QRA for IOCL’s Hydrocarbon Pipeline, Gujarat Refinery to Dumad Terminal

Indian Oil Corporation Ltd (IOCL) operates a hydrocarbon pipeline corridor transferring product from its Gujarat Refinery to Dumad Terminal, carrying High Molecular Weight Linear Alkyl Benzene (HMW LAB) through a 6-inch line, Low Molecular Weight Linear Alkyl Benzene (LMW LAB) through a 10-inch line, and Pipeline Compatible Kerosene (PCK) and Aviation Turbine Fuel (ATF) each through a 12-inch line. iFluids Engineering carried out a Quantitative Risk Assessment (QRA) for this pipeline system to quantify and rank the risks each product and pipe size presents by severity and probability, assess the adequacy of existing control measures, and identify the consequences of credible hazards to personnel at a range of distances from the pipeline. A four-product, three-diameter corridor does not carry one uniform risk profile: LAB’s handling characteristics differ from a fully volatile fuel like ATF, and a QRA has to rank each product-pipe combination on its own terms rather than apply a single generic pipeline hazard model.

Field	Detail
Sector	Oil & Gas / Refining (Pipeline Transfer)
Location	Gujarat Refinery to Dumad Terminal, Gujarat, India
Facility Type	Cross-country hydrocarbon pipeline (multi-product)
Client	Indian Oil Corporation Ltd (IOCL)
Scope of Work	QRA for HMW LAB (6″), LMW LAB (10″), PCK (12″), and ATF (12″) pipelines
Standards / Regulatory Framework	OISD-STD-141, PNGRB petroleum product pipeline regulations
Risk Ranking Basis	Severity and probability-based risk ranking, per project scope
Project Duration	Not publicly disclosed for this engagement
iFluids Team Size	Not publicly disclosed for this engagement

The Engineering Challenge of the Gujarat Refinery-Dumad Pipeline

IOCL’s Gujarat Refinery-to-Dumad corridor carries four distinct products across three pipe diameters, a configuration a regulator requires to be assessed product by product and pipe by pipe, because HMW LAB, LMW LAB, PCK, and ATF each fail and release differently along the same length of right-of-way.

Linear Alkyl Benzene, in both its high and low molecular weight grades, is a heavier feedstock with lower volatility than PCK or ATF, so a rupture on the 6-inch HMW LAB line tends toward a pool-formation release rather than a rapidly dispersing vapour cloud. A rupture on either 12-inch line carrying PCK or ATF behaves differently again: both are more volatile distillates, so the same pipe failure produces a larger flash fraction and a wider dispersion or flash-fire footprint for a comparable release rate. PNGRB’s technical standards and safety regulations for petroleum product pipelines require a Quantitative Risk Assessment before a cross-country pipeline of this kind can be authorised to operate. That requirement is what turns a four-product corridor into four separate technical problems rather than one combined pipeline hazard.

Pipe diameter compounds the difference: a 12-inch line has a larger available release rate for the same operating pressure than the 6-inch HMW LAB line, which changes the credible worst-case inventory even before product-specific volatility is factored in.

iFluids’ QRA Approach and Methodology

iFluids Engineering’s Quantitative Risk Assessment (QRA) service identifies credible failure scenarios along a pipeline route, quantifies their consequence and failure probability, and ranks each scenario by severity so an operator can see exactly which product, pipe size, and location segment drives the corridor’s risk.

The methodology followed a standard sequence for the Gujarat Refinery-Dumad corridor:

1. Hazard identification: catalogue credible loss-of-containment scenarios for each of the four pipelines along the route.
2. Consequence modelling: quantify jet fire, pool fire, flash fire, and vapour cloud dispersion effect distances specific to each product’s volatility.
3. Frequency and probability analysis: assign failure probabilities per pipe segment using recognised pipeline failure-rate data.
4. Severity-probability ranking: combine consequence severity and failure probability into a ranked risk register for each product-pipe combination.
5. Control measure adequacy review: assess whether existing controls, isolation valves, leak detection, and right-of-way management, adequately address the ranked risks.
6. Risk reduction recommendations: for scenarios ranked outside acceptable levels, recommend engineering or procedural mitigation.

OISD-STD-141 specifies minimum depth of cover, spacing from habitation, and right-of-way width requirements for cross-country hydrocarbon pipelines, and the QRA uses those figures to define how close a credible release could reach populated areas along the corridor. Ranking by severity and probability rather than a single combined hazard score also lets the recommendations target the specific product-pipe combination driving each ranked risk, instead of applying one corridor-wide fix to problems with different root causes.

