Product Information

-Diameter Class

Grandpipe GRP pipes technologized by us can be produced between 100 - 4000 mm diameter.

Standard diameters are given below (in mm)

According to customer request, others intermadiate diameter can be produced between 100 - 4000 mm diameter. Please contact Grandpipe Marketing Department for more information.

-Pressure Class

Grandpipe GRP pipes have standard pressure class range as shown below. Other pressure classes can be provided if necessary. For non-standard products, please contact Grandpipe Marketing Department.

Pressure ratings of GRP pipes have been established in accordance with design approach outlined in AWWA M45 Fiberglass Pipe Design Manual. Pipes are pressure-rated at full operating pressure even buried to the maximum depth recommended.

To ensure the long service life for which our pipes are designed, following capabilities should be noted and observed in service.

-Hydrostatic Test Pressure

(For a safe and proper field test, other structures and equipments at pipelines should be properly selected and installed.)


-Stiffness Class

Definitions of GRP pipes' stiffness classes are provided in ISO and AWWA standards based on same principle with different coefficients. Mostly used definition is “initial specific ring stiffness” included in ISO standard based on the formula EI/D3 , in , N/m2 (Pa).

Stifness class is selected according to two parameters. These are: (1) burial conditions which include native soil, type of backfill and cover depth and (2) negative pressure. The native soil characteristics are rated according to ASTM D 1586 standard penetration test.

Grandpipe GRP pipes are produced based on following Standard stiffness classes.

Accordance with customer requests, Grandpipe GRP pipes can be produced more than 10.000 Pa and intermediate stiffness values.

-Pipe Length

Standard length of Grandpipe GRP pipes is 12 m for diameters over 300 mm. Smaller diameters are available in 6 meters standard length.

Grandpipe GRP pipes can be produced in the range of 0.30 – 15 m length for diameters over 300 mm. (including intermediate lengths.)

-Flow Velocity

Maximum recommended flow velocity is 3.0 m/sec. Velocities upto 5.0 m/sec can be used if water is clean and does not contain any abrasive material.

-Poisson's Ratio

Poisson's ratio is influenced by pipe construction. For Grandpipe GRP pipes, ratio for hoop (circumferential) loads and axial response ranges from 0,22 to 0,29. For axial loading and circumferential response Poisson's ratio will be slightly less.

-Resistance to Direct Sunlight (Ultraviolet -UV) Radiation

Sunlight is the main ultraviolet radiation. Tests and researches done by technology partner of Grandpipe absolutely show that ultraviolet degradation is not considerable issue for long-term service life of GRP pipes produced by using this Technology. Technologic background of Grandpipe is fully capable to do custom-made designs where the customers request extra safety factors.

-Load Capacity (Strength) Values

For design purposes the following values can be used for hoop tensile and axial tensile load capacity.

-Temperature Consideration

Maximum permitted temperature of fluent without pressure derating is 45 °C. Grandpipe recommends that pressure rating should be dropped one class where operating temperatures are set between from 46 °C upto 60 °C (For example, a PN16 pipe with pressure rating of 16 bar would be used as a PN 10 rated product).  Temperature resistance of GRP pipes can increase upto 100 °C by using appropriate types of resins.

-Thermal Expansion

Thermal coefficient of axial expansion and contraction for Grandpipe GRP pipes is 24 – 30 * 10-6 cm/cm/°C.

-Flow Coefficients

Based on the tests carried out, Colebrook – White Coefficient can be taken as 0.029. This corresponds to a Hazen – Williams Flow Coefficient approximately C = 150 – 165 and a Mannings Roughness Coefficient of n=0.009 and a Surface Roughness Number of 0.00518 in Darcy-Weisbach Equation.

-Hydraulic Properties

Due to special flow coefficients, GRP pipes have some specific charateristics:

>    Extremely smooth internal surface of GRP pipes decrease flow resistance and therefore required energy and cost of pumping are reduced.

>    Due to corrosion resistance of GRP pipes, pipe quality doesn't differ throughout time. Unlike concrete and steel pipes, flow coefficients of GRP pipes don't change during their service life.

>      For a specific discharge, an smaller diamater pipe can be chosen in comparison with other type of pipes.

Example:  We will see that instead of using 2000 mm steel pipe, we can transfer same amount of fluid at a same head-loss through a 1800 mm GRP pipe.

Hazen  Williams Equation: HF = formül:

HF (head loss in meter water)
Q ( discharge in cubic meter)
L ( length of pipe line)
C (roughness coefficient)
D (pipe diameter in meter)
C (steel) = 110
C (GRP) = 150
Q (steel) = Q (GRP)
L (steel) = L (GRP)
HF (steel) = HF (GRP)
D (steel) = 2000 mm

-Abrassion Resistance

Abrasion resistance is related with effects of sand or similar granular materials which there are possibly interior surface of the pipe. Although there is no widely-used standard test procedure or ranking method, Grandpipe GRP pipes have been evaluated by using Darmstadt Rocker Method that is mostly known in sector. Using gravel, average abrassion loss of GRP pipes is 0.34 mm / 100.000 cycles. Results can be varied depending on type of abrasive material used in test.