# 46 CFR § 153.1126 - Discharge of NLS residue from a slop tank to the sea: Categories A, B, C, and D.

§ 153.1126 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


$Q=\frac{VK{U}^{14}{L}^{16}}{N}×{10}^{-5}{m}^{3}/hr$

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.