Goodwin Pipe Factory

The Goodwin pipe factory manufactures GRP pipes of various types and varying pressure, stiffness and diameter through the Dual Helical Filament Winding and Hoop Filament Winding Process.

The Reinforced Thermosetting Resin Pipe is a composite material consisting of a thermosetting polymer, often a type of polyester, reinforced with glass or other fibre. Glass fibre provides strength and stiffness to the composite material. The different types of resins used for the manufacturing of GRP, GRV and GRE Pipes are Isophthalic resin, Vinyl ester resin and Epoxy resin respectively, which are selected according to the required properties like chemical resistance, temperature resistance and mechanical properties. The properties of GRP Pipes can be varied by changing the ratio of the raw materials and also by changing the winding angle.

GRP Pipes have many advantages over other conventional pipes as far as installation is concerned….

  • The smooth interior of GRP Pipes results in low fluid resistance, which could lower horsepower requirements for pumped systems. This characteristic could contribute to a substantial cost savings over the life of typical piping systems. The interior surface of the pipe remains smooth over time in most fluid services. Therefore, fluid resistance does not increase with age. The smooth interior allows the pipe diameter to be reduced while maintaining the desired flow.
  • GRP Pipe, being highly corrosion resistant, requires no separate lining or Cathodic protection, hence virtually no maintenance cost. Also no outside protection is needed against ground water, aggressive industrial gases and fumes or chemicals leaking from the neighbouring pipes and valves. Expected life span of GRP pipe is 60 years
  • The relatively high compliance (low modulus of elasticity) of GRP Pipe contributes to a self-dampening effect as the pressure wave travels through the piping system. The magnitude of the pressure wave and hence surge pressure in a metallic piping system is much higher due to the higher modulus of elasticity of these materials.
  • GRP Pipes are supplied in 12 m lengths, and therefore number of joints required is less. This means there are less chance of leakage and less time is required for installation resulting in substantial cost saving. GRP Pipes can have rigid joints, due to which thrust blocks can be eliminated also resulting in reduction of cost during the installation.
  • The low thermal conductivity of GRP Pipes not only causes low temperature losses, but also in many cases eliminates condensation or the need for additional thermal insulation.
  • The thermal end loads developed in GRP Pipes are small, restraining equipment like guides and anchors need not be as strong or heavy as for metallic piping. Short lengths, adjustment pipes or special fittings can be readily made available at a short notice. Unforeseen modifications can be made at site easily without delay and much cost.
  • GRP Pipes are manufactured with an external liner, which acts as a barrier against ultra violet rays and have good abrasion resistance.

Applications Industries

  • Highly Corrossion Resistant
  • Cost Effective
  • Low Thermal Conductivity
  • Low Fluid Resistance

Pipe Composition

GRP Pipe wall consists of three layers, perfectly adherent to each other and having different characteristics and properties in relation to their function.

Inner Liner Veil (Glass) 10% 10%
Resin 90% 90%
CSM (Glass) 30% -
Resin 70% -

Liner is the innermost layer which is in direct contact with the conveyed fluid. This characteristic of smoothness reduces the fluid head losses to minimum and opposes the growth of mineral deposits and algae. The liner is made of two monolithic sub layers. The inner one, in direct contact with the fluid, is reinforced with glass veil, with a resin content of 90% and the outer one is reinforced with CSM glass, with a resin content of 70% by weight. The standard liner thickness is about 0.5 to 1.5mm, higher thickness can be produced on request.

Structure Roving (Glass) 70% 70%
Resin 30% 30%

Glass reinforced layers guarantee the mechanical resistance of the whole pipe against stresses due to internal and external pressure, external loads and thermal loads. For GRP pipes, this layer is obtained by applying on the previous partly cured liner, continuous roving of glass wetted with resin, under controlled tension. For GRE Pipes, the structural wall is wound directly on a wet liner. This layer can contain aggregates like silica sand, if allowed by specifications. Thickness of the mechanical layer depends on the design condition.

External Liner Veil (Glass) 10% 10%
Resin 90% 90%

Top coat or external liner is the outer layer of the pipe which consists of pure resin. If required, UV protectors shall be added to protect the pipe from exposure of sun. In case of severe exposure conditions like aggressive soil or very corrosive environment, the external liner can be reinforced with a surfacing veil or added with fillers or pigments.

Raw Materials

Fibreglass composites consists of glass fibre reinforcements, thermosetting resins and additives, designed and processed to meet the specific functional performance criteria:-

FIBRE GLASS REINFORCEMENTS: The amount, type and orientation of the glass fibres in the pipe provides the required mechanical strength. C-Glass, E-Glass & ECR Glass are used commonly, depending on the application of the pipe. The various forms of glass reinforcements are surface veil, chopped strand mat (CSM), chopped roving, filament

RESINS: Isophthalic, Vinyl ester and Epoxy are common type of resins used. This will provide the thermal and chemical properties such as glass transition temperature, resistance to heat, chemical resistance etc. required for the finished product.

AUXILIARY RAW MATERIALS: Raw materials like catalyst, accelerators, exhibitors, aggregates and pigments are used together with resin and glass reinforcements to achieve the desired properties of the Fibre Glass product. Catalyst is the organic compound which when added to resin in presence of an accelerator determines the polymerization reaction at ambient temperatures. Accelerator is the chemical compound used together with a catalyst to shorten the polymerization time. Inhibitor is added to the resin to reduce its reactivity at ambient temperatures.

Ultimate Hoop Stress-Rupture (Uni-axial) ASTM1559 570 570 570 MPa
Hydrostatic Design Basis (Bi-axial) ASTM D 2992 B 350 350 - MPa
Hydrostatic Design Stress (Uni-axial) ASTM D 2992 B 175 175 - MPa
Hydrostatic Design Stress (Bi-axial) ASTM D 2992 B 68 68 87 MPa
Axial Tensile Stress ASTM D 2105 35 50 75 MPa
Axial Tensile Modulus ASTM D 2105 13000 13000 15000 MPa
Hoop Tensile Stress ASTM D 2290 250 250 300 MPa
Hoop Tensile Modulus ASTM D 2290 24000 24000 30000 MPa
Hoop Bending Modulus ASTM D 2412 25000 25000 25000 MPa
Poisson’s ratio (Hoop loading) - 0.45 0.45 0.45 -
Poisson’s ratio (Helical loading) - 0.65 0.65 0.65 -
Coefficient of Linear Thermal Expansion 20 x 10 -6 20 x 10 -6 15 x 10 -6 Mm / mm / °C
Specific Gravity 1.8 1.8 1.8 -
Glass content (by weight) 65 65 65 %
Hazen William Coefficient 150 150 150 -
Maximum Temperature 60 90 110 °C
Thermal Conductivity 0.3 0.3 0.3 W / m-K
Roughness factor (Including head loss over joints) 0.04 0.04 0.04 mm
Effective Roughness (only pipe) 0.0015 0.0015 0.0015 mm