OISD 118
Oil Industry Safety Directorate Standard 118
OISD 118 is the Oil Industry Safety Directorate standard governing layout, inter-distance, and safety provisions for petroleum installations in India. It defines minimum separation distances between storage tanks, process equipment, and site boundaries; HAZOP study requirements; safety device provisions; and emergency response capability. Every Indian refinery, petrochemical plant, oil terminal, and LPG installation must comply with OISD 118 for MoPNG, PNGRB, and PESO approval.
OISD 118 (Oil Industry Safety Directorate Standard 118, formally titled 'Layout for Oil and Gas Installations') is the mandatory layout and safety standard for Indian petroleum and hydrocarbon installations. Maintained by the Oil Industry Safety Directorate (OISD) under the Ministry of Petroleum and Natural Gas (MoPNG), the standard codifies inter-distance tables (minimum separation between tanks, equipment, public roads, site boundaries), HAZOP study and follow-up requirements, safety device and emergency response provisions, and audit-trail documentation. OISD 118 compliance is verified during MoPNG site audits, PNGRB inspections, and CCOE pre-commissioning checks. See the OISD 118 compliance product for the automation Pathnovo provides on this standard.
Inter-distance encoding
OISD 118 Chapter 3 codifies minimum separation distances between tanks (storage to storage), between tanks and process equipment, between tanks and site boundary, and between tanks and public roads. The tables are indexed by product class (Class A, B, C petroleum; LPG; LNG; industrial gases), tank capacity, and tank type (atmospheric, low pressure, refrigerated). For a typical refinery layout, dozens to hundreds of inter-distance pairs must be computed and verified during design and revalidated at each modification. Manual computation is error-prone and time-intensive; automation is the modern approach.
HAZOP study requirements
OISD 118 mandates HAZOP studies for every new installation and at any major modification. The HAZOP must follow IEC 61882 methodology with documented node-by-node deviation analysis, consequence assessment, safeguard identification, and recommendation tracking. Completed HAZOP studies (typically 800-3,000 pages per refinery) must be archived as queryable registers, with every recommendation mapped to closure status and the closing P&ID revision. MoPNG and PNGRB auditors verify HAZOP coverage and closure during plant inspections.
Safety device provisions
OISD 118 codifies safety device requirements for petroleum installations: pressure relief valves (PRV) on every pressurised vessel with set pressure validated against ASME Section VIII or equivalent; emergency shutdown valves (ESD) at strategic points; high-level alarms and high-high-level shutdown on storage tanks; fire-water capacity computed per tank-farm volume; vapour recovery for Class A petroleum; flame arresters on atmospheric vents. The safety device register cross-references each device against the corresponding P&ID and ISA 5.1 tag.
Audit and inspection cycle
OISD audits occur on a 2-3 year cycle for active petroleum installations. Audit teams verify layout compliance (inter-distance table), HAZOP closure status, safety device register currency, and emergency response capability. Non-conformities surface during desk review (documentation) and walk-down (physical inspection). MoPNG-led audits are typically organised through OISD; PNGRB conducts parallel audits focused on gas processing and pipeline operations.
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Indian PSU refineries (IOCL, BPCL, HPCL, ONGC-Mangalore, Reliance, Nayara) operate under continuous OISD 118 compliance with 2-3 year audit cycles. Each refinery typically carries 500-3,000 OISD-scoped inter-distance pairs across the plant.
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Greenfield refinery and petrochemical EPC projects must demonstrate full OISD 118 compliance at mechanical completion. The OISD 118 deliverable package includes inter-distance compliance table, HAZOP study close-out, safety device register, and emergency response plan.
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Petrochemical plants handling Class A petroleum intermediates (naphtha, gasoline, MTBE) operate under OISD 118 jurisdiction. Multi-product complexes typically maintain unified OISD 118 registers across processing, storage, and pipeline segments.
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LPG bottling plants, LNG terminals, and oil marketing depots fall within OISD 118 scope alongside refinery and petrochemical operations. Multi-site operators (Indian Oil Marketing Companies, Reliance retail) maintain consolidated OISD 118 portfolios.
