FIELD OF THE INVENTION

The present invention relates to a method for the provision of fire and corrosion protected objects, preferably pipe and/or pipe systems.

Further, the present invention relates to a method for the provision of substantially pipe- or hose-shaped fire protec¬ ted objects, preferably a conduit conducting fuel from a source to a consumption apparatus, for example a propulsion motor in a vessel, especially a driving vehicle.

The invention also relates to fire and corrosion protected objects, as well as substantially pipe- or hose-shaped pro¬ tected objects.

PRIOR ART

In connection with industrial process plants, for example chemical plants or oil refineries, etc., it is usual that for the transmission of the raw material which is to be treated, and the materials included in the treathment, there are used steel pipes due to their resistance against heat and fire. The liquids and/or gasses passing through the pipes are however often corrosion promoting, and will there¬ fore subject the steel pipes to heavy corrosion. Not at least in connection with oil refineries for refining off¬ shore oil which is often mixed with salt water and other impurities, the pipes are strongly subjected to corrosion. This implies that the frequency of maintenance is high, which in turn involves that the operation must be stopped for control and maintenance. Consequently, the corrosion problem involves losses in productivity, and also represents a danger of leakage and plant failure.

Further, in connection with propulsion motors in vessels, especially driving vehicles, it is of greatest importance that the conduit conducting fuel from the gasoline tank to the motor, is very well protected against fire, such that the gasoline supply system remains a protected system as long as possible after the occurence of a fire on the vessel or in the vehicle.

A requirement to be met by the gasoline pipe or the gasoline hose which is to be mounted between the gasoline tank and the gasoline intake of the motor of a car, is that the conduit itself should be bendable or flexible, so that it can easily be mounted along the framework of the vehicle, said conduit also being so effect-ivly insulated agains fire that the driver and possible passengers will have time to leave the car in case of fire.

Within the car industry there is worked out certain direc¬ tions giving an indication of how long a gasoline pipe should resist a fire, but this periode of time varies in dependence of the classification of the vehicle. For example, it is a question of 90 seconds in connection with certain types of vehicles and certain types of fire appro- aces, whereas for other vehicles this periode of time can be approximately five minutes.

DISCUSSION OF THE INVENTION

An object of the present invention is to give instructions for fire and corrosion protected articles , preferably pipes and/or pipe systems which are just a^ applicable as steel pipes as regards corrosion resistance and heat resistance, said articles according to the present invention enabling the production thereof from inexpensive material, alowing for installation in the form of pre-fabricated elements, and alowing for a simplified control and maintenance of the installed articles.

Further, an object of the present invention is to give in¬ structions for substantially pipe- or hose-shaped fire pro¬ tected articles, which especially in connection with the supply of fuel from a source to a consumption apparatus, for example a propulsion motor on a vessel, should be able to resist high temperatures and the effect of flames in case of fire in the motor or the vessel. The fire protected article should also be flexible, or at least bendable for thereby allowing for the mounting thereof without bending the conduit with special tools. Further, the article might be manufactured from relatively inexpensive materials, for example in running lengths which are delivered in finished fire protected condition to the place of installation.

These objects are achieved in a method as stated in the pre¬ amble, which according to the invention is characterized in that there is provided an inner pipe of plastic, for example a polymer, that around the pipe there is provided a light, thermally insulating material which normally does not stand exposure to fire, and that around the light, thermally insulating material there is provided a fire resistant mate¬ rial which at high temperature renders a ceramic stable fire protecting phase.

More especially, the objects are achieved in a method accor¬ ding to the art as stated in the preamble, which according to the invention is characterized in that around a substan¬ tially bendable plastic pipe there is applied a first layer of insulation having a relatively low heating conductance in a lower temperature range (approximately 100-300 C) , and that around the first layer of insulation there is applied a second layer of a fire resistant material which at higher temperatures (approximately 300-900 C) renders a fire protecting effect.

