MXPA98003210A - Fu resistant pipe - Google Patents

Abstract

Fire-resistant tubing and pipe fittings are described which include a wall (2) of structural tubing from a helically wound reinforcing fiber (14), which are joined together (16) thermoformable polymeric. A first embodiment of pipe includes a fire-resistant layer (18) in the form of a resin-rich carrier that is applied to the wall surface (2) of the structural pipe. The resin used to impregnate the carrier is selected from the same group of resins used to form the wall of the structural pipe. A second embodiment of pipe includes a variety of layers (26) of energy absorbing material, arranged around the wall of the structural pipe and formed from a material capable of absorbing the thermal energy of a surrounding outer layer to produce a thermally insulating gas between them. A variety of fiber reinforced resin layers are arranged around the wall of the structural tubing that is formed from a shock absorbing configuration of release layers and resin layers reinforced with alternating fiber. The fire resistant pipe embodiments of this invention are configured to protect the structural wall from heat induced faults caused by exposure of the outermost pipe wall to a flame having a temperature of 1000 ° C for at least 5 minutes in an anhydrous condition

Description

FIRE-RESISTANT PIPING Field of the Invention The present invention relates generally to fire-resistant pipe and fittings and more particularly to tubing and pipe fittings reinforced with coiled filament fiber, having one or more layers impregnated with resin reinforced with surrounding fiber, which exhibit improved fire resistance, burst strength and impact resistance when compared to conventional fiber reinforced pipe and pipe fittings.

BACKGROUND OF THE INVENTION Pipes and pipe fittings formed from fiber reinforced plastics have gained wide acceptance as viable alternatives to their steel counterparts in such applications where cost, weight, and / or chemical resistance is a concern. Conventional fiber reinforced plastic pipes include a filament component, which is wound onto a mandrel and a resin component that is used to join the windings of the filament together. The filament winding acts to structurally reinforce the resin pipe in another way by providing a desired degree of REF: 27320 tangential strength and longitudinal resistance to the pipe. The fiber and resin components are selected by one or more desired physical properties, which make the pipe particularly suited to a specific application. Polyester and epoxy resins are normally favored for use in the formation of such pipes and pipe fittings, due to their good outdoor weathering, corrosion resistance and chemical resistance. Pipe and pipe fittings made of fiber-reinforced plastic are used in applications where some degree of temperature resistance is desired, as well as resistance to weather conditions, corrosion and chemical resistance. An example of one such application is fire piping used in industrial plants, offshore platforms and the like. Normally, piping and pipe fittings used in fire piping must be designed to accommodate and supply a desired pressure of water or other liquid for fire extinguishing, foam or foam / liquid mixture, when subjected to high discharge conditions. temperatures, or when placed in close proximity to the flame. Fiber-reinforced plastic pipes are favored for use as pipe for extinguishing fires in offshore oil rigs and are normally maintained in an empty or unloaded state until a fire is detected. Once a fire is detected, the water is routed to the pipes at pressures that can be as high as 16 kgf / cm2 (225 pounds per inch2), depending on the nominal pressure for the pipe. Thus, the fiber reinforced pipes used in such applications must have the capacity to withstand high temperature and / or close contact with the flame for a brief period of time when they are empty, that is, without the benefit of being loaded with water and have water as a means of heat transfer to minimize the damaging temperature effects. The fiber reinforced plastic pipes used in such fire extinguishing pipe applications include those made from epoxy resin because of their improved corrosion resistance. A rigorous test has been devised to qualify fiber reinforced pipes for use in such fire extinguishing pipe applications. The test requires the placement of the assembly or assembly of pipe and pipe fitting in close proximity to a flame at a temperature of 1,000 ° C with the pipe dry for a period of time of five minutes, and then filling the pipe with water to The nominal pressure for approximately 20 minutes. To pass the test, the assembly or assembly of pipe and pipe fittings should not show any signs of structural damage and only minor leaks. Pipe and pipe fittings made of fiber-reinforced plastic, forfrom epoxy resin, have demonstrated a significant temperature-induced deterioration at temperatures as low as 120 ° C and therefore have proved capable of passing the test. Pipe and pipe fittings reinforced with fiber forfrom polyester resin are also unable to pass the test, since these pipes have demonstrated a deterioration induced by significant temperature, at temperatures as low as 94 ° C. In order to pass the test, fiber reinforced plastic pipes forfrom epoxy resin can be coated with an intumescent coating or forfrom an epoxy resin containing intumescent. When exposed to high temperature conditions or flame contact, the intumescent coating foams, which form an insulating barrier at the temperature that serves to protect the surface of the underlying pipe. However, a disadvantage of using an intumescent coating is that it increases the cost of fiber-reinforced plastic tubing, thereby reducing the cost incentive to use the tubing and generates toxic smoke when subjected to contact with the flame.

An alternative to the use of fiber reinforced epoxy pipes, coated with intumescent in pipe applications for fire extinguishing, is to build the pipe from phenolic resin, instead of epoxy resin, which is known to provide resistance to the temperature improved. However, pipe and pipe fittings for fire extinguishing, made from phenolic resin, reinforced with fiber have also been found to be incapable of passing the test, exhibiting faults of the side walls induced by the breakdown of the fiber when expose to nominal pressures. It is known that fiber reinforced plastic pipes formed from epoxy, polyester and phenolic resins exhibit a limited amount of impact resistance and flexibility. The physical properties of impact resistance and flexibility are desirable in applications such as pipes and pipe fittings for fire extinguishing, because it is desired that such a pipe still be capable of retaining a nominal water pressure even when subjected to some amount of movement, possibly created by falls, faults or distortion of adjacent structures during a fire. Accordingly, it is desired that fiber reinforced resin pipe and fittings be constructed in such a manner that they are lightweight, weather resistant, corrosion resistant, resistant to chemical compounds and have sufficient burst strength. and temperature resistance to pass the test described above for use in pipe applications for fire fighting. It is desirable that the fiber reinforced resin pipe does not produce toxic smoke when exposed to contact with the flame and provides a desired degree of impact resistance and flexibility. It is also desired that the fiber reinforced resin pipe be formed from available materials by using conventional manufacturing techniques.

Brief Description of the Invention Accordingly, in the practice of this invention, pipes and fittings of fire-resistant pipes are provided, which are constructed with sufficient resistance to temperature and resistance to contact with the flame to allow their use in such applications. high temperature such as the pipe for fire extinguishing. Fire resistant pipes prepared according to the principles of this invention include a structural pipe wall, formed from helically wound reinforcing fiber which is bonded together with a thermosetting polymeric resin. The polymeric resin is selected from the group consisting of phenolic resins, siloxane modified phenolic resins, furan resins, and mixtures thereof. The helically wound reinforcing fiber is moistened by the resin, such that it is in the range of about 10 to 40 percent by weight of the resin. The structural wall is formed from multiple layers of the windings, wherein the number of layers depends on such factors as the tangential strength and longitudinal strength, and the resistance to the desired temperature for a particular pipe application. In a first embodiment, a fire resistant layer is applied to the surface of the structural pipe wall. The fire resistant layer is a layer rich in resin that acts as an ablative heat shield. The fire-resistant layer includes a carrier adapted to accommodate a large amount of thermosetting polymer resin. The carrier is selected from the group of mat-like, fibrous materials, which include, fiberglass, carbon fiber, nylon fiber, polyester fiber, felts of similar fibers, fragmented fibers and their combinations. The resin component is selected from the same group of resins previously described for the formation of the wall of the structural pipe. It is desired that both resins are compatible and preferably the same, to facilitate the formation of a chemical bond between the structural pipe wall and the fire resistant layer during curing. The fire-resistant layer comprises approximately three times the resin content of the helically wound reinforcing fiber layer. In a second embodiment, a plurality of layers of energy absorbing material are arranged around a surface of the structural wall. The energy absorbing material used to form the layers is selected from the group of materials capable of absorbing thermal energy from an external surrounding layer by phase transformation, for example, to produce a gas, at a temperature lower than the degradation temperature of the structural wall. The gas formed by such a phase transformation produces an enclosure or cavity of thermally insulating air therebetween. A variety of resin layers reinforced with fiber are disposed on the energy absorbing layers. The fiber reinforced layers can be made from the same fiber or resin or different components used to form the structural wall. In a third embodiment, a liner or jacket is disposed around a surface of the structural wall.

The lining or jacket is composed of alternating release layers and resin layers reinforced with fiber. The release layers are formed from a material that is unable to form a bond with the resin component of the resin layers reinforced with surrounding fibers and / or structural wall to form a separation layer therebetween. Such a separation layer improves the impact resistance of the pipe because it is energy absorbing to improve the impact resistance and reduces the thermal stresses to prevent the transfer of an impact wave from an exterior pipe surface to the structural wall. The fire-resistant layer in the first embodiment, the layers of energy absorbing material in the second embodiment and the lining or jacket in the third embodiment are each formed in such a way that they have a sufficient wall thickness to protect the structural wall of the second embodiment. pipe or pipe fitting of heat-induced degradation caused by exposing the outer pipe wall to a flame at a temperature of 1,000 ° C for at least five minutes when the pipe is in a dry condition, this is, when the pipe is not loaded with water. Fire resistant pipe and pipe fittings, prepared in accordance with the principles of this invention, are lightweight, weather resistant, corrosion resistant, resistant to chemical compounds and have sufficient temperature resistance to be used. in applications for the extinction of fires without suffering faults related to temperature or contact to the flame. The fire resistant pipes of this invention, when exposed to contact with the flame, do not produce toxic smoke and have improved impact resistance and flexibility when compared to conventional fiber reinforced plastic pipes, formed from resin ingredients. epoxy and polyester.

