§ 153.1608 — Calculation Of Total Nls Residue And Clingage Nls Residue

(a) The total NLS residue for each tank is calculated by adding the stripping quantity and the clingage NLS residue.

(b) The clingage NLS residue for each tank is calculated using the following formula:

Qclingage = 1.1 × 10−4 Ad + 1.5 × 10−5 Aw + 4.5 × 10−4 L

1/2 Ab

where:

Ab = Area of the tank bottom added to the area in square meters of tank structural components projected on a horizontal surface

Ad = Area of the tank underdecks added to the area in square meters of tank structural components projected on a horizontal surface

Aw = Area of the tank walls added to the area in square meters of tank structural components projected on a vertical surface

L = Length of tank in meters from fore to aft

Qclingage = volume of clingage in cubic meters

When using the formula in this paragraph, areas that are inclined more than 30° from the horizontal may be assumed to be vertical.