1 This regulation
shall apply to oil tankers delivered on or after 1 January 2010,
as defined in regulation 1.28.8.
2 For the purpose
of this regulation, the following definitions shall apply:
.1 
Load line draught (d_{S})
is the vertical distance, in metres, from the moulded baseline
at midlength to the waterline corresponding to the summer freeboard
to be assigned to the ship. Calculations pertaining to this
regulation should be based on draught d_{S},
notwithstanding assigned draughts that may exceed d_{S},
such as the tropical load line. 
.2 
Waterline (d_{B}) is
the vertical distance, in metres, from the moulded baseline
at midlength to the waterline corresponding to 30% of the depth
D_{S}. 
.3 
Breadth (B_{S}) is the
greatest moulded breadth of the ship, in metres, at or below
the deepest load line draught d_{S}. 
.4 
Breadth (B_{B}) is the
greatest moulded breadth of the ship, in metres, at or below
the waterline dB. 
.5 
Depth (D_{S}) is the
moulded depth, in metres, measured at midlength to the upper
deck at side. 
.6 
Length (L) and deadweight
(DW) are as defined in regulations 1.19
and 1.23, respectively. 
3 To provide adequate
protection against oil pollution in the event of collision or stranding,
the following shall be complied with:
.1 
for oil tankers of 5,000 tonnes deadweight (DWT) and above,
the mean oil outflow parameter shall be as follows:


O_{M} ≤ 0.015 
for C ≤ 200,000 m^{3} 

O_{M} ≤ 0.012
+ (0.003/200,000)(400,000  C) 


for 200,000 m^{3} <
C < 400,000 m^{3} 

O_{M} ≤ 0.012 
for C ≥ 400,000 m^{3} 
for combination carriers between
5,000 tonnes deadweight (DWT) and 200,000 m^{3} capacity,
the mean oil outflow parameter may be applied, provided calculations
are submitted to the satisfaction of the Administration, demonstrating
that, after accounting for its increased structural strength,
the combination carrier has at least equivalent oil outflow
performance to a standard double hull tanker of the same size
having a O_{M} ≤ 0.015. 

O_{M} ≤ 0.021 
for C ≤ 100,000 m^{3} 

O_{M} ≤0.015
+ (0.006/100,000)(200,000  C) 

for 100,000 m^{3} <
C ≤ 200,000 m^{3} 
where: 
O_{M} = mean oil
outflow parameter 
C = total volume of cargo
oil, in m^{3}, at 98% tank filling. 
.2 
for oil tankers of less than 5,000 tonnes deadweight (DWT):
The length of each cargo tank shall not exceed 10 m or one
of the following values, whichever is the greater: 

.2.1 
where no longitudinal bulkhead is provided inside the cargo
tanks:
but not to exceed 0.2L 

.2.2 
where a centreline longitudinal bulkhead is provided inside
the cargo tanks:


.2.3 
where two or more longitudinal
bulkheads are provided inside the cargo tanks: 


.2.3.1 
for wing cargo tanks: 0.2L 


.2.3.2 
for centre cargo tanks: 



.2.3.2.1 




.2.3.2.2 




.2.3.2.2.1 
where no centreline longitudinal bulkhead is provided:




.2.3.2.2.2 
where a centreline longitudinal bulkhead is provided:


