Last Updated: 2026
Quantitative Risk Assessment (QRA) Services for Industrial Facilities
QRA Study, Consequence Modelling & Risk Contour Mapping for Oil & Gas, Chemical, LPG & Hazardous Industrial Facilities
Serving industrial facilities across India and supporting international QRA projects worldwide.
Service summary
A Quantitative Risk Assessment (QRA) identifies credible loss-of-containment scenarios, estimates how often they may occur, models toxic, fire and explosion consequences, and combines the results into individual-risk contours and societal-risk curves. Elion provides independent QRA studies for industrial and high-hazard facilities in India and worldwide, with deliverables prepared for engineering decisions, emergency planning and the applicable regulatory review.
Quantitative Risk Assessment (QRA) calculates the numerical probability and consequence of major hazard scenarios — fire, explosion, toxic release — at your facility, expressed as risk contours and individual/societal risk values, then evaluated against ALARP (As Low As Reasonably Practicable) criteria. Elion delivers a QRA study with risk contour maps and mitigation recommendations — trusted since 2010 across 30,000+ audits.
OISD
CCPS
API RP 752/753
NFPA
PNGRB
Since 2010
30,000+ Audits
QRA Study — Track Record
- Frequency analysis & consequence modelling
- Individual & societal risk estimation
- Risk contour maps & F-N curves
- PHAST · SAFETI · ALOHA
- OISD, CCPS, API, NFPA, PNGRB aligned
30,000+
Audits Completed
Since 2010
Independent Practice
PHAST / SAFETI
Risk Modelling Software
OISD / CCPS
Process Safety Standards
QRA Study for Oil & Gas Facilities, Chemical Plants, LPG Bottling Units, Refineries & Hazardous Installations in India — OISD, CCPS, API, NFPA & PNGRB Aligned
Elion Technologies & Consulting Pvt. Ltd. is an independent engineering audit and safety consultancy established in 2010, delivering third-party QRA studies and process safety assessments for Indian process industries. 30,000+ audits completed. ISO 9001 · 14001 · 50001 certified. NSIC Approved. Pan-India execution with in-house qualified engineers — no subcontracting. QRA reports accepted by statutory authorities, regulatory bodies, and project stakeholders.
A Quantitative Risk Assessment (QRA) study (also referred to as a QRA analysis, quantitative risk analysis, process risk assessment, major hazard risk assessment, or industrial risk assessment) is a structured analytical process that estimates the probability and magnitude of harm arising from hazardous industrial operations. It combines frequency analysis — estimating the likelihood of hazardous events such as fires, explosions, and toxic releases — with consequence modelling — quantifying the geographic extent and severity of potential outcomes — to produce numerical risk estimates expressed as individual risk (IR) and societal risk (F-N curves). QRA studies are required for facilities handling hazardous substances above MSIHC threshold quantities, for petroleum and natural gas facilities under PNGRB and OISD guidelines, and as part of safety case preparation, Environmental Impact Assessment (EIA) submissions, and land-use planning adjacent to major hazard installations. Elion conducts independent QRA studies aligned with OISD standards, CCPS guidelines, API Recommended Practices, NFPA standards, and PNGRB technical requirements.
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What is a Quantitative Risk Assessment (QRA) Study?
A QRA study is a structured engineering analysis that quantifies the risk from hazardous industrial operations by combining frequency analysis (how likely a hazardous event is) with consequence modelling (how far and how severely it causes harm). The outputs — individual risk contours and societal risk F-N curves — are compared against regulatory tolerability criteria to determine whether risk is acceptable and what mitigation is required.
Frequency analysis — failure rates from OREDA, EGIG, API 581
Consequence modelling — PHAST, SAFETI, ALOHA
Individual risk (IR) contour maps
Societal risk F-N curves
ALARP evaluation & mitigation recommendations
Aligned with OISD, CCPS, API, NFPA, PNGRB
What is a QRA Study?
A QRA study quantifies risk at hazardous industrial facilities by combining hazard event frequency with modelled consequence severity. The output provides a numerical basis for risk acceptability decisions, regulatory submissions, and integrated safety audits, and the prioritisation of risk reduction measures.
