WO2000026022A1

WO2000026022A1 - Multi-layer material

Info

Publication number: WO2000026022A1
Application number: PCT/NO1999/000317
Authority: WO
Inventors: Magne Steinseidet; Trond Saele; Rune HELLEBØ
Original assignee: R & M Isolering
Priority date: 1998-10-20
Filing date: 1999-10-20
Publication date: 2000-05-11
Also published as: NO984893L; AU6374499A; NO984893D0

Abstract

There is described a multi-layer material comprising at least one layer of a metal foil, for example of stainless steel, and at least one layer of a heat-penetration-retarding material, for example a carbo-flex cloth. The material comprises optionally additional insulation material and a protective cloth as a jacket or case which envelops vital installations such as pipe members, flanges and the like for reducing heat penetration to the installation. The material is furthermore explosion proof and exhibits good sound-absorbing ability.

Description

Multi - Layer Material

The present invention relates to a novel multi-layer material with improved resistance to jet and hydrocarbon fires of high temperature. The material is also explosion proof and exhibits good sound absorption ability. The invention also relates to the use of the material as an insulation jacket or case for the protection of equipment such as pipe members, flanges, valves and the like against heat penetration in connection with jet and hydrocarbon fires . If fires occur on oil/gas installations it is important with respect to the safety of the personnel that a reasonable time for evacuation is achieved. In such installations there are a number of hydrocarbon-conducting pipe conduits, and if fires in the installation result in these pipe conduits, plus valves and the like being heated too rapidly to too high a temperature, these will spring leaks, and further quantities of hydrocarbons (oil/gas) will flow out, and the extent of the fire will be made substantially worse. If vital equipment is not protected sufficiently a cascade reaction of explosions and fire can be experienced. Furthermore the time gained due to the equipment being sufficiently protected will make it possible to get the oil and gas flow pipes shut off.

In order to protect such vital equipment pipe members, flanges, valves and the like are wrapped in a fire - retardent material so that the rise in temperature of the equipment during a fire is delayed. The standards which are used to-day vary greatly, but a delay ought to be achieved- of the order of magnitude of 15 - 120 minutes before the temperature of the equipment becomes so high that the equipment is destroyed. There are described in the literature various fire- protecting combination coatings, i.e. multi-layer materials where several separate layers are arranged on top of each other, in order to reduce the penetration of heat. Various fire-retardent materials are also described.

However, there is a continuos search for new materials plus new combinations of materials in order to improve the ability of the material to resist heat, i.e. materials which extend " the delay time ", i.e. the time it takes before the temperature of an object which is applied an external high temperature has risen above a harmful temperature. For example the time it takes before the object has reached a temperature of 400°C if there is applied an external temperature of 1100°C. NO-177812 describes a multi-layer coating comprising a number of layers (3 - 5) with fire-protecting properties, namely a mechanical protective layer (5) outermost, a flame-stopping layer (4) and an insulating layer (3) . The thermal insulating material comprises a natural or synthetic elastomer, vulcanising chemical materials and zinc and/or magnesium oxide. The flame-stopping material is an inorganic material which for example can consist of glass fibre tape having a rubber or plastic material applied on both sides. The two layers (3 and 4) are vulcanised to each other. It is stated that this material can withstand a fire having a temperature of 1100°C for two hours without the internal temperature exceeding 120°C. This is however only related to an increased ambient temperature, and this material is in no way pressure proof so that it prevents a jet fire striking through.

UK 2300900 describes a multi-layer material which can stand a jet fire of 1200°C for a period of two hours. The outermost layer consists of a wire netting mat (wire mesh) which will prevent erosion of the protective layer. Furthermore aluminium foil is employed for separating laye^'r 16 from a second compressible layer 20.

The present invention aims to provide a material which provides, in relation to the materials known within the state of the art, improved properties. First of all, with respect to improved resistance against an applied hydrocarbon and/or jet fire, i.e. a material having improved resistance to the penetration of heat and pressure. It is furthermore an object of the present invention to provide a material which provides improved properties with respect to sound absorption, plus that the material is simpler and more reasonable to produce. Further it is an object according to the invention to increase the possibilities for use of the material, and there are therefore developed solutions which ensure the possibility for inspection of the object of interest without the multi-layer material having to be removed, together with methods for safely fastening of the material to the object, and methods for splicing the material without the above described effects being reduced.

