fire performance of naval composite structures - CiteSeerX

FIRE PERFORMANCE OF NAVAL COMPOSITE STRUCTURES Joëlle Gutierrez, Patrick Parneix DCN, France Andrea Bollero CETENA, Italy Bjørn Høyning FiReCo, Norway Dag McGeorge Det Norske Veritas, Norway Geoff Gibson, Peter Wright University of Newcastle, UK SUMMARY The fire behaviour of composite structures is a major concern for their large-scale use on board naval vessels. Within the framework of a 3-year European military project involving six nations (Denmark, France, Italy, Netherlands, Norway, United Kingdom) and which aimed at strengthening the technological basis for the large-scale application of fibre-reinforced composite materials to naval vessels and structures, a fire test programme was conducted in order to assess and to improve the fire performance of naval composite structures in peacetime and wartime scenarios. Various tests were carried out on composite structures representative of structural elements used in superstructures of a frigate-sized vessel. This included: – Small scale fire reaction and fire resistance tests (cone calorimeter tests, small scale tests in furnaces) in order to make a preliminary selection of materials. – Full scale fire propagation test on a 6-meter long composite corridor. – Full scale fire resistance tests : tests on stiffened and non-stiffened decks, test on composite/metal joints (representative of the attachment of the composite superstructure to the steel hull), test on T-joint. Most of the structures were mechanically loaded during the tests. Two types of fire curve were used : the cellulosic fire curve (950°C after 60 min) and the hydrocarbon fire curve (maximum temperature: 1100°C). Some of the panels had been submitted to blast and fragments before testing. This paper describes the main findings and lessons learnt from this test programme. INTRODUCTION For both military and commercial vessels, fire hazards are of great concern and hence have an important impact on design and operation. The behaviour of structures made of composite materials in fire is quite different from the behaviour of those made of steel. For civilian vessels, particular requirements are specified for composite structures to take these differences into account. In fire scenarios of particular relevance for naval vessels, the differences in behaviour between steel and composite structures are even more profound. Hence, suitable strategies to control fire hazards

are needed for naval composite structures that differ both from the established ones for civilian composite vessels and from those for naval steel vessels. This paper reports on a fire test programme conducted as part of a three-year European collaborative research project undertaken under the auspices of the EUCLID programme and entitled "Survivability, durability and performance of naval composite structures" (EUCLID project RTP3.21). "EUCLID" is an acronym for EUropean Collaboration for the Long-term In Defence. The EUCLID projects are organised within the Western European Armaments Group (WEAG). The EUCLID project RTP3.21 involved research institutions, material suppliers and yards from six nations (Denmark, France, Italy, Netherlands, Norway and the United Kingdom). It was partially funded by the Ministries of Defence of these six countries and had a total budget of 9.2 M€. The overall objective of this project was to strengthen the technological basis for the large-scale application of fibre-reinforced composite materials to naval vessels and structures. The application case selected in this project was a superstructure with a helicopter hangar located to the rear of a frigate-sized naval ship with a traditional steel hull (see Figure 6). For this application case, a composite sandwich structure presents a number of advantages compared to a traditional steel design, in particular reduced weight, lowered centre of gravity, reduced maintenance costs,

reduced signatures, the possibility to integrate sensors and other functions in the structural material. However, to benefit from these advantages, some challenges must be overcome, in particular reducing the vulnerability of the combustible composite structures to fires. The work built on a previous EUCLID project, RTP3.8, which aimed at establishing a sound technical basis for the large-scale use of composite materials in naval vessels. The EUCLID RTP3.21 project was completed in December 2003. The major threats to a frigate superstructure were considered within the project. These included internal and external blast and weapon-induced fire. The development of a fire depends crucially on the early stages of fire: what was ignited and what is present nearby the fire. Typical fire ignition sources are listed in Table 1 indicating the categories of fire that may result 6 . Minor fires were represented in fire resistance tests by a standard fire curve whereas the major and pyrotechnic fires were represented by a more severe fire curve with shorter rise time and higher maximum temperature (cf. Figure 1). Furthermore, weapon-induced damage may affect the development of fires. Structures damaged by blast and fragments were tested to represent this.

Table 1: Types of weapon-induced fires Causes of fire I II III IV

V

Severity of fire Minor

Major

Pyrotechnic

Fragment hitting equipment that catches fire. Shock that damages equipment that catches fire. Hollow charge.

Local fire in electrical equipment or structure.

