CFR > Title 46 - Shipping > CHAPTER I—COAST GUARD, DEPARTMENT OF HOMELAND SECURITY > SUBCHAPTER O—CERTAIN BULK DANGEROUS CARGOES (parts 150 to 155) > PART 153—SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS > SUBPART B—Design and Equipment (§153.190 to §153.812) > 153.481—Stripping quantities and interim standards for Category B NLS tanks on ships built before July 1, 1986: Category B.

153.481—Stripping quantities and interim standards for Category B NLS tanks on ships built before July 1, 1986: Category B.

Unless waived under § 153.483 or § 153.491, each Category B NLS cargo tank on ships built before July 1, 1986 must meet the following:
(a) Unless the tank meets the interim standard provided by paragraph (b) of this section and is prewashed in accordance with § 153.1118, the tank must have a stripping quantity determined under § 153.1604 that is less than 0.35m 3.
(b) Before October 3, 1994, the tank may have a total NLS residue determined under § 153.1608 that is less than 1.0 m 3 or 1/3000 th of the tank's capacity and an NLS residue discharge system meeting the following:
(1) The system must be capable of discharging at a rate equal to or less than Q in the following formula:

Code of Federal Regulations

Q=K U1.4 L1.6×10−5 m3/hr
where:
K=4.3, except K=6.45 if the discharge is equally distributed between two NLS residue discharge outlets on opposite sides of the ship (see §§ 153.470(c) and 153.1126(b)).
L=ship's length in meters.
U=for a ship that is self-propelled, the minimum speed in knots specified in the approved Procedures and Arrangements Manual for discharging Category B NLS residue, but at least 7;
U=for a ship that is not self-propelled, the minimum speed in knots specified in the approved Procedures and Arrangements Manual for discharging Category B NLS residue, but at least 4.
(2) The system must have equipment capable of automatically recording—
(i) The time of day that discharge of NLS residue through the residue discharge system starts and ends; and
(ii) The dates on which discharge begins and ends unless the equipment allows a person to enter these dates on the record manually.
(3) Each system that has the capacity to exceed Q calculated in paragraph (b)(1) of this section must have equipment that—
(i) Records the NLS residue flow through the system; and
(ii) Is sufficiently accurate that its recorded values averaged over any 30 second period differ no more than 15% from the actual flow averaged over the same 30 second period.
(4) Each system that has the capacity to exceed Q calculated under paragraph (b)(1) of this section and does not automatically control the flow rate must have—
(i) Manual controls that enable the flow to be adjusted to the value of Q calculated in paragraph (b)(1) of this section and that must be moved through at least 25% of their total range of movement for the discharge rate to change from 0.5Q to 1.5Q; and
(ii) A flow rate meter located where the flow is manually controlled.
[CGD 81-101, 52 FR 7781, Mar. 12, 1987, as amended by CGD 81-101, 53 FR 28974, Aug. 1, 1988 and 54 FR 12629, Mar. 28, 1989]