IOCL Vishakhapatnam Oil Depot Overfill Protection Certified Following Site Acceptance Testing Under IEC 61511
Risknowlogy has certified the overfill protection systems on 20 tanks at the IOCL Vishakhapatnam Oil Depot, held by Indian Oil Corporation Limited, following independent validation of site acceptance testing against IEC 61511:2016.
What Was Certified
The certified system protects 20 tanks at the depot in Visakhapatnam, Andhra Pradesh. Sixty safety instrumented functions are implemented across them, three per tank. On a high-high level signal from either radar gauge, or on loss of the fuse supply, the tank inlet, outlet and recirculation valves close within 30 seconds. All 60 functions operate in low demand mode with a one-year proof test interval.
The certificate covers site acceptance testing: Risknowlogy witnessed the tests and confirmed that each was carried out completely and its result recorded. The design, the application program and the system configuration are outside the scope — Risknowlogy did not perform, modify or approve them.
Scope of certification: Site acceptance testing (SAT) of 60 safety instrumented functions across 20 tanks, against IEC 61511:2016. Holder: Indian Oil Corporation Limited. System integrator: Emerson Process Management (India) Pvt Ltd. Not in scope: design, application programming and system configuration.
What the Site Acceptance Test Verified
Testing ran from 4 to 7 August 2026 at the depot, executed by Emerson and witnessed by Risknowlogy, with IOCL observing. Each function was tested against the safety requirements specification:
- Inlet valve closure on a simulated high-high signal from the primary radar gauge
- Inlet valve closure on the same signal from the secondary radar gauge
- Outlet and recirculation valve closure on both gauge signals
- Response of all three valves to a fuse disconnection on the overfill protection system
- Closure within 30 seconds
All 60 functions passed. No modifications were carried out during testing and no punch list items were recorded.
What This Means for Operators and Stakeholders
The depot operator has evidence that the installed protection works as specified on the plant, not only in design documents. Contractors and integrators inherit a witnessed, documented close-out of the validation phase, with no open items carried into operation. Insurers, auditors and regulators get an independent record that all 60 functions were tested against the safety requirements specification and passed.
About Indian Oil Corporation Limited
Indian Oil Corporation Limited operates the Vishakhapatnam depot where the certified systems are installed. Putting the overfill protection through independent, witnessed validation before handover confirms performance on the plant rather than assuming it.
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