BRIEF DESCRIPTION OF THE DRAWINGS These and other features and advantages of the present invention will be appreciated as it is better understood with reference to the specification, claims and drawings in which: FIGURE 1 is a side elevational view of a first embodiment of fire resistant pipe constructed in accordance with the principles of this invention, prior to the application of one or more flame resistant layer (s), - FIGURE 2 is a side elevational view of the pipe fire resistant of FIGURE 1, after the application of one or more fire resistant layer (s), - FIGURE 3 is a cross-sectional view of the fire resistant pipe of FIGURE 2, taken at through section 3-3; FIGURE 4 is a cross-sectional view of a second embodiment of fire-resistant pipe that compresses a layer of energy absorbing material interposed between a structure pipe wall and an outer fiber reinforced resin layer, - FIGURE 5 is a cross-sectional view of a second alternative fire-resistant pipe method, comprising layers of successive energy-absorbing material, interposed between a wall of the structural pipe and a layer of resin reinforced with external fiber, - FIGURE 6 is a view in perspective of a third embodiment of fire resistant pipe, comprising a liner or jacket of release layers and repeated fiber reinforced resin layers, interposed between a wall of structural pipe and a layer of resin reinforced with external fiber, - and FIGURES 7A to 7C are side elevation views of fire resistant pipe fittings constructed in accordance with n the principles of this invention.

Detailed Description With reference to FIGURE 1, a fire resistant pipe 10, constructed in accordance with the principles of this invention, includes a structural pipe wall 12, formed from multiple layers of helically wound reinforcing fiber 14, bonded or bonded together with a resin 16. The structural pipe wall 12 can be formed by the use of conventional techniques well known in the art for the formation of plastic pipe. fiber reinforced (FRP), such as by winding the reinforcing fiber around a mandrel to one or more specific winding or winding angles and in one or more directions, to obtain a particular degree of tangential and longitudinal strength. In a preferred embodiment, the fiber windings or windings are wound under tension at an angle of about 54 degrees around the mandrel, in one direction and then in an opposite direction, since it is known that this winding or winding angle produces a pipe which has an optimum degree of tangential and longitudinal resistance. The number of windings or winding of fibers that are used to build the wall of the structural pipe depends on the particular size of, and the application for the pipe. While the technique described above has been directed towards the construction of pipe, it will be understood that the same technique can be used to construct pipe fittings, such as tees, elbows and the like as well. The reinforcing fiber component can be selected from conventional filament materials, used for the formation of FRP pipe (fiber reinforced plastic) that do not melt when exposed to fire, such as glass, carbon and the like , and their combinations. In a preferred embodiment, the reinforcing fiber is glass. The wall of the structural pipe is constructed in such a way that a sufficient amount of the resin component is used to wet and bond or bond the fiber windings or coils together. The wall of the structural pipe may comprise in the range of about 10 to 40 percent by weight of the resin component. In a preferred embodiment, the wall of the structural pipe comprises approximately 25 percent by weight resin. The resin is applied to the fiber windings by a conventional application technique, such as by running the windings or windings through a resin bath. The resin component can be selected from the group of resins consisting of phenolic resins, siloxane modified phenolic resins, furan resins and mixtures thereof. Any type of phenolic resin can be used as the resin component and is finally selected based on the physical properties desired for the proposed end-use application. Preferred preferred phenolic resins for use in forming the wall of the structural pipe include phenolic resole resins and phenolic novolac resins. Suitable phenolic resins can include those based on phenol, substituted phenols such as para-cresol, xyleneol, bisphenol A, paraphenylphenol, para-tert-butylphenol, para-t-octyl phenol and resorcinol. The phenolic resin can be prepared by combining an appropriate phenol with an aldehyde such as formaldehyde, acetaldehyde, paraldehyde, glyoxal, hexamethylene tetraamine and furfural. Preferred phenolic resins are low viscosity phenolic resins resins, due to their optimum wetting of the fiber reinforcing material and their contribution to the production of a reinforced fiber pipe having a high vitreous content. The preferred phenolic novolac resins that are most useful in this invention are prepared from any of the phenols and aldehydes described previously and have molecular weights in the range of about 400 to 5,000, with glass transition temperatures in the range of about 40. ° C to 90 ° C. The phenolic resols found most useful in this invention have molecular weights in the range of about 300 to 3., 000 solids content of 50 to 90% by weight, and can contain from 2 to 20% by weight of free phenol or substituted phenol and from 1 to 10% by weight of water. Suitable phenolic resin manufacturers include: B.P. Chemical Division of British Petroleum of Barry U.K.; the Packaging and Industrial Products Division of Borden, Inc., of Columbus, Ohio, - the Hard Western Petroleum Division of Dallas, Texas, - Georgia-Pacific Corporation of Atlanta, Georgia; Neste Resins Corporation of Eugene, Oregon, also as a diversity of other small producers. Some preferred phenolic resins include Cellobond J19961L, J2018L and J2027L from B.P. Chemicals, phenolic resole, SL-898 from Borden, and phenolic resole GP5018 from Georgia-Pacific. Particularly preferred siloxane-modified phenolic resins useful in the formation of the structural pipe wall include those prepared by combining, in a first embodiment, a silicone intermediate, a substituted phenol or phenol and an aldehyde donor, by combination , in a second embodiment, of one of the phenolic novolac resins described above, with a silicone intermediate or by the combination in a third embodiment, of one of the phenolic resole resins described above with a silicone intermediate.

In a first embodiment, a siloxane-modified phenolic resin is prepared by the combination of a phenol or a substituted phenol described above, with an aldehyde described above and a silicone intermediate. The amount of aldehyde present and the type of catalyst used will determine whether a modified phenolic novolac resin is formed by siloxane or a resole resin. With respect to the silicone intermediate, alkoxy-functional and silanol-functional silicone intermediates can be used. The silicone intermediates, referred to in this invention, are chemical polymer structures having a fundamental chain-Si-O- and having the ability of further experimental reaction, for example hydrolysis and / or condensation to form a cured polymer structure. A preferred class of silicone intermediates have the formula wherein each R 2 is independently selected from the group consisting of the hydroxy group, alkyl, aryl, aryloxy and alkoxy groups having up to six carbon atoms, wherein each R x is independently selected from the group consisting of hydrogen, alkyl and aryl groups which they have up to 12 carbon atoms, and wherein n is an integer in the range of 1 to 56, selected such that the average molecular weight of the silicone intermediate is from about 150 to about 10,000. It is believed that the molecular weight of the silicone intermediate can have an impact on the degree to which an interpenetrating network (IPN) of phenolic polymer and siloxane polymer is formed and the proportion of siloxane groups that copolymerize with the phenolic polymer to form a phase. keep going. Another group of silicone intermediates can be represented by a silicone material containing hydroxyl (OH) in which those materials are included wherein the OH group or groups are directly attached to the silicon atom, such as the silanol materials which have the general formulas OH * S * 5 HO-S¡ -0-S¡ -OH *H.H wherein each R5 group may comprise a hydrocarbon radical selected from the group including alkyl, alkenyl, cycloalkyl, aryl, alkaryl or aralkyl radicals and wherein, nx may be an integer in the range of about one to thirty. Still another group of OH-containing silicone materials are materials comprising two or more OH groups attached to a silicon atom, and having two or more silicon atoms attached via divalent organic radicals, such as those having the formula general R * R < wherein each R6 group may comprise another OH group or may comprise a hydrocarbon radical selected from the group including alkyl, cycloalkyl, aryl, alkaryl and alkylaryl radicals, wherein R7 may comprise a divalent organic radical selected from the group including methylene, polymethylene , araliene, polyaraliene, cycloalkylene and polycycloalkylene. The methoxy functional silicone intermediates useful in this invention include, but are not limited to: DC-3074, DC-3037 from Dow Corning Corporation of Midland, Michigan; SY-231 (molecular weight of about 1,000) and MSE-100 of Wacker Silicone Corporation; and SR-191 of General Electric. The functional silanol silicone intermediates are generally in the range of about 0.5% to 6% by weight of Si-OH. Commercially available silanol-functional silicone intermediates useful in this invention include, but are not limited to: Diphenylsilandiol (molecular weight of approximately 216), SY-409 (molecular weight approximately 10,000) of Wacker Silicones and SY-430, - and the following Dow Corning materials: DC804, DC805, DC806A, DC840, Z-6018, DC-1-2530, DC-6-2230, DC-1-0409, DC-1-0410 and laminating resins 2103, 2104 and 2106. A first preferred embodiment of a phenolic resin modified by siloxane is prepared by the combination of phenol, or substituted phenol., an aldehyde such as formaldehyde and a silicone intermediate. Based on a weight of one mole of phenol, the weight of the formaldehyde will vary between 0.75 and 0.90 moles and the weight of the silicone intermediate will vary between 0.01 and 0.3 moles. The molar ratio of phenol to formaldehyde in a phenolic novolac resin is usually 1: 0.75-0.90. Table 1 shows the typical molar ranges of the silicone intermediates, which have different molecular weights, used to prepare the phenolic novolac resin modified by siloxane.

TABLE 1 A first preferred embodiment of a siloxane-modified phenolic resole resin is prepared by the combination of phenol or substituted phenol, an aldehyde such as formaldehyde and a silicone intermediate. Based on a weight of one mole of phenol, the weight of the formaldehyde will vary between 1.2 and 3 moles, and the weight of the silicone intermediate will vary between 0.01 and 0.7 moles. The molar ratio of phenol to formaldehyde in a resole phenolic resin is usually 1: 1.2-3. Table 2 shows the typical ranges of silicone intermediates having different molecular weights used to prepare the siloxane modified phenolic resole resin.

TABLE 2 For each of the first embodiments described above of siloxane modified and resole phenolic novolac resins, it is desired that it be used in the range of about 0.5 to 35 weight percent of the silicone intermediate.