The invention will now be described in more detail with reference to the accompanying Figures, in which:

Fig. 1 shows in a section the build-up of the multi- layer material according to the invention.

Fig. 2 shows in a section a embodiment of a joint where there is established a double overlap.

Fig. 3 shows a multi -layer material which forms a part of an inspection hatch. In Figure 1 the various layers are illustrated which constitute the heat- and pressure-resistant multi-layer material 10 according to the invention. The material 10 shall as explained above protect various technical installations, and there is therefore shown in the Figure such an intended object 11. The multi-layer material 10 is tailor-made in one piece to fit to such an arbitrary object 11. It is evident from the Figure that there is an insulating layer 12 innermost against the object 11. This insulating layer 12 can be of different thicknesses, for example 5-15 cm. In the embodiment illustrated, and in the^' examples which are indicated, this material is glass wool fibre of the type Firemaster X607, which is commercially available from J. H. Bjørklund A/S (Norway) , but the invention is not restricted to this material as other suitable insulation materials such as ceramic materials can be employed.

Outside the insulation layer 12 there is arranged a heat-resistant cloth 14 which exhibits great resistance to the penetration of heat . In the embodiment which is shown in the Figure, and which is employed in the Example section, this cloth is a so-called carbo-flex cloth, i.e. a woven carbon fibre cloth having a thickness of about 1.5 mm. Such cloths are commercially available, for instance from Alpha, Sherborne, Dorset DT9 3Rb, England.

Outside the heat-resistant layer 14 there is arranged a metal foil 16. It is a prerequisite that this foil 16 is not perforated, and furthermore it ought to be of a material which can withstand temperatures of up to 1370°C. This distinguishes the invention from the prior art solution where an aluminium lattice cloth is used for separating dissimilar layers.

The inventors of the present invention have surpris- ingly shown that the combination of a heat-resistant cloth 14 and a metal plate or foil 16 gives a synergistic effect with respect to reduced heat penetration, and this is the central concept of the invention. This effect is evident from Example 1. The metal foil which is employed in the embodiment which is illustrated in Figure 1 is of the stainless acid- resistant steel type, which is commercially available from Avestia Sheffield, and is a stainless foil having a thick^¬ ness of 0.05 mm. Outermost, i.e. outside the metal foil 16, there is arranged a weather-proof glass fibre cloth 18. In the embodiment which is illustrated this cloth is of the Alpa Maritex 4210-2 -65R type, commercially available from Totto Bugge A/S, but other cloths such as of rubber and plastic can also be employed.

A first aspect of the invention thus relates to a material which is characterised in that the multi-layer material comprises at least one layer of a metal foil 16, and at least one layer of a carboflex cloth 14. A combination of these layers exhibits with respect to heat- penetration resistance and explosion resistance a total effect which cannot be deduced from each of the separate components.

Additional aspects of the invention relate to the material according to claim 1 in combination with other materials known per se, such as a layer of insulating material 12 and a protective layer 18. Furthermore the invention comprises a system where the material 10 according to the invention is used as a case which is removably mounted on an object 11 for protecting the latter. The system comprises fastening means for fastening the material 10 to the object 11, methods and means for ensuring sufficiently good joints, plus a multilayer material which forms a part of a cover solution for making inspection of the object possible without the material 10 being removed from the object 11.

An aspect according to the present invention is thus characterised by end edges 10a and 10b of the multi-layer material which constitute a joint and which are designed with two equivalent flange portions, and where in the overlapping horizontal joint portion which consists of the portions 10a2 and 10b2 there are arranged at least two layer of metal foils 16, and at least two layer of carbo- flex cloths 14.