Risk-Based Approach
QRA evaluates risk as the product of frequency (how often a hazardous event occurs) and consequence (the severity and geographic extent of harm if it occurs). This two-dimensional approach distinguishes QRA from qualitative hazard identification methods such as HAZOP, which identify what can go wrong but do not quantify the probability or magnitude of outcomes. QRA produces absolute risk values — individual risk per year (IRPY) and F-N curves for societal risk — that can be compared against regulatory tolerable risk criteria.
Regulatory Relevance in India
Factors That Decide QRA Cost in India
How a QRA quotation is prepared: Elion reviews the facility type, hazardous-material inventory, number of process units and credible scenarios, available plot plans/P&IDs, study purpose, applicable regulator, site-visit requirement, modelling deliverables and required completion date before issuing a fixed-fee proposal.
- Scope: basis of study, scenario register, frequency and consequence modelling, individual-risk contours, societal-risk F-N analysis, ALARP evaluation and recommendations.
- Cost drivers: scenario count, facility complexity, input-data quality, population and meteorological analysis, CFD or specialist modelling, regulatory review cycles, site travel and requested native model files.
- Deliverables: assumptions and data register, model basis, consequence zones, risk contours, F-N curve where applicable, mitigation action register and revision-controlled report.
Typical timeline: a small single-hazard-source study normally takes 2–3 weeks; a medium or multi-unit facility generally takes 4–8 weeks; complex refineries, petrochemical complexes or multi-site assignments may require 8 or more weeks after complete inputs are available.
Commercial clarity: the proposal should state inclusions, exclusions, assumptions, number of review cycles, site-visit basis, model-file handover and the information required from the client. This allows quotations to be compared on equivalent technical scope instead of headline price alone.
Key Risk Metrics Defined
The probability per year that a specific individual at a defined location will be fatally harmed by a hazardous event at the facility. Expressed as contours on a facility map (e.g., 10−5 per year, 10−6 per year). Used to assess land-use planning compatibility and worker risk.
The relationship between the frequency (F) of incidents causing N or more fatalities across the exposed population. Plotted as a cumulative frequency curve and compared against the ALARP (As Low As Reasonably Practicable) criteria and tolerability limits.
Modelled distances for thermal radiation (jet fire, pool fire, BLEVE), overpressure (vapour cloud explosion), and toxic dispersion (LC50, IDLH, ERPG limits). Used to establish emergency planning zones and land-use buffer distances.
– Hazard identification for major-accident scenarios (fire, explosion, toxic release)
– Frequency analysis — how likely each scenario is to occur
– Consequence modelling — the potential impact radius and severity of each scenario
– Risk contour mapping — plotting individual risk levels across the site and surrounding area
– Societal risk (F-N curve) evaluation for facilities near populated areas
– Comparison against ALARP (As Low As Reasonably Practicable) risk-acceptance criteria
– Mitigation recommendations to reduce risk where it exceeds acceptable levels — forming the basis for an integrated safety management plan
When Is a QRA Study Required?
QRA studies are required at specific lifecycle stages and under defined regulatory frameworks. The following represent the principal triggers for commissioning an independent QRA in India.
- MSIHC Rules 1989 — mandatory for facilities handling Schedule 2 or 3 hazardous chemicals above threshold quantities (MAH installations); safety report including risk assessment is a statutory obligation
- PNGRB compliance — required for city gas distribution (CGD) network authorisation, cross-country pipeline safety cases, and LNG terminal safety management system documentation
- OISD standards — referenced in OISD-STD-117, 118, 144, and 150 for petroleum storage, LPG installations, and pipeline siting; QRA determines mandatory separation distances
- MoEFCC EIA Notification — Category A process industry projects requiring Environmental Clearance must include quantitative risk analysis as part of the EIA documentation submitted to SEIAA / MoEFCC
- PESO licensing / approval — Petroleum, compressed gas, explosives and other installations falling within PESO's regulatory jurisdiction may require safety and risk-assessment documentation depending on the applicable rules, facility configuration and approval requirement.