Ignition in

Ignition of munitions

Ignition of external structural panel by direct exposure to air blast and subsequent collapse of external panel

Limited fire in affected compartments.

Fire in many compartments.

Residual propellant fire

-

-

•

hydrocarbons (fuel store, filter stations etc.)

•

pressurised pipes Ignition of munitions.

Ignition of hydrocarbons (fuel store, filter stations etc.). Initial phase determined by amount of residual propellant and subsequent phase on contents of room.

THE FIRE TEST PROGRAMME Objectives and participants The EUCLID RTP3.8 project, which was completed in 1998, as well as subsequent internal projects aimed at improving the fire behaviour of composite structures, but without taking into account the particular features of naval vessels. Technical solutions which met the IMO regulation requirements for composite structures used in high speed craft were developed 1, 2, 3 . The main objectives of the EUCLID RTP3.21 fire test programme were as follows : • To strengthen the knowledge of the behaviour of composite superstructures of frigate-sized vessels in fire conditions, both in peacetime and in war, in order to be able to design superstructures with confidence with respect to fire behaviour. • To establish guidelines for the design of composite superstructures in naval vessels taking into account fire aspects. The following partners participated in the fire test programme : Denmark : Danyard Aalborg (manufacturing of structures). France : DCN (co-ordination of the fire test programme, manufacturing of structures, cone calorimeter tests). DCE/GERBAM (full scale fire resistance tests, full-scale fire propagation tests). Italy : CETENA (co-ordination of the tests carried out in Italy). CSI (full scale fire resistance tests). Oto Melara (blast tests). Norway : Det Norske Veritas (fire safety strategy, DNV also managed the EUCLID RTP3.21 project as a whole). FiReCo (fire safety strategy, small scale fire resistance tests). Umoe Mandal (manufacturing of structures). Netherlands : Royal Schelde (structure manufacturing).

United-Kingdom :

University of Newcastle (mechanical tests at elevated temperatures, fire resistance tests). BAe Systems (structure manufacturing). VT (structure manufacturing).

General considerations about the fire tests used for composite marine structures There is no specific military regulation concerning the use of composite materials for manufacturing structural elements such as decks and bulkheads of surface ships in any of the countries which participated in the project. However, the Ministries of Defence of these countries often tend to refer to the International Maritime Organisation (IMO) regulations in their specifications. For this reason, it was decided to take as a basis the requirements of the IMO/HSC code (Code of Safety for High Speed Craft), which permits the use of combustible materials on board of high speed craft provided they comply with a certain number of fire requirements, in order to define the fire tests that should be carried out in this project. However, in order to take into account the specific requirements for naval ships, and in particular for composite superstructures of frigate-sized vessels, the fire tests were adapted to consider these additional requirements as explained above. The HSC code defines different kinds of areas in the ship, with different levels of fire hazard. All the divisions of the ship should be made of “Fire restricting materials” and should comply with reaction to fire requirements (they should release only small amount of heat and smoke in a fire) 4 . Furthermore, the divisions of areas of moderate and major fire hazard (machinery spaces, storerooms containing flammable liquids,…) should be qualified as “Fire resisting”. It means that they should prevent the fire and smoke propagation to adjacent compartments during a defined period of time (60 min in case of areas of major fire hazard, 30 min in case of areas of moderate fire hazard) 5 . In addition, those structures that are load-bearing should be “Load-bearing fire resisting divisions” and should be able to maintain their load-bearing capacity within the specified period of time (30 or 60 min). The test to be performed for the classification of a material as “Fire restricting” is the room corner test (ISO 9705). The material to be tested is mounted in a room (width x length x height = 2.4 x 3.6 x 2.4 m) so as to cover completely three walls and the ceiling, while the wall with the door is not lined with the material. A gas burner is placed on the floor in a corner, opposite to the doorway wall. The burner output is 100 kW for the first 10 minutes, and it is then increased to 300 kW for another 10 minutes. It is requested not to have a flashover during the 20 minutes of the test and there are requirements concerning the rate of heat release, the smoke production and debris which should not reach the floor of the test room. The tests for the selection of "fire resisting divisions" are carried out in full scale furnaces according to the cellulosic fire curve (see

Figure 1). The structures (decks or bulkheads) are exposed under the direct influence of the heat by putting them at the furnace opening in such a way that they become one side of the furnace. Simultaneously, a load should be applied to the panels requested to be load-bearing. Figure 9 shows a full scale fire resistance test on a deck which was mechanically loaded. The requirements to be classified as "load bearing fire resisting divisions" are as follows : • • •

Insulation : The average unexposed face temperature rise should not be more than 140°C, and the temperature rise recorded by any of the individual unexposed face thermocouple should not be more than 180°C. Integrity : There should be no flaming on the unexposed face. There should be no ignition, i.e. flaming or glowing, of a cotton wool pad. It should not be possible to enter the gap gauges into any opening in the specimen. Load-bearing performance : The specimen should be capable to support the static load during the full test period. Support of the test load is determined by both the amount and rate of deflection. Limit values are calculated for these parameters taking into account the dimensions of the specimens.

