Flammable Liquid Storage Quantity Calculator

Checks planned flammable liquid storage quantities against OSHA 29 CFR 1910.106(d)/(e) limits for storage cabinets and incidental (outside-cabinet) storage per fire area.

Scope note: This tool covers OSHA 1910.106(d)(3) storage cabinet limits and 1910.106(e)(2)(ii) incidental storage limits only — the two most commonly needed checks. It does not cover inside storage room construction/ventilation requirements, outdoor pile storage, tank storage, or the full NFPA 30 Maximum Allowable Quantity (MAQ) per control area tables, which depend on occupancy type, construction, and sprinkler protection. Verify classification against each liquid's SDS (Section 9) and confirm final storage arrangement with your local Authority Having Jurisdiction (AHJ).

Storage Cabinet(s)

Incidental Storage (No Cabinet)

Number of Storage Cabinets in This Fire Area

Quantity per Cabinet (gallons)

Category 1 Flash point < 73°F, boiling point ≤ 95°F (≈ old Class IA — e.g., gasoline, acetone)

Category 2 Flash point < 73°F, boiling point > 95°F (≈ old Class IB — e.g., toluene)

Category 3 Flash point 73–140°F (≈ old Class IC/II — e.g., diesel, mineral spirits)

Category 4 Flash point 140–199°F (≈ old Class IIIA — e.g., some lubricating/hydraulic oils)

Per OSHA 1910.106(e)(2)(ii) — applies only where flammable liquid use is incidental to the principal business (e.g., a maintenance shop within a manufacturing plant), stored outside a cabinet or inside storage room, per fire area.

Category 1 in Containers (gal) Limit: 25 gallons (≈ old Class IA)

Categories 2, 3, 4 Combined, in Containers (gal) Limit: 120 gallons (≈ old Class IB, IC, II, III)

In a Single Portable Tank (gal) Limit: 660 gallons (Category 2, 3, or 4 liquids)

OSHA 1910.106(d)(3) — Storage Cabinet Limits

Category 1, 2, or 3 combined	Max 60 gallons per cabinet
All categories combined (incl. Category 4)	Max 120 gallons per cabinet
Cabinets per fire area	Max 3 without sprinkler protection/AHJ approval (beyond 3, separate by 100 ft or use an inside storage room)

OSHA 1910.106(e)(2)(ii) — Incidental Storage (No Cabinet)

Category 1 in containers	Max 25 gallons per fire area
Categories 2, 3, 4 in containers	Max 120 gallons per fire area
Single portable tank	Max 660 gallons

Per OSHA's own clarifying interpretation letter, the 60-gallon and 120-gallon cabinet limits are not additive — a cabinet holds at most 120 gallons total, of which no more than 60 gallons may be Category 1, 2, or 3 liquid.

Based on OSHA 29 CFR 1910.106(d) and (e). Category numbers reflect OSHA's current GHS-aligned classification system; older "Class IA/IB/IC/II/IIIA" labels are shown for reference only and the mapping is approximate at the boundaries — always classify each liquid from its SDS Section 9 flash point and boiling point data. NFPA 30 and local fire codes may impose additional or stricter requirements beyond this federal OSHA baseline. For customized calculators tailored to your organization, please contact Impact Tech Solutions.