4.3.2.1 The internal pressure P
eq in bar gauge resulting from the design vapour
pressure P
o and the liquid pressure P
gd defined in 4.3.2.2, but
not including effects of liquid sloshing, should be calculated as
follows:
Equivalent calculation procedures may be applied.
4.3.2.2 The internal liquid
pressures are those created by the resulting acceleration of the centre
of gravity of the cargo due to the motions of the ship referred to
in 4.3.4.1. The value of internal
liquid pressure P
gd resulting from combined
effects of gravity and dynamic accelerations should be calculated
as follows:
where:
|
aβ
|
= |
dimensionless
acceleration (i.e. relative to the acceleration of gravity), resulting
from gravitational and dynamic loads, in an arbitrary direction β;
(see
figure 4.1).
|
|
Zβ
|
= |
largest
liquid height (m) above the point where the pressure is to be determined
measured from the tank shell in the β direction (see
figure 4.2). Tank domes considered to be
part of the accepted total tank volume should be taken into account
when determining Z
β unless the total
volume of tank domes V
d does not exceed the
following value:
|
where:
|
V
t
|
= |
tank volume without any domes |
|
FL
|
= |
filling
limit according to chapter 15
|
|
ρ |
= |
maximum cargo
density (kg/m3) at the design temperature.
|
The direction which gives the maximum value (P
gd)max of P
gd should be considered. Where
acceleration components in three directions need to be considered,
an ellipsoid should be used instead of the ellipse in figure 4.1. The above formula applies only
to full tanks.