NLS residue in a slop tank may not be discharged into the sea unless—

1. (a) The ship meets the conditions for discharging the NLS residue from a cargo tank in § 153.1128; and

2. (b) For Category B NLS residue transferred to the slop tank under § 153.1119(b), the NLS is discharged—

   1. (1) Through an NLS residue discharge system with the flow recording equipment required in § 153.481(b)(2) operating; and

   2. (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.