- New facility approval — QRA is conducted at the design or FEED stage to establish safe separation distances, inform facility layout, and support regulatory clearances before construction
- Facility expansion or modification — any change that increases hazardous inventory, modifies process conditions, or introduces new chemicals requires QRA update to revalidate existing risk contours and separation distances
- Land-use planning — QRA risk contours are required by town planning authorities and DMIC/industrial cluster developers to establish buffer zones and determine compatible land use adjacent to major hazard installations
- Safety case preparation — facilities developing a formal safety case or safety management system (SMS) require QRA to demonstrate that risk is reduced to ALARP and to define emergency planning zone boundaries
- Periodic review — QRA studies should be reviewed at defined intervals (typically 5 years) or following significant changes to the facility, neighbouring land use, or the regulatory tolerability criteria
Where QRA Studies Are Required
QRA is applicable to facilities where hazardous substances are present in quantities that could, in the event of a loss of containment, cause harm beyond the facility boundary or to a significant on-site workforce.
Oil & Gas Facilities
Onshore oil and gas processing terminals, gathering stations, natural gas compressor stations, crude oil storage depots, product pipelines, and city gas distribution (CGD) facilities. OISD standards and PNGRB regulations require QRA for pipeline siting, terminal design, and safety management system development. Hazard scenarios include flammable vapour cloud formation, jet fires, pool fires, and high-pressure gas releases.
Chemical Manufacturing Plants
Facilities manufacturing, processing, or storing toxic, flammable, or reactive chemicals above MSIHC threshold quantities are classified as Major Accident Hazard (MAH) installations. QRA is required as part of safety case preparation, EIA documentation, and periodic risk review. Scenarios typically cover toxic gas dispersion (chlorine, ammonia, HF), reactive chemical runaway, and fire and explosion events.
LPG Bottling & Storage Plants
LPG bottling plants, bulk LPG storage installations, and LPG auto-LPG dispensing stations require QRA under OISD-STD-144, OISD-STD-150, and PESO licensing requirements. Primary hazard scenarios are BLEVE (Boiling Liquid Expanding Vapour Explosion) from pressurised LPG vessels, vapour cloud explosion (VCE) following unconfined vapour cloud formation, and pool fire from liquid spill ignition. Risk contours determine mandatory exclusion zone distances.
Hazardous Chemical Warehouses
Warehouses storing flammable, toxic, oxidising, or corrosive substances above MSIHC Schedule 2 or 3 thresholds require risk assessment to determine safe storage quantities, separation distances, and emergency response planning zones. QRA identifies the credible loss-of-containment scenarios for the stored inventory and quantifies consequence zones for fire, explosion, and toxic dispersion to support site layout decisions and emergency planning.
Refineries & Petrochemical Complexes
Petroleum refineries and integrated petrochemical complexes involve a wide inventory of flammable and toxic hydrocarbons under elevated temperature and pressure. QRA for these facilities addresses multiple simultaneous hazard sources, domino effect scenarios between adjacent process units, and occupied building siting in accordance with API RP 752 and API RP 753. OISD-STD-116 and OISD-STD-118 provide the primary Indian regulatory framework.
Infrastructure & Port Projects
Liquefied natural gas (LNG) import terminals, CNG mother stations, jetty-based petroleum product transfer facilities, and industrial park developments adjacent to major hazard installations require QRA as part of project clearance. Consequence modelling establishes safety buffer distances, informs land-use planning decisions, and supports Environmental Clearance (EC) documentation submitted to MoEFCC under the EIA Notification.
QRA Study Methodology
Elion’s QRA studies follow a structured six-stage process aligned with CCPS Guidelines for Chemical Process Quantitative Risk Analysis and applicable OISD, API, and NFPA frameworks. The methodology is applied consistently regardless of facility type, with scope and hazard scenario selection configured for each engagement.
Hazard Identification
Systematic identification of credible hazard scenarios for the facility’s chemical inventory and process conditions. Sources include process flow diagrams (PFDs), P&IDs, material safety data sheets, HAZOP study records, incident history, and site walkthrough. Scenarios selected for quantification include loss-of-containment events: rupture, leak, catastrophic failure, and pipeline breach for each significant hazard source term.
