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8 The probability PS of breaching a compartment from side damage shall be calculated as follows:
.1 PS = PSL PSV PST
where:
PSL = 1 - PSf - PSa = probability the damage will extend into the longitudinal zone bounded by Xa and Xf;
PSV = 1 - PSu - PSl = probability the damage will extend into the vertical zone bounded by Z1 and Zu; and
PST = 1 - PSy = probability the damage will extend transversely beyond the boundary defined by y.
.2 PSa, PSf, PSl, PSu and PSy shall be determined by linear interpolation from the table of probabilities for side damage provided in paragraph 8.3 of this regulation, where:
PSa = the probability the damage will lie entirely aft of location Xa/L;
PSf = the probability the damage will lie entirely forward of location Xf/L;
PSl = the probability the damage will lie entirely below the tank;
PSu = the probability the damage will lie entirely above the tank; and
PSy = the probability the damage will lie entirely outboard of the tank.
Compartment boundaries Xa, Xf, Zl, Zu and y shall be developed as follows:
Xa = the longitudinal distance from the aft terminal of L to the aftmost point on the compartment being considered, in metres;
Xf = the longitudinal distance from the aft terminal of L to the foremost point on the compartment being considered, in metres;
Zl = the vertical distance from the moulded baseline to the lowest point on the compartment being considered, in metres;
Zu = the vertical distance from the moulded baseline to the highest point on the compartment being considered, in metres. Zu is not to be taken greater than DS; and
y = the minimum horizontal distance measured at right angles to the centreline between the compartment under consideration and the side shell in metres,*
*For
symmetrical tank arrangements, damages are considered for one side of the ship only, in which case all
"y" dimensions are to be measured from that same side. For assymetrical arrangements reference is made
to the Explanatory Notes to the probabilistic methodology for oil outflow analysis, adopted by the Organization
by resolution MEPC.[..](..).
.3 Table of probabilities for side damage
| Xa/L |
PSa |
| 0.00 |
0.000 |
| 0.05 |
0.023 |
| 0.10 |
0.068 |
| 0.15 |
0.117 |
| 0.20 |
0.167 |
| 0.25 |
0.217 |
| 0.30 |
0.267 |
| 0.35 |
0.317 |
| 0.40 |
0.367 |
| 0.45 |
0.417 |
| 0.50 |
0.467 |
| 0.55 |
0.517 |
| 0.60 |
0.567 |
| 0.65 |
0.617 |
| 0.70 |
0.667 |
| 0.75 |
0.717 |
| 0.80 |
0.767 |
| 0.85 |
0.817 |
| 0.90 |
0.867 |
| 0.95 |
0.917 |
| 1.00 |
0.967 |
|
| Xf/L |
PSf |
| 0.00 |
0.967 |
| 0.05 |
0.917 |
| 0.10 |
0.867 |
| 0.15 |
0.817 |
| 0.20 |
0.767 |
| 0.25 |
0.717 |
| 0.30 |
0.667 |
| 0.35 |
0.617 |
| 0.40 |
0.567 |
| 0.45 |
0.517 |
| 0.50 |
0.467 |
| 0.55 |
0.417 |
| 0.60 |
0.367 |
| 0.65 |
0.317 |
| 0.70 |
0.267 |
| 0.75 |
0.217 |
| 0.80 |
0.167 |
| 0.85 |
0.117 |
| 0.90 |
