site by road tanker from Orica‟s
Kooragang Island site and stored in bunded areas. ANS is stored in hot water jacketed
tanks to ensure the AN remains in solution.
A range of fuels / oils can be used at the new ANE Plant including diesel and canola to
create different blends of emulsion. These are all C1 or C2 combustibles, no
flammable materials will be used. They are delivered by tanker and stored in a
dedicated bunded area well separated from the ANE Plant and oxidiser storage area
(at least 30m away) to minimise fire in the oils storage areas affecting the ANE Plant.
Smaller quantities of other materials (eg thiourea, other oxidisers, acetic acid and
caustic soda) are also stored and used in the ANE process to adjust pH etc.
Inventories of materials to be used at the ANE Plant can be found in Table A1.1. As
noted in the comments column, due to their properties and / or the small quantities
stored, some of these materials present relatively minor / localised risks and are not
considered further in the FHA.
TABLE A1.1: OXIDISERS (FEEDS TO ANE PLANT)
Material DG Class
Delivery Max quantity (t)
Storage Comments
80% - 88% ANS
5.1 from Kooragang Island (KI) in road tankers
890 2 x 250 kL tanks
2 x 60 kL tanks
1 x 20 kL tank
Nominally 80-90% ANS. 250kL of ANS is approximately 330 tonnes ANS. All tanks have temp maintenance using hot water.
Weak ANS (30% - 55%)
5.1 from Kooragang Island (KI) in road tankers
90 1 x 60kL tank
2 x 10 kL tanks
Ammonium nitrate
5.1 From Kooragang Island by truck
9.6 Covered store, bulk bags
Calcium nitrate
n/a By truck 8 Covered store, bulk bags
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Material DG Class
Delivery Max quantity (t)
Storage Comments
Thiourea (solid)
6.1 PGIII
dry thiourea will be supplied in 1000 kg bags.
8 Covered store
Localised hazards. Combustible dust, may decompose (NOx, SOx if heated). Not considered in QRA – hazards similar to other materials and is stored in much smaller quantities. .
10% Thiourea solution
n/a Made from dry thiourea in hot water-heated dissolving tank, to make 10% thiourea solution.
Not yet defined
Batch tank Localised hazards. Not considered in QRA.
Urea n/a In 1000 kg bags 10 Covered store, bulk bags
Localised hazards. Not considered in QRA.
75% Acetic Acid
8 PGII by 20 tonnes tanker
30 Localised hazards. Odours if spilled. Not considered in QRA. It has a flash point of 67°C and so is a combustible liquid. Orica has selected a concentration of 75% as concentrations of acetic acid over 80% are Class III flammable liquids.
50% Caustic Soda
8 PGII by 20 te tanker 30 Localised hazards. Not considered in QRA.
Sodium Nitrite 5.1 In 25 kg bags 8 Covered Store
Dedicated store area.
Weak sodium nitrite solution
n/a 2 x 10 kL tanks
Localised OHS hazards. Not considered in QRA.
TABLE A1.2: FUELS (FEEDS TO ANE PLANT)
Material DG Class Delivery Storage Comments
Diesel C1 Tanker 100,000 L bunded storage tank
Canola C2 Tanker 80,000 L bunded storage tank
Paraffin C2 Tanker 100,000 L bunded storage tank
E26-66 C2 Tanker 60,000 L bunded storage tank
SFBHP90 C2 Tanker 80,000 L bunded storage tank
Fuel Dye C1 Truck 300 L in total concentrate diluted with paraffin
Development fuel blends C1 Truck 1 x 3000 L tank Mixed onsite
Fuel IBCs C1, C2 Truck Up to 4,000 L total in 4 off 1,000 L IBCs
Waste oil, small batch trial fuel ingredients, stored in Fuel Blend bund.
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A2. Oxidiser Solution Preparation
Oxidiser Solution (OXS) batches are prepared by adding the required liquid ingredients
into batch tanks as defined by the product recipe. Solid material (urea) is added via
forklift and screw feeder to one batch tank if required.
Three batch tanks will be provided. The OXS tanks will be stainless steel, hot water
heated, agitated and insulated.
A3. Dry Oxidiser Store
A small dry oxidiser store of 25 tonne total capacity will also be provided for
ammonium nitrate (AN), calcium nitrate and/or urea. AN is a Dangerous Good Class
5.1 (total quantity 9.6 tonnes). Calcium nitrate and urea are not classed as Dangerous
Goods.
A4. ANE Manufacture, Storage and Loadout
ANE will be made by blending OXS and fuel in a process mixer known as an Elk.
Emulsion manufacture will be started, monitored and shut down from the control room.
The process is a recipe based batch process which will have fully automated sequence
control. Routine observation and sampling for quality control will be carried out.
Four overhead ANE product surge tanks will be provided, each pair of tanks providing
nominally 40 tonne capacity to supply B-double tankers. As different vehicles vary in
tank size, the maximum operating capacity of ANE will be limited to about 100 tonnes
(out of a maximum design capacity of 120 tonnes). These tanks will generally be
empty and will only be filled with a tanker load when an empty tanker is expected.