In the preparation of the first embodiments of the siloxane modified phenolic resins, catalysts are used to form either a phenolic novolac resin or a desired phenolic resole prepolymer. For example, when the modified siloxane phenolic resin is formed, a strong acid, such as sulfuric acid, sulfonic acid, oxalic acid or phosphoric acid is used to facilitate the formation of the phenolic novolac resin prepolymer. When the modified siloxane phenolic resin is formed, a strong base such as sodium hydroxide, calcium hydroxide or barium hydroxide is used to facilitate the formation of the phenolic resole prepolymer. In the first preferred embodiments, a siloxane modified phenolic novolac resin can be prepared by using up to about five percent by weight of acid catalyst and a siloxane modified phenolic resole resin can be prepared by using up to about five percent by weight. weight of basic catalyst. Other different catalysts and in addition to those described above, can optionally be used in the preparation of the first embodiments of the siloxane-modified phenolic resin to facilitate the condensation of the phenolic resin and the silicone intermediate by reducing the time and / or the temperature associated with such reactions. The catalysts useful for facilitating the condensation of the phenolic resin and the silicone intermediate are the same and can be used in the same proportion as those described below which can be used optionally for the preparation of the second and third types of the resin phenolic modified by siloxane. The first embodiments of siloxane-modified phenolic novolac resins and resole are prepared by first combining the ingredients of the phenol and silicone intermediate and then adding the aldehyde ingredient to form a mixture of phenolic polymers, siloxane polymers and phenolic polymers. -siloxane. The elevation of the temperature of the combined mixture is desirable to reduce the reaction times associated with the formation of the modified siloxane phenolic resin. For example, a first embodiment of the siloxane modified phenolic novolac resin can be prepared by a batch process using a jacketed stainless steel reaction vessel, equipped with a turbine wing or anchor type stirrer, a steam condenser and a temperature controller. Normally, the molten phenol is charged to the reaction vessel, the agitator is operated and the silicone intermediate is added. An acid catalyst can be added at this point to facilitate the formation of the phenolic novolac polymer.

Then, formalin (37-40 percent aqueous formaldehyde) is charged to the reaction vessel, either before raising the temperature or by controlled addition at elevated temperature. Then a vigorous condensation reaction is carried out which is highly exothermic. The condensation step is continued until the desired molecular weight distribution has been obtained. During this time, the mixture can be converted into two phases with separation of the resinous component. The actual reaction time will vary depending on the distribution of the desired molecular weight, the use of one or more catalysts, the pH and the molar ratios of aldehyde to phenol to silicone intermediate. The ingredients are mixed together, during which time, the phenol, aldehyde and silicone intermediate undergo polycondensation, which polycondensation can optionally be accelerated by the action of a catalyst, as described hereinafter. During this time, the alkoxy-functional silicone intermediates also undergo hydrolysis to form silanol-functional silicone intermediates, which polymerize to form a siloxane polymer and also copolymerize with the newly formed phenolic novolac resin prepolymer to form a resin phenolic modified by siloxane. Thus, the resulting resin comprises an IPN of phenolic novolac polymer and siloxane polymer and a continuous phase formed from the phenolic polymer having one or more siloxane groups in its fundamental chain. The hydrolysis of the alkoxy-functional silicone intermediates can be optionally accelerated by the action of a catalyst, as described hereinafter. Alternatively, silanol-functional silicone intermediates can be used in the process, which can directly copolymerize with the newly formed phenolic novolac resin prepolymer. At the end of the condensation period, water, residual moisture, unreacted phenol and low molecular weight species can be separated by atmospheric, vacuum or steam distillation. The point at which the distillation is stopped is usually determined by taking a sample of resin and measuring its viscosity in the molten state. After the resin has cooled, it can be treated in several ways. It can be sold in the form of fragments or flakes, compounded to form molding powders or can be ground and combined with hexamine and other fillers. As another example, a first embodiment of the siloxane-modified phenolic resole resin can be prepared by a batch process using the same equipment previously described for the preparation of a first embodiment of the siloxane-modified phenolic novolac resin. Commonly, the molten phenol is charged to the reaction vessel, the agitator is put into operation and added to the silicone intermediate. At this time alkaline catalysts can be added to facilitate the formation of the phenolic resole polymer. The formalin is added and the batch heated. The initial reaction is exothermic. The condensation is usually carried out at an atmospheric pressure and at a temperature in the range of 60 to 100 ° C or at reflux. Because the siloxane-modified phenolic resole siloxane resins are by themselves thermosetting, dehydration is carried out rapidly and at low temperature to prevent overreaction or gelation. The final point is found by manually determining a specific hot plate gelling time, which decreases as the formation of the resin progresses. Siloxane modified phenolic resole resins can be refrigerated to prolong their stability during storage. Second and third embodiments of a siloxane modified phenolic novolac resin and a siloxane modified phenolic resole resin, respectively, are prepared by using a phenolic novolac resin and a phenolic resole resin respectively as starting materials. Suitable phenolic resole resins and novolac phenolic resins include those described above. The second embodiment of the siloxane-modified phenolic novolac resin is prepared by combining in the range of 75 to 95 percent by weight of the phenolic novolac resin. The third embodiment of the siloxane-modified phenolic resole resin is prepared by blending in the range of 65 to 99.5 percent by weight of the phenolic resole resin. With respect to the silicone intermediary, those silicone intermediates previously described for the preparation of the first embodiments of the siloxane-modified phenolic resin are also used to prepare the second and third embodiments of the siloxane modified phenolic resins. Each of the second and third embodiments of the siloxane-modified phenolic resins comprises in the range of 0.5 to 35 weight percent of the alkoxy-functional or silanol-functional silicone intermediate. In the second embodiment, the siloxane-modified phenolic novolac resin is prepared by combining a phenolic novolac resin with a formaldehyde donor and a silicone intermediate. Suitable formaldehyde donors include solutions of aqueous formaldehyde, paraformal, trioxane, hexamethyltetraamine and the like, a preferred material is hexamethyltetraamine. The second embodiment of the siloxane modified phenolic novolac resin may comprise in the range of about 3 to 15 weight percent of the formaldehyde donor. The third embodiment of a siloxane-modified phenolic resole resin is prepared by combining a phenolic resole resin with a silicone intermediate. If desired, either an acidic or basic catalyst can optionally be used to reduce the reaction time associated with the final curing of the resin. Suitable inorganic acid catalysts which may optionally be used in the third embodiment include phosphoric, hydrochloric and sulfuric acids. Suitable organic acids that can optionally be used in the third embodiment include paratoluenesulfonic acid and phenylsulfonic acid. Latent acid catalysts can also be used to improve the lifetime and increase the application space without gel formation. The basic catalysts suitable for the curing of phenolic resins include various forms of barium and magnesium oxide and the like. Proprietary commercially available latent acid catalysts useful in this invention are available from British Petroleum Chemicals under the trade name Phencat 381 and Phencat 382. Other patented catalysts include Borden RC-901, an ester of diphenylphosphoric acid supplied from Dover Corp. , which has the product name Doverphos 231L, and GP3839 and GP308D50 from Georgia Pacific. The third embodiment of the siloxane-modified phenolic resole resin can comprise up to about 15 percent by weight of the optional acid or base catalyst or curing agent. If desired, the first, second and third embodiments of the siloxane-modified phenolic resins may each optionally comprise a sufficient amount of catalyst to reduce the reaction time and reduce the reaction temperatures associated with the condensation of the silicone intermediate and copolymerize it. with the phenolic polymer during the formation of the phenolic resin modified by siloxane. Suitable catalysts are selected from the group consisting of organometallic compounds, amine compounds and mixtures thereof. Combinations of an organometallic compound with an amine compound are preferred, when desired to catalyze the hydrolysis and / condensation of the silicone intermediate. Useful organometallic compounds include metal deicers well known in the paint industry, such as zinc, manganese, cobalt, iron, lead and tin octoate, neodecannates and naphthenates and the like. Organotitanates such as butyl titanate and the like are also useful in the present invention.