Frequency Analysis
Estimation of the likelihood of each identified hazard event using failure frequency data from industry databases (OREDA, EGIG, UKOPA, API 581). Event tree analysis (ETA) is applied to determine conditional probabilities of different outcome scenarios (ignited / unignited, immediate / delayed ignition, VCE / flash fire / jet fire) for each initiating release event. Failure frequencies are modified to reflect site-specific safeguarding systems where appropriate.
Consequence Modelling
Quantification of the physical effects of each hazard outcome scenario using PHAST (DNV) or SAFETI (DNV) dispersion and effects modelling software. Models applied include: Gaussian and heavy gas dispersion for toxic and flammable cloud formation, pool fire radiation modelling, jet fire thermal flux, BLEVE fireball and fragment throw, and vapour cloud explosion overpressure using multi-energy or Baker-Strehlow-Tang methods. Meteorological data for the facility location is incorporated to model atmospheric stability and wind direction effects.
Risk Estimation
Individual risk (IR) is calculated by integrating the frequency and consequence of all hazard scenarios at each spatial location around the facility, accounting for wind direction probability and population distribution. Societal risk is estimated by calculating the expected number of fatalities per scenario, combined with scenario frequencies to produce the F-N curve. Risk results are compared against ALARP criteria and regulatory tolerability thresholds to determine whether risk is acceptable, requires reduction, or exceeds intolerable limits.
Risk Contour Mapping
Individual risk contours (typically 10−4, 10−5, 10−6, and 10−7 per year) are overlaid on a georeferenced facility map and surrounding land-use plan. Contours define the risk significance zones used for land-use planning, siting of occupied buildings, and emergency planning zone delineation. The F-N curve is plotted against relevant societal risk tolerability criteria. Both outputs are included in the QRA report as primary regulatory submission deliverables.
Risk Mitigation & ALARP Demonstration
For risk scenarios identified as unacceptable or requiring ALARP justification, risk reduction options are evaluated and documented. Options assessed include: enhanced passive protection (berms, blast walls, secondary containment), active safeguarding (ESD systems, HIPPS, detection and deluge), procedural controls, and land-use buffer maintenance. Residual risk following proposed measures is re-estimated to confirm ALARP compliance. Recommendations are presented with implementation priority and indicative risk reduction magnitude. For fire protection system adequacy, a concurrent fire safety audit is commonly commissioned to verify installed systems against NBC 2016 and NFPA standards.
Software Tools Used for QRA Studies
Elion uses industry-standard consequence modelling and risk quantification software accepted by Indian and international regulatory authorities.
PHAST
PHAST (Process Hazard Analysis Software Tool) by DNV is used for individual hazard scenario consequence modelling — dispersion, fire, and explosion effects for a single release event. Applied to determine hazard distances for toxic dispersion (LC50, IDLH, ERPG endpoints), thermal radiation from pool fires and jet fires, BLEVE fireball parameters, and VCE overpressure zones. PHAST outputs are used as direct inputs to SAFETI for risk integration.
SAFETI
SAFETI (Software for the Assessment of Flammable, Explosive and Toxic Impact) by DNV integrates consequence modelling outputs with failure frequency data, population distribution, meteorological data, and ignition probability to calculate individual risk contours and F-N curves across the facility and surrounding area. SAFETI produces the georeferenced risk contour maps required for regulatory submission and land-use planning assessments.
ALOHA
ALOHA (Areal Locations of Hazardous Atmospheres), developed by the US EPA and NOAA, is used for atmospheric dispersion modelling of toxic chemical releases and emergency response planning zone estimation. Applied to determine protective action distances for toxic gas releases (chlorine, ammonia, HF, phosgene) under site-specific meteorological conditions. ALOHA outputs are used to define Emergency Planning Zones (EPZs) for on-site and off-site emergency response planning. For hazardous area classified facilities, an electrical safety audit verifying IEC 60079 Area Classification is recommended alongside QRA to validate ignition source assumptions used in frequency analysis.