Tankers (including B-doubles) and ISO containers will be filled either from the
overhead ANE surge tanks or directly from the manufacturing process. ANE loadout
will be observed and controlled by the tanker driver. The driver will stop the transfer of
ANE from the overhead tank to the tanker when correct tanker weight is obtained. The
tanker is provided with a high level switch to stop overfilling. The risks from an ANE
spill are low as ANE will fudge almost as soon as it hits the ground, ie does not run
freely like most liquid spills.
Mobile Manufacturing Units (MMUs) will not be directly loaded in the ANE Plant.
A5. Companion and Gasser Solutions
The plant will also manufacture gasser solutions and companion solution and transfer
these to ANE tankers for distribution. Gasser solutions are dilute mixtures of sodium
nitrite and water and companion solution is a dilute AN solution.
These solutions are handled in dilute form (high water content) and have only localised
hazards. They are not specifically considered in the risk assessment.
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A6. Services
Various utility and service chemicals will also be provided as shown in Table A1.3. Due
to their non-hazardous properties and small quantities stored, these materials present
relatively minor / localised risks and are not considered further in the risk assessment.
TABLE A1.3: UTILITY CHEMICALS
Material Delivery Storage Comments
Various Class 8 water treatment chemicals.
Small containers by truck
~ 100 L In service storage area
Process water Road tanker 120 m3 May be recycled
Potable water Road tanker 30 m3
Fire water Road tanker 10 m3. Bushfire firefighting water
A7. Offspec ANE Product
Where possible, off spec product will be diverted to a lower specification product or
mixed with on spec product. If the off spec material cannot be reused it will be sent to
authorised contractors for disposal.
A8. Summary of Tank Inventories Onsite
The summary of tank inventories onsite used in QRA is given in Table A1.4
TABLE A1.4: TANK INVENTORIES FOR QRA
Tank Name Concentration Capacity
ANS Storage Tank 1 (33-4301) 88.5 % AN 330 tonne (239 m3) - 88.5 % AN
ANS Storage Tank 2 (33-4302) 88.5 % AN 330 tonne (239 m3) - 88.5 % AN
Weak ANS Storage Tank (33-4303) 35 % AN 75 tonne (66 m3) - as 35% AN
OXS Batch Tank 1 (33-4218) 83 % AN (maximum) 26 tonne (19 m3) as 83% AN
OXS Batch Tank 2 (33-4201) 83 % AN (maximum) 80 tonne (58.8 m3) as 83% AN
OXS Batch Tank 3 (33-4202) 83 % AN (maximum) 80 tonne (58.8 m3) as 83% AN
ANE Surge Tank 1 (33-4540) Emulsion 30 tonne (23 m3) - as emulsion
ANE Surge Tank 2 (33-4541) Emulsion 30 tonne (23 m3) - as emulsion
ANE Surge Tank 3 (33-4542) Emulsion 30 tonne (23 m3) - as emulsion
ANE Surge Tank 4 (33-4543) Emulsion 30 tonne (23 m3) - as emulsion
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APPENDIX B. HIRAC INFORMATION
HIRAC Overview
HIRACs have been carried out independently of the FHA as part of Orica‟s normal risk
assessment activities.
The HIRAC methodology is broadly based on AS/NZS 4360 Risk Management. A team of
experienced site engineering, operations and maintenance personnel is convened to carry
out the HIRAC on a particular scenario, such as “Explosion in the ANS Tank”.
A HIRAC comprises the following steps for each scenario:
Hazardous event identification
Identification of potential causes
Establishment of potential consequences (safety, health, environment and
business) and the severity of those consequences both onsite and offsite
Identification of existing controls (both hardware and procedural) and review of their
probable effectiveness
Estimation of likelihood of initiating events based on plant knowledge and
experience, historical incident reviews and generic frequency data
Estimation of the reliability of the existing controls in preventing and/or mitigating the
hazardous event
Using the above data, estimation of the final likelihood of each of the various
consequences identified earlier (in some cases this requires fault tree or similar
analysis)
Comparison of the likelihood and severity (risk) of each of the consequences
against Orica‟s standard risk matrix
Determination as to whether additional controls are required to reduce risks further
or whether the existing risks are acceptable
Recommendation for additional controls if required and if so, a timeline for their
implementation.
The estimate of the final likelihood of the major consequence event (ie explosion with
offsite effects) is the value used in the FHA.
HIRAC Scenarios
A list of the HIRAC scenarios extracted from the SHE Risk Register is given on the
following pages. For security reasons complete details of the scenarios have not been
provided.
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HIRAC SCENARIOS (as extracted from Orica’s Lotus Notes Explosives Risk Register 15/9/09)
P01 EXTERNAL FIRE / EXPLOSION Inclusion in PHA?
1. Potential for external fires (from various mechanisms) to result in burning embers entering the fuel compound with
ignition of combustible materials and vapours and progression to a significant fire with radiant heat.
Fuel fire source of
heat to ANE / ANS
inventories only.
