Pipes and fittings from GRP - economical overall investment

Fiberpipe pipe systems consist of various base materials which ideally complement each other. These base materials are various types of glass and reaction resins.

When these base materials are joined together, a "division of work" exists. The quantity and the type of glass determine the mechanical properties such as tensile strength, compressive resistance and elastic modulus. The choice of resin determines the chemical resistance and the thermal behaviour of the compound result. As it is not as easy to cut or apply an additional connecting piece for any other material, Fiberpipe pipe systems also set new standards in the area of assembly costs. The simple and cost effective assembly of Fiberpipe pipe systems ensures that you will be interested in not only the pipe prices but also the overall investment.

Manufacturing process

The manufacturing process can be seen as another important parameter. There are essentially two different ways to manufacture pipes from glass and resin.

Centrifugal casting process

The centrifugally cast pipe represents the optimum in terms of chemical resistance and abrasion resistance.

Centrifugal pipes are manufactured in a process in which blanks corresponding to the circumference and the length of the mould are manufactured from various types of glassfibre and glass mat. These blanks are placed on a mould; this mould is rotated (centrifugal casting). Resin is subsequently injected from inside.

This process offers the following benefits:

  • The highest thermal resistance because of the optimum impregnation of the glassfibre with resin.
  • The highest chemical resistance as there is only resistant resin in the inner chemical protective layer.
  • The lowest flow losses as there is a "completely" smooth internal and outer wall.

Winding process

As the production of centrifugally cast pipes over a nominal width of DN 350 is no longer economically interesting, the so-called winding process has been perfected as a further production method. Filament-wound pipes are manufactured in a process in which endless long filaments (roving) are fed to a mould via a wide comb. Here either the mould or the filaments are impregnated with resin and superimposed on the mould (winding). This technology can be improved by varying the winding angle and adjusting this to the requirements (e.g. in the case of internal pressure a winding angle of 54º to the tubular axle). In the case of this production method, we also strive to achieve a highest percentage of resin in the inside of the pipe. For this purpose, a non-woven fabric or mat is applied as a bearing for the resin at the start of production of the pipe.

  • The lowest wall thickness as optimum arrangement of the fibres for loading.
  • High chemical resistance as the strength of the internal chemical protective layer is variable.
  • Economic alternative to other materials such as rubberised steel.

Wall mounting of Fiberpipe filament-wound pipes made from epoxy resin or vinyl ester resin.

The right resin for any requirement

We come to the first important decision for the optimum GRP system with the selection of the suitable resin and hardener. Our criteria are the medium – what resistance is needed? –, the working temperature and local operating parameters. You can find precise details concerning the resistance of the various resin types from our chemical resistance list.

Here is a summary of the resin types which we use the most:

Isophthalic acid – low chemical resistance

GRP pipes and containers made from isophthalic resin are ideal for cooling water and similar applications. They are particularly economic if there are low demands for chemical resistance. The temperature resistance is up to 80º C.

The principle: The integration of resin and hardener occurs in a monomer solution – as long as monomers are available. The changeover into the spatially cross-linked form is chemically initiated by catalysts (e.g. peroxide).

Vinyl ester resins – chemical resistant standard

Bisphenol-A vinyl ester resins such as Derakane 411 are the standard resins in the area of pipeline construction and container manufacturing. Here we combine high resistance to many media (acids, brines, bleaching agents and solvents) with good processability. We at Fiberpipe use vinyl ester resin pipes in temperatures of up to 95º C. If gases are to be conveyed, higher temperatures are also possible (please see our chemical resistance list).

The principle: Vinyl esters which are dissolved in styrene harden through copolymerisation with the solvent in a cross-linked way. These further linking results in oscillation resistant, hard and tough products.

Novolaks – high temperatures and chemical resistance

Novolak vinyl ester resins such as Derakane 470 are designed for maximum thermal and chemical resistance. They are particularly well-suited for use in contact with solvents, acids and oxidising substances – such as chlorine gas.

Through their good toughness at high temperatures of up to 170º C they have also proven excellently in exhaust gas applications.

The principle: Novolak vinyl ester, dissolved in styrene, also harden through copolymerisation with the solvent in a cross-linked way.

Epoxy resins – maximum resistance and resistance to high temperatures

Preparing our combination is very demanding, resin and hardener, for example, must be preheated at a particular temperature. We process bisphenol-A epichlorohydrin epoxy resin with so-called aromatic amine hardening.

It is precisely with this combination that we achieve the best resistance against a great number of acids, brines, solvents or oils and oil products. Through the high degree of cross-linking and the very dense molecule lattice, our epoxy resin pipes and containers can also be used at significantly higher temperatures including for liquid media.

Up to 130º C is possible (you can also find out more about this on the chemical resistance list.)

The principle: The reactants are embedded in the molecule lattice through a poly-addition reaction. Unlike in the case of polyester or vinyl ester resins, here we ensure that the stoichiometric equivalent is precisely maintained. In this way, we achieve the highest quality and resistance.

Connection types

What use are even the best pipes and fittings if they cannot be connected together or are very difficult to connect together?

Essentially, almost all connection types are possible in the processing of Fiberpipe pipes. The most common are ADHESION, LAMINATING, BELL & SPIGOT and assembly of flange connections!

Bonding

The bonding technology is the most common way of manufacturing a pipeline from pipes and fittings around the world. For this purpose, the pipes are cut to length, the bonding surfaces roughened, the adhesive applied, the end of the pipe pushed into the bushing, fixed and then tempered.

This quick and cost-efficient method of assembly has proven itself over the last 20 years across the world and is undoubted today.

Laminate connection

The laminate connection is the classic way of joining GRP parts together. Anyone who has already repaired their car, boat, surfboard or something similar with GRP should be confident with this procedure. Here the surface is also roughened and then resin impregnated glass mats and fibre cloth are applied according to the specifications. After the desired wall thickness has been achieved, the laminate is allowed to dry, cure and the connection can be immediately charged.

Bell & Spigot connection

The plug-in connection is particularly well-suited to longer distances. In the case of this type of connection, there is a groove for the locking rod in the bushing area of the pipes and one or two O rings. The procedure is designed as follows: the pipes are plugged together and then the heated locking rod is driven through the corresponding groove. The fittings are also joined to the pipe with adhesive in this type of connection.

Flange connection

All standard flange connections can also be presented with Fiberpipe pipe systems.

Whether a fixed flange, DIN, ISO, GRP collar or loose flange, galvanized steel, polypropylene coated or special flange… anything is possible.

Special connections

Fiberpipe or Fibercast pipe systems stand out for a large degree of variation with connection type.

Whether Straub, Mewa, Gruvlock or anything else, feel free to put us to the test.

GRP pipes

Here you will find information about GRP pipe systems, GRP fittings and GRP containers. Including information on processing GRP pipes and on the resistance of GRP pipes.