Thus, within the process industry a corrosion resistant plastic can be taken as a starting point, more specifically a polymer, for example glass fiber reinforced epoxy or poly- ester. Even if such plastic materials are corrosion resis-

tant, they have so to say no protection against high tempe¬ ratures which develop during a fire, especially not in connection with hydrocarbon fires, wherein the temperature can reach 1500 C or more.

In most of the chemical plants there exists a requirement that the temperature in the interface between the article to be insulated and the insulation itself, shall not exceed a certain level when the insulated article is subjected to fire over a certain period of time. Surprisingly, it has appeared that this interface temperature can be kept below the discussed value if said inner pipe of plastic in the first instance is insulated by means of a light, thermally insulating material, for example glass wool, ceramic fibers or mineral wool, which normally does not stand the exposure to fire, i.e. a temperature which is higher than approxima¬ tely 800 C, and this light, thermally insulating material is covered with a skin of a fire resistant material which at higher temperatures than 800 C renders a ceramic stable and fire protecting phase.

For example mineral wool will have good fire protecting pro¬ perties up to 400 C, whereas in the range between 400 C and 800 C it loses its fire protecting property, since the binding material between the mineral fibers are destruc- ted and the mineral wool loses its original filament struc¬ ture. Because the mineral wool is surrounded by a skin of the fire resistant thermo plastic ceramic material it will, however, at higher temperatures than 800 C, for example in the temperature range 1100-1200 C convert to a ceramic stable fire protecting phase contributing to keeping the mineral wool in a temperture range wherein the mineral wool retains its heat insulating properties.

For a further fire retardent insulation of the inner pipe there may between the light, thermally insulating material and said pipe be provided a further layer of said fire resistant material.

Possibly, there may outermost be provided a metal foil as a radiation screen, a layer of glass fiber tape, steel wire or a sealing and chemical resistant layer of foil or varnish.

Preferably, the fire resistant material may be provided in the form of tape, which is advantageously in the pre-fabri- cation of fire-insulated pipe-lengths. In connection with pipe installations such pre-fabricated fire insulated pipe- lengths may be brought direct to the place of installation for the mounting there, whereas for the protection of pipe flanges, T-pieces , pipe bends, etc. there may preferably be provided moulded or extruded elements of the fire resistant material, said elements being provided as shells which are lined with an appropriate light weight insulation. These lined shells including fire resistant material in the form of tape can, both as regards the pre-fabrication and the keeping together of the shell-shaped insulation parts, be sealed by means of heat, for example a hot air stream.

It is to be understood that the fire and corrosion protected articles not only may comprise pipe-shaped articles or pipe systems as such, but can also comprise containers, walls, plates, etc., all having regard to the field of application in which the articles are to be protected against fire and corrosion.

Especially in connection with fire protection of bendable pipes the first layer of insulation may be constituted by for example glass fiber implemented as tape or woven texture, whereas the second layer of insulation may be con¬ stituted by a fire resistant material which at higher tempe¬ ratures renders a ceramic stable fire protecting phase.

By this combination of an inner layer of insulation which prevents the intrusion of heat to the inner pipe during the first phase of a fire, i.e. when the temperature is in the range of approximately 100-300 C, the outermost layer will more rapidly reach the higher temperature at which it is converted from a good thermally conducting mass, to its

expanding phase and finally to the phase wherein it develops a ceramic stable fire protecting material.

Rather than using an inner layer of glass wool or glass fiber, there may be used a foamed thermally insulating mate- rial which at higher temperatures renders a fire resistant effect, the second layer of insulation at the same time still constituting a non-foamed layer of fire resistant material which at higher temperatures renders a stable ceramic fire protecting phase.

By this combination of foamed and non-foamed fire resistant material, it is achieved that the foamed inner layer consti¬ tutes a relatively good heat barrier in the lower tempera¬ ture range, i.e. in the range of approximately 100-300 C, such that the outer layer will rapidly be heated to higher temperatures, i.e. approximately 300-900 C and higher, for thereby more rapidly to be converted to its cell-shaped ceramic structure forming an especially good fire protecting cover.

