iFluids Engineering successfully executed SIL (Safety Integrity Level) Assessments across multiple IOCL refineries, including Mathura, Panipat, and Gujarat Refinery. These critical assessments were conducted in full compliance with IEC 61508, IEC 61511, OISD-150, and OISD-179 standards, using LOPA (Layer of Protection Analysis) methodology. The studies were supported by industry-recognized tools such as PHA-Pro to assess and classify Safety Instrumented Functions (SIFs) and identify risk reduction requirements.
Methodology
SIL Assessments were performed using the LOPA methodology supported by PHA-Pro software, ensuring alignment with relevant international and national safety standards.
Collaborative workshops were held with the client’s safety, instrumentation, and process teams to evaluate, prioritize, and assign appropriate SIL levels to all critical SIFs.
1. Identification of SIFs
Safety Instrumented Functions (SIFs) were identified from P&IDs and Cause & Effect matrices to determine functions critical to process safety across the given units.
2. Definition of Initiating Events
Initiating events (IEs) such as high pressure, low flow, or equipment failure were defined for each SIF based on operational data and industry standards.
3. Consequence Assessment
Each IE was evaluated for potential impacts on personnel, environment, assets, and reputation using IOCL’s approved risk matrix.
4. Identification of IPLs
Independent Protection Layers like PSVs, ESDs, and control systems were identified and validated to reduce risk independently of the SIF.
5. Application of Conditional Modifiers
Realistic factors such as operator presence and ignition probability were applied to refine the estimated frequency of hazardous scenarios.
6. Risk Reduction Factor (RRF) & SIL Assignment
RRF was calculated using the ratio of unmitigated to tolerable event frequency, leading to assignment of SIL-a, SIL-1, SIL-2, or SIL-3.
7. Documentation of SIL Results
SIF-wise SIL classifications were documented with logic, loop references, and drawing links to support further SIS design and verification.
Outcome
Delivered SIL reports with a structured SIF register, SIL ratings, and risk reduction recommendations. Ensured regulatory compliance, improved process safety, and enhanced operational reliability. All deliverables were completed on time, supporting smooth implementation and informed decisions.
1. SIL Assessment – IOCL Mathura Refinery
iFluids Engineering carried out a SIL Assessment at IOCL’s Mathura Refinery, ensuring full compliance with applicable safety regulations, including site-specific standards such as OISD-152.
Scope:
The study covered 19 process units, including:
- AVU – Atmospheric Vacuum Unit
- VBU – Viscosity Breaking Unit
- FCCU – Fluidized Catalytic Cracking Unit
- CCRU – Continuous Catalytic Reforming Unit
- MEROX – Merox Units
- PRU – Propylene Recovery Unit (Old & New)
- OHCU – Once Thru Hydro Cracker Unit
- HGU-I & II – Hydrogen Generation Units I & II
- DHDS – Diesel Hydro Desulphurization
- DHDT – Diesel Hydro Treatment
These units, along with hydrocarbon storage tanks, cooling towers, fire stations, and loading areas, were assessed to determine their required SIL ratings for Safety Instrumented Functions – SIFs.
2. SIL Assessment – IOCL Panipat Refinery
iFluids Engineering conducted a comprehensive SIL Assessment at IOCL’s Panipat Refinery and Petrochemical Complex, covering both refinery and polymer units.
Scope:
The study included 30+ units, such as:
- RFCCU – Resid Fluidized Catalytic Cracking Unit
- SRU – Sulphur Recovery Unit
- CCU – Cryogenic Condensation Unit
- NCU – Naphtha Cracker Unit
- PGHU – Pressure Gauge Hydrogenation Unit
- BEU – Butene Extraction Unit
- BDEU – Butadiene Extraction Unit
- HDPE – High-Density Polyethylene Unit
- PPU – Polypropylene Unit (PP Lines 1 & 2)
The objective was to evaluate and assess the Safety Instrumented Functions (SIFs) across these units and determine their required Safety Integrity Levels (SILs).
3. SIL Assessment – IOCL Gujarat Refinery (JR)
iFluids Engineering executed a SIL Assessment for IOCL’s Gujarat Refinery (Jawaharlal Nehru Refinery), ensuring full compliance with applicable safety standards.
Scope:
The assessment covered 16 major units, including:
- AU-I – Atmospheric Distillation Unit 1
- AU-II – Atmospheric Distillation Unit 2
- AU-III – Atmospheric Distillation Unit 3
- AU-IV – Atmospheric Distillation Unit 4
- FPU-I – Feed Preparation Unit 1
- FPU-II – Feed Preparation Unit 2
- VDU – Vacuum Distillation Unit
- DCU – Delayed Coker Unit
- MTBE – Methyl Tertiary Butyl Ether
- FGH – Food Grade Hexane
The objective was to evaluate the Safety Instrumented Functions (SIFs) and determine the required Safety Integrity Levels (SILs), ensuring compliance with regulatory standards and optimizing operational safety.
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