A preferred class of organometallic compounds, useful as a catalyst in organotin compounds which have the general formula *, I I * ?? where R8, R9, R10 and Rl? are selected from the group consisting of alkyl, aryl, aryloxy, and alkoxy groups, having up to 11 carbon atoms, and wherein any two of R8, R & R10, and RX1 are additionally selected from a group consisting of inorganic atoms which consist of halogen, sulfur and oxygen. Organotin compounds useful as catalysts include tetramethyltin, tetrabutyltin, tetraoctyltin, tributyltin chloride, tributyltin methacrylate, dibutyltin dichloride, dibutyltin oxide, dibutyltin sulfide, dibutyltin acetate, dibutyltin dilaurate, dibutyltin maleate polymer, dibutyltin dilaurate dibutyltin, tin octoact, dibutyltin bis (isooctylthioglycolate), butyltin trichloride, butylstannoic acid, dioctyltin dichloride, dioctyltin oxide, dioctyltin dilaurate, dioctyltin oxide, dioctyltin dilaurate, dioctyltin maleate polymer, bis (isooctylthioglycolate) of dioctyltin, dioctyltin sulfide and dibutyltin 3-mercaptopropionate. The first, second and third embodiments of the siloxane modified phenolic resin can comprise up to about five percent by weight of the oganometallic catalyst. With respect to the amine compound, the preferred amine compounds to optionally catalyze the hydrolysis and / or condensation reactions of the silicone intermediate have the general formula wherein R12 and R13 are each selected from the group consisting of hydrogen, aryl and alkyl groups having up to 12 carbon atoms, and wherein R14 is selected from the group consisting of alkyl, aryl and hydroxyalkyl groups, having up to 12 carbon atoms; carbon atoms. Suitable amine compounds useful as catalysts include dimethylmethanolamine, ethylaminoethanol, dimethylethanolamine, dimethylpropanolamine, dimethylbutanolamine, dimethylpentanolamine, dimethylhexanolamine, methylethylmethanolamine, methylpropylmethanolamine, methylethylethanolamine, methylethylpropanolamine, monoisopropanolamine, methyldiethanolamine, triethanolamine, diethanolamine and ethanolamine. Preferred amine compounds include dimethylethanolamine and ethylaminoethanol. The first, second and third embodiments of the siloxane-modified phenolic resin can comprise up to about five percent by weight of the amine catalyst. If desired, each of the organometallic compound and the amine compound can be used independently to form a phenolic resin modified by siloxane. However, it has been found that when combined, the organometallic compound and the amine compound act synergistically to catalyze the curing process, thereby reducing the curing time further and / or the reaction temperatures higher than those observed when using either the organometallic or amine catalyst alone. Thus, if desired under the circumstances, it is preferred that an organometallic compound be used in combination with an amine compound to catalyze the formation of hydroxide by hydrolysis of the silicone intermediate, in the case that an alkoxy silicone intermediate is used. functional and condensation polymerization of the alkoxy and silanol-functional silicone intermediate. An exemplary combination of the organometallic compound and amine is dibutyltin diacetate and ethylaminoethanol. The dibutyltin diacetate, when combined with the amine, reacts synergistically to catalyze the curing process. Although it is believed that the synergistic effect of the organotin compound and the amine compound is mechanical in character, the exact mechanism is not known. A preferred ratio of the organometallic compound to the amine compound, when used together as the catalyst is approximately one to one. Accordingly, the first, second and third siloxane modified phenolic resins can comprise up to about 10 weight percent of combined organometallic and amine catalyst. Thus, the siloxane-modified phenolic resins, prepared by the combination of an organometallic and amine catalyst and an optional acid or base catalyst, can comprise up to about 25 percent by weight of catalyst. The first, second and third preferred siloxane modified phenolic resins comprise in the range of 5 to 25 weight percent of the combined catalysts. The water may be present in the form of an aqueous phenolic resole or in the form of an aqueous formaldehyde. For example, phenolic resole may comprise in the range of 3 to 12 percent by weight of water, and formaldehyde may comprise formalin, which consists of about 37-40 percent aqueous formaldehyde. The first, second and third embodiments of the siloxane-modified phenolic resin can result in the formation of phenolic resins having a low or zero water content, which provides improved fire stability and improved processing characteristics. The silicone intermediate functions as a reactive diluent to give a stable product with generally low viscosity. The second and third embodiments of the siloxane-modified phenolic resin are prepared by combining in the above-described proportions of a phenolic novolac resin or resole with a methoxy or silanol-functional silicone intermediate. A formaldehyde donor is added in the second modality. If desired, the catalyst for the phenolic resin and the catalyst for the silicone intermediate, that is, the organometallic compound and / or the amine compound, can optionally be added to reduce the reaction and curing time and reduce the temperature of reaction. Fire resistant pipes having the structural pipe wall and fire resistant layer formed from siloxane-modified phenolic resins exhibit improved physical properties of tangential strength, chemical resistance, flexibility, impact resistance and flexural modulus when compared with pipes formed in another way from unmodified phenolic resins, without affecting the physical properties of heat resistance, flame resistance and chemical resistance inherent in phenolic resin. Additionally, fire resistant pipes formed from such siloxane-modified phenolic resins have reduced microvoke formation, and therefore, densities closer to the theoretical density when compared to conventional unmodified phenolic resins. A smaller formation of microvoids also prevents the possible entrapment of water that would adversely affect the resin's temperature resistance properties due to the generation of steam and failing ratios of the resin matrix. Furan resins can be selected for use in the formation of the structural pipe wall due to their improved temperature resistance when compared to conventional epoxy and polyester FRP resins. However, furan resins exhibit a lower degree of temperature resistance and are more expensive either than phenolic resins or phenolic resins modified by siloxane. The structural pipe wall, fire resistant pipe, is constructed in such a way that it has one or more layers of windings or fiber coils. For example, for a pipe with an internal diameter of approximately 51 mm (two inches), nominal pressure of 16 kg / cm2 (225 psi) for pipe service for fire extinguishing, it is desired that the structural wall comprises in the range of 2 to 20 layers of fiber winding and optimally 6 to 16 layers of fiber winding. A structural pipe wall having less than about 2 layers of fiber winding will have a degree of tangential and longitudinal strength and a temperature resistance lower than that desired for use in a pipe application for fire fighting. A structural pipe wall constructed in such a way that it has more than about 20 fiber winding layers is more than necessary to provide a sufficient degree of tangential and longitudinal strength, and temperature resistance for use in a pipe application for the extinction of fires and consequently, sum, weight and unnecessary expenses to the pipeline. Referring now to FIGURE 2, in a first embodiment, a fire resistant layer 18 is disposed around the outer surface of the structural pipe wall 12. The fire-resistant layer 18 is generally a heat-rich ablative shield, rich in resin, which is used to surround the wall 12 of the structural pipe and protect it from exposure to high temperature or direct contact with the flame. The fire resistant layer 18 comprises a carrier component 20 which is impregnated with a resin component 22. Commonly, the fire resistant layer 18 is wound circumferentially around the outer surface of the structural pipe wall 12, until a desired number of layers is obtained, that is wall thickness of the thermal shield. However, the fire resistant layer can be applied by a spray or spray application technique. FIGURE 3 illustrates a first embodiment of a fire-resistant pipe 10, constructed in accordance with the principles of this invention, comprising a structural wall 12 formed from multiple windings or windings 14 of fiber, and multiple layers 18 resistant to fire . The number of fire resistant layers that are used to form the pipe or fire resistant pipe fitting varies, depending on such factors as the size of the pipe, the potential temperature or exposure to the flame, the pipe, the type of fiber and / or resin component selected to form the wall of the structural pipe, the type of carrier and / or the resin component selected to form the fire resistant layer and the like. Preferred embodiments of the first fire resistant mode may include in the range of 1 to 15 fire resistant layers, depending on the factors mentioned above. In one example, for an inner diameter pipe of approximately 51 mm (two inches), the fire resistant pipe comprises in the range of 2 to 15 fire resistant layers. The fire-resistant layer 18 can be wound around the wall 12 of the structural pipe by conventional winding techniques, such as those described above for the construction of the structural pipe wall. It is desirable that the fire resistant layer be wound at a sufficient tension to provide a good interface between the enclosed pipe wall and the surfaces of the fire resistant layer. In a first preferred embodiment, fire-resistant layer 18 is briefly applied after the formation of the wall of the structural pipe and before the resin component of the pipe wall has cured, to provide a good interlayer bond during the curing between the interface resin components and the wall of the pipe and the fire resistant layer. Thus, as described below, it is desirable that the resin component of the fire resistant layer be compatible with the resin used to form the structural pipe wall.

