Discharge of NLS residue from a slop tank to the sea: Categories A, B, C, and D.

NLS residue in a slop tank may not be discharged into the sea unless— (a) The ship meets the conditions for discharging the NLS residue from a cargo tank in § 153.1128; and (b) For Category B NLS residue transferred to the slop tank under § 153.1119(b), the NLS is discharged— (1) Through an NLS residue discharge system with the flow recording equipment required in § 153.481(b)(2) operating; and (2) At a rate maintained at or below Q in the following: For tank contents that are miscible For tank contents that are immiscible Q = KU 1.4 L 1.6 × 10 −5 m 3 /hr where: Q = maximum permissible slops discharge rate in cubic meters per hour. V = volume of slops in the tank in cubic meters. K = 4.3, except K = 6.45 if Q is distributed between two NLS residue discharge outlets on opposite sides of the ship (see §§ 153.470(c) and 153.481(b)). U = ship's speed in knots. L = ship's length in meters. N = number of tanks containing Category B NLS residue pumped into the slop tank.