Flammable Liquid Cabinet Storage (OSHA 1926.152(b))
Everyone knows the per-cabinet rule -- 60 gal of Category 1/2/3 or 120 gal of Category 4 in any one cabinet.
Example
You enter
- Category 1/2/3 liquid to store (gal; old Class I and II) 200
- Cabinets available in the area (0 to skip) 4
- Per-cabinet Category 1/2/3 limit (gal) 60
- Per-cabinet Category 4 limit (gal) 120
- Cabinets permitted in one storage area 3
You get
- Cabinets for 123 4
- Cabinets needed 4
- Area cap cat123 (gal) 180
- Area cap cat4 (gal) 360
- Over area cap (gal) 20
Checked against published worked examples from: Occupational Safety and Health Administration.
Details, formula, and sources
ScopeThe 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 NFPA 30's is used: 120 gal is the cabinet total, of which at most 60 may be Category 1-3. Naming note: GHS Categories 1-3 are the old Class I and II; Category 4 is Class III.
Formula or tablecabinets for Category 1-3 = ceil(gallons / 60); cabinets on the Category 4 limit = ceil((Category 1-3 + Category 4 gallons) / 120), since NFPA 30 9.5.3 makes 120 gal the cabinet total (the standard itself gives no blending rule); cabinets needed = the larger of the two; the area ceiling is 3 cabinets, so 180 gal of Category 1-3 or 360 gal of Category 4 per storage area.
Source and editionOSHA 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.
Free access29 CFR is published in full at no cost by OSHA and the eCFR.
What governsEstimate. AHJ and licensed professional govern.
API field namescat123_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 1926.152; NFPA 30 9.5.3's is used - 120 gal total per cabinet, at most 60 of it Category 1-3NFPA 30 9.5.3 / 29 CFR 1910.106(d)(3)
- 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