The foaming of the inner insulation layer may for example be such that this material achieves a density of approximately 1,0, whereas the non-foamed outer layer can be given a den¬ sity of approximately 1,5. It is to be understood that these values may be altered within wide limits, both individually and mutually.

Appropriately, there may be applied a combination of insula¬ ting material, comprising an inner layer of glass fiber, an intermediate layer of foamed fire resistant material, and an outer layer of fire resistant material which at higher tem¬ peratures than approximately 800-900 C renders a ceramic stable and fire protecting phase, together with the foamed intermediate layer.

Possibly, the foamed qualities may comprise glass fibers, the contents of glass fibers and foaming agents being varied within wide limits.

If such a transportation conduit for for example fuel is mounted within a stiff shell, it could be appropriate be¬ tween the layers of insulation and the stiff shell to pro¬ vide a layer of woven glass fiber and fabrics which can burn away under the influence of high temperature, the fabrice at the same time allowing for the swelling of the insulating material to twice its volume during a fire. The insulating material may then reach its fully foamed ceramic condition without changing the physical outer dimensions of the encap¬ sulated pipe.

Thus, fire protected articles according to the present invention will comprise features as disclosed above, and as appearing from the further appended patent claims.

SHORT DESCRIPTION OF THE DRAWINGS

In the following the invention will be further described, reference being had to the drawings illustrating embodiments of the invention.

Fig. 1 is a perspective view of a pipe-shaped article which is insulated in accordance with a first embodiment of the invention.

Fig. 2 is a perspective view of a pipe-shaped article which is insulated in accordance with a second embodiment of the invention .

Fig. 3 is an end view of a pipe- or hose-shaped fire protec¬ ted article in accordance with a further embodiment of the invention .

Fig. 4 is an end view of a pipe- or hose-shaped article insulated in accordance with yet another embodiment of the invention .

Fig. 5 is an end view of a pipe- or hose-shaped article

insulated in accordance with a fifth embodiment of the invention.

DESCRIPTION OF EMBODIMENTS

In Figure 1 reference numeral 1 designates an inner pipe of corrosion resistant material, for example a polymer plastic.

More specifically the pipe may be manufactured from a glass fiber reinforced epoxy or polyester.

Around the pipe 1 there is provided a layer of light, thermally insulating material which normally does not stand the exposure to fire, for example glass wool, ceramic fiber or mineral wool. In the illustrated embodiment the layer of insulating material 2 may be mineral wool, applied to the pipe 1 in the form of semi-circular-shaped elements having approximately the same inner diameter as the outer diameter of the pipe.

Outside the insulating layer of mineral wool 2 there is pro- videt a fire resistant material 3, said material being applied in three layers 3a, 3b, 3c, respectively. The appli¬ cation in layers of the fire resistant material 3 may pre¬ ferably be realized by a wrapping of the fire resistant material in the form of tape, the tape-shape being illustra¬ ted by reference numeral 3n in Figure 1.

Outside the fire resistant material 3 there is provided a glass fiber tape 4 and outside the latter there is provided a layer of epoxy 5.

In connection with the embodiment illustrated in Figure 2 the plastic pipe 10 is covered directly with a fire resis- tant material 13, said material being applied in two layers, here 13a and 13b, preferably in the form a tape 13n. Outside the fire resistant material 13 there is provided a needle mat 20 which in turn is surrounded by an outer layer of fire resistant material 23, here in the shape of two layers 23a

and 23b applied in the form of tape 23n. Outside the layers 23a and 23b of fire resistant material there is provided a glass fiber tape 14.

In general the embodiment according to Figure 2 differs from the embodiment according to Figure 1 only by comprising a further inner layer of fire resistant material. Possibly, the discussed embodiments may include an aluminium foil as a radiation screen, possibly a steel net, depending on the existing circumstances at the place of installation.