Standards & Regulatory Framework for QRA Studies
QRA studies for Indian process industry facilities are structured in accordance with Indian statutory requirements and internationally recognised process safety guidelines. The applicable framework is confirmed during the study scoping stage based on facility type, hazardous substance inventory, and regulatory submission requirements.
| Standard | Application |
|---|---|
|
OISD
|
Oil Industry Safety Directorate standards — OISD-STD-116, 118, 144, 150 for petroleum, LPG, and natural gas facilities; mandatory for OISD-regulated oil sector operations |
|
PNGRB
|
Petroleum and Natural Gas Regulatory Board — technical and safety standards for CGD networks, pipelines, and LNG terminals; QRA required for network authorisation and safety management systems
|
|
MSIHC Rules
|
Manufacture, Storage and Import of Hazardous Chemicals Rules 1989 — requires safety reports including risk assessment for MAH installations above Schedule 2/3 threshold quantities |
|
CCPS
|
Center for Chemical Process Safety — Guidelines for Chemical Process Quantitative Risk Analysis (CPQRA); provides the primary methodological framework for QRA study structure and risk criteria
|
|
API RP 752/753
|
Management of Hazards Associated with Location of Process Plant Permanent / Portable Buildings — applied for occupied building siting and blast risk assessment in petroleum facilities |
|
NFPA 59A
|
Standard for Production, Storage and Handling of Liquefied Natural Gas (LNG) — thermal radiation and vapour dispersion exclusion zone requirements for LNG facilities |
|
EIA Notification
|
MoEFCC Environmental Impact Assessment Notification 2006 — risk analysis including QRA required for Category A process industry projects requiring Environmental Clearance |
ALARP Principle: Indian and international regulatory frameworks apply the ALARP (As Low As Reasonably Practicable) principle to risk acceptability. QRA studies quantify residual risk after existing safeguards and evaluate whether further risk reduction is reasonably practicable. Elion’s QRA reports document ALARP justification in the format required for submission to OISD, PNGRB, MoEFCC, and state regulatory authorities.
OISD Standards for Indian Petroleum Facilities
OISD-STD-116 covers fire protection for petroleum refineries and oil/gas processing plants; OISD-STD-117 covers fire protection for petroleum depots, terminals, and pipeline installations; OISD-STD-118 covers layouts and safe-distance requirements for oil and gas installations generally; OISD-STD-144 covers design and fire protection for LPG bottling plants; and OISD-STD-150 covers fire protection for LPG storage (mounded bullet) installations.
PNGRB Technical Standards
The Petroleum and Natural Gas Regulatory Board requires QRA as part of the safety management system for city gas distribution (CGD) network authorisation, cross-country pipeline safety cases, and LNG terminal safety documentation. PNGRB T4S regulations specify risk-based approach requirements for network design and emergency response planning.
CCPS CPQRA Methodology
The CCPS Guidelines for Chemical Process Quantitative Risk Analysis (CPQRA, 2nd edition) provides the reference methodology for scenario development, frequency estimation, consequence modelling integration, and risk characterisation used in Elion’s QRA studies. The CCPS ALARP framework and risk tolerability criteria are applied where site-specific regulatory criteria are not specified.
Independence & Regulatory Acceptance
Elion does not supply, install, or operate process equipment, safety systems, or guarding services at assessed facilities. QRA studies are conducted on a fully independent basis — recommendations are engineering-neutral and not influenced by equipment or service supply interests. Elion’s QRA reports are structured to address applicable technical and documentation requirements for regulatory or stakeholder review, including requirements associated with OISD, PNGRB, MoEFCC, PESO and State Pollution Control Boards, where relevant to the project.
QRA Study Deliverables
Every Elion QRA study produces a documented deliverable set structured for regulatory submission, safety case preparation, EIA documentation, and emergency response planning. All deliverables are produced by in-house qualified engineers.