The carrier component 20 used to form the fire-resistant layer 18 can be formed from any of material capable of accommodating a large amount of the resin component and providing a support structure for the resin in a wet and cured or solidified state . Additionally, it is desirable that the carrier be able to support the resin and not crumble or flake off the structural pipe wall when subjected to high temperature or direct flame. It is desirable that the carrier be able to accommodate in the range of from 75 to 95 percent by weight of the resin component, or approximately three times the resin content of the fiber reinforced windings or coils. In a first preferred embodiment, the fire resistant layer comprises about 90 weight percent resin. Suitable carrier materials include fibrous mat-like structures comprising glass fiber, carbon fiber, blends of polyester fibers or nylon fibers with other high temperature resistant fibers, felts of similar fibers, fragmented fibers and the like and combinations thereof. the same. A preferred glass fiber containing carrier material is one manufactured by Owens Corning of Toledo, Ohio, under the product name C-Veil, product code number GC 70E, which consists of a thin mat of cut glass fibers C , disorderly oriented, which are joined together by a dispersion of binder. A preferred polyester fiber-containing material is one manufactured by Precision Fabrics Groups of Greensboro, North Carolina, under the product name Nexus, product code number 111-00005, which is formed from stretched and thermofixed 100 Dacron® polyester. and that it does not contain any fiberglass. Although the carrier component has been described and illustrated as consisting of a mat-like structure, applied by conventional winding technique, it will be understood that the carrier may alternatively be in the form of a spray-applied material containing staple fibers and resin. Applicable carriers by appropriate spraying include those that have the ability to be loaded with the amount described above of the resin component for spray application on the surface of the structural pipe wall to use conventional spray application techniques. The carrier component provides a fibrous reinforcement in the resin matrix of the fire resistant layer. The fibers provide mechanical strength for the resin which can be somewhat brittle. The thermal decomposition of the resin makes it fragile even though it is relatively resistant to impact before exposure. The effect is that the fire-resistant layer mostly erodes into fine particles instead of flaking into large flakes that would rapidly deplete the resin-rich protective layer and expose the underlying structural wall of the pipe to thermal degradation. Surprisingly, some thermoplastic resin fibers can be used although it would appear to be subject to significant degradation in a flame test. However, such fibers work best when mixed with fibers resistant to high temperatures. However, glass fibers are preferred in terms of their strength and resistance to temperature. The resin component 22 used to impregnate the carrier component to form the fire resistant layer 18 is selected from the same group of phenolic resins, siloxane modified phenolic resins, furan resins and mixtures thereof described above for the resin used to form the resin. the structural pipe wall. The resin component is applied to the carrier, when implemented as a mat-like structure, by the same technique described above for the application of the resin to the windings or coils reinforced with fi It is preferred that the resin component selected for the fire resistant layer be the same as that selected to form the wall of the underlying structural pipe to ensure chemical compatibility and thereby provide a good chemical bond between the interface structural pipe wall and the surfaces of the fire-resistant layer during curing. further, when using the same resin, a single curing cycle is used for the entire pipe. The first embodiment of fire resistant pipe can be constructed in such a way that it has one or more layers of the same type of fire resistant material or it can be constructed in such a way that it has one or more layers of different types of fire resistant material. It is desirable that the resin component of each different type of fire resistant material be compatible with the resin component from adjacent structural pipe or the surface of the fire resistant layer to promote good interlayer bonding. For example, the pipe or fire resistant pipe fitting may include, when moving out of the wall surface of the pipe, one or more layers of the C-Veil type material, one or more layers of the Nexus type material and one or more layers of C-Veil type material, each impregnated with the same resin component as that used to form the structural pipe wall. The use of different types of fire resistant layers may be desirable to reduce raw material costs, optimize temperature resistance, minimize weight or the like. In a first embodiment of fire resistant pipe, the fire resistant layer is formed from alternating layers of glass fiber C (C-Veil) and polyester material (Nexus) impregnated with a phenolic resin composition modified by siloxane. After the structural pipe wall has been formed, and the tough fiber layer has been applied, the resin components of the first fire resistant pipe form are simultaneously cured by exposing the pipe to a temperature in the range of approximately 60 to 88 ° C (140 to 190 * F) for a period of approximately 30 minutes. It is desirable that the resins used to form the structural pipe wall and the fire resistant pipe comprise sufficient catalyst to effect curing at a temperature of less than about 100 ° C (212 ° F). It will be understood that the pipe curing conditions may vary depending on the amount and / or type of catalyst used, the type of resin selected, the number of windings or coils reinforced with fiber, the number of fire resistant layers and the like. . The cured, fire resistant layer acts as a heat erosion coating, which forms a porous outer layer when exposed to high temperature or direct flame conditions. The porous outer layer does not erode from the pipe, but remains in contact to form a heat insulating layer that protects the underlying structural pipe wall from the potentially damaging effects of such high temperature or direct flame conditions. Referring now to FIGURE 4, a second embodiment of fire resistant pipe, constructed in accordance with the principles of this invention, includes a structural wall 24, constructed as described above for the first embodiment of fire resistant pipe and one or more layers of an energy absorbing material 26, disposed on the surface of the structural pipe wall. The energy absorbing material used to form the layer is preferably one capable of absorbing a high degree of heat from an outer surrounding layer and using such energy, for example, by an endothermic reaction, to effect a phase change, for example from solid gas, at a temperature lower than the degradation temperature of the structural wall. The gas formed from the layers produces a thermally insulating air space between the outer surrounding layer and the structural pipe wall. Suitable energy absorbing materials include polymeric materials, solid hydrate or hydrate materials and the like, which have the ability to undergo a transformation of the endothermic phase to vaporize or release a gas at a temperature lower than the degradation temperature of the gas. selected resin to form the underlying structural wall, that is, a temperature of less than about 300 ° C. Examples of preferred energy absorbing materials include polyethylene, hydrated calcium sulfate (gypsum), aluminum trihydroxide, and other hydroxy-containing or hydrated compounds capable of vaporizing or producing a gas constituent at a temperature of less than about 300 ° C. Polymeric materials, such as polyethylene and the like, filled with a powder component are also desirable, since the combination of gas and dust produced during vaporization produces a layer of gas and dust between the outer surrounding layer and the structural pipe wall. which has thermally improved insulating properties. When polyethylene is used as the energy-absorbing material to form a second embodiment of fire-resistant pipe, it can be wound in the form of a sheet or sheet around the structural pipe wall 24 a plurality of times to form a desired number of layers or layers. layer thickness. When using polyethylene in the form of a 0.15 mm thick sheet, it is desirable that they be used in the range of 4 to 20 layers, thereby providing a wall thickness of the total energy absorbing material in the range of about 0.6. to 3 millimeters. The polyethylene sheet is applied by the same winding technique described above for the structural pipe wall and the fire resistant layer of the first fire resistant pipe method. It is not necessary for the polyethylene layer to be applied at a specific winding angle, since it is proposed to be sacrificial and does not contribute to the tangential or longitudinal resistance of the pipe. Where the energy absorbing material is different from polyethylene, it can be applied in the form of sheet or sheet, in the form of spray or spray or in the form of halves of solid sheets configured to fit over part of the structural pipe wall. The fiber reinforced resin layers 28 are wound around an outer surface of the layer 26 of energy absorbing material. The fiber reinforced resin can be the same as that selected to form the structural pipe wall 24, or it can be different. In a second preferred embodiment of fire resistant pipe, the fiber reinforced resin is the same and is applied in the same manner as that selected to form the structural pipe wall. The number of layers of the fiber reinforced resin that is applied depends on the particular pipe application and the degree of heat resistance or the desired flame. The second preferred embodiments of the fire resistant pipe can include in the range of 2 to 20 layers of the fiber reinforced resin 28. Alternatively, a second fire resistant embodiment may comprise a variety of fiber reinforced resin layers and layers of repeated energy absorbing material. For example, a fire resistant pipe may include first layers of energy absorbing material, disposed on the structural pipe wall, the first fiber reinforced resin layers, arranged on an outer surface of the first layers of energy absorbing material, second energy absorbing layers disposed on a surface of the first fiber reinforced resin layers and second fiber reinforced resin layers disposed on an outer surface of the second layers of energy absorbing material. In such an embodiment, the energy absorbing materials, selected to form the first and second layers of energy absorbing material, may be the same or may be different, and may be selected in such a way that an energy absorbing material, having an Relatively higher vaporization temperature at a temperature lower than the degradation temperature of the fiber reinforced resin layers is used to form the outermost energy absorbing material layer. In such modality, the number of each layer of energy absorbing material may be the same or less than that described above for a modality having a single layer of energy absorbing material. With reference to FIGURE 5, a second alternative embodiment of fire resistant pipe, may include two different types of layers of energy absorbing material positioned adjacent to each other to provide a desired degree of energy absorption and thermal insulation. For example, a variety of first layers 30 of energy absorbing material, of a first type of energy absorbing material, are disposed on a surface of the structural pipe wall 32. A variety of second layers 34 of energy absorbing material, of a second type of energy absorbing material, are disposed on a surface of the first layers of energy absorbing material. Preferably, the second type of energy absorbing material has a relatively higher vaporization temperature than the first type of energy absorbing material, such that the two layers act as a thermal insulator to prevent the harmful thermal energy reaches the wall of the structural pipe. A variety of layers 36 of fiber reinforced resins are wrapped around an outer surface of the second layer of energy absorbing material. The number of layers 36 of fiber reinforced resin that are used may be the same, or less than that used to form the wall of the structural pipe. Additionally, the type of fiber and resin reinforcing material used to form the fiber reinforced resin layer 36 may be the same as or different from that used to form the wall of the structural pipe. The number of layers of energy absorbent material used to form the first and second energy layers can be the same or different from that used to form the single layer mode of energy absorbing material above. If desired, the second alternative embodiment of fire resistant pipe can be formed in such a way that it has more than one set of layers of energy absorbing material to provide a desired degree of heat and / or flame protection to the fire wall. the structural pipe. For example, the fire resistant pipe can be formed in such a way that it has a structural pipe wall, a first set of layers of the different energy absorbing material, a first layer of fiber reinforced resin, a second set of layers of material different energy absorber and a second layer of fiber reinforced resin. In such an embodiment, the types of energy absorbing materials that are used to form the first set of layers of energy absorbing material may be the same or different from that used to form the second set of layers of energy absorbing material. Alternatively, the first embodiment of fire resistant pipe can be constructed in such a way that it has one or more layers of an energy absorbing material described above, interposed between the wall of the structural pipe and the fire resistant layers to provide an improved grade of heat or flame protection to the wall of structural pipes. In such an embodiment, the resin component used to form the heat shield may be different than the resin component used to form the wall of the structural pipe. Additionally, if desired, the first embodiment of the fire resistant pipe can be constructed by having one or more layers of energy absorption between the different types of fire resistant layers, therefore, it is understood within the scope of this invention, a or more layers of absorption material, can be placed between the wall of the structural pipe and fire resistant layers and / or between different types of fire resistant layers as desired, depending on the particular application, to provide an optimum degree of protection to heat and flame to the wall of the structural pipe.