The advantages of the discussed embodiments for combined fire and corrosion protected pipe parts can be summarized as follows :

1. There might be used inexpensive, light, thermally well insulating inner materials, for example glass wool, ceramic fibers or mineral wool, which normally do not resist exposion to fire at higher temperatures, or which lose their good heat insulating properties at higher temperatures. Higher temperatures are to be understood as 800 C and higher, as for example in connection with hydrocarbon fires. In combination with a fire resistant material which at higher temperatures than approximately 800 C renders a ceramic stable and fire protecting phase, this combination will in case of fire render a temperature which in the interphase between the fire resistant material and the light, thermally insulating material will not exceed values rendering the light, thermally insulating material ineffec- tiv as heat insulator. In its ceramic phase the fire resis¬ tant material can protect the elements accommodated inside thereof at temperatures above 1500 C.

2. The fire resistant material constitutes a very effective heat insulator during the phase transitions, i.e. from being an approximately plastic material at temperatures below 200 C, to become a porous, thermally insulating material at temperatures above 200 C, and to a ceramic- like material at temperatures of approximately 1200 C and higher. The insulation can in connection with the fire

resistant material be made substantially thinner than in connection with alternative methods .

3. Said combination becomes mechanically very strong both in relation to damages during normal conditions of operation and in case of explosions .

4. The use of the fire resistant material in the form of tape makes it simpler to pre-fabricate fire insulated corrosion resistant pipes, and the repear of possible dama¬ ges can easily be carried out on site.

5. For the protection of flanges, T-pieces , pipe bends, etc. in connection with a pipe conduite installation, there may be pre-fabricated moulded pipe elements of the fire resistant material, which constitute a fire protecting shell being lined with appropriate light weight insulation.

6. In the embodiment wherein the protected pipe com¬ prises an inner layer of fire resistant material, the endo- thermic heat capasity of the material is utilized in a very favourable manner in case of fire. The inner layer can then as long as the endothermic reaction persists, be stabilized thermally at activation temperature for hydrates constitut¬ ing a component of the fire resistant material.

Appropriately, the fire resistant material may comprise 60- 100 parts of weight of a thermoplast, 50-450 parts of weight of aluminum hydroxide and 150-600 parts of weight of calsium carbonate and/or calsium magnesium carbonate.

Especially in connection with the production of fire resis¬ tant material in the form of tape, the material comprises ethylen vinyl acetate.

In connection with the manufacturing of the fire resistant material in the form of pre-fabricated, moulded pipe ele¬ ments this might comprise a compound including generally an ethylen copolymer, and more specifically ethylen vinyl

acetate .

From a production technical point of view the fire resistant material may comprise an elasticiser, a lubricating agent, and antioxidant agent.

As regards the protection of flexible pipes the embodiments illustrated in Figures 3, 4 and 5 might be appropriate.

In Figure 3 the reference numeral 31 designates an inner pipe or a hose which is made from plastic, for example nylon. It is to be understood that the inner pipe can of course be manufactured from other kinds of plastic, for example glass fiber reinforced epoxy or polyester.

Around the pipe 31 there is provided a layer of glass fiber 32, which has a good insulating property at relatively low temperature, i.e. in the area of approximately 100-300 C. Outside the low temperature insulating layer 32 there is provided a fire resistant material 33 , said fire resistant material having good heating conductivity at temperatures below approximately 200 C, whereas the material exhibits high heat and flame resistance at temperatures above for example 900 C.

In case a fire should occur the outer layer 33 will in first instance constitute a good heat conductor, whereas the inner insulating layer 32 will constitute a heat barrier, which in turn will entail that the outer layer 33 rapidly will be given a high temperature which results in that the material is converted to a cell-shaped, ceramic structure rendering superior flame retardent properties, all the way up to 1500°C.