Presentation of the fire test programme The fire test programme was divided into three phases : • Phase 1 : assessment of so called “base design” structures and protections. In this phase, composite structures already in service and state of the art fire protections were evaluated. • Phase 2 : development of “candidate new designs”. Based on the results of the base design phase, candidate new improved designs were defined and evaluated. • Phase 3 : assessment of “new-improved design” structures selected following the "candidate new designs" phase. Various tests were carried out, ranging from small scale or medium scale tests, to full scale tests on 3-D structures including joints (T-joint, composite/metal joint representative of the attachment of the composite superstructure to the steel hull). In order to take into account the threats frigate-sized vessels are supposed to survive, fire tests were carried out on structures damaged by blast and fragments. In fire resistance tests, both fire curves (hydrocarbon and cellulosic, see Figure 1) were used. The main results and lessons learned from these tests are presented below. PRESENTATION OF THE RESULTS Reaction to fire and fire propagation The material chosen for this application case was a sandwich construction made up of GRP (glass reinforced plastic) skins and a balsa core. Balsa wood was selected for the core because of its good mechanical behaviour at elevated temperatures, combined with low smoke production when burning and low toxicity. The resin used for the skins was a vinylester resin. This type of resin shows rather poor reaction-to-fire behaviour and is likely to ignite quite quickly in a fire (time to flashover in the room corner test is around 2 – 3 min). Therefore, if we refer to the IMO/HSC code reaction-to-fire requirements, vinylester-based sandwich structures should always be protected to pass the room corner test requirements and to be classified as "fire restricting materials" . In phase 1 and phase 2, only small scale reaction-to-fire tests in the cone calorimeter (ISO 5660) were performed in order to select the fire protection to be used in "low fire hazard" areas. The reason is that, firstly, room corner tests are quite expensive and, secondly, previous work carried out in the EUCLID RTP3.8 project had shown that good agreements between cone calorimeter test results and room corner test results could be found2 .

Figure 2 shows rate of heat release vs. time curves obtained in the cone calorimeter at 50 kW/m² for various types of material with and without fire protection (all these protections were 10 – 20 mm in thickness and were commercially available) : – GRP laminate without any protection, – GRP laminate protected with a layer of glass reinforced phenolic foam coated with a white decorative surface, – GRP laminates protected with 2 different types of ceramic wool ; with a glass fabric coated with a layer of

– –

paint on the surface of the ceramic wool materials, GRP laminate protected with 3D-glass fabrics impregnated with phenolic resin and coated with a white decorative surface (dotted line), GRP laminate protected with 3D-glass fabrics impregnated with phenolic resin without decorative surface (straight grey line).

The GRP laminate without any fire protection shows a rapid increase in heat release rate after approx. 50 sec. of testing due to the burning of the resin. All the types of protection investigated made it possible to reduce the heat release rate of the GRP laminate. However, when the protection was coated with a decorative layer, the latter burnt, leading to an increase in heat release rate. This can be seen clearly, for example, in the case of the laminate protected by the 3D-glass fabrics impregnated with phenolic resin (

