NFPA 1142 Water Supply

Structure name (optional)

Total volume — enter area × height, or L × W × H

Area (sq ft)

Avg height (ft)

— or dimensions —

L (ft)

W (ft)

H (ft)

Occupancy Hazard Classification (OHC)

Construction Classification (CC)

Exposure hazards

Minimum water supply

— gal

Minimum flow rate—

Building volume—

Calculated (pre-minimum)—

Supply = (Volume ÷ OHC) × CC × exposure multiplier, with NFPA 1142 minimums (2,000 gal, or 3,000 with exposures). Flow rate tiers: ≤15k→250, ≤22.5k→500, ≤30k→750, >30k→1000 gpm.