153.1112—Prewash for tanks containing Category A NLS residue.
Unless § 153.1114 allows the prewash to be omitted, a cargo tank that unloads a Category A NLS cargo must be prewashed following the procedures in § 153.1120.
Except where the approved Procedures and Arrangements Manual prescribes a different procedure, each of the following steps must be done in the order listed for the Coast Guard to consider the tanks prewashed under this part:
(a)
When this part requires a prewash of a tank containing Category A NLS residue and the alternative prewash procedure in paragraph (b) of this section is not used, the prewash must meet the following:
(ii)
Instrumentation or equipment is available that is capable of measuring the concentration of the Category A NLS in the NLS residue and determining whether it is below 0.1 per cent by weight.
(2)
The equipment specified in § 153.484 must be used as prescribed in the approved Procedures and Arrangements Manual for the prewash.
(3)
The wash water must be heated if required by § 153.1108, and water or tank washings must pass through the cargo pump and piping, including any stripping equipment, during washing or during discharge of tank washings.
(4)
The tank washing machine must be placed in all positions specified for the tank's Category A NLS prewash procedure in the approved Procedures and Arrangements Manual.
(5)
The tank must be pumped out each time there are enough tank washings collected in the bottom of the tank for the pump to gain suction, and if the NLS is immiscible with water or is a solidifying cargo, all floating and suspended NLS must be discharged.
(6)
The washing machine must be operated until samples of the discharged tank washings taken by the Surveyor are tested using the equipment required by paragraph (a)(1)(ii) of this section and the concentration of NLS is below 0.1 per cent by weight.
(8)
The Cargo Record Book must have items 12 through 14 completed and must show the Surveyor's written certification of their accuracy.
(9)
The Cargo Record Book must have the Surveyor's written concurrence that the prewash procedures specified in the approved Procedures and Arrangements Manual were followed.
(b)
When this part requires a prewash of a tank containing Category B or C NLS residue or when the procedure in this paragraph is used as an alternative to the prewash procedure under paragraph (a) of this section, the prewash must meet the following:
(2)
The equipment specified in § 153.484 must be used as prescribed in the approved Procedures and Arrangements Manual for the prewash.
(3)
The wash water must be heated if required by § 153.1108, and water or tank washings must pass through the cargo pump and piping, including any stripping equipment, during washing or during discharge of tank washings.
(4)
Except as required in paragraph (b)(5) of this section, the number of washing machine cycles specified in Table 153.1120 must be completed. If a prewash is required by a section listed under Column 1 of Table 153.1120 and another section listed under Column 2, the number of cycles in Column 1 must be completed but no additional cycles are necessary.
(5)
If the approved Procedures and Arrangements Manual specifies that a tank washing machine must be moved for the prewash of a tank from which a Category A NLS or a solidifying NLS has been unloaded, the number of washing machine cycles specified in Table 153.1120 must be completed at each position to which the washing machine is moved.
(6)
When the NLS is immiscible with water or is a solidifying cargo, the tank must be pumped out each time enough tank washings collect in the bottom of the tank for the pump to gain suction, or the procedures in paragraphs (b)(3), (b)(4), and (b)(5) of this section must be repeated two additional times with the tank pumped out each time, for a total of three washings.
(7)
Items 12 through 14 in the Cargo Record Book must be completed and, if the prewash is for a Category A NLS, verification that the procedures specified in the approved Procedures and Arrangements Manual were followed shown by the Surveyor's endorsement in the Cargo Record Book.
| Number of washing machine cycles | ||
|---|---|---|
| Column 1: Prewash under § 153.1116 or for a solidifying NLS under § 153.1108 | Column 2: Prewashes except those listed under column 1 | |
| Category A NLS | 2 | 1 |
| Category B or C NLS | 1 | 1/2 |
[CGD 81-101, 52 FR 7785, Mar. 12, 1987, as amended by CGD 81-101, 53 FR 28975, Aug. 1, 1988 and 54 FR 12629, Mar. 28, 1989]
Tank washings that do not result from a prewash and that contain Category A, B, or C NLS residues must be discharged to a reception facility or discharged to the sea under § 153.1126 or § 153.1128 except those tank washings resulting from washing a tank that has been cleaned following a ventilation procedure in the approved Procedures and Arrangements Manual.
NLS residue from Category D NLSs must be discharged to a reception facility or discharged to the sea using the following procedure:
(a)
Before discharge begins, drain or flush the NLS residue in the tank's piping systems into the tank.
(b)
After draining or flushing, discharge the NLS residue to the sea in accordance with § 153.1128 or transfer it to a slop tank and discharge in accordance with § 153.1126.
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
For tank contents that are miscible
For tank contents that are immiscible
Code of Federal Regulations
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.
The discharge of NLS residue to the sea must be made with the ship at least 22.24 km (12 nautical miles) from the nearest land, and must meet the following additional conditions:
(2)
Category B or C NLS residue resulting from washing a tank after the following washing procedure has been completed:
(i)
If the tank is not required to be prewashed under this part, the tank must be washed following the procedures that apply to a prewash of a Category B NLS in § 153.1120 using one washing machine cycle, and the tank washings discharged to a reception facility or to the sea under § 153.1126 or paragraph (a)(1), (c) or (d) of this section.
(ii)
After the tank has been prewashed or has been washed under paragraph (a)(2)(i) of this section, the tank must then be washed with one cycle of the tank washing machine, and the tank washings discharged to a reception facility or to the sea in accordance with § 153.1126 or paragraph (a)(1), (c), or (d) of this section.
(b)
To discharge a Category D NLS residue to which 10 times its volume in water is added and mixed, the ship must be—
(c)
Each ship built before July 1, 1986 that discharges Category A, B or C NLS residues before January 1, 1988 must be—
(2)
If discharging the residue of a Category A NLS cargo, discharging only residue created by washing the Category A NLS's cargo tank after a prewash;
(3)
If discharging the residue of a Category B NLS cargo, discharging no more than the larger of 1 m 3 or 1/3000th the volume of the Category B cargo loaded;
(4)
If discharging the residue of a Category C NLS cargo, discharging no more than the larger of 3 m 3 of or
1/1000th the volume of the Category C cargo loaded;
(d)
To discharge Category A, B, C, or D NLS residue other than as allowed under paragraphs (a) through (c) of this section, the ship must be—
(3)
If self-propelled, maintained at speed no less than the minimum specified in the approved Procedures and Arrangements Manual but at least 12.97 km/hr (7 knots);
(4)
If not self-propelled, maintained at a speed no less than the minimum specified in the approved Procedures and Arrangements Manual but at least 7.41 km/hr (4 knots);
(5)
If discharging the residue of a Category A NLS cargo, discharging only residue created by washing the Category A NLS's cargo tank after a prewash;
(6)
If discharging the residue of a Category B NLS cargo, discharging no more than the larger of 1 m 3 or 1/3000th the volume of the Category B cargo loaded;
(7)
If discharging the residue of a Category C NLS cargo, discharging no more than the larger of 3 m 3 of or
1/1000th the volume of the Category C cargo loaded;
[CGD 81-101, 52 FR 7785, Mar. 12, 1987, as amended by CGD 81-101, 53 FR 28976, Aug. 1, 1988 and 54 FR 12629, Mar. 28, 1989]