Figure 2 – right). When the protection is not coated with a decorative layer, this system is very effective in protecting the GRP laminate. The rate of heat release is very low. However, when it is covered with a decorative surface, the rate of heat release is higher and it can be assumed that it is high enough to lead to a flashover in the room corner test in less than 20 min. This shows that commercial products which were not initially designed to pass the room corner test requirements to be a "fire restricting material" should be selected carefully. Actually, some traditional products used on board steel ships may not pass the very strict HSC code requirements. The next phase consisted in testing a full scale structure representative of a corridor. The objective of this test was to assess the fire reaction behaviour and the fire propagation in a composite structure, using a higher thermal load than in the room corner test. The results of this test were also used for the validation of computer simulations which are not presented here. Following the cone calorimeter tests, it was decided to select the glass reinforced phenolic foam protection for this test. This thin fire protection (13.5 mm thick) enables vinylester-based composite structures to meet the IMO HSC code requirements to be a "fire restricting material". Therefore, it can be considered as the minimum fire protection to be applied on a composite structure on board a ship. The corridor was 6 m long (cf. Figure 7). A gas burner (the same type as in the room corner test) was placed at one of its ends. The burner output was 300 kW during the first 20 minutes, after which it was increased to 500 kW. 300 kW corresponds to the heating power used for the last 10 minutes of the room corner test. After 20 min at 300 kW, the temperatures inside the upper part of the corridor ranged from 300 to 750°C. They decreased progressively from the upper part to the lower part of the corridor. Shortly after the burner output was increased to 500 kW, flashover was observed. The test was then stopped. A window used for a camera was dismounted (cf. Figure 8). This opening was used to put out the fire. The firemen were able to extinguish the burning structure very quickly and without any risk: the temperatures outside the corridor remained below 50°C, except in the area close to the chimney where they reached 140°C. Before the fire was extinguished, the temperatures inside the corridor had reached 1250°C close to the burner and 1150°C in the centre of the corridor. After the test, the internal fire protection was charred but the exterior of the composite structure was not damaged visually (cf. Figure 8).

These test results show that relatively thin phenolic -based fire protection is sufficient to protect a vinylester-based sandwich structure as long as the heating power remains below 300 kW in a corridor-sized room. Thicker fire protection would, of course, be necessary to withstand higher fire loads. It can be added that the outside temperatures remained very low and there is therefore no risk of fire propagation to adjacent compartments caused by the materials when using such a type of structure. Fire resistance tests on undamaged panels In the first two phases, small scale furnace tests on panels exposed to the hydrocarbon fire curve were carried out in order to select the fire protection to be used in Phase 3. Following these tests, it was decided to select a 60 mm-thick glass reinforced phenolic foam protection for the Phase 3 fire resistance tests because it proved to be both more effective and lighter than the other protections which were tested, in particular various kinds of mineral wool and silica wool. The following types of fire resistance tests were carried out on undamaged panels in Phase 3 : – Tests on stiffened and flat panels mechanically loaded according to the hydrocarbon fire curve or to the cellulosic curve. – Test on a 3-D structure incorporating a T-joint submitted to a mechanical loading and to the cellulosic curve (see Figure 10). – Test on structures incorporating a composite/metal joint and submitted to the hydrocarbon fire curve (cf. Figure 11). Whatever the fire curve, the acceptance criteria for all the tests were as in the IMO/FTP code to classify a composite structure as "fire resistant division" 5 . The following conclusions were drawn from these tests : • The structures exposed to the hydrocarbon fire curve behaved very well and failed later than expected. Figure 3 shows the averaged temperature recorded through the thickness of a deck submitted to the hydrocarbon fire curve. The stiffeners were on the fire side. The mechanical load was as in the FTP code5 . It can be seen that the temperature at the interface between the fire protection and the composite structure remained very low and below the glass transition temperature of the resin during the first 30 minutes of testing. The composite structure was therefore not damaged at that time. At 60 minutes of testing, the averaged temperature on the unexposed side of the panel was 80°C, which is still below the glass transition temperature of the resin. Figure 3 also shows the deflection as a function of time for the same panel. It can be noted that it remained below the permitted limit and did not start accelerating for the first 90 min. This panel actually failed after approximately 90 min because the maximum temperature rise allowed was exceeded in one point (some parts of the fire protection had fallen away). • The same remarks apply to the specimens incorporating a composite/metal joint. However, it can be noted that the temperatures recorded on the fire side of the joint behind the fire protection were lower at the end of the first hour fire exposure (200 – 500°C). This difference may be explained by the fact that the fire protection remained in place during the test, at least in part. Mechanical tests at elevated temperatures carried out within this project showed that the mechanical properties of the C/M joint started decreasing dramatically at about 100°C. It took approximately 30 minutes for the exposed side of the joint to reach this temperature. Therefore, it can be concluded that the joint had kept its structural integrity and was not damaged during this time period. • All the structures exposed to the cellulosic fire curve withstood the fire and mechanical loads more than one and a half hour. Figure 4 shows the averaged temperatures through the thickness of a deck. It can be noted