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Mid-cycle modifications (debottlenecking, capacity expansion, new unit addition) require fresh OISD 118 inter-distance validation. Pathnovo's OISD 118 product computes the delta scope automatically when P&ID revisions arrive.
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EPC contractors (L&T, Toyo, KBR, Tata Projects, Engineers India Limited) producing OISD 118-compliant deliverables for Indian PSU clients use the inter-distance table and HAZOP register as procurement and inspection-readiness artifacts.
Pathnovo encodes OISD 118 natively as part of the Indian EPC compliance bundle. The product digitises HAZOP study PDFs (800-3,000 pages) into structured queryable registers per register extraction, encodes OISD 118 Chapter 3 inter-distance tables and computes plant-wide compliance from plot plan dimensions, builds the safety device register from instrument index and datasheets, and produces MoPNG / PNGRB audit-ready documentation packs. Indian PSU refineries running Pathnovo report 60-80% reduction in OISD audit-day desk review time. See the OISD 118 compliance product for the full workflow.
What does OISD stand for?
OISD stands for Oil Industry Safety Directorate, a body under India's Ministry of Petroleum and Natural Gas (MoPNG). OISD publishes industry safety standards for petroleum and hydrocarbon installations, maintains audit programmes, and coordinates with PNGRB and CCOE on regulatory enforcement.
What is OISD 118?
OISD 118 (formally titled 'Layout for Oil and Gas Installations') is the standard governing layout, inter-distance, HAZOP, and safety provisions for petroleum installations in India. Compliance with OISD 118 is mandatory for every refinery, petrochemical plant, LPG bottling unit, LNG terminal, and oil marketing depot operating in India.
What does OISD 118 inter-distance mean?
OISD 118 Chapter 3 codifies minimum separation distances between petroleum storage tanks, between tanks and process equipment, between tanks and site boundaries, and between tanks and public roads. Distances are indexed by product class (Class A, B, C petroleum; LPG; LNG) and tank capacity. A typical refinery carries 500-3,000 inter-distance pairs requiring compliance verification.
Is OISD 118 mandatory?
Yes. OISD 118 is mandatory for every Indian petroleum installation under MoPNG jurisdiction. Compliance is verified at design stage (during plot plan and HAZOP study), at pre-commissioning, and during periodic OISD audits (2-3 year cycle). Non-compliance can trigger MoPNG enforcement action including operational shutdown.
How does OISD 118 differ from PESO and CCOE?
OISD 118 is the layout and safety standard published by MoPNG. PESO is the regulatory body administering the Petroleum Act and Gas Cylinders Rules. CCOE is the executive head of PESO and the formal licensing and inspection authority. OISD 118 compliance is verified during CCOE inspections and forms part of the technical evidence supporting CCOE licence approval.
What is in an OISD 118 audit package?
A typical OISD 118 audit package includes the plot plan with inter-distance compliance table (per Chapter 3), complete HAZOP study with closure status (per IEC 61882), safety device register cross-referenced to P&IDs, fire-water capacity calculation, emergency response plan, and previous-audit non-conformity closure evidence. Pathnovo automates the documentation pack as part of the OISD 118 compliance product.
Can Pathnovo automate OISD 118 compliance?
Yes. Pathnovo digitises HAZOP study PDFs into queryable registers, encodes OISD 118 Chapter 3 inter-distance tables, builds the safety device register from P&IDs and instrument index, and produces audit-ready documentation packs for MoPNG / PNGRB review. Used by Indian PSU refineries to compress audit preparation from weeks to hours.
OISD 118 Compliance Software
Pathnovo's OISD 118 compliance automation product page.
HAZOP Register Extraction
Digitise 800-3,000 page HAZOP study PDFs into structured registers.
Indian EPC Compliance Bundle
IBR + OISD 118 + PESO + CCOE unified compliance automation.
HAZOP Safety Intelligence Pillar
End-to-end HAZOP digitisation, follow-up, and audit-readiness workflow.
Indian EPC AI for Hydrocarbons
Indian PSU refinery and hydrocarbon plant engineering AI.
PESO Compliance Software
PESO and CCOE compliance complementing OISD 118.
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