Risk contour maps — individual risk contours (10 −4 to 10 −7 per year) georeferenced on facility and surrounding area plan
F-N curve — societal risk cumulative frequency curve plotted against ALARP tolerability criteria
Individual and societal risk quantification results with ALARP evaluation and tolerability assessment
Consequence modelling outputs — thermal radiation zones, overpressure contours, toxic dispersion footprints for each modelled scenario
Hazard scenario register — identified release scenarios with source term parameters, outcome event tree, and frequency estimates
Emergency Planning Zone (EPZ) delineation for on-site and off-site emergency response planning
Domino effect assessment for facilities with adjacent hazard sources (where applicable)
Occupied building risk assessment per API RP 752/753 (for petroleum and petrochemical facilities)
Risk mitigation recommendations — prioritised engineering, administrative, and procedural risk reduction measures with residual risk re-estimation
Executive summary structured for regulatory or stakeholder submission — OISD, PNGRB, MoEFCC, PESO or other applicable authority/project requirements.
Why Organisations Commission QRA Studies from Elion
The following reflects Elion’s operational track record and structural characteristics relevant to QRA study commissioning decisions.
Independent Third-Party Study
Elion does not supply, install, or operate process equipment, safety instrumented systems, or emergency response services at assessed facilities. QRA studies are conducted on a fully independent basis — recommendations are engineering-neutral and not influenced by vendor or contractor relationships. Independent third-party assessment can support objectivity and submission credibility where independent evaluation is required by an authority, client, insurer, lender or project specification.
Established Practice Since 2010
Elion has operated as an independent engineering audit and safety consultancy since 2010 — over 15 years of continuous independent practice across Indian process industries. The QRA team draws on accumulated experience across oil and gas, chemical, LPG, refining, and infrastructure sectors, providing the industry-specific hazard knowledge that is essential for credible scenario selection and failure frequency estimation.
30,000+ Audits & Studies Completed
30,000+ engineering and safety audits and studies completed across Indian industries since 2010. The breadth of field experience across facility types, process categories, and regulatory environments directly informs QRA study quality — particularly in hazard scenario selection, safeguard crediting, and the interpretation of consequence modelling outputs in the context of the actual facility configuration and operating practices.
Multi-Industry Process Safety Experience
Elion has conducted process safety studies across oil and gas, chemical manufacturing, LPG, petrochemical, pharmaceutical, and infrastructure sectors. This cross-industry experience is relevant to QRA because many Indian facilities involve mixed chemical inventories and non-standard process configurations that require adapted hazard scenario development beyond standard industry templates. Related services including energy audits for process facilities are also delivered by the same in-house team, providing an integrated view of process operations and energy flows that supports more accurate source term definition in consequence modelling.
Pan-India Execution
Elion delivers QRA studies for facilities across India including refinery clusters in Gujarat and Rajasthan, petrochemical complexes in Maharashtra, chemical manufacturing zones in Tamil Nadu and Gujarat, LPG installations across multiple states, and city gas distribution projects in Tier-1 and Tier-2 cities. All study work is conducted by in-house qualified engineers — no subcontracting — ensuring consistent methodology and report quality regardless of project location.
Related Process Safety & Compliance Services
A QRA study is most effective as part of a broader process safety programme. The services below are commonly commissioned alongside or preceding a QRA study.
HAZOP Study
HAZOP — Hazard & Operability Study
Systematic qualitative identification of process deviations and their causes, consequences, and safeguards. HAZOP is typically conducted before QRA — hazard scenarios identified in HAZOP are selected and quantified in the QRA study. Both studies are commonly commissioned as a combined process safety package.
Fire Safety Audit
Fire Safety Audit
Independent audit of fire detection, suppression, and emergency response systems against NBC 2016 and NFPA standards. QRA consequence modelling identifies credible fire scenarios and hazard distances; the fire safety audit verifies whether installed passive and active fire protection systems are adequate to manage those scenarios.
Electrical Safety Audit
Electrical Safety Audit
CEA Regulations and IS-code-aligned audit of HT/LT electrical systems. For hazardous area classified facilities, electrical safety audits verify Area Classification compliance (IEC 60079), which directly affects the credibility of ignition source assumptions used in QRA frequency analysis.