that they remained very low during the first hour fire exposure. The composite structure should therefore not be damaged after this time. The same remarks apply to the structure incorporating a T-joint which failed after approximately 105 minutes. Fire resistance tests on damaged panels One specific request to the project expressed from the MoDs regarded the fire resistance assessment of the composite structures during a “war-time” scenario consisting in a weapon attack and the consequent fire in the superstructure. To comply with this request, a two-phase experimental programme was performed, by submitting the New Improved Design sandwich protected with the glass reinforced-phenolic insulation, first to a real blast test, and after, to a fire resistance test in a furnace. The main characteristics of the two tests are the following (see Figure 5): • Blast test: a 127 mm projectile detonated at a 3 metre distance from two flat panels (overall dimensions 2 x 2.8 m); these were identical but facing different sides to the explosion: the first, the insulated side, the second the un-insulated part, this in order to obtain, at same time, two different configurations of fragmentation effects. • Fire tests: horizontal furnace test of the two damaged panels and of a third one, identical but undamaged. Cellulosic fire curve adopted. Mechanical distributed load applied. Few repairing with ceramic wool of the largest holes, in order to limit the risk of early flaming on unexposed side and to attribute an adequate level of repeatability to such “un-conventional” trial. The fire test results demonstrated that the damaged panels were able to survive both for more than 2 hours: no significant differences with respect to the undamaged one were noted, meaning that the global structural capacity was almost unaffected from the local damage induced by fragments, although very widespread in distribution all over the panels. Temperatures, in the worst case, remained under 140° C within 115 minutes. DISCUSSION The very good fire performance demonstrated for well-designed composite structures suggests that such structures can be used with confidence onboard naval ships provided that additional measures be taken to account for the particular properties of composites. Such measures have been proposed in a separate article 6 . Of particular relevance in this context is that all surfaces should be protected by a thin liner of fire restricting material. However, the safe use of composite structures in naval ships would depend on the following issues: 1. The risk that a composite structure would collapse during fire fighting due to exposure to fire loads. 2. The risk that fragment damage would weaken the structure to such an extent that the structure would prematurely collapse during a fire. 3. The risks that the fire may propagate through fragment holes and ignite the structure on the “back side”. These issues are discussed below. Collapse during fire fighting The risk of such collapse was assessed by fire resistance tests. The original aim was to survive for 60 minutes in a standard IMO fire and for 30 minutes in a standard hydrocarbon fire. The fire resistance tests proved survival times far beyond these, both for standard decks and for decks supported at an edge by a T-joint. Hence, the time available for fire fighting would be substantially longer than originally aimed for. To avoid structural collapse of a composite sandwich structure, it is necessary to extinguish the fire before the capacity of the fire protection is exceeded. In the event of failure of fixed extinguishing systems in the fire area, this may require access by mobile fire fighting means to the fire area. The feasibility of fighting a fire in an FRP sandwich structure through a small opening was demonstrated in the corridor test described above. To manage the risk for fire fighters, there is a need for a decision criterion for when the capacity of the fire

protection is nearly exceeded. A basis for this is provided by the fire resistance tests carried out within this project. Premature collapse due to fragment damage One may speculate that degradation of the structure in fire would be accelerated by the presence of such holes. Tests carried out on such damaged panels proved the opposite: the damaged panels had the same survival time as the undamaged one. In these tests, the largest holes had been plugged. If not plugged, one may speculate that the flames in the hole may attack the panel locally and hence degrade the panel’s resistance. Given the limited availability of oxygen and the low thermal conductivity of the structural materials, the effect of such local attacks on the panel’s overall capacity is expected to be modest. This could be assessed by testing in a future project. Fire propagation through fragment holes If flames are allowed to enter the “back side” of the fire division, they are likely to ignite items in the adjacent compartment. However, it has been concluded that all composite surfaces should at least be protected with a fire restricting liner. Hence, the backside of the panel itself would be well protected. Ignition of items in the compartment should be expected, however. Such flammable items may e.g. be cables. For steel structures, compartments separated from a fire only by a fragment-damaged boundary would normally be given up. Due to the inherent insulating properties of composite sandwich structures, this practice may not be necessarily maintained for such structures. Suitably equipped fire fighters should be able to plug the holes and establish a fire boundary at the damaged panel. This view is supported by the ease with which the fire-fighters were able to dismount a window in the burning composite sandwich corridor during the corridor test (see above). CONCLUSION The fire behaviour of composite structures is a major concern for their large-scale use on board naval vessels. A fire test programme was conducted as part of a three-year European collaborative research project undertaken under the auspices of the EUCLID programme (EUCLID project RTP3.21). The following conclusions were drawn from this fire test programme. • FRP sandwich structures can be used with confidence in naval ship structures provided that the fire fighting strategy is adapted to account for the particular properties of such structures. • Considering the reaction-to-fire properties of vinylester-based sandwich structures and the fact that the position of a hit can not be predicted, one of the conclusions of the EUCLID RTP3.21 project was that it is necessary to protect from the fire this type of material in all the areas on board a naval ship. • The reaction-to-fire properties of the fire protections are strongly influenced by their very surface, i.e. by the behaviour of the decorative layer applied for aesthetic and/or protection purpose on the surface of the fire protection. Some fire protections may show very good behaviour when tested without decorative coating, but their properties may decrease significantly when coated by a decorative surface. Therefore, the protections should be selected carefully. • For areas of low fire hazard, the thin phenolic -based fire protection used in this project seems sufficient to protect a vinylester-based sandwich structure. In case of flashover, the fire can be extinguished easily from the outside through a small opening. • For areas of major fire hazard, the 60 mm-thick phenolic -based fire protection has proved to be very effective in protecting the vinylester/balsa sandwich structures. All the structures withstood the fire load longer than expected. In partic ular, a stiffened sandwich deck exposed to a hydrocarbon fire was able to withstand the mechanical load without collapsing for one and a half hour. • The joints are not a weak point in the structure if they are protected correctly. • Adequate level of survivability in case of fire arising from a “wartime” scenario can be achieved: this will be even improved when an active fire fighting strategy is performed.

