S500 Class-of-Loss Screen by Wetted-Surface Fraction

ScopeTurns the wetted-surface field read (how much of the floor, wall, and ceiling is wet, and whether low-evaporation assemblies are wet) into a candidate IICRC S500 Class of water intrusion and the matching per-class evaporation factor: the wet share of the combined floor, wall, and ceiling surface under 5% is Class 1, 5-40% Class 2, over 40% Class 3, and wet low-evaporation materials Class 4. A deterministic screen that proposes a Class and states the rationale; the inspector's classification and a moisture map govern.

Formula or tablewet_share = (floor x floor area + wall x wall area + ceiling x ceiling area) / total area (a 12 x 12 x 8 ft room's proportions when no areas are entered); top-down: Class 4 if low-evaporation materials wet; else Class 3 if wet_share > 40%; else Class 2 if wet_share >= 5%; else Class 1. Output carries the matching per-class evaporation factor (gal/ft^2).

Source and editionANSI/IICRC S500 (4th ed. 2015 / 5th ed. 2021) Class-of-loss definitions by name, keyed to the wet share of the combined floor, wall and ceiling surface; the pre-2015 floor and 24 in wick rules no longer define the class.

Free accessS500 keys the Class to the wet share of the combined floor, wall and ceiling surface and the presence of low-evaporation assemblies. The four Class definitions are public.

What governsEstimate. AHJ and licensed professional govern.

API field namesfloor_wet_fraction, wall_wet_fraction, wick_height_ft, water_class

• Class framework the four S500 Classes keyed to the combined wet share (under 5% / 5-40% / over 40%) and low-evaporation materials (hardwood / plaster / lightweight concrete / masonry -> Class 4)ANSI/IICRC S500
• Thresholds the 5% and 40% combined wet-share breaks as published in trade summaries of S500ANSI/IICRC S500
• Scope a screen that proposes a Class and feeds the per-class evaporation factor; the inspector and a moisture map governANSI/IICRC S500