Flammable Liquid Cabinet Storage (OSHA 1926.152(b))

The rule that actually decides a jobsite is the second sentence: not more than THREE such cabinets in a single storage area. That is a hard ceiling of 180 gal, and you cannot buy your way past it with a fourth cabinet -- past it you need a genuinely separate area or a specially constructed inside storage room, which is a building problem rather than a purchasing one, and far cheaper to discover at planning than at inspection. The standard gives no blending rule for a cabinet holding both category groups, so the conservative read used here is the LARGER of the two counts, not a sum. Naming note: GHS Categories 1-3 are the old Class I and II; Category 4 is Class III.

cabinets for Category 1-3 = ceil(gallons / 60); cabinets for Category 4 = ceil(gallons / 120); cabinets needed = the larger of the two, since the standard states a limit for each rather than a blending rule; the area ceiling is 3 cabinets, so 180 gal of Category 1-3 or 360 gal of Category 4 per storage area.

OSHA 29 CFR 1926.152(b)(3), a US federal regulation in the public domain, quoted directly. Quantities beyond what cabinets may hold go to specially constructed inside storage rooms under the same section.

29 CFR is published in full at no cost by OSHA and the eCFR.

Estimate. AHJ and licensed professional govern.

Field names used by the API: cat123_gallons, cabinets_available, per_cabinet_cat123_gal, per_cabinet_cat4_gal, max_cabinets_per_area, cabinets_for_123, cabinets_needed, area_cap_cat123_gal, area_cap_cat4_gal, over_area_cap_gal

• Per cabinet 60 gal Category 1/2/3, or 120 gal Category 429 CFR 1926.152(b)(3)
• Area ceiling not more than three cabinets in a single storage area29 CFR 1926.152(b)(3)
• Mixed contents no blending rule in the standard; each cap applied independently, count is the largerconservative reading, stated
• Beyond the ceiling a separate area or a specially constructed inside storage room, not a fourth cabinet29 CFR 1926.152(b)
• Category naming Categories 1-3 are the old Class I and II; Category 4 is Class IIIGHS alignment
• Not checked cabinet approval, container sizes, outside-cabinet quantities, ignition separation, dispensingstated scope limit