No offsite effects from
fire radiant heat
2. Exposure to ANE from radiant heat from an external fire from other external processes to the ANE storage causes
thermal decomposition of the Ammonium Nitrate generating toxic fumes. A section of fixed pipe work with enclosed
emulsion heated under confinement could cause an explosion possibly escalating to adjacent equipment.
Yes – see Table 5.5
3. Exposure to ANE from radiant heat from an external fire from other external processes to the AN storage causes
thermal decomposition of the Ammonium Nitrate generating toxic fumes.
Yes – see Table 5.5
P01.1 EXTERNAL FIRE
4. Potential for external fires from human failing leading to introduction of ignition sources to the fuel compound with
ignition of combustible materials and vapours and progression to a significant fire with radiant heat.
Fuel fire source of
heat to ANE / ANS
inventories only.
No offsite effects from
fire radiant heat
5. Potential for external vehicle fire to result in burning embers entering the fuel compound with ignition of combustible
materials and vapours and progression to a significant fire with radiant heat.
6. Potential for external fires from chemical decomposition due to mixing of incompatible materials in waste bins etc.
leads to burning embers entering the fuel compound with ignition of combustible materials and vapours and
progression to a significant fire with radiant heat.
7. Potential for external fires from electrical source to result in ignition of combustible materials and vapours and
progression to significant fire with radiant heat.
8. Major leak of fuel oil into the fuel compound which ignites
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P01 EXTERNAL FIRE / EXPLOSION Inclusion in PHA?
9. External fire engulfs ANE storage due to human failure. Leading to exposure of ANE to radiant heat causing thermal
decomposition of the Ammonium Nitrate and generation of toxic fumes with potential propagation to detonation
(under confinement).
Fuel fire source of
heat to ANE / ANS
inventories only.
No offsite effects from
fire radiant heat
10. External vehicle fire leads to exposure of ANE to radiant heat causing thermal decomposition of the Ammonium
Nitrate leading to generation of toxic fumes and potential propagation to detonation (under confinement).
11. External fire caused by chemical decomposition of incompatible materials leads to exposure of ANE to radiant heat
causing thermal decomposition of the Ammonium Nitrate leading to generation of toxic fume and potential
propagation to detonation. Section of fixed pipe work with enclosed emulsion heated under confinement could cause
explosion possibly escalating to adjacent equipment.
12. External fire engulfs ANE storage or transfer equipment due to electrical fault. Leading to exposure of ANE to radiant
heat causing thermal decomposition of the Ammonium Nitrate and generation of toxic fumes with potential
propagation to detonation (under confinement) possibly resulting in significant damage to plant , with potential for
people in the localised area to be seriously injured.
13. Collapse or catastrophic failure of ANE Surge Bin resulting in loss of containment of emulsion phase ammonium
nitrate which ignites causing injury \ fatality to personnel and a pool fire.
No. Local impact only
14. External fire engulfs AN storage due to human failure. Leading to exposure of AN to radiant heat causing thermal
decomposition of the Ammonium Nitrate and generation of toxic fumes with potential propagation to detonation
(under confinement).
Yes – see Table 5.5
15. External vehicle fire leads to exposure of AN to radiant heat causing thermal decomposition of the Ammonium Nitrate
leading to generation of toxic fume and potential propagation to detonation (under confinement).
16. External fire caused by chemical decomposition of incompatible materials leads to exposure of AN to radiant heat
causing thermal decomposition of the Ammonium Nitrate leading to generation of toxic fume and potential
propagation to detonation.
17. External fire engulfs AN storage due to electrical fault. Leading to exposure of AN to radiant heat causing thermal
decomposition of the Ammonium Nitrate and generation of toxic fume with potential propagation to detonation (under
confinement).
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P01 EXTERNAL FIRE / EXPLOSION Inclusion in PHA?
18. Exposure to AN from radiant heat from an external fire due to natural causes to the AN storage causes thermal
decomposition of the Ammonium Nitrate generating toxic fume.
Yes – see Table 5.5
19. External fire engulfs Sodium Nitrite being handled within gasser manufacture building leading to thermal
decomposition of Sodium Nitrite with release of noxious gases.
No – smaller case
than ANS decomp –
see Section 0
20. Vehicle fire or accident causes external heating of gasser storage resulting in ignition of combustible material with
consequential fire and combustion products from thermal decomposition of gasser solution.
No – smaller case
than ANS decomp –
see Section 0
21. External fire engulfs Sodium Nitrite being unloaded or stored causing heating leading to thermal decomposition of
Sodium Nitrite with release of noxious gases.
No – smaller case
than ANS decomp –
see Section 0
22. Chemical contamination of spilled gasser residue causes thermal decomposition and external fire in proximity of
gasser storage. Exposure to heat from a fire leading to generation of noxious fumes and potential violent rupture of
container.
No – local impact only
23. Radiant heat from an external fire heats the acetic acid tank and the contents reach the flashpoint (67 C for 75 %
solution)
No
P02 INTERNAL FIRE / EXPLOSION
24. Fire inside workshop caused by poor control of hot work or electrical fault. Combustible or flammable materials
present.
