1 For the purpose of applying composite materials
for load-bearing "A" class of "B" class divisions of superstructures,
structural bulkheads except for those in contact with liquids, decks
and deckhouses of ships, as equivalent to steel, it should be demonstrated
that they are able to withstand the applied loads during and at the
end of fire, by means of the following test procedure.
2 The composite materials should meet criteria
of non-combustibility, passage of smoke/flame and toxicity as determined
by relevant test procedures developed by the Organization.footnote
3 The following definitions apply for the purpose
of these guidelines:
-
.1
Composite material means a material
with an organic or inorganic matrix (e.g. polyester, melamine formaldehyde,
phenolic resins or ceramic), reinforced by fibres (e.g. glass, carbon,
ceramic fibres) with suitable orientation.
-
.2
Composite strength means the tension,
compression, bending, shear and torsion ultimate strength at each
temperature multiplied by a safety factor assigned to the satisfaction
of the Administration (e.g. 0.8) (see
figure 1).
-
.3
Core region means the inner part
or the outer part not exposed to fire of the load-bearing division,
capable of a minimum residual strength and stiffness to withstand
the applied loads during and at the end of fire.
-
.4
Insulation means the outer part
of the load-bearing division with suitable thickness to ensure thermal
protection of the core region (i.e. the structural strength of the
insulating material, if any, should be fully disregarded).
-
.5
Load-bearing division means a
panel made of composite material(s) (e.g. layers of laminates, adhesives
bonds and a core region of composite or other materials) which is
able to withstand the applied functional, environmental and local
loads.
-
.6
Transition temperature means the
temperature corresponding to an abrupt loss of stiffness of the material
(see figure 2, when applicable).
Figure 1 Example of structural stiffness reduction
Figure 2 Typical stiffness - temperature relation
Determination of structural properties
3 Tests should be performed on small specimens
of suitable shape, including all the elements of the core region.
Such specimens should be tested in a uniform temperature furnace and
the temperature of the core region should be determined, to define
the behavioural relationship between the applied loads and temperature.
4 The tension, compression, bending, shear and
torsion loads appropriate for the material's application on board,
should be scaled and applied in specimens with a different orientation
to take account of the anysotropic behaviour of the composite material.
5 Tests should be performed at a temperature of
the furnace increasing from the ambient temperature to the temperature
foreseen for the core region at the end of the standard fire test
on the prototype of the division of composite material.
6 The composite strength should be scaled from
the dimensions of the small specimens to the actual dimensions of
the composite material used on board.
Selection of the critical temperature
7 The critical temperature is the temperature
of the composite strength corresponding to the most critical applied
load relative to the application on board. When the application involves
a combination of load (e.g. compression and bending), the most critical
load should be defined for the most unfavourable load combination.
8 The critical temperature should not exceed the
transition temperature, when applicable, to ensure that deformation
is adequate for the intended application.
Performance of standard fire tests
9 Standard fire tests should be performed on larger
scale specimens, in accordance with the provisions of SOLAS regulation II-2/3.2 and the Recommendation
on Fire Test Procedure for "A", "B" and "F" Class Divisions, adopted
by the Organization by resolution A.754(18).
10 In addition to SOLAS regulations II-2/3.3 and II-2/3.4, the temperature in any point
of the most exposed side of the core region of load-bearing divisions
should be lower than the critical temperature. Special considerations
should be given to the measured temperatures, thermal distortions
and transmission of loads of joints.