Failure probability for a given pipe segment typically draws on industry pipeline-incident databases, calibrated to that line’s diameter, wall thickness, coating condition, and inspection regime, rather than a single generic per-kilometre failure rate applied across every line in the corridor. That calibration is what lets a ranking distinguish a well-inspected 12-inch ATF line from an older section of 6-inch HMW LAB pipe with a different corrosion history.

Technical Decisions and Engineering Rationale

Ranking four products across three pipe diameters by severity and probability, rather than assessing the corridor as one pipeline, is the technical decision that let the QRA correctly separate a lower-consequence HMW LAB release from a higher-consequence ATF release occurring at the same point along the corridor.

OISD-STD-141 also sets minimum separation between parallel product pipelines sharing a right-of-way, a requirement that limits how a rupture on one line could escalate into an adjacent line in the same corridor. Where the four lines run in the same right-of-way for part of the route to Dumad, that separation requirement is what the QRA checks before assuming an incident on the PCK line stays isolated from the adjacent ATF or LAB lines. Pipe age, wall thickness, and corrosion allowance also differ by service: LAB’s lower corrosivity compared with distillate fuels can justify a different inspection interval, which in turn affects the failure probability assigned to that line in the ranking. Treating all four lines under one generic “pipeline” failure-rate assumption would have flattened these differences and produced a risk ranking that didn’t reflect which line and product combination actually needed attention first.

Where the corridor crosses roads, waterways, or other utility lines, OISD-STD-141 also sets additional protective requirements, such as increased wall thickness or casing pipe, at each crossing. The QRA has to treat these crossing points as distinct, higher-consequence locations along the route rather than assume uniform risk along the corridor’s full length.

Outcomes and Deliverables

The QRA gave IOCL a severity-and-probability-ranked risk register for the Gujarat Refinery-to-Dumad corridor, evaluating existing control measures against each product-pipe combination’s ranked risk and identifying where isolation, detection, or right-of-way improvements were needed to bring risk levels down toward an acceptable band.

Deliverable	Basis	Outcome
QRA report (hazard identification, consequence and probability ranking)	Severity/probability risk ranking, OISD-STD-141	Risk ranked separately for HMW LAB (6″), LMW LAB (10″), PCK (12″), and ATF (12″) pipelines
Control measure adequacy review	Existing isolation, detection, and right-of-way controls	Adequacy assessed against each product-pipe combination’s ranked risk
Risk reduction recommendations register	PNGRB / OISD-STD-141	Mitigation measures identified for scenarios ranked outside acceptable levels

PNGRB requires a pipeline operator to act on QRA-driven risk-reduction recommendations as a condition of maintaining its pipeline authorisation, which is why the recommendations register functions as a compliance deliverable rather than a supplementary suggestion.

Lessons and Applicability for Multi-Product Pipeline Risk Assessment

Cross-country corridors carrying more than one product, including iFluids’ Cauvery Basin cross-country pipeline risk assessment, share a lesson worth generalising from the Gujarat Refinery-Dumad corridor: ranking risk by product and pipe size, rather than by corridor as a whole, is what actually locates where mitigation budget belongs.

A multi-product corridor built or expanded over time often ends up with lines of different age, diameter, and service running the same right-of-way, and a QRA that scores the corridor as a single asset will understate the risk contribution from whichever line actually has the least favourable combination of volatility, diameter, and inspection history. OISD-STD-141’s spacing and separation requirements set a uniform design baseline, but they do not rank which line on a shared right-of-way needs attention first; that ranking has to come from the product-by-product QRA. Any operator running more than one product line through a shared corridor should treat a single combined pipeline risk score as insufficient for prioritising mitigation spend.

Conclusion and Next Steps

iFluids Engineering’s QRA for IOCL’s Gujarat Refinery-to-Dumad pipeline ranked the risk of four products across three pipe diameters by severity and probability, assessed existing control measures against that ranking, and identified where risk reduction was needed under the PNGRB and OISD-STD-141 framework governing cross-country hydrocarbon pipelines. This project is representative of iFluids’ work for multi-product pipeline operators across India who need risk ranked by product and pipe size rather than assessed as a single generic corridor. If your pipeline network needs a Quantitative Risk Assessment benchmarked against OISD or PNGRB requirements, contact iFluids Engineering to discuss scope.