No – OHS
25. Fuel fed into Hot Water Generator combustion chamber creating fuel rich atmosphere which later ignites violently. No – local impact only
26. Fire in fuel unloading or transfer pumps with progression to significant fire with radiant heat. No – local heat
radiation only
27. Chemical unloading errors leading to the mixing of caustic and acetic acid. Heat of reaction, no
hazardous products
28. Thiourea dust explosion No – local impact only
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P01 EXTERNAL FIRE / EXPLOSION Inclusion in PHA?
29. Internal fire/ heating caused by chemical decomposition of incompatible materials leads to exposure of AN to radiant
heat causing thermal decomposition of the Ammonium Nitrate leading to generation of toxic fume and potential
propagation to detonation.
Yes – see Table 5.5
30. No flow in hot water recirculation pump. No – operational
upset, ANS blockages
31. Loss of feed water to HWG. Tubes overheated and melt causing fire. No – local impact only
P04 EXPLOSIVE DECOMPOSITION / DETONATION Inclusion in FHA?
32. Incompatible chemicals contaminate the emulsion which starts to decompose in the surge bin with the potential to
raise the temperature and detonate.
No – smaller inventory
33. Incompatible chemical (or contaminated water – domestic or process) added to concentrated ANS (ANS Storage or
OXS) or overheating of solution resulting in explosive decomposition / detonation
Yes – see Table 5.5
34. Dead heading or dry running ammonium nitrate solution pumps leading to overheating of ammonium nitrate and
internal explosion in the pump and\or pipe work.
Yes – see Table 5.5
35. Dead heading or dry running emulsion phase coarse and\or fine hopper mono pumps leading to overheating of
ammonium nitrate emulsion phase and internal explosion in the pump and\or pipe work
Yes – see Table 5.5
36. Thermal heating by dry running or dead heading the ANE Unloading pump (NAPCO gear pump). Heating of
emulsion under confinement can lead to thermal decomposition.
Yes – see Table 5.5
37. Dry running of plant sump pumps resulting in potential fire or explosion. No
38. Local or spot heating caused by friction or impact in Progressive Cavity transfer pump leading to decomposition of the
enclosed material .Heating of emulsion under confinement can lead to thermal decomposition. Pump casing may fail
due to pressure build-up.
Yes – see Table 5.5
39. Compositional change could lead to sensitisation or heating of pump contents. This could be caused by air
entrainment leading to sensitisation by density reduction, compression ignition or dry running of pump caused by
trying to pump crystalline product/ more viscous product.
Yes – see Table 5.5
40. Tanker unloading ANS explodes due to cook-off from external fire Yes – see Table 5.5
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P04 EXPLOSIVE DECOMPOSITION / DETONATION Inclusion in FHA?
41. AN contamination inside heating coils decomposes when heated in Hot Water Generator causing damage to
equipment.
No – asset damage
P05 TOXIC / HARMFUL EXPOSURE
Accidental Operator exposure (splash) to harmful process chemicals (eg ANS, Caustic, Acetic Acid, Gasser, Fuel
Dye Concentrate, hydrocarbons)
No – OHS
Accidental ingestion of Gasser solution (poison) No – OHS
Accidental Operator exposure (inhalation) of Thiourea and Sodium Nitrite dusts (poisons) No – OHS
42. Decomposition of ANS leading to emissions of NOx (low pH) or Ammonia (high pH) from ANS and OXS Batch Tanks. Yes – see Table 5.5
43. Addition of Thiourea to Oxidiser Solution (at low pH) can form Hydrogen Sulphide (H2S). The H2S can then react to
form NOx provided nitric acid is present. H2S has a low STEL limit.
No – small quantities – local impact only
P06 PHYSICAL OVER OR UNDER PRESSURE
44. Failure of air receiver or connecting components due to overpressure causes injury. No – OHS
45. Contamination of Gasser with Comsol (or vice versa) by incorrect loading of truck tanks could lead to a reaction and
over pressure of truck tank.
No – asset damage
P07.1 VIOLENT RELEASE OF ENERGY
Catastrophic failure of a storage tank while operator in bund. No – OHS
Failure of air hose connection on air driven diaphragm pump used for emptying bunds causes "whipping" of air lines. No – OHS
Document: J20210-007 APPENDIX B Revision: 0 Revision Date: 24 February 2011 Document ID: J20210-007 FHA Rev 0
P07.2 EXPOSURE TO DAMAGING ENERGY
46. Failure of transfer hose/line under pressure leads to operator being sprayed with process liquids (eg. Caustic, acetic
acid, diesel, emulsion, AN solution) causing injury
No – OHS
47. Vehicle impact to process storage and handling equipment (in particular Emulsion Surge Tanks) No – asset damage
48. Vehicle impact to pedestrian No – OHS
49. Operator injured by fall from height during operation of fuel storage, emulsion tanker loading No – OHS
50. Contact with moving parts can cause operator injury. No – OHS
51. Contact with hot surfaces can cause operator injury No – OHS
52. Operator injured by residual pressure in compressor air receiver and lines No – OHS
53. Operator injured by bag/ IBC falling from height. No – OHS
1. Operator electrocuted by electrical fault. No – OHS
P08 ENVIRONMENTAL POLLUTION
54. Loss of containment of process chemicals either during tanker unloading or during transfer to the process. Storage
tanks are bunded therefore any loss of containment is restricted to unloading hose and transfer lines.