With reference to FIG. 6, a third embodiment of fire resistant pipe 38 is shown, constructed in accordance with the principles of this invention, including a release layer 40 disposed on an exterior surface of the wall 42 of the structural pipe and a layer 44 of fiber reinforced resin disposed on a surface of the release layer 40. In such a third embodiment, the wall of the structural pipe is formed in the same manner as described above for the first and second embodiments of the fire resistant pipe. In an exemplary embodiment, the third embodiment of fire-resistant pipe comprises a liner or jacket 46 of release layers 40 and resin layers 44 reinforced with alternating fiber, arranged around the external surface of the wall 42 of the structural pipe. The materials useful for the formation of the release layer 40 are preferably those which do not bind or bond with the resin used to form the wall of the adjacent structural pipe or with the resin wall used to form the resin layer reinforced with fiber. It is desirable that the release layer does not form a bond or bond with a wall of the adjacent structural pipe or the fiber reinforced resin wall to allow the release layer to act as a separation layer between the resin containing layers. This action of separation of the release layer serves to improve the impact of the fire resistant pipe by attenuating the travel of any shock wave through the pipe caused by the contact made with the external surface. By operating in this manner, the release layers act to potentially eliminate or prevent harmful impact shock waves traveling completely through the pipe to the structural wall, to prevent possible fractures or ruptures. Suitable materials for the formation of the release layers include films formed from polymeric materials that are chemically incompatible with the particular resin used to form the structural pipe wall and the fiber reinforced resin layers. Examples of such polymeric materials include polyolefins such as polypropylene, polyethylene and the like. A particularly preferred release layer is formed from polypropylene. It is also desirable that the material selected to form the release has the ability to absorb the applied thermal energy from the surface of the pipe and preferably be a material capable of absorbing a high degree of heat from an outer surrounding layer and use such energy , for example via an endothermic reaction, to effect a phase change, for example, from solid to gas, at a temperature lower than the degradation temperature of the structural wall. The gas formed from the release layer (s) acts to form a thermally insulating air gap between the adjacent fiber reinforced resin layer and the fiber reinforcing layers and the structural pipe wall. The air gap allows each of the resin layers reinforced with independent fibers to act as a shield to the radiation to increase the thermal resistance of the pipe by requiring the radiant heat to be progressively transferred through each layer of resin reinforced with fiber before reaching the wall of the structural pipe. The multi-radiation shielding function of the air spaces avoids the potentially high wall stresses in the pipe caused by the high thermal gradient on the outside of the pipe during a fire. The materials indicated above for the formation of the release layers are also heat absorbers and therefore useful in the formation of a release layer that is separation and energy absorbing. Other suitable release layer materials include solid hydrated or hydrate materials and the like, as discussed above for the formation of layers of energy absorbing materials, which have the ability to undergo an energy phase transformation to vaporize or release a gas at a temperature lower than the degradation temperature of the selected resin to form the underlying structural wall, that is, at a temperature less than about 300 CC. Examples of preferred energy absorbing materials include polypropylene, polyethylene, hydrated calcium sulfate (gypsum), aluminum trihydroxide, and other hydrated or hydroxide-containing compounds having the ability to vaporize or produce a gas constituent at a temperature of less than about 300 ° C. Polymeric materials, such as polypropylene, polyethylene and the like, filled with a powder component, are also desirable, since the combination of gas and dust produced during vaporization results in a layer of gas and dust between the outer surrounding layer and the structural pipe wall that has improved thermal insulation properties. The number of release layers and alternating fiber reinforced resin, used to form the lining or casing that surrounds the wall of the structural pipe, depends on the application of pipe for particular fire extinguishing and the degree of heat resistance or the desired flame. In an exemplary embodiment, for a pipe having a structural pipe wall diameter of approximately 51 millimeters (two inches), 33 A minimum liner or jacket thickness is approximately 3 millimeters (1/8 inch) comprising four release layers and alternating fiber reinforced resin, as shown in FIG. 6. In the formation of pipe fittings, such as elbows, Y-connections, T-connections and the like, a minimum liner thickness of about 3 millimeters (1/8 inch) is desirable. It will be understood that the exact number of release layers and fiber reinforced resin layers that are used to make up the liner of any designated thickness depends on the thickness of the material of the release layer and the fiber reinforcing material. When the liner or jacket release layer is made of polypropylene tape, it is applied to the structural pipe wall by the same winding technique described above for the wall of the structural pipe. When the release layer is different from polypropylene or other tape-like material, it can be applied in the form of a sheet or sheet, in the form of spray or spray or in the form of solid half sheets configured to fit over part of the wall of the structural pipe. Each layer of fiber reinforced resin is wound around an outer surface of a respective release layer. The material used to form the fiber reinforced resin layers may be the same as that selected to form the wall of the structural pipe or may be different. In a preferred embodiment, the fiber reinforced resin layers are formed from the same materials as the wall of the structural pipe and are applied in the same manner as that selected to orient the wall of the structural pipe. Similarly to the release layers, the number of the fiber-reinforced resin layers that are applied depends on the application of the particular fire-resistant pipe and the degree of heat resistance or the desired flame. The liner or jacket surrounding the wall of the structural pipe may comprise repeated release layers which are each formed from the same or different materials. For example, a fire resistant pipe may have a jacket or liner comprising release layers that are formed from progressively more energy absorbing materials as they move from the wall of the structural pipe to the outermost fiber reinforced resin layer , to provide by this a stepped degree of heat protection, where the highest protection is located where it is most needed, that is, closest to the external surface of the pipe. In such an embodiment, it is desirable that the selected material to form an external release layer, which has a relatively higher temperature vaporization than the remaining release layers, which would be below the degradation temperature of the fiber resin layers. reinforced adhyacentes. Additionally, the liner or jacket surrounding the wall of the structural tubing may comprise an outer reinforced fiber resin layer, having at least one carbon fiber as the filament component that serves to hold the liner or liner together during exposure to fire or fire temperatures that exceed the melting temperature of the glass filament. Although the construction of the fire resistant pipe embodiments have been specifically described and illustrated above, it will be understood that this invention also includes the construction of fire resistant pipe fittings. With reference to FIGS. 7A to 7C, fire-resistant pipe fittings, such as elbows 48, tees 50, Y-fittings 52 and the like are also prepared in accordance with the principles of this invention. The fire-resistant pipe and fittings of the invention can be used alone or in combination to form a pipe assembly or assembly suitable for use in fire extinguishing pipe applications., such as sets or assemblies of pipes for the extinguishing of fires that are used in marine platforms and similar. The pipes and pipe fittings used in such applications must have the capacity to operate under conditions of high temperature and density to the narrow flame without suffering significant reductions in tangential strength and longitudinal strength. The fire-resistant pipe and pipe fittings constructed in accordance with the principles of this invention were subjected to a high, rigorous temperature to qualify for use in fire extinguishing pipe applications. The test involved the placement of the pipe and / or pipe fittings approximately 10 centimeters (4 inches) from a flame at a temperature of 1,000 ° C, with the pipe dry, that is, it did not contain water in it, for a approximately five minutes. After five minutes, the pipe and / or pipe fittings are filled with water at a nominal pressure of 21 Kg / cm2 (300 psig) for approximately fifteen minutes while still undergoing the flame. To qualify for use in a fire extinguishing pipe application, pipe and / or pipe fittings must remain structurally sound when subjected to nominal pressure and show no signs of leakage in excess of 10% of nominal flow of the pipe. In order to determine the capacity to withstand the total pressure of pipes subjected to such extreme temperature conditions and to better understand the mechanism regarding heat-related faults, the pressure was increased on the pipe samples and pipe fittings They showed no signs of pipe leaks or structural damage beyond the nominal pressure until the pipeline failures. The following examples illustrate different embodiments of fire resistant pipe constructed with the principles of the present invention and / or the test results for each pipeline mode. In each of the following examples, the pipe has an inner diameter of approximately 51 mm. (2 inches) .

Example No. 1 - Fiber Reinforced Pipe A fiber reinforced pipe was constructed by using twelve layers of a fiber reinforced resin, forming a wall thickness of approximately 0.37 centimeters (cm). The wall of the structural pipe was formed by using windings or windings of fiberglass reinforcing fiber together with a phenolic resin modified by siloxane, comprising approximately 83% by weight of BP-J2027L (phenolic resole resin), 9% by weight. weight of SY-231 (methoxy-functional silicone intermediate), 7% by weight of Phencar 381 (latent acid catalyst) 0.6% by weight of Melacure Cotlin Tl (organotin catalyst) and 0.4% by weight of ethyl aminoethanol (catalyst of amine). This pipeline did not include a fire resistant layer. The pipeline was subjected to the test identified above and showed signs of water leakage at a rate of approximately 0.008 cubic meters per hour (m3 / h) at line pressure and had water leakage at a speed of approximately 0.21 m / h when pressurized at a pressure between 14 to 21 kgf / cm2. The pipe failed at a pressure of approximately 35 Kgf / cm2. The failure mode of the pipe consisted of a break in the fiber reinforcing component of the wall of the structural pipe.

Example No.2 - First mode of fire resistant pipe A fiber reinforced pipe was constructed in a manner similar to that described by Example No. 1, except that the wall thickness of the structural pipe was approximately 0.40 cm. Additionally, the pipe was constructed in such a way that it has two fire resistant layers, arranged around the external surface of the wall of the structural pipe. The fire resistant layers were formed from C-Veil impregnated with the same resin combination that was used to form the wall of the structural pipe. The fire resistant layers had a total wall thickness of approximately 0.21 cm. The pipeline was subjected to the test identified above and showed slight signs of water leakage at a rate of approximately 0.0045 m / h in the line pressure and had water leaks at a rate of approximately 0.0025 m / h when pressurized to a pressure between 14 to 21 Kgf / cm2. The pipe failed at a pressure of approximately 84 Kgf / cm2. The failure mode of the pipe consisted of a break in the fiber reinforcing component of the structural pipe wall. This pipe wall did not pass the test but exhibited improved resistance to the effects of the flame test when compared to the fiber reinforced pipe of Example No. 1.

Example No. 3 - First Fire Resistant Pipe Modality A fiber reinforced pipe was constructed in a manner similar to that described by Example No. 1, except that the wall thickness of the structural pipe was approximately 0.38 cm. Additionally, the pipe was constructed in such a way that it has four fire resistant layers arranged around the outer surface of the structural pipe wall. The fire resistant layers were formed from the same materials as that described by Example No. 2. The fire resistant layers had a total wall thickness of about 0.33 cm. The pipeline was subjected to the test identified above and showed no signs of water leakage at line pressure, showed slight signs of water leakage at a rate of approximately 0.016 m3 / h when pressurized at a pressure of approximately 31.6 Kgf / cm2. The pipe failed at a pressure of approximately 126 Kgf / cm2. The failure mode of the pipeline was cracking in the resin matrix in the wall of the structural pipe and resulting leaks. There was no structural failure of the fiber reinforcement. This example illustrates the improved strength provided by two additional fire resistant layers when compared to Example No. 2.

Example No. 4 - First Fire Resistant Pipe Modality. A fiber reinforced pipe was constructed in a manner similar to that described by Example No. 1, except that the wall thickness of the structural pipe was approximately 0.36 cm. Additionally, the pipe was constructed in such a way that it has eight fire resistant layers arranged around the outer surface of the wall of the structural surface. The fire resistant layers were formed from a Nexus material impregnated in the same resin as that described by Examples No. 2 and 3. The fire resistant layers had a total wall thickness of about 0.2 cm. The pipeline was subjected to the test identified above and showed slight signs of water leakage at a rate of approximately 0.001 Kg / cm2 (0.02 psig), showed signs of water leakage at a rate of approximately 0.04 ra3 / h when pressurized to a pressure between 14 to 21 Kgf / cm2. The pipe fails at a pressure of approximately 80 Kgf / cm2. The failure mode of the pipe was a break in the fiber component of the wall of the structural pipe. This example illustrates the relatively improved heat resistance by the C-Veil fire resistant layers of Example No. 2, and demonstrates the improved heat resistance provided by the Nexus fire resistant layers when compared to the pipe of Example No. 1 .