As mentioned above the multi-layer material 10 is tailor-made in size so that it fits the object of interest. Furthermore while not a prerequisite it is strongly recommended that " the insulation jacket " is designed in one piece. It will however always be necessary to splice the multi-layer material 10, and these splices represent a weak point for corresponding materials within the state of the art . According to the present invention this problem is avoided in that the two end edges 10a and 10b of the material which are to be spliced together are fashioned with equivalent flange portions, as is evident from Fig. 2, so that the two end edges 10a and 10b will provide an overlap, for example of about 5 cm..

The flange portion of the end edge 10a is designed by the insulation layer 12 having in the surface facing towards the object 11 a longitudinal recess, so that end edges lOal, 10a2 and 10a3 are formed. Correspondingly, the flange portion of the end edge 10b is designed by the insulation layer 12 having in the surface facing towards the carbo-flex layer 14 a longitudinal recess, so that edge edges lObl, 10b2 and 10b3 are formed.

It is also evident from the Figure that the carbo-flex cloth 14 extends over the whole splice portion of the end edges and furthermore a distance beyond the inner surface 12a of the insulation layer 12. The metal foil 16 extends for the end edge 10a over the end edge portions lOal, 10a2 and partly over the portion 10a3, and over the end edge portions lObl, 10b2 and partly over the portion 10b3 for the end edge portion 10b respectively. This ensures a double layer of metal foil in the horizontal part of the splice portion.

Furthermore it is evident from Figure 2 that the silicon cloth 18 also completely covers the end portions 10a and 10b and is drawn a distance inwards of the inner surfaces 12a of the insulation layer. In addition to the particular design of the end edges which form a part of the joint a protective strip 22 is arranged externally in the longitudinal direction of the joint. In the illustrated embodiment this is constructed of a carbo-flex layer 14 ' which is enveloped by a metal foil 16' and a silicon cloth 20' respectively. The cross-section through such a protective strip 22, i.e. the embodiment which is illustrated in Fig. 2, thus consists of one layer of carbo-flex cloth 14', two layers of metal foil 16' and two layers of silicon cloth 18'. This protective strip 22 completely covers the joint region, and is fastened to the ^' multi -layer material 10 and the object 11 with fastening means, as further explained below. The multi -layer material according to the present invention is fastened to the object it is to protect with hose clips which are constructed of a material which is stainless, for example of the Bandimex type which is commercially available from Rogaland Iron Ware.

In many connections it is necessary to be able to inspect the actual object, and this must preferably be able to be carried out without the protective jacket being removed. According to the present invention there is thus provided a multi-layer material 26 which can be used as an inspection hatch 26. In Fig. 3 a cover 26 is illustrated consisting of a core which is adapted to cover a corresponding opening in the multi-layer material 10 which covers the actual object 11. This core consists of an insulation material 26a which is covered, on the surface which faces towards the object, by a carbon fibre cloth 26b. Furthermore the cover 26 consists of a protective case which extends beyond the opening in the multi -layer material 10. This case consists of a mat 26c and a metal foil 26d enveloped by a carbon fibre cloth 26e. The mat 26c can for example be of the Interam E5A-4 type, commercially available from 3M.

The cover 26 is fastened to the case with tension bands or box locks. The tests which are conducted, and which are given in the Examples, are carried out with an inspection hatch of the embodiment which is shown in Fig. 4.

A numbers of tests are conducted on the multi-layer material 10 according to the invention and these are given as Examples below. It shall be observed that these Examples are not to be considered as limiting the scope and idea of the invention as will be evident from the patent claims. Example 1

Svnercristic effect for multi-layer material Tests which are conducted with the multi-layer material, see Example 2, where the material is applied a jet fire indicates that the multi-layer material has properties which are improved with respect to reduced heat penetration for the combined material . The inventors of the present invention believe that this synergistic effect results from a combination of the metal foil and carbo-flex cloth layers, and there are postulated heat-penetration parameters as follows.

Heat-penetration time (min.)

Metal foil 3

Carbo-flex 12

Metal foil plus carbo-flex 30

Tests are started so as to confirm this anticipation.

Example 2a. Jet Fire

The experiments are conducted at Sintef, Trondheim. The object of the experiments is to document the resistance capability by a simulated jet fire where the jet-pressure, - force or shock which is used is suited for simulating the jet-pressure which occurs after a break in a gas line on an offshore platform.

