Section 2 Static load components

2.1 Symbols

2.1.1 For the purposes of this Section, the following symbols apply:

Rule length, in metres, as defined in Pt 4, Ch 1, 5 Definitions

moulded breadth, in metres, as defined in Pt 4, Ch 1, 5 Definitions

moulded depth, in metres, as defined in Pt 4, Ch 1, 5 Definitions

wave coefficient, as defined in Pt 10, Ch 2, 3.1 Symbols

block coefficient, as defined in Pt 4, Ch 1, 5 Definitions

density, tonnes/m³, as defined in Pt 10, Ch 2, 1.2 Definitions 1.2.3

acceleration due to gravity, 9,81 m/s²

permissible hull girder hogging and sagging still water bending moment envelopes for transit condition, in kNm

permissible hull girder hogging and sagging still water bending moment envelopes for operational condition, in kNm

permissible hull girder hogging and sagging still water bending moment envelopes for inspection/maintenance condition, in kNm

permissible hull girder positive and negative still water shear force limits for transit condition, in kN

permissible hull girder positive and negative still water shear force limits for operational condition, in kN

permissible hull girder positive and negative still water shear force limits for inspection/maintenance condition, in kN

length of cargo tank under consideration, in metres

deep load draught, in metres, is the maximum draught on which the scantlings are based

volume of centreline cargo tank under consideration, in m³

volume of side cargo tank under consideration, in m³

2.2 Static hull girder loads

2.2.1 Permissible hull girder still water bending moment and shear force.

The designer is to provide the permissible hull girder hogging and sagging still water bending moment limits for the transit condition, , operational condition, , and inspection/maintenance condition, .
The designer is to provide the permissible hull girder positive and negative still water shear force limits for the transit condition, , operational condition, , and inspection/maintenance condition, .
The permissible hull girder still water bending moment and shear force limits are to be given at each transverse bulkhead in the cargo area, at the middle of cargo tanks and at significant structural discontinuities, including internal turrets.
The permissible hull girder still water bending moment envelope is given by linear interpolation between values at the longitudinal position given in Pt 10, Ch 2, 2.2 Static hull girder loads 2.2.1.
The permissible hull girder still water bending moment and shear force envelopes are to be included in the loading manual as required in Pt 4, Ch 3, 1.1 Application 1.1.3 and Pt 4, Ch 3, 1.1 Application 1.1.4.

2.2.2 New build.

Loadings patterns representative of the loading conditions for all modes of operation are to be assessed considering those cases which will induce the largest forces in the hull structure.
The static loading conditions to be used in combinations with the applicable dynamic loads in Section 6 should be appropriate for the intended operation of the unit. In general, they should include:
- homogeneous full load;
- emergency ballast;
- ‘chequer-board’ loading;
- all cargo tanks full with any two adjacent cargo tanks empty (this is to allow repair of any tank boundary whilst in service); and
- all cargo tanks empty with any one cargo tank full;
- most onerous partial loading conditions as applicable.

2.2.3 Conversions and redeployments.

The loading conditions should be as for new build units, see Pt 10, Ch 2, 2.2 Static hull girder loads 2.2.2, suitably modified to take account of the following:
- Loading limitations previously assigned prior to conversion/redeployment.
- Where the loading conditions defined for new build units are too restrictive or too onerous.

2.3 Local static loads

2.3.1 General.

The following static loads are to be considered, as appropriate:
1. static sea pressure;
2. static tank pressure;
3. tank overpressure, in addition to the static tank pressure when appropriate;
4. static deck load;
5. accidental pressure.

2.3.2 Static pressure.

The static pressures for the static loads defined in Pt 10, Ch 2, 2.3 Local static loads 2.3.1are given in Pt 10, Ch 2, 2.3 Local static loads 2.3.3.

2.3.3 Static deck loads from heavy units.

The scantlings of structure in way of heavy units of cargo and equipment are to consider gravity forces acting on the mass. The load acting on supporting structures and securing systems for heavy units of cargo, equipment or structural components,

, is to be taken as:

= kN

where

mass of unit, in tonnes.

Table 2.2.1 Static load pressures

Load cases	Static pressure, in kN/m²
(a) Static sea pressure
(b) Static tank pressure
(c) Static tank pressure + overpressure
(d) Static deck pressure
(e) Accidental pressure
Symbols
z = vertical coordinate of load point, in metres, and is not to be greater than , see Pt 10, Ch 2, 2.3 Local static loads 2.3.3
= density of sea-water, 1,025 tonnes/m³
= draught in the loading condition being considered, in metres
= vertical distance from highest point of tank, excluding small hatchways, to the load point, see Pt 10, Ch 2, 2.3 Local static loads 2.3.3, in metres
= vertical distance from top of air pipe or overflow pipe to the load point, whichever is the lesser, see Pt 10, Ch 2, 2.3 Local static loads 2.3.3, in metres
=
= height of air pipe or overflow pipe, in metres, is not to be taken less than 0,76 m above highest point of tank, excluding small hatchways. For tanks with tank top below the weather deck, the height of air pipe or overflow pipe is not to be taken less than 0,76 m above deck at side, unless a lesser height is approved by the Flag Administration. See also Pt 10, Ch 2, 2.3 Local static loads 2.3.3
= vertical distance from the load point to the deepest equilibrium waterline in damaged condition obtained from applicable damage stability calculations or to freeboard deck if the damage waterline is not given, in metres
= vertical distance to the load point is to be taken as defined in Pt 10, Ch 2, 2.3 Local static loads 2.3.3
= setting of pressure relief valve, if fitted, is not to be taken less than 25 kN/m²
= uniformly distributed pressure on lower decks and decks within superstructures, including platform decks in the main engine room and for other spaces with heavy machinery components, in kN/m². is not to be taken less than 16 kN/m²
NOTE
1. The added overpressure due to sustained liquid through the air pipe or overflow pipe in the case of overfilling, , is to be taken as 25 kN/m². Additional calculations may be required where piping arrangements may lead to a higher pressure drop, e.g. long pipes or arrangements such as bends and valves.

Figure 2.2.1 Static sea pressure, pressure-heads and distances of static tank pressure

Table 2.2.2 Testing load height

Compartment or structure to be tested	Testing load height, in metres
Cargo tanks and other tanks designed for liquid filling, including double bottom tanks, hopper side tanks, topside tanks, double side tanks, deep tanks, fuel oil bunkers, slop tanks, fresh water tanks, lube oil tanks, fore and after peaks used as tanks and/or fitted with air pipe. Cofferdams	The greater of the following:
	=
	=
	=
Fore and aft peaks not used as tanks and not fitted with air pipe	To be tested for tightness, see Note
Watertight doors below freeboard deck	To be tested for tightness, see Note
Chain locker	=
Ballast ducts	Testing load height corresponding to ballast pump maximum pressure
Symbols are as defined in Pt 10, Ch 2, 2.3 Local static loads 2.3.3
= equivalent head of pressure safety valve, in metres
=
= setting pressure, in bar, of pressure safety valve where applicable
NOTE
When hose testing cannot be performed without damaging possible outfittings already installed, it may be replaced by a careful visual inspection of all the crossings and welded joints. Where necessary, dye penetrant test or ultrasonic leak test may be required.