Example No. 5 - First Fire Resistant Pipe Modality A fiber reinforced pipe was constructed in such a way that it has six layers of fiber reinforced resin of the same fiber and resin components described above by Example No. 1, and that It has a wall thickness of approximately 0.18 cm. Additionally, the pipe was constructed in such a way that it has four fire resistant layers arranged around the outer surface of the structural pipe wall. Fire-resistant layers were formed from the same materials as those described by Examples Nos. 2 and 3. The fire-resistant layers had a total wall thickness of about 0.33 cm. The pipeline was subjected to the test identified above and leaked water at a rate of approximately 0.032 m3 / h at line pressure, and leaked water at a rate of approximately 0.31 m3 / h when pressurized to a pressure of between 14 to 21 Kgf / cm2. The pipe failed at a pressure of approximately 35 Kgf / cm2. The failure mode of the pipe was a break in the fiber component of the wall of the structural pipe. When compared to Example No. 3, this example illustrates the improved heat resistance that is obtained when the wall of the structural pipe is formed from twelve instead of six layers of fiber reinforced resin.

Example No.6 - First Fire Resistant Pipe Modality A fiber reinforced pipe was constructed in such a way that it has twelve layers of a fiber reinforced resin of the same fiber and resin components described above in Example No. 1. Wall of the structural pipe has a wall thickness of approximately 0.38 cm. The pipe was constructed in such a way that it has two fire resistant layers arranged around the outer surface of the wall of the structural pipe. The fire resistant layers were formed from C-Veil impregnated with the same resin that was used to form the wall of the structural pipe. The fire resistant layers had a total wall thickness of approximately 0.18 cm. The pipe was subjected to the test identified above and showed no signs of water leakage at line pressure and showed slight signs of water leakage at a rate of approximately 0.007 m3 / h when pressurized at a pressure of between 14 to 21 Kgf / cm. The pipe failed at a pressure of approximately 112 Kgf / cm. The failure mode of the pipe consisted of cracking in the resin matrix of the wall of the structural pipe. There was no structural failure of the fiber reinforcement. This pipe construction showed an improved resistance to the effects of the flame test when compared to the pipe of Example No. 2.

Example No. 7 - First Fire Resistant Pipe Modality. A fiber reinforced pipe was constructed in the same manner as that described by Example No. 6, which has twelve layers that form the wall of the structural pipe. The pipe was constructed in such a way that it has four fire resistant layers arranged around the outer surface of the wall of the structural pipe. The fire resistant layers were formed of the same materials described by Example No. 6, to have a total wall thickness of about 0.33 cm. The pipe was subjected to the test identified above and showed no signs of water leakage at line pressure and showed slight signs of water leakage at a rate of approximately 0.009 m3 / h at a pressure of approximately 63 Kgf / cm2. The pipeline failed at a pressure of approximately 133 Kgf / cm2. The failure mode of the pipe consisted of a break in the fiber component of the wall of the structural pipe. This construction of the pipe showed an improved resistance to the effects of the flame test when compared to the pipe of Example No. 3.

Example No. 8 - First Fire-Resistant Pipe Modality A fiber-reinforced pipe constructed in the same manner as that described for Examples Nos. 6 and 7, having twelve layers that form the wall of the structural pipe having a thickness wall of approximately 0.38 cm. The pipe was constructed in such a way that it has six fire-resistant layers arranged around the outer surface of the wall of the structural pipe. The fire resistant layers were formed from the same materials described for Examples Nos. 6 and 7, which have a total wall thickness of about 0.45 cm. The pipe was subjected to the test identified above and showed no signs of water leakage at the line pressure and showed slight signs of water leakage at a rate of approximately 0.004 m3 / h at a pressure of approximately 60 Kgf / cm. " The pipeline failed at a pressure of approximately 161 Kgf / cm2 It was discovered that the failure mode of the pipeline consisted of cracking of the resin matrix of the structural pipe wall No structural failure of the fiber reinforcement occurred. This example illustrates the improved heat resistance provided by six fire resistant layers when compared to the fire resistant pipe of Example No. 7, which has four fire resistant layers.

Example No. 9 - First Fire Resistant Pipe Modality A fiber reinforced pipe was constructed in the same manner as that described for Examples Nos. 6, 7 and 8, which has twelve layers that form the wall of the structural pipe and which has a wall thickness of approximately 0.37 cm. The pipe was constructed in such a way that it has eight fire resistant layers arranged around the outer surface of the wall of the structural pipe. The fire-resistant layers were formed from the same materials described for Examples Nos. 6, 7 and 8, which have a total wall thickness of approximately Q.55 cm. The pipe was subjected to the test identified above and showed no signs of water leakage at line pressure and showed no signs of water leakage at a pressure of approximately 204 Kgf / cm. The pipe failed at a pressure of approximately 250 Kgf / cm. The failure mode of the pipe was cracking of the resin matrix of the wall of the structural pipe. Again, there were no structural failures of the fiber reinforcement. This example illustrates the improved heat resistance provided by eight fire resistant layers when compared to the fire resistant pipe of Example No. 8 having six fire resistant layers.

Example No. 10 - First Fire Resistant Pipe Modality A fiber reinforced pipe was constructed in the same manner as that described by Examples Nos. 6-9, which has twelve layers that form the wall of the structural pipe and which has a wall thickness of approximately 0.37 cm. The pipe was constructed in such a way that it has a total of six fire resistant layers arranged around the outer surface of the wall of the structural pipe. The fire-resistant layers comprise, when advancing outward from the wall of the structural pipe, two layers of C-Veil, followed by two layers of Nexus, followed by two layers of C-Veil. The resin component for each of the fire resistant layers is the same as that used to form the wall of the structural pipe. The fire resistant layers have a total wall thickness of approximately 0.35 cm. The pipeline was subjected to the test identified above and showed no signs of water leakage at line pressure and showed slight signs of water leakage at a rate of approximately 0.025 m3 / h at a pressure of approximately 77 Kgf / cm. The pipe failed at a pressure of approximately 147 Kgf / cm2. The failure mode of the pipe was cracking of the resin matrix of the wall of the structural pipe. This example illustrates the improved heat resistance provided by the use of a combination of different fire resistant layers when compared to the fire resistant pipe of the pipe of Example No. 8, which has six fire resistant layers of the same type.

Example No. 11 - First Fire Resistant Pipe Modality. A fiber reinforced pipe was constructed in the same manner as that described for Examples 6-10, which has twelve layers that form the wall of the structural pipe and which has a wall thickness of about 0.41 cm. The pipe was constructed in such a way that it has a total of eight fire resistant layers arranged around the outer surface of the wall of the structural pipe. All fire resistant layers were formed from the inverse Nexus material in the same resin component as that used to form the structural pipe and had a total wall thickness of approximately 0.22 cm. The pipeline was subjected to the test identified above and showed slight signs of water leakage at the line pressure and showed slight signs of water leakage at a rate of approximately 0.016 m3 / h at a pressure of between 14 to 21 Kgf / cm2. The pipe failed at a pressure of approximately 91 Kgf / cm. The failure mode of the pipe consisted of a break in the fiber component of the structural pipe wall.

Example No. 12 - Second Fire Resistant Pipe Modality. A structural pipe reinforced with fiber was constructed by using the same fiber and resin components as those used in the previous examples. The wall of the structural pipe was formed from twelve layers of the fiber reinforced resin and had a wall thickness of approximately 0.4 cm. The pipe was constructed in such a way that it has eight layers of polyethylene arranged around the outer surface of the wall of the structural pipe. The polyethylene layers had a total wall thickness of approximately 1.2 millimeter. A total of four outer fiber reinforced resin layers were formed from the same materials as the wall of the structural pipe and were arranged around the outer surface of the polyethylene layer. The outer fiber reinforced resin layers had a total wall thickness of approximately 0.13 cm. The pipe was subjected to the test identified above and showed no signs of water leakage at line pressure and no sign of leaks at a pressure that is twice the nominal pressure (21 Kgf / cm2). The pipeline showed first signs of leakage at a pressure of approximately 108 Kgf / cm2, leaking at a speed of approximately 31 m3 / h. The pipe failed at a pressure of approximately 715 Kgf / cm2. The failure mode of the pipe consisted of a break in the fiber component of the structural pipe wall. This example illustrates the improved heat resistance, provided by using the layer of polyethylene energy absorbing material instead of the fire resistant layer.

Example No. 13 - Fiber Reinforced Pipe A fiber reinforced structural pipe wall, 51 millimeters (2 inches) in diameter, was constructed in such a way that it comprises approximately 12 layers of a fiber reinforced resin prepared as summarized in Example No. 1 above. The impact resistance of the wall of the structural pipe was tested by dropping a 60 mm steel ball, which weighs 0. 9 Kg. From progressive heights to make impact with the pipe perpendicularly. After the impacts were consummated, the pipe was pressurized with air at a pressure of 1.8 Kgf / cm2 (25 psig) and kept under water for the detection of visible air leaks.

Under these test conditions, the unlined wall of the structural pipe exhibited a 75% chance of failure, that is three of the four impacts had air leaks, after four falls of a fall height of the ball of approximately 25 centimeters (10 inches) . The same wall of unlined structural tubing exhibited a full or 100% failure probability, that is, each of the four impacts caused air leakage, after four falls when the height of fall of the ball was further increased to 30 centimeters (12 inches).

Example No. 14 - Third Fire Resistant Pipe Modality. A 51 mm structural pipe wall (2 inches) in diameter was constructed according to the Example No. 13 above and a liner or jacket was laid around the wall of the structural pipe to form a fire resistant pipe. The liner or jacket was formed from approximately four repeated layers of polypropylene tape and fiber reinforced resin. The fiber reinforced resin layers were formed from the same materials used to form the wall of the structural pipe.