b_{i} is the minimum
distance from the ship's side to the outer longitudinal bulkhead
of the tank in question measured inboard at right angles to
the centreline at the level corresponding to the assigned summer
freeboard. 
4 The following general
assumptions shall apply when calculating the mean oil outflow parameter:
.1 
The cargo block length extends between the
forward and aft extremities of all tanks arranged for the carriage
of cargo oil, including slop tanks. 
.2 
Where this regulation refers to cargo tanks,
it shall be understood to include all cargo tanks, slop tanks
and fuel tanks located within the cargo block length. 
.3 
The ship shall be assumed loaded to the load
line draught d_{S} without trim or heel. 
.4 
All cargo oil tanks shall be assumed loaded to 98% of their
volumetric capacity. The nominal density of the cargo oil
(ρ_{n}) shall be calculated as follows:
ρ_{n} = 1000(DWT)/C
(kg/m^{3}) 
.5 
For the purposes of these outflow calculations,
the permeability of each space within the cargo block, including
cargo tanks, ballast tanks and other nonoil spaces, shall be
taken as 0.99, unless proven otherwise. 
.6 
Suction wells may be neglected in the determination
of tank location provided that such wells are as small as practicable
and the distance between the well bottom and bottom shell plating
is not less than 0.5h, where h is the height as
defined in regulation 19.3.2. 
5 The following assumptions
shall be used when combining the oil outflow parameters:
.1 
The mean oil outflow shall be calculated independently for
side damage and for bottom damage and then combined into the
nondimensional oil outflow parameter O_{M},
as follows:
O_{M} = (0.4O_{MS}
+ 0.6O_{MB})/C
where:
O_{MS} = mean outflow for side damage,
in m^{3}; and
O_{MB} = mean outflow for bottom damage,
in m^{3}. 
.2 
For bottom damage, independent calculations for mean outflow
shall be done for 0 m and minus 2.5 m tide conditions, and
then combined as follows:
O_{MB} = 0.7O_{MB(0)}
+ 0.3O_{MB(2.5)}
where:
O_{MB(0)} = mean outflow for 0 m tide condition;
and
O_{MB(2.5)} = mean outflow for minus 2.5 m
tide condition, in m^{3}. 
6 The mean outflow
for side damage O_{MS} shall be calculated as follows:
where:
i 
represents each cargo tank under
consideration; 
n = 
total number of cargo tanks; 
P_{S(i)}
= 
the probability of penetrating
cargo tank i from side damage, calculated in accordance
with paragraph 8.1 of this regulation; 
O_{S(i)}
= 
i) = the outflow, in m^{3},
from side damage to cargo tank i, which is assumed equal to
the total volume in cargo tank i at 98% filling, unless it is
proven through the application of the Guidelines referred to
in regulation 19.5 that any significant
cargo volume will be retained; and 
C_{3} = 
P n 0.77 for ships having two
longitudinal bulkheads inside the cargo tanks, provided these
bulkheads are continuous over the cargo block and P_{S(i)}
is developed in accordance with this regulation. C_{3}
equals 1.0 for all other ships or when P_{S(i)}
is developed in accordance with paragraph 10 of this regulation. 
7 The mean outflow
for bottom damage shall be calculated for each tidal condition as
follows:
.1 
where: 

i 
represents each cargo tank under
consideration; 

n = 
the total number of cargo tanks; 

P_{B(i)}
= 
the probability of penetrating
cargo tank i from bottom damage, calculated in accordance
with paragraph 9.1 of this regulation; 

O_{B(i)}
= 
the outflow from cargo tank i,
in m^{3}, calculated in accordance with paragraph 7.3
of this regulation; and 

C_{DB(i)}
= 
factor to account for oil capture
as defined in paragraph 7.4 of this regulation 
.2 
where:
i, n, P_{B(i)} and C_{DB(i)}
= as defined in subparagraph .1 above;
O_{B(i)} = the outflow from cargo tank
i, in m^{3}, after tidal change. 
.3 
The oil outflow O_{B(i)}
for each cargo oil tank shall be calculated based on pressurebalance
principles, in accordance with the following assumptions: 

.3.1 
The ship shall be assumed stranded
with zero trim and heel, with the stranded draught prior to
tidal change equal to the load line draught d_{S}. 

.3.2 
The cargo level after damage shall be calculated as follows:
where: 


h_{c} = 
the height of the cargo oil above
Z_{l}, in metres; 


t_{c} = 
the tidal change, in metres. Reductions
in tide shall be expressed as negative values; 


Z_{l} = 
the height of the lowest point
in the cargo tank above baseline, in metres; 


ρ_{s} = 
density of seawater, to be taken
as 1025 kg/m^{3}; 


p = 
if an inert gas system is fitted,
the normal overpressure, in kilopascals, to be taken as not
less than 5 kPa; if an inert gas system is not fitted, the overpressure
may be taken as 0; 


g = 
the acceleration of gravity, to
be taken as 9.81 m/s^{2}; and 


ρ_{n} = 
nominal density of cargo oil,
calculated in accordance with paragraph 4.4 of this regulation. 

.3.3 
For cargo tanks bounded by the
bottom shell, unless proven otherwise, oil outflow O_{B(i)}
shall be taken not less than 1% of the total volume of cargo
oil loaded in cargo tank i, to account for initial exchange
losses and dynamic effects due to current and waves. 
.4 
In the case of bottom damage,
a portion from the outflow from a cargo tank may be captured
by nonoil compartments. This effect is approximated by application
of the factor C_{DB(i)} for each tank,
which shall be taken as follows: 


C_{DB(i)}
= 
0.6 for cargo tanks bounded from
below by nonoil compartments; 