No – local impact. Minor environmental
55. Loss of containment of emulsion from Surge Tank or associated process lines, valves and other fittings. Loss of
containment from tanker, or associated lines, valves and fittings during loading.
No – local impact. Minor environmental
56. Loss of containment of solid raw materials during unloading, storage and addition to the process No – local impact. Minor environmental
57. Gaseous emissions from Hot Water Generator Stack No – local impact. Minor environmental
58. Gaseous emissions from Thiourea and Sodium Nitrite dust extraction systems No – local impact. Minor environmental
Document: J20210-007 APPENDIX B Revision: 0 Revision Date: 24 February 2011 Document ID: J20210-007 FHA Rev 0
P09 WASTE PRODUCTS AND MATERIALS
59. Badly contaminated storm water or bund water captured and recycled into the process. No – operations
60. Disposal of contaminated packaging materials. No – local impact. Minor environmental
61. Fire and fume from mixing of incompatible waste raw material packaging. No – local impact. Minor environmental
62. Disposal of contaminated/offspec emulsion product (if process upset occurs). No – local impact. Minor environmental
63. Disposal of contaminated/offspec oxidiser solution. No – local impact. Minor environmental
Document: J20210-007 APPENDIX C Revision: 0 Revision Date: 24 February 2011 Document ID: J20210-007 FHA Rev 0
APPENDIX C. EXPLOSION OVERPRESSURES CONSEQUENCE MODELLING METHODOLOGY
Ref: Department of Defense Explosives Safety Board Alexandria, VA2 February 2007
TP no 14 Rev 3 APPROVED METHODS AND ALGORITHMS FOR DOD RISK-BASED EXPLOSIVES SITING
Objective: Use Kingery-Bulmash TNT correlation to estimate effect distances to set overpressure levels for AN explosions
Method: This worksheet solves the K-B equations for a range of overpressure levels to determine the equivalent effective hazard factor (Zo)
The estimated Z is then used to calculate impact distance from the NEQ on worksheets "Explosions".
P psi
d feet
Y pounds
Z ft/lbs1/3
Zo = d/NEQ 0.333
Xo = ln (Zo )
Ref: pg 22, and pg A-3, Table A-3
P = e (A + B.Xo + C.Xo2 + D.Xo
3 + E.Xo4)
Z (ft/lbs1/3) A B C D E
0.5 - 7.25 6.9137 -1.4398 -0.2815 -0.1416 0.0685
7.25 - 60 8.8035 -3.7001 0.2709 0.0733 -0.0127
60 - 500 5.4233 -1.4066 0 0 0
P (kpa) 70 35 21 14 7 2
P (psi) 10.15 5.075 3.045 2.03 1.015 0.29
ln(P) psi 2.317473705 1.6243265 1.1135009 0.7080358 0.0148886 -1.2378744
Use Excel Solver to solve for Xo (ft):
Upper X
1.9810 2.2937 2.8903 2.8903 2.8903 2.8903 2.8903 Don't use - errors in results, outside upper X limit
4.0943 2.2715 2.6585 2.9852 3.2728 3.8112 4.7304
6.2146 2.2080 2.7008 3.0640 3.3522 3.8450 4.7357
Excel solver ln(P) recalc 2.3175 1.7621 1.7621 1.7621 1.7621 1.7621
2.3175 1.6243 1.1135 0.7080 0.0149 -1.2379
2.3175 1.6243 1.1135 0.7080 0.0149 -1.2379
solver check 0.0000 0.1377 0.6486 1.0540 1.7472 3.0000 Don't use - errors in results, outside upper X limit
(aim: diff in ln(P) ~ 0) 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
Z (ft/lbs1/3) Z range
0.5 - 7.25 9.911749761 17.998674 17.998674 17.998674 17.998674 17.998674 Don't use - errors in results, outside upper X limit
7.25 - 60 9.69395392 14.274424 19.790032 26.384216 45.2041 113.34265
60 - 500 9.097840801 14.891939 21.412668 28.5667 46.759795 113.93812
Z (m/kg1/3
) Z range
2.882924057 3.941354735 7.1570772 7.1570772 7.1570772 7.1570772 7.1570772 Don't use - errors in results, outside upper X limit
23.85868185 3.854749374 5.6761492 7.8694012 10.491544 17.97517 45.070104 Use this one to calculate d (m) - covers Z range
198.8223487 3.617708153 5.9217006 8.514634 11.359397 18.593784 45.306889
Conversion: 0.397644697
ft/lb^.333 to m/kg^.333
Document: J20210-007 APPENDIX D Revision: 0 Revision Date: 24 February 2011 Document ID: J20210-007 FHA Rev 0
APPENDIX D. QRA SCENARIOS
Rev Date Description By Checked
A 10/10/2008 Initial Issue for comment J Polich -
B 4/12/2008 Revised draft J Polich P Johnson
C 22/12/2008 Updated quantities, ANE storage, ANE plant escalation
event
J Polich -
D 26/06/2009 Updated ANS concentrations J Polich P Johnson
E 5/08/2009 Updated ANS concentrations back to 0.885 J Polich P Johnson
QRA Scenario Consequence Model Parameters Distance to Overpressure (kPa)
(m)
Separation distances as per AS2187.1 1998 Table 3.2.3.2
(m)
Distance to
nearest
boundary
(m)
Potential
Offsite fatality
effect (i.e.