The impact resistance of the fire-resistant pipe thus formed was tested according to the method described above. The fire resistant pipe showed no sign of air leakage, this is 0% chance of failure, until a ball drop height of approximately 100 centimeters (35 inches) was reached. At a height of 100 centimeters (35 inches), only one impact of eight showed signs of leakage. At heights of 102 centimeters (40 inches) and 137 centimeters (54 inches), only three out of eight impacts, and therefore a 50% probability of failure of lined or jacketed pipe, was observed to be approximately 114 centimeters ( 45 inches), compared to 25 centimeters (10 inches) or 28 centimeters (11 inches) with the wall of the structural pipe unlined. Thus, based on such test data, the lined pipe exhibited a 400% improvement in impact resistance when compared to an unlined pipe. Although specific embodiments and examples of fire-resistant pipe and pipe fittings have been described and illustrated, many modifications and variations will be apparent to those skilled in the art. It will be understood, therefore, that, within the scope of the appended claims, pipes and fittings of fire-resistant pipes of this invention may be constructed differently than as specifically described herein. It is noted that the best method known to the applicant to carry out the said invention is that which is clear from the present invention. Having described the invention as above, the content of the following is claimed as property.

Claims (21)

1. A fire resistant pipe characterized in that it comprises: a structural wall comprising layers of helically wound reinforcing fiber, bonded with a resin selected from the group consisting of phenolic resins, siloxane modified phenolic resins, furan resins and mixtures thereof, - and at least one fire resistant layer superimposed on the structural wall, wherein the fire resistant layer includes a fibrous carrier component impregnated with a resin selected from the group consisting of phenolic resins, siloxane modified phenolic resins, furan resins and mixtures thereof and wherein the resin selected to form the fire resistant layer is compatible with the resin selected to form the structural wall.

2. The fire resistant pipe according to claim 1, characterized in that the resins selected to form the structural wall and the fire resistant layer are the same.

3. The fire resistant pipe according to claim 1, characterized in that the fire resistant layer comprises at least 75% resin.

4. The fire resistant pipe according to claim 1, characterized in that the resin used to form the structural wall and the fire resistant layer are both phenolic resins modified by siloxane and wherein the fire resistant layer comprises at least three times the resin content as the helically wound reinforcing fiber that forms the structural wall.

5. The fire resistant pipe according to claim 1, characterized in that it comprises a variety of layers of energy absorbing material interposed between the structural wall and the fire resistant layer.

6. A fire resistant pipe characterized in that it comprises: a structural wall comprising layers of coiled reinforcing fiber, helically joined with a resin selected from the group consisting of phenolic resins, siloxane modified phenolic resins, furan resins and mixtures thereof, - a variety of layers of energy absorbing material superimposed on the structural wall, wherein the energy absorbing material is selected from the group consisting of materials capable of absorbing energy by phase transformation at a temperature lower than the degradation temperature of the wall structural; and a variety of fiber reinforced resin layers disposed on an outer surface of the layers of energy absorbing material, wherein the resin component is selected from the same group of resins used to form the structural wall.

7. The fire resistant pipe according to claim 6, characterized in that the resin is a siloxane modified phenolic resin, prepared by the combination of: a higher proportion of phenolic resole resin or phenolic novolac resin; a smaller proportion of silicone intermediate; and a sufficient amount of catalyst to facilitate processing and effect curing.

8. A fire resistant pipe characterized in that it comprises: a structural wall comprising layers of coiled reinforcing fiber, helically joined with a resin selected from the group consisting of phenolic resins, siloxane modified phenolic resins, furan resins and mixtures thereof, - and a liner or casing disposed around the structural wall, the liner comprises: at least one release layer of material that is chemically incompatible with the resin used to form the structural wall; and at least one layer of fiber reinforced resin disposed around a surface of the release layer.

9. The fire resistant pipe according to claim 8, characterized in that the liner or jacket comprises a variety of release layers and resin reinforced with alternating fiber.

10. The fire resistant pipe according to claim 8, characterized in that the fiber reinforced resin layer comprises wound reinforcing fibers, helically joined with a resin selected from the group consisting of phenolic resins, siloxane modified phenolic resins, furan resins and mixtures thereof.

11. The fire resistant pipe according to claim 8, characterized in that the release layer is formed from a polyolefin material.

12. The fire resistant pipe according to claim 8, characterized in that the resin used to form the structural wall and the fire resistant layer are both phenolic resins modified by siloxane.

13. A fire-resistant pipe characterized in that it comprises: a structural wall comprising layers of helically wound reinforcing fiber bonded with a resin selected from the group consisting of phenolic resins, phenolic resins modified by siloxane, furan resins and mixtures thereof, - a lining or jacketing arranged around the structural wall, wherein the liner comprises a variety of release layers and layers of resin reinforced with alternating fiber, wherein a layer of fiber-reinforced resin forms a pipe, an outer pipe layer and in wherein the release layers are formed from a material that is unable to form a bond or bond with the resin component of the structural wall and the fiber reinforced layers.

14. The fire resistant pipe according to claim 13, characterized in that the fiber reinforced resin layer comprises layers of rolled reinforcing fiber, helically joined with a resin selected from the group consisting of phenolic resins, phenolic resins modified with siloxane, resins of furan and mixtures thereof.

15. A fire resistant pipe characterized in that it comprises: a structural wall comprising layers of coiled reinforcing fiber, helically joined with a resin selected from the group consisting of phenolic resins, siloxane modified phenolic resins, furan resins and mixtures thereof, - and a liner or jacket positioned around the structural wall, the liner comprises at least one release layer of material that is chemically incompatible with the resin used to form the structural wall; and at least one layer of fiber reinforced resin disposed around a surface of the release layer, wherein the fiber reinforced resin layer comprises a helically wound reinforcing fiber, bonded with a resin selected from the group consisting of phenolic resins. , phenolic resins modified with siloxane, furan resins and mixtures thereof and wherein the release layer is formed from a material that is chemically incompatible with the resin used to form the fiber reinforced resin layer.

16. A fire resistant pipe characterized in that it comprises: a structural wall comprising layers of coiled reinforcing fiber, helically joined with a resin selected from the group consisting of phenolic resins, siloxane modified phenolic resins, furan resins and mixtures thereof; and a liner or jacket positioned around the structural wall, wherein the liner or jacket comprises a variety of release layers and alternating fiber reinforced resin layers, wherein a release layer is disposed around an outer surface of the wall structural, wherein a layer of fiber-reinforced resin forms an outer pipe layer, wherein each layer of fiber-reinforced resin comprises a reinforcing fiber bonded to the same resin used to form the structural wall and wherein each release layer is formed from a material that is incompatible to form a bond or bond with the resin component of the structural wall and the fiber reinforced layers.

17. The pipe according to claim 16, characterized in that the material used to form the release layer is selected from the group consisting of materials capable of absorbing energy by phase transformation at a temperature lower than the degradation temperature of the structural wall.

18. A method for the formation of a fire-resistant pipe, characterized in that it comprises the steps of: helically winding a wetted or wetted reinforcing fiber with a resin selected from the group consisting of phenolic resins, siloxane modified phenolic resins, furan resins and mixtures of the same, for the formation of a structural pipe wall; and placing a fibrous carrier moistened with the same resin on the wall of the structural pipe, for the formation of a fire resistant layer; and curing the resin in the wall of the structural pipe and the fire resistant layer to form a joint between them.

19. A method for the formation of a fire-resistant pipe, characterized in that it comprises the steps of: helically winding a reinforcing fiber moistened with a first resin for the formation of a structural pipe wall, wherein the first resin is selected from the group consisting of of phenolic resins, siloxane modified phenolic resins, furan resins and mixtures thereof, and winding a fibrous carrier moistened or moistened with a second resin around the wall of the structural pipe to form a fire resistant layer, where the second resin is selected from the group consisting of phenolic resins, siloxane modified phenolic resins, furan resins and mixtures thereof, wherein the second resin is compatible with the first resin and wherein the carrier comprises at least 75% by weight of the second resin.

20. A method for the formation of a fire-resistant pipe, characterized in that it comprises the steps of: helically winding a reinforcing fiber moistened with a resin selected from the group consisting of phenolic resins, siloxane modified phenolic resins, furan resins and mixtures of the same, to form a structural pipe wall; placing a variety of energy absorbing layers on the wall of the structural pipe, wherein the energy absorbing layers are formed from materials selected from the group consisting of materials capable of absorbing energy by phase transformation at a lower temperature than the degradation temperature of the wall of the structural pipe; and helically winding a variety of layers of fiber reinforced resin onto the energy absorbing layers, wherein the resin component used to form the fiber reinforcing layers is selected from the same group of resins used to form the wall of the structural pipe.

21. A method for the formation of a fire-resistant pipe, characterized in that it comprises the steps of: helically winding a reinforcing fiber moistened with a resin selected from the group consisting of phenolic resins, siloxane modified phenolic resins, furan resins and mixtures of the same, to form a structural pipe wall; the formation of a lining or casing around an exterior surface of the wall of the structural pipe, by placing a release material around the outer surface of the wall of the structural pipe and placing a resin reinforced with fiber on the material of release, wherein the release material is formed from a material that is unable to form a bond or bond with the resins used to form the wall of the structural pipe and the fiber-reinforced resin layer, - and curing of the resin in the wall of the structural pipe and the resin layer reinforced with fiber. SUMMARY OF THE INVENTION Fire-resistant tubing and pipe fittings are described which include a wall (2) of structural tubing from a helically wound reinforcing fiber (14), which are bonded together (16) thermoformable polymeric. A first embodiment of pipe includes a fire-resistant layer (18) in the form of a resin-rich carrier that is applied to the wall surface (2) of the structural pipe. The resin used to impregnate the carrier is selected from the same group of resins used to form the wall of the structural pipe. A second embodiment of pipe includes a variety of layers (26) of energy absorbing material, arranged around the wall of the structural pipe and formed from a material capable of absorbing the thermal energy of a surrounding outer layer to produce a thermally insulating gas between them. A variety of fiber reinforced resin layers are arranged around the wall of the structural tubing that is formed from a shock absorbing configuration of release layers and resin layers reinforced with alternating fiber. The fire resistant pipe embodiments of this invention are configured to protect the structural wall from heat induced faults caused by exposure of the outermost pipe wall to a flame having a temperature of 1000 ° C for at least 5 minutes in an anhydrous condition.