The material which was tested is an insulation case having an inspection hatch. The insulation case comprises successive layers reckoned from the outermost to the innermost (towards underlying pipes/equipment) ; weatherproof glass fibre cloth, about 0.05 mm. stainless/acid- resistant steel foil, about 1.5 mm. carbon-fibre cloth, 50 mm. insulation material of glass wool fibre, and weatherproof glass fibre cloth. The inspection hatch is of the same material as the insulation case, but the carbon fibre cloth is omitted and replaced by a 10 mm. thick layer of ceramically bound material. The layer gives a cooling effect in that on strong heating (about 350°C) it emits water of crystallization.

Fastening method (insulating case to test pipe) : Stainless, acid-resistant hose clips. Fastening method (inspection hatch to insulation case) : Stainless, acid-resistant tension bands with box locks .

Execution of Experiment: The material (test piece) was designed as an insulation case with inspection hatch, and fastened round an 8 inch pipe. The whole arrangement is placed in a 1500 x 1500 mm. and 500 mm. deep steel box. The jet mouthpiece was aimed in centered towards the test piece, distance 1500 mm. The test piece was placed horizontally and centered in the opening of the box. The jet fire had a pressure of 550 kPa . The source was commercial propane, delivered through the mouthpiece as vapour without liquid components, and with a uniform consumption of 0.3 kg. pr. second (+/- 0.05 kg. pr. second) . The temperature in the fire was over 1100°C. Results: There exists comprehensive documentation of the results which were obtained. Inter alia can be mentioned that the estimated temperature of the underlying pipe after 20, 30 and 60 minutes jet fire exposure was

120 189 and 399 C.

Example 2b Hydrocarbon Fire

The experiments were conducted by Sintef, Trondheim, and the object was to document the insulation capability in a simulated hydrocarbon fire (without jet) . 3 experiments were tested (see specification below) . ' Experiment 1 :

The insulation case: successive layers reckoned from the outermost to the innermost (towards underlying pipe/equipment) : weather-proof glass fibre cloth, about 0.05 mm. stainless/acid resistant steel foil, about 1.5 mm. carbon fibre cloth, 50 mm. insulation material of glass wool fibre, weather-proof glass fibre cloth.

The inspection hatch: As the insulation case, but carbon fibre cloth is omitted and replaced by a 10 mm. thick layer of ceramically bound material. The layer provides a cooling effect in that on strong heating (about 350°C) water of crystallization is emitted.

Experiment 2 ;

Insulation case and inspection hatch: As experiment 1, but without carbon fibre cloth.

Experiment 3 :

Insulation case and inspection hatch: As experiment 1, but with 2 x 50 mm. insulation material of glass wool fibre.

Fastening method for all three experiments, insulation case for test pipe: Stainless, acid-resistant hose clips.

Fastening method for all three experiments, inspection hatch for insulation case: Stainless, acid-resistant tension band with box lock.

Execution of experiment: The experiment was conducted in accordance with IMO, Res A. 754 (18) . Heating to above 1100°C took place simultaneously for all three experiments in a glass-operated floor furnace. Pressure: 20 Pa.

Results: It took 35, 46 and 100 minutes before the temperature of the underlying test pipe reached 400°C in the 3 respective test pieces.

Example 3. Explosion experiments.

The experiments were conducted at CMR, Bergen, to document the resistance capability in realistic gas explosions.

Material description: Insulation case with inspection hatch, material compositions and fastening in methods as indicated in Example 2a. Execution of experiment: Two insulation cases with inspection hatches were mounted, 1 piece on each of two test pipes having diameters 100 and 200 mm. respectively. The test pieces were arranged in an approximate copy of a Gullfaks A-module at a scale of 1:5. Module dimensions: 8 m. x 2.5 m. x 2.5 m. , i.e. 50 m³. The module had two decks, upper and lower. Test pipe 200 mm. was arranged on the upper deck, and the 100 mm. pipe on the lower. The module had arrangements which resulted in being able to get varied explosion pressures. The test pieces were exposed to 4 successive explosions produced by an explosive mixture of 9.5 vol % methane/air, i.e. a " stoichiometric " mixture.