Energy Audit
Energy Audit
BEE-aligned energy flow analysis for process facilities. Energy audits at process plants frequently identify process inefficiencies and operational deviations that are also relevant to process safety — abnormal pressure profiles, heat exchanger fouling, and relief valve cycling that may indicate process hazard precursors.
QRA vs Other Process Safety Studies
QRA Knowledge & Compliance Resources
Use this structured resource hub to move from QRA fundamentals and calculations to regulatory submission, technical review and specialist applications.
Fundamentals, methodology and reporting
- QRA full form, meaning and method comparisons
- QRA methodology, calculations and applications
- Frequency, consequence and risk calculations
- QRA report contents, structure and review checklist
Regulation and submission
- When QRA is required in India
- OISD, PESO, PNGRB and MoEFCC compliance
- OISD-STD-118 layout review checklist
- PESO submission and review checklist
- QRA integration with EIA submissions
- International standards and risk-acceptance criteria
Quality, software and consultant selection
- PHAST, SAFETI, ALOHA and software selection
- Design-stage inputs and project-gate checklist
- How to select a QRA consultant
- Independent QRA review and validation
- Consultant competency and certification evidence
- QRA versus HAZOP and the combined workflow
Applications and evidence
HAZOP is a qualitative, team-based study that identifies process deviations and their causes using structured guidewords (MORE, LESS, NO, REVERSE). It identifies what can go wrong and what safeguards exist, but does not estimate the frequency or magnitude of consequences numerically.
QRA takes credible scenarios — many sourced from HAZOP — and quantifies them: failure frequencies from industry databases, consequence extents from PHAST/SAFETI modelling, and integrated individual and societal risk estimates. QRA is required where regulators (PNGRB, MoEFCC, OISD) need numerical risk evidence; HAZOP alone is insufficient for these submissions. The two studies are typically commissioned together as a combined process safety package.
HIRA (Hazard Identification and Risk Assessment) is a semi-quantitative or qualitative technique commonly used for occupational safety and general industrial risk management. It evaluates hazards using severity × likelihood risk matrices and produces risk ratings (High / Medium / Low) that guide control measure selection. HIRA does not generate individual risk contours, F-N curves, or consequence footprints.
QRA uses absolute numerical risk estimates derived from failure frequency databases and consequence modelling software, making it appropriate for major hazard facility siting, land-use planning, and regulatory safety case submissions where a numerical risk basis is mandatory. HIRA is appropriate for routine operational safety management; QRA is required for major hazard risk decisions.
QRA Study — FAQ
Common questions about quantitative risk assessment methodology, regulatory requirements, and deliverables. For study-specific queries, submit a request or contact the team.
What is a Quantitative Risk Assessment (QRA)?
A Quantitative Risk Assessment (QRA) is a numerical assessment of the likelihood and consequences of major accident scenarios such as fire, explosion and toxic release. It combines failure-frequency analysis with consequence modelling to estimate individual and societal risk. Depending on the scope, outputs may include individual risk contours, societal risk (F-N) curves and ALARP evaluation to support risk-reduction decisions.
When is a QRA study required in India?
A QRA may be required depending on the type of facility, hazardous-material inventory, applicable regulations, project approval conditions and sector-specific standards. QRA is commonly undertaken for petroleum and natural-gas installations, refineries, chemical and petrochemical plants, LPG/LNG facilities and other major-hazard installations. It may also form part of environmental-clearance documentation, facility expansion studies, layout or siting assessments and regulatory or stakeholder requirements.
Is QRA legally mandatory, or a best practice?
The requirement for QRA depends on the applicable regulatory framework, facility type and project conditions. Certain OISD standards, PNGRB regulations and project-specific approval requirements may require risk assessment or QRA in defined circumstances. Some OISD standards have statutory backing where incorporated into applicable rules. Even where a specific QRA is not expressly mandated, it may be required by an approving authority, project specification, insurer, lender or corporate risk-management framework.
What is the difference between QRA and HAZOP?
HAZOP is a structured, team-based study used to identify process deviations, causes, consequences and safeguards using guidewords. It primarily identifies what can go wrong. QRA quantitatively evaluates selected accident scenarios using failure-frequency data and consequence modelling to estimate numerical risk levels. HAZOP findings may therefore provide useful input for identifying scenarios for a QRA.