>21kPa at
boundary)
Potential Offsite
fatality effect
(i.e. >14kPa at
boundary)
Potential
Offsite injury
effect (i.e.
>7kPa at
boundary)
Discuss in
QRA?
Escalation
Area MAE Ref MAE Description Material Max storage
quantity
(te)
proportion
AN
Theoretical
Mass Avail
for Explosion
(te)
Equivalence Efficiency NEQ
(kg)
70 35 21 14 7 2 Explosives
(unmounded)
D = 4.8 NEQ1/3
Explosives
(mounded)
D = 2. 4NEQ1/3
Process
building
D = 8 NEQ1/3
AN
(unmounded)
D = 1.8 NEQ1/3
Class A PW
Note 1
Class B PW
(unmounded)
Note 2
Class B PW
(mounded)
Note 2
Vulnerable
facilities
D = 44 NEQ1/3
Distance to
Nearest Existing
Explosives
Inventory (Test
Cell)
Potential onsite
escalation effect
(AS2187)
ANS Storage ANS-01
ANS-02
ANS-03
Explosion in ANS storage tank due to contamination or
external fire
ANS 330 0.885 292.05 0.353 0.3 30928 121 178 247 329 564 1415 151 75 251 57 465 697 697 1381 260 N Y Y Y 215 N
ANS Storage ANS-04 Explosion in ANS tanker ANS 26 0.885 23.01 0.353 0.6 4874 65 96 133 178 305 764 81 41 136 31 251 376 376 746 260 N N Y Y 215 N
OXS Batch Tank OXS-01
OXS-02
OXS-03
Explosion in OXS batch tank due to contamination or
external fire
ANS 80 0.83 66.4 0.353 0.3 7032 74 109 151 201 344 863 92 46 153 34 284 425 425 843 260 N N Y Y 215 N
ELK Area ELK-01
ELK-02
Explosion in ELK ANE 2 1 2 0.68 1 1360 43 63 87 116 199 499 53 27 89 20 123 180 184 487 260 N N N N 215 N
ANE Storage ANE-01
ANE-02
Explosion in single ANE storage tank due to contamination
or external fire
ANE 30 1 30 0.68 1 20400 105 155 215 287 491 1231 131 66 219 49 404 607 607 1202 260 N Y Y Y 215 N
ANE Storage ANE-01
ANE-02
Explosion in all (4) ANE storage tanks due to
contamination or external fire
ANE 120 1 120 0.68 1 81600 167 246 341 455 780 1955 208 104 347 78 642 963 963 1908 260 Y Y Y Y 215 N
AN Storage AN-01 Explosion in Dry Oxidiser store due to contamination AN 20 1 20 0.32 0.5 3200 57 84 116 155 265 664 71 35 118 27 204 311 311 648 280 N N N N 185 N
AN Storage AN-02 Explosion in Dry Oxidiser store due to fire AN 20 1 20 0.32 0.16 1024 39 57 79 106 181 454 48 24 81 18 102 180 152 443 280 N N N N 185 N
AN Storage AN-03 Explosion in Dry Oxidiser store due to missile / high
energy shock wave
AN 20 1 20 0.32 1 6400 72 105 146 195 334 837 89 45 149 33 275 412 412 817 280 N N Y Y 185 N
AN Storage
(offspec)
Explosion in Dry Oxidiser store due to contamination AN (off
spec)
0 1 0 0.32 0.5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 280 N N N N n/a N
ANE Plant all
inventory
ESC-01 ANE plant - ANS storage tank explosion and sympathetic
detonation, aggregate inventory including largest ANS (1 x
350 te ANS, 4 x 30te ANE and 20 te AN)
ANS+ANE+A
N
470 as per
individual
scenarios
as per
individual
scenarios
as per
individual
scenarios
as per
individual
scenarios
118928 190 279 387 516 884 2216 236 118 393 89 728 1092 1092 2164 280 Y Y Y Y 215 Y
ANE Plant all
inventory
ESC-02 ANE plant - knock on (any causes except ANS explosion)
and sympathetic detonation, aggregate inventory (4 x
30te ANE and 20 te AN)
ANE + AN 140 as per
individual
scenarios
as per
individual
scenarios
as per
individual
scenarios
as per
individual
scenarios
88000 171 252 350 467 800 2005 214 107 356 80 658 987 987 1957 280 Y Y Y Y 215 N
Notes:
1. PWA
D = NEQ2/3 NEQ <= 2500kg
D = 3.6NEQ1/2 2500 kg < NEQ <= 4500kg
D = 14.8NEQ1/3 NEQ > 4500kg
2. PWB
D = 1.5 NEQ2/3 NEQ <= 2500kg
D = 5.5NEQ1/2 2500 kg < NEQ <= 4500kg
D = 22.2NEQ1/3 NEQ > 4500kg
Minimum of 180m for unmounded magazines
3. "n/a" means the event is not credible or is the result of an escalation and does not further escalate as all inventories already involved (i.e. NEQ is aggregate inventory)
20210 QRA scenarios KURRI Rev E
Explosions proposed ANE plant
Print Date: 20/08/2009
Page 1 of 1
Rev Date Description By Checked
A 10/10/2008 Initial Issue for comment J Polich -
B 4/12/2008 Revised draft J Polich
QRA Scenario Consequence Model Parameters Distance to Overpressure (kPa)
(m)
Separation distances as per AS2187.1 1998 Table 3.2.3.2
(m)
Distance to
nearest
boundary
(m)
Potential
Offsite
fatality
effect (i.e.