0.068 |
| 0.95 |
0.023 |
| 1.00 |
0.000 |
|
| Zl/DS |
PSl |
| 0.00 |
0.000 |
| 0.05 |
0.000 |
| 0.10 |
0.001 |
| 0.15 |
0.003 |
| 0.20 |
0.007 |
| 0.25 |
0.013 |
| 0.30 |
0.021 |
| 0.35 |
0.034 |
| 0.40 |
0.055 |
| 0.45 |
0.085 |
| 0.50 |
0.123 |
| 0.55 |
0.172 |
| 0.60 |
0.226 |
| 0.65 |
0.285 |
| 0.70 |
0.347 |
| 0.75 |
0.413 |
| 0.80 |
0.482 |
| 0.85 |
0.553 |
| 0.90 |
0.626 |
| 0.95 |
0.700 |
| 1.00 |
0.775 |
|
| Zu/DS |
PSu |
| 0.00 |
0.968 |
| 0.05 |
0.952 |
| 0.10 |
0.931 |
| 0.15 |
0.905 |
| 0.20 |
0.873 |
| 0.25 |
0.836 |
| 0.30 |
0.789 |
| 0.35 |
0.733 |
| 0.40 |
0.670 |
| 0.45 |
0.599 |
| 0.50 |
0.525 |
| 0.55 |
0.452 |
| 0.60 |
0.383 |
| 0.65 |
0.317 |
| 0.70 |
0.255 |
| 0.75 |
0.197 |
| 0.80 |
0.143 |
| 0.85 |
0.092 |
| 0.90 |
0.046 |
| 0.95 |
0.013 |
| 1.00 |
0.000 |
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Psy shall be calculated as follows:
PSy = (24.96 -199.6 y/BS) (y/BS) for y/BS≤0.05
PSy = 0.749 + {5 -44.4 (y/BS - 0.05)} (y/BS - 0.05) for 0.05 <y/BS <0.1
PSy = 0.888 + 0.56 (y/BS - 0.1) for y/Bs≥0.1
PSy shall not be taken greater than 1.
9 The probability PB of breaching a compartment from bottom damage shall be calculated as follows:
.1 PB = PBL PBT PBV
where:
PBL = 1 - PBf - PBa = probability the damage will extend into the longitudinal zone bounded by Xa and Xf;
PBT = 1 - PBp - PBS = probability the damage will extend into the transverse zone bounded by Yp and YS; and
PBV= 1 - PBz = probability the damage will extend vertically above the boundary defined by z.
.2 PBa, PBf, PBp, PBs, and PBz shall be determined by linear interpolation from the table of probabilities for bottom damage provided in paragraph 9.3 of this regulation, where:
PBa = the probability the damage will lie entirely aft of location Xa/L;
PBf = the probability the damage will lie entirely forward of location Xf/L;
PBp = the probability the damage will lie entirely to port of the tank;
PBs = the probability the damage will lie entirely to starboard of the tank; and
PBz = the probability the damage will lie entirely below the tank.
Compartment boundaries Xa, Xf, Yp, Ys, and z shall be developed as follows:
Xa and Xf are as defined in paragraph 8.2 of this regulation;
Yp = the transverse distance from the port-most point on the compartment located at or below the waterline dB, to a vertical plane located BB /2 to starboard of the ship's centreline, in metres;
YS = the transverse distance from the starboard-most point on the compartment located at or below the waterline dB, to a vertical plane located BB /2 to starboard of the ship's centreline, in metres; and
z = the minimum value of z over the length of the compartment, where, at any given longitudinal location, z is the vertical distance from the lower point of the bottom shell at that longitudinal location to the lower point of the compartment at that longitudinal location, in metres.
