46 CFR § 153.481 - Stripping quantities and interim standards for Category B NLS tanks on ships built before July 1, 1986: Category B.
(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 1/3000th 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:
(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.