The first two explosions, of 300 m bar and 500 m bar, were chosen to document that the cases could withstand the pressure forces platforms are constructed to tolerate. The next two explosions were chosen to document that the cases tolerated higher pressures.

Results: There exists comprehensive documentation of the results which were obtained. Inter alia both test pieces withstood all four explosions without visible damage. The explosion pressures varied from 0.3 bar to 1.8 bar. " Drag- loading " is calculated to 78 - 120 kN for test pipe 100 mm. (lower deck) , and 52 - 53 kN for test pipe 200 mm. , respectively.

Example 4 : Sound tests

The tests were conducted by Sinus, Stavanger for documenting and classifying sound-absorbing properties in accordance with Norwegian Standard R CR -004.

Experiment 1: Insulation case (without inspection hatch) , material compositions and fastening in methods as indicated in Example 2a. Experiment 2: As test 1, but 2 - 50 mm insulation material .

Execution of test: The test was conducted by measuring noise inserted into insulated pipes with an opening in the insulation. Then there was correspondingly measured in two rounds (test 1 and 2) , but the opening now insulated/ enveloped by the insulation case. The frequency span inserted: 50 - 10,000 Hz.. Reliable results within 315 - 6,300 Hz..

Results: The insulation case with 50 and 100 mm. insulation material satisfy the requirements according to Norwegian Standard class 6 ( 10 dB insertion absorption within the frequency range 500 - 2,000 Hz.) and Norwegian Standard class 7 ( 20 dB insertion absorption within the frequency range 500 - 2000 Hz.), respectively.

Claims

Patent Claims

1. Multi-layer material 10 which is resistant to jet fires and hydrocarbon fires, characterised in that the material 10 comprises at least one layer of a metal foil 16, and at least one layer of a heat penetration-retarding material 14.

2. Multi -layer material in accordance with claim 1, characterised in that the metal foil is of stainless acid- resistant steel.

3. Multi-layer material in accordance with claim 1, characterised in that the heat penetration-retarding material is carbo-flex.

4. Multi-layer material 10 in accordance with one of the claims 1 - 3, characterised in that the multi-layer material 10 further comprises a layer of a weather-proof material 18, for example a silicon cloth.

5. Multi-layer material in accordance with one of the claims 1- 4, characterised in that multi-layer material 10 further comprises an insulating material 12, for example of glass wool fibre, ceramic fibre or the like.

6. System for protecting an installation 11 against jet- and/or hydrocarbon fires, characterised in that the object is enveloped with a multi-layer material in accordance with one of the claims 1 - 5.

7. System in accordance with claim 6, characterised in that the multi-layer material is fastened to the object by using known hose clips of a stainless material.

8. System in accordance with claim 6, characterised in that the end edges 10a and 10b which constitute a joint are designed with two equivalent flange portions, and where in the overlapping horizontal joint portion which consists of the portions 10a2 and 10b2 there are arranged at least two layers of metal foil 16, and at least two layers of carbo- ^' flex cloth 14.

9. System in accordance with claim 8, characterised in that there is arranged outside the joint a sealing strip 22 which consists of at least one layer of metal foil 16' and one layer of carbo-flex cloth 14', plus optionally at least one layer of silicon cloth 18'.

10. System in accordance with claim 6, characterised in that in the multi-layer material 10 which envelops the installation 11 there is arranged an opening for inspection of the installation 11, and that the opening is equipped with a detachable cover 26, which is formed of a multi -layer material comprising a layer of a ceramically bound material 26c, for example Interam E5A-4, a layer of metal foil 26d and a layer of carbon fibre cloth 26e, and where this material extends beyond the opening, and that the cover optionally in the portion which covers the opening is equipped with an insulation layer 26a and a carbon fibre cloth 26b.

11. System in accordance with claim 1, characterised in that the cover 26 is fastened to the case by the use of box locks or tension bands.

12. System in accordance with claim 6, characterised in that a temperature of 1100°C is withstood for a period at least 63 minutes without the temperature of the object exceeding 400°C.