.3 Table of probabilities for bottom damage
| Xa/L |
PBa |
| 0.00 |
0.000 |
| 0.05 |
0.002 |
| 0.10 |
0.008 |
| 0.15 |
0.017 |
| 0.20 |
0.029 |
| 0.25 |
0.042 |
| 0.30 |
0.058 |
| 0.35 |
0.076 |
| 0.40 |
0.096 |
| 0.45 |
0.119 |
| 0.50 |
0.143 |
| 0.55 |
0.171 |
| 0.60 |
0.203 |
| 0.65 |
0.242 |
| 0.70 |
0.289 |
| 0.75 |
0.344 |
| 0.80 |
0.409 |
| 0.85 |
0.482 |
| 0.90 |
0.565 |
| 0.95 |
0.658 |
| 1.00 |
0.761 |
|
| Xf/L |
PBf |
| 0.00 |
0.969 |
| 0.05 |
0.953 |
| 0.10 |
0.936 |
| 0.15 |
0.916 |
| 0.20 |
0.894 |
| 0.25 |
0.870 |
| 0.30 |
0.842 |
| 0.35 |
0.810 |
| 0.40 |
0.775 |
| 0.45 |
0.734 |
| 0.50 |
0.687 |
| 0.55 |
0.630 |
| 0.60 |
0.563 |
| 0.65 |
0.489 |
| 0.70 |
0.413 |
| 0.75 |
0.333 |
| 0.80 |
0.252 |
| 0.85 |
0.170 |
| 0.90 |
0.089 |
| 0.95 |
0.026 |
| 1.00 |
0.000 |
|
| Yp/BB |
PBp |
| 0.00 |
0.844 |
| 0.05 |
0.794 |
| 0.10 |
0.744 |
| 0.15 |
0.694 |
| 0.20 |
0.644 |
| 0.25 |
0.594 |
| 0.30 |
0.544 |
| 0.35 |
0.494 |
| 0.40 |
0.444 |
| 0.45 |
0.394 |
| 0.50 |
0.344 |
| 0.55 |
0.297 |
| 0.60 |
0.253 |
| 0.65 |
0.211 |
| 0.70 |
0.171 |
| 0.75 |
0.133 |
| 0.80 |
0.097 |
| 0.85 |
0.063 |
| 0.90 |
0.032 |
| 0.95 |
0.009 |
| 1.00 |
0.000 |
|
| Ys/BB |
PBs |
| 0.00 |
0.000 |
| 0.05 |
0.009 |
| 0.10 |
0.032 |
| 0.15 |
0.063 |
| 0.20 |
0.097 |
| 0.25 |
0.133 |
| 0.30 |
0.171 |
| 0.35 |
0.211 |
| 0.40 |
0.253 |
| 0.45 |
0.297 |
| 0.50 |
0.344 |
| 0.55 |
0.394 |
| 0.60 |
0.444 |
| 0.65 |
0.494 |
| 0.70 |
0.544 |
| 0.75 |
0.594 |
| 0.80 |
0.644 |
| 0.85 |
0.694 |
| 0.90 |
0.744 |
| 0.95 |
0.794 |
| 1.00 |
0.844 |
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PBz shall be calculated as follows:
PBZ = (14.5 - 67z/DS)(z/DS) for z/DS≤0.1,
PBZ = 0.78+ 1.1 (z/DS - 0.1) for z/DS>0.1.
PBZ shall not be taken greater than 1.
10 This regulation uses a simplified probabilistic approach where a summation is carried out over the contributions to the mean outflow from each cargo tank. For certain designs such as those characterized by the occurrence of steps/recesses in bulkheads/decks and for sloping bulkheads and/or a pronounced hull curvature, more rigorous calculations may be appropriate. In such cases one of the following calculation procedures may be applied:
.1 The probabilities referred to in 8 and 9 above may be calculated with more precision through application of hypothetical sub-compartments.*
.2 The probabilities referred to in 8 and 9 above may be calculated through direct application of the probability density functions contained in the Guidelines referred to in regulation 19.5.
.3 The oil outflow performance may be evaluated in accordance with the method described in the Guidelines referred to in regulation 19.5.
11 The following provisions regarding piping arrangements shall apply:
.1 Lines of piping that run through cargo tanks in a position less than 0.30BS from the ship's side or less than 0.30DS from the ship's bottom shall be fitted with valves or similar closing devices at the point at which they open into any cargo tank. These valves shall be kept closed at sea at any time when the tanks contain cargo oil, except that they may be opened only for cargo transfer needed for essential cargo operations.
.2 Credit for reducing oil outflow through the use of an emergency rapid cargo transfer system or other system arranged to mitigate oil outflow in the event of an accident may be taken into account only after the effectiveness and safety aspects of the system are approved by the Organization. Submittal for approval shall be made in accordance with the provisions of the Guidelines referred to in regulation 19.5.
*Reference is made to the Explanatory Notes to the matters related to the accidental oil outflow performance regulation
adopted by the Organization by resolution MEPC.[..](..).
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