The fire fighting strategy for FRP sandwich structures must be adapted to account for the particular properties of such structures. This should include development of means to plug holes in panels, development of means to fight a fire from an adjacent compartment (e.g. through a hole in a panel), a criterion for when to withdraw from a compartment due to risk of structural collapse and dedicated education and training of fire fighters in FRP sandwich structures. If these recommendations are followed, composite structures can be used with confidence in naval structures. This is in agreement with the conclusions from an independent study7 . ACKNOWLEDGMENTS The authors acknowledge the financial support given by the Ministries of Defence of Denmark, France, Italy, Netherlands, Norway and the United-Kingdom. All the partners of the fire test programme are gratefully acknowledged for their fruitful collaboration. REFERENCES 1

Gutierrez, J., Parneix, P., Porcari, R., Høyning, B., van de Weijgert, H., Sandwich Construction 5, 5 – 7 September 2000, Zürich, Switzerland, vol. 1, p.265 - p.278 2 Gutierrez, J., Le Lay, F., 21st SAMPE Europe /JEC 2000 Int. Conf., Paris, France, April 2000, p391 p403 3 Gutierrez, J., Le Lay, F., Rousseau, L., Parneix, P., NATO Symposium AVT -088, Specialists' Meeting on "Fire safety and survivability", Aalborg, Denmark, 23-26 September 2002 4 Resolution MSC.40(64), "Standard for qualifying marine materials for high-speed craft as fire-restricting materials", International Code for Application of Fire Test Procedures, International Maritime Organization, London, 1998 5 Resolution MSC.45(65), "Test procedures for fire-resisting divisions of high speed craft", International Code for Application of Fire Test Procedures, International Maritime Organization, London, 1998 6 McGeorge, D., Høyning, B.: "Fire safety of naval vessels made of composite materials: fire safety philosophies, ongoing research and state of the art passive fire protection", NATO RTO specialists' meeting on Fire Safety and Survivability, Aalborg, Denmark, September 2002 7 P. C. Potter, P. C., “Survivability of Composite Structures for Naval Applications”, NATO RTO AVT Symposium AVT -087/RSY-012 on “Combat Survivability of Air, Sea and Land Vehicles”, Aalborg, Denmark, September 2002.

Temperature [°C]

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Figure 1 : Fire curves used in fire resistance tests

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Figure 2 : Cone calorimeter tests at 50 kW/m² on GRP laminates with and without fire protections

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Figure 4 : Furnace fire resistance test – Averaged through-thickness temperatures

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Figure 5 : Wartime scenario: blast and fire tests on flat sandwich panels with insulation Pan #2

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Figure 6 : Example of a composite helicopter hangar – La Fayette frigate

Figure 7 : Corridor fire propagation test

Figure 8: Corridor after the fire test

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Figure 9 : Fire resistance test on a loaded

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Figure 10 : Fire resistance test on a structure incorporating a T-joint

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Figure 11 : Fire resistance test on a C/M panel exposed to the hydrocarbon fire curve (after 2 hours of fire exposure)