>14kPa at
boundary)
Potential
Offsite
injury effect
(i.e. >7kPa
at
boundary)
Discuss in
QRA?
Base Case Comments re frequency Escalation
Area MAE Ref MAE Description Material Max storage
(te)
% AN Theoretical
Mass Avail
for Explosion
(te)
Equivalence
(ref Orica AN
CoP v8)
Efficiency
(ref Orica AN
CoP v8)
NEQ
(kg)
70 35 21 14 7 2 Explosives
(unmounded)
D = 4.8 NEQ1/3
Explosives
(mounded)
D = 2.
4NEQ1/3
Process
building
D = 8 NEQ1/3
AN
(unmounded)
D = 1.8 NEQ1/3
Class A PW
Note 1
Class B PW
(unmounded)
Note 2
Class B PW
(mounded)
Note 2
Vulnerable
facilities
D = 44
NEQ1/3
Frequency
(per yr)
X Y Distance to
Proposed
ANE Plant /
AN Store
Potential onsite
escalation effect (i.e.
less than AS2187
process building sep
distance to ANE Plant
/ AN Store inventory)
Research Magazine
(RM) and Quarry
Service Depot (QS)
RM/QS-01 Explosion in Research
Magazine or Quarry
Services Depot which
propagates to involve
entire inventory in this
plant location
Explosive n/a n/a n/a n/a n/a 50220 142 209 290 387 663 1663 177 89 295 66 546 819 819 1623 635 N Y Y 1.00E-06 Upper boundary of "extremely
unlikely"
325 N
Research
Laboratory (RL)
ML-01 Explosion in Mixing Lab
which propagates to
involve entire inventory in
this plant location
Explosive n/a n/a n/a n/a n/a 11620 87 129 178 238 407 1021 109 54 181 41 335 503 503 997 715 N N N 1.00E-06 Upper boundary of "extremely
unlikely"
525 N
Mixing Laboratory
(ML)
RL-01 Explosion in Research
Laboratory which
propagates to involve
entire inventory in this
plant location
Explosive n/a n/a n/a n/a n/a 560 32 47 65 86 148 371 40 20 66 15 68 180 102 363 480 N N N 1.00E-06 Upper boundary of "extremely
unlikely"
820 N
Test Cell TC-01 Explosion in Test Cell
which involves entire
inventory in this plant
location
Explosive n/a n/a n/a n/a n/a 50 14 21 29 39 66 166 18 9 29 7 14 180 20 162 450 N N N 1.00E-06 Upper boundary of "extremely
unlikely"
185 N
20210 QRA scenarios KURRI Rev D
Explosions Existing Kurri
Print Date: 2/07/2009
Page 1 of 1
Document: J20210-007 APPENDIX E Revision: 0 Revision Date: 24 February 2011 Document ID: J20210-007 FHA Rev 0
APPENDIX E. SUMMARY OF ASSUMPTIONS
The key assumptions made at each stage of the risk assessment are summarised in the
table below.
Stage Assumption Comments
Hazard ID Hazards from ANE Plant are associated with ANS, ANE or AN. Other chemicals not significant.
Hazards from existing facilities are associated with Class 1 explosives, ANE and AN. Other chemicals are not significant. Pool fires from combustible storage present localised heat radiation risks only.
All other chemicals either oxidizers or corrosives (stored as per relevant codes with bunding etc). Localised risks only.