In Figure 4 there is illustrated yet another embodiment of the invention, an inner pipe or an inner hose 31, for example of nylon, being surrounded by a first layer of insulating material, here foamed insulating material 33a of the above discussed type, which at higher temperatures,

above approximately 300-900 C renders a fire resistant effect. Since the plastic/ceramic material 33a is foamed, it will already at a temperature of approximately 100-300 C develop a relatively low heat conductance capacity, such that it rapidly will form a heat barrier against the inter- nal nylon hose 31, in case a fire should occur. Due to the foamed plastic/ceramic material 33a the outer insulating layer 33, which is a non-foamed plastic/ceramic mixture having good heating conducting properties below approxi¬ mately 200 C but a high fire resistant effect at tempera¬ tures above approximately 300-900 C, will rapidly gain a temperature at which it is converted from its plastic-like consistency at lower temperatures, i.e. lower than approxi¬ mately 90 C, via its swelling, water expelling condition in the range 90-200 C, for thereafter rapidly to be con¬ verted to its rigid cellular ceramic form at approximately 900 C, for thereby defining a heat resistant outer cellu¬ lar cover.

The first insulating layer 33a may for example be foamed to render a density of approximately 1, whereas the outer insu¬ lating layer 33 which is to be destignated as non-foamed, may have a density of approximately 1,5-1,8. It is to be understood that the degree of foaming can vary within wide limits, and it is also to be understood that the foamed material 33a may have added thereto other fire insulating materials, for example glass fibers or similar.

In Figure 5 there is illustrated a fifth embodiment of the invention, the inner nylon pipe 31 here being surrounded by a fire retardent plastic/ceramic material 33, said latter layer 33 having provided therearound a layer 34 δf a mate¬ rial which is capable of absorbing the swelling which is implied to the plastic/ceramic layer 33 during a fire. The layer 34 may for example be an appropriate fabric or a woven glass fiber which has a filling percentage depending on the thickness of the plastic/ceramic compound 33 arranged inter¬ nally thereof, which during a fire swells to approximately 2 times its original volume.

In order to achieve the above discussed effect with an inner barrier layer which renders good thermal protection also at lower temperatures of approximately 100-300 C, a part of the plastic/ceramic material may be foamed, and then prefer¬ ably in a layer which faces the inner hose 31.

Appropriately, the fire resistant plastic/ceramic material may also here comprise 60-100 parts of weight of a ther o plastic material, 50-450 parts of weight of aluminum hydrox¬ ide and 150-600 parts of weight of calsium carbonate and/or calsium-magnesium carbonate.

Preferably there may be used an ethylen-vinylacetate, and due to production technical reasons the fire resistant mate¬ rial may comprise a softening agent, a lubricating agent, a colouring agent and possibly an antioxidant agent.

As mentioned above the fire resistant material may be brought about in a more or less foamed condition, the foamed qualities comprising glass fiber filaments and foaming agent of various quantities and qualities. The glass fiber fila¬ ments may for example be provided together with other glass qualities, for example glass frit. The fire resistant mate- riale may possibly comprise fatty acids and phosphate esters in suitable quantities.

Depending on the composition of the fire resistant material, and to which degree the material has been foamed or not, the convertion phace of the material during a fire can be varied within appropriate limits.

For example, the fire resistant material will under the influence of temperatures larger then 90 C be subjected to a softening process, whereas the material at temperatures exceeding 200 C will be subjected to swelling, at the same time as water is repelled. At temperatures above 300 C the polymer will be subjected to pyrolysis, and in the tempera¬ ttuurree rraannggee 330000--550000°CC oorr 330000--600 C an organic residual materials will be developed

When the temperature of the material exceeds 800-900 C there will be formed a relatively sturdy cellular ceramic, which will have fire retardent qualities up to 1500 C.

_- Thus, the material is a good thermal conductor in its origi- b nal state, whereas at temperatures above 200 C, due to expelled water, it will constitute a good thermal insula¬ tion, whilst at the same time swelling to approximately 2 times its original size. In its cellular ceramic condition it renders good mechanical stability, the material also 0 being a flame barrier without expelling poisonous smoke or gass .

Thus, the fire resistant material is converted from having approximately thermoplastic properties at room temperature, 5 in which the thermal conductivity is approximately 0,7 w/mc, and to a cellular ceramic having a thermal conductivity of approximately 0,07 w/mc.

0

5

0

5