How is QRA different from HIRA?
HIRA generally identifies hazards and evaluates risk using qualitative or semi-quantitative methods such as severity and likelihood matrices. QRA goes further by estimating numerical event frequencies and consequences and may generate individual risk contours, societal risk estimates and F-N curves. QRA is particularly useful where quantitative risk information is required for major-hazard evaluation, facility siting, land-use considerations or regulatory assessment.
What software is used for QRA studies?
Depending on the project requirements, QRA studies may use specialised software such as DNV PHAST for consequence modelling and DNV SAFETI for quantitative risk calculations. ALOHA may also be used for selected atmospheric-release and emergency-planning assessments. The appropriate software and modelling methodology depend on the substances, scenarios, facility complexity and required study outputs.
How long does a QRA study take?
The study duration depends on facility complexity, number of hazardous scenarios, availability of technical inputs and required deliverables. A relatively small facility may typically require around 2–3 weeks after complete data is available, while larger multi-unit or complex facilities may require 4–8 weeks or more.
What does a QRA study cost in India?
The cost of a QRA study depends on facility complexity, hazardous-material inventory, number of process units and scenarios, modelling requirements, societal-risk analysis, site-visit requirements and the required report format. Elion can provide a fixed-fee technical and commercial proposal after reviewing the facility details and available technical documents.
What information is required to conduct a QRA study?
Typical inputs include the facility layout or plot plan, process description, PFDs and P&IDs, hazardous-material inventory, storage capacities, operating pressures and temperatures, pipeline and equipment details, SDS/MSDS information, meteorological data where applicable, occupancy or population information and the purpose or regulatory requirement of the study. The exact data requirement depends on the project scope.
What do I receive after a QRA study?
Depending on the agreed scope, the QRA report may include the hazard-scenario register, failure-frequency analysis, consequence modelling results, thermal-radiation and explosion-overpressure zones, toxic-dispersion results, individual risk contours, societal risk or F-N curves, ALARP evaluation, emergency-planning considerations and prioritised risk-reduction recommendations.
What is ALARP and how does it relate to QRA?
ALARP means “As Low As Reasonably Practicable.” It is a risk-management principle used to evaluate whether additional risk-reduction measures should reasonably be implemented. Where applicable, QRA results can be compared with recognised risk criteria and ALARP principles to support decisions on further mitigation.
What is an individual risk contour?
An individual risk contour is a line plotted on a site or surrounding-area map connecting locations with the same calculated individual-risk level, for example 10⁻⁵ per year. It helps show how risk varies with distance from hazardous sources and can support facility-layout, siting and land-use decisions.
What is an F-N curve?
An F-N curve represents societal risk. It plots the cumulative frequency (F) of accident events capable of causing N or more fatalities. Where relevant risk criteria are available, the curve can be used to evaluate risks affecting groups of people rather than the risk to a single individual at a particular location.
Which industries commonly require QRA studies?
QRA is commonly undertaken for oil and gas facilities, petroleum refineries, chemical and petrochemical plants, LPG and LNG installations, gas-processing facilities, terminals, tank farms, hazardous-chemical storage facilities and other installations where major fire, explosion or toxic-release hazards need to be quantitatively evaluated.
Are QRA findings kept confidential?
Yes. Client documents, facility information, technical data and study findings are treated as confidential and handled in accordance with Elion’s agreed confidentiality and document-control requirements. Where required, a project-specific non-disclosure agreement can also be executed.
How can I request a QRA consultation with Elion?
Share the facility type, location, process description, hazardous-material inventory and available technical documents such as the layout, PFD or P&ID. Elion’s technical team can review the information, identify any additional data requirements and provide a technical and commercial proposal for the QRA study.
Request an Independent QRA Study for Your Facility
Submit your facility type, process description, hazardous substance inventory, and regulatory submission requirements. Our team will review your requirements and provide a fixed-fee technical proposal within a defined period. Applicable for new facility siting, existing installation periodic review, EIA documentation, and regulatory compliance submissions across India.