Consequence Assessment
100% maximum inventory (NEQ) for each storage (proposed ANE Plant and existing facilities) is assumed to be involved in any explosion event. Orica Draft AN Code of Practice (version 8) assumptions for TNT equivalence estimates for AN, ANS. ANE assumptions based on Orica's ideal detonation (IDEx) code. Kingery and Bulmash scaled distance correlation for overpressure impact distance estimates. (Ref: US DoD Technical Paper no 14 Rev 3 Feb 2007). HIPAP 4 endpoints for overpressure vs probability of fatality calculation for base case as follows for receptors located indoors and outdoors Probability of fatality: indoors outdoors 70kPa 100% 100% 35kPa. 50% 15% 21kPa 20% 1% 14kPa 1% 0.1%
Refer to main report for inventory basis for proposed ANE Plant and existing facilities. Refer to main report for consequence results. Inside risk results are more conservative than outside.
Frequency Assessment
Upper end of Orica qualitative risk matrix frequency band for all ANS / ANE explosion events. (Generally each decomposition event involving a particular ANS / ANE inventory was rated as “very unlikely” and the frequency has been set at 1 x10
-5 per
year). Explosions are set a factor of ten lower (ie 1 x 10
-6 per year) This approach does not
account for factors such as delivery frequency, numbers of tanks etc.
NOTE: Publicly available frequency data is very poor. Fault tree approach is an alternative however would be order of magnitude at best
Document: J20210-007 APPENDIX E Revision: 0 Revision Date: 24 February 2011 Document ID: J20210-007 FHA Rev 0
Stage Assumption Comments
Escalation Risk
Escalation risk between the proposed ANE Plant and existing facilities has been assessed by comparing the layout with the separation distances required in Table 3.2.3.2 in AS2187.1 - 1998. If the required separation distance is met, escalation is not credible for the purposes of the risk assessment. Worst case escalated event within the ANE Plant is aggregated inventory NEQ (ie ANE and AN, also ANS only if ANS is initiating inventory).
Knock on events affecting the AN store or ANE storage (ie part of ANE Plant) or existing Class1 explosives, ANE or AN inventories are assumed to contribute to escalation risk (as AN, ANE and Class1 explosives may detonate if subjected to a high energy shock wave). ANS is not susceptible to impact / shock detonation therefore an external explosion may result in a loss of containment of AN solution due to storage vessel damage, but not a subsequent explosion event.
Risk Calculation
- NOTE: Risk contours not prepared for site due to very low number of scenarios with potential offsite effects.
Document: J20210-007 APPENDIX F Revision: 0 Revision Date: 24 February 2011 Document ID: J20210-007 FHA Rev 0
APPENDIX F. REFERENCES
1 NSW Department of Planning (Reprinted 1997) Hazardous Industry Planning Advisory
Paper (HIPAP) No. 6 Guidelines for Hazard Analysis
2 NSW Department of Planning (Reprinted 1997) Hazardous Industry Planning Advisory
Paper (HIPAP) No. 4 Risk Criteria for Land Use Planning
3 NSW Department of Planning (1997) Multi-Level Risk Assessment
4 Orica Draft Ammonium Nitrate Code of Practice (v8) available in the SHE Risk Register
5 Sherpa Consulting Pty Ltd (19 Oct 2009) Proposed ANE Facility Kurri Kurri Technology
Centre, Orica Australia Pty Ltd, Preliminary Hazard Analysis Doc ref:J20210-004 Rev 1
6 Orica Engineering (Feb 2011) Hazop Study Report, Orica Mining Services, Kurri Kurri
Ammonium Nitrate Emulsion Project Application Number: 09_0090 Rev C
7 Sherpa Consulting Pty Ltd (5 Aug 2010) Proposed ANE Facility Kurri Kurri Technology
Centre, Orica Australia Pty Ltd, Fire Safety Study Doc ref:J20210-006 Rev 2
8 Pinnacle Risk Management (7 Feb 2011) Construction Safety Study Report,
Ammonium Nitrate Emulsion Plant, Orica Australia Pty Ltd, Kurri Kurri, NSW Rev B
9 ICI Engineering (16 April 1992) Updated Hazard Analysis ICI Mining Services
Technology Park
10 Australian Explosives Manufacturers Safety Committee (AEMSC), Code of Good
Practice Precursors For Explosives Edition 1 – 1999
11 Orica Liddell ANE Plant Uprate Process Description Doc Ref: KIEG1150-02-26001_A
12 Acute Exposure Guideline Levels (AEGLs) for Nitrogen Dioxide, October 2006.
13 Bushfire Consulting Specialists 090201 Orica Kurri
14 http://www.aiha.org/Committees/documents/erpglevels.pdf ,
http://www.eh.doe.gov/chem_safety/teel.html
15 TNO Purple Book, Guidelines for Quantitative Risk Assessment, CPR 18E, ,
Committee for the Prevention of Disasters, 1st edition 1999
16 Department of Defense Explosives Safety Board Alexandria, VA TP no 14 Rev 3
Approved Methods And Algorithms For DOD Risk-Based Explosives Siting (IMESAFR)
17 Adams, W.D. UK HSE, Hazardous Installation Directorate The Toxic Effects from a Fire
Involving Ammonium Nitrate.
18 Geoscience Australia What Cause Bushfires?
http://www.ga.gov.au/hazards/bushfire/causes.jsp
19 http://www.bushfirecrc.com/research/downloads/Fire%20Bugged%20-%20MW.pdf