C_{DB(i)}
= 
1.0 for cargo tanks bounded by
the bottom shell. 
8 The probability
PS of breaching a compartment from side damage shall be calculated
as follows:
.1 
P_{S} = P_{SL} P_{SV}
P_{ST}
where: 
P_{SL} = 1  P_{Sf}
 P_{Sa} = 
probability the damage will extend
into the longitudinal zone bounded by X_{a} and
X_{f}; 
P_{SV} = 1  P_{Su}
 P_{Sl} = 
probability the damage will extend
into the vertical zone bounded by Z_{l} and Z_{u};
and 
P_{ST} = 1  P_{Sy}
= 
probability the damage will extend
transversely beyond the boundary defined by y. 
.2 
P_{Sa}, P_{Sf},
P_{Sl}, P_{Su} and P_{Sy}
shall be determined by linear interpolation from the tables
of probabilities for side damage provided in paragraph 8.3 of
this regulation, where: 
P_{Sa} = 
the probability the damage will
lie entirely aft of location X_{a}/L; 
P_{Sf =} 
the probability the damage will
lie entirely forward of location X_{f}/L; 
P_{Sl =} 
the probability the damage will
lie entirely below the tank; 
P_{Su =} 
the probability the damage will
lie entirely above the tank; and 
P_{Sy =} 
the probability the damage will
lie entirely outboard of the tank. 

Compartment boundaries X_{a},
X_{f}, Z_{l}, Z_{u}
and y shall be developed as follows: 

X_{a} 
the longitudinal distance from
the aft terminal of L to the aftmost point on the compartment
being considered, in metres; 

X_{f} 
the longitudinal distance from
the aft terminal of L to the foremost point on the compartment
being considered, in metres; 

Z_{l} 
the vertical distance from the
moulded baseline to the lowest point on the compartment being
considered, in metres; 

Z_{u} 
the vertical distance from the
moulded baseline to the highest point on the compartment being
considered, in metres. Z_{u} is not to be taken
greater than D_{S}_{}; and 

y 
the minimum horizontal distance
measured at right angles to the centreline between the compartment
under consideration and the side shell, in metres;* 
.3 
Tables of probabilities for side damage
X_{a}/L 
P_{Sa} 
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 

X_{f}/L 
P_{Sf} 
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 

Z_{l}/D_{S} 
P_{Sl} 
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 

Z_{u}/D_{S} 
P_{Su} 
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 

P_{Sy} shall be calculated as follows:
P_{Sy} = (24.96  199.6y/B_{S})(y/B_{S})
for y/B_{S} ≤ 0.05
P_{Sy} = 0.749 + {5
 44.4(y/B_{S}  0.05)}(y/B_{S}
 0.05)
for 0.05 < y/B_{S} < 0.1
P_{Sy} = 0.888 + 0.56(y/B_{S}
 0.1) for y/B_{S} ≥ 0.1
P_{Sy} shall not be
taken greater than 1. 
9 The probability
P_{B} of breaching a compartment from bottom damage
shall be calculated as follows:
.1 
P_{B} = P_{BL} P_{BT}
P_{BV}
where: 

P_{BL} = 1  P_{Bf}
 P_{Ba} = 
probability the damage will extend
into the longitudinal zone bounded by Xa and Xf; 

P_{BT} = 1  P_{Bp}
 P_{Bs} = 
probability the damage will extend
into the transverse zone bounded by Yp and Ys; and 

P_{BV} = 1  P_{Bz}
= 
probability the damage will extend
vertically above the boundary defined by z. 
.2 
P_{Ba}, P_{Bf},
P_{Bp}, P_{Bs}, and P_{Bz}
shall be determined by linear interpolation from the tables
of probabilities for bottom damage provided in paragraph 9.3
of this regulation, where: 

P_{Ba =} 
the probability the damage will
lie entirely aft of location X_{a}/L; 

P_{Bf =} 
the probability the damage will
lie entirely forward of location X_{f}/L; 

P_{Bp =} 
the probability the damage will
lie entirely to port of the tank; 

P_{Bs =} 
the probability the damage will
lie entirely to starboard of the tank; and 

P_{Bz =} 
the probability the damage will
lie entirely below the tank. 

Compartment boundaries X_{a},
X_{f}, Y_{p}, Y_{s},
and z shall be developed as follows: X_{a}
and X_{f} are as defined in paragraph 8.2 of
this regulation; 

Y_{p =} 
the transverse distance from the
portmost point on the compartment located at or below the waterline
d_{B}, to a vertical plane located B_{B}/2
to starboard of the ship's centreline, in metres; 

Y_{s =} 
the transverse distance from the
starboardmost point on the compartment located at or below
the waterline d_{B}, to a vertical plane located
B_{B}/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 
Tables of probabilities for bottom damage
X_{a}/L 
P_{Ba} 
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 

X_{f}/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 

Y_{p}/B_{B} 
P_{Bp} 
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 

Y_{s}/B_{B} 
P_{Bs} 
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 

P_{Bz} shall be calculated as follows:
P_{Bz} = (14.5  67z/D_{S})(z/D_{S})
for z/D_{S} ≤ 0.1,
P_{Bz} = 0.78 + 1.1(z/D_{S}
 0.1) for z/D_{S} > 0.1.
P_{Bz} 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 subcompartments.† 
.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 0.30D_{S} 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. 
