Shell-to-shell spacing and property-line / public-way distance checks for aboveground tanks
◉ NFPA 30 / OISD-118 STYLE CHECK · NOT A REGULATORY SUBMISSION TOOL
⚠ Indicative tool only. The NFPA 30 tables here (22.4.2.1 shell-to-shell spacing, 22.4.1.1(b) property-line/public-way distance) are cross-verified across three independently-sourced extracts of the 2008 edition, not a single scan - but they're still compiled extracts, not the current official code text. OISD-118's Table-4 (within-dyke spacing) is sourced from the 2025 revision directly. OISD-118's Table-3/Table-5 (tank-to-offsite-facility matrix) is manually transcribed from a legible, non-OCR'd training-deck image (a GAIL India presentation on OISD-118) rather than the code text itself - the "T4" cells resolve the "Note-i" gap from the 2025 revision (refer to Table-4), but two things remain unresolved: the 2025 revision layers additional footnotes (Note-g/j) onto a few Table-3 cells that this older-edition image doesn't show, and two cell pairs read asymmetrically in the source image itself (Storage Tank Class C ↔ Tank Vehicle Loading A/B in Table-3; Flameproof Pump Motor ↔ Office Building in Table-5) - both flagged, neither silently resolved. Confirm all figures against the current published edition before relying on any of this for a real assessment.
Identification
Research entries stay private to you for practice/testing. Switch to Official once this is a real assessment your company should see.
Tank-to-Tank Shell Spacing
NFPA 30 Table 22.4.2.1 or OISD-118 Table-4 — required spacing as a function of the two tanks' diameters, roof type, and (NFPA) size/impounding condition or (OISD) diameter threshold.
Diameters in feet for NFPA 30, meters for OISD-118 — the label updates when you switch standards; enter in the unit shown.
Result Not evaluated
Sum of diameters—
Multiplier / formula applied—
Required spacing—
Surplus / deficit—
Tank-to-Offsite-Facility Distance (OISD-118)
Table-3 (large installations) or Table-5 (small installations) — pick the pair of categories and the tool looks up the required separation. Large installation applies when total Class A/B storage exceeds 5000 m³ or any Class A/B tank exceeds 9m diameter; otherwise use Table-5. Manually transcribed from a legible training-deck image (GAIL India, OISD-118 training material) rather than OCR — cross-check before relying on it, and see the note below on two specific cell pairs that read asymmetrically in the source.
Diameter only matters for cells expressed as a fraction of tank diameter (0.5D, D, etc.) — leave blank for flat-number cells.
Result Not evaluated
Cell value—
Required distance—
Surplus / deficit—
Tank-to-Property-Line / Public-Way Distance
NFPA 30 Table 22.4.1.1(b), the base reference table for stable liquids ≤2.5 psig at 1× multiplier. Other tank/pressure categories (Table 22.4.1.3) use a multiple of this table (commonly ½×, 1½× with a 25 ft floor, 2×, or 3× with a 50 ft floor) — set the multiplier manually since which sub-case applies depends on tank pressure rating and construction, not modeled here.