Circumferential and axial load bearing capacities of the manufactured pipes are proven by routine tests. In addition, the structure and composition of the pipe are checked and verified by tests.
Controls during manufacturing phase
- Raw material control tests
- Barcol hardness
- Wall thickness measurement
- Pipe length measurement
- Outer diameter measurement
- Hydrostatic pressure test
Controls performed by taking samples
Being a physical property of the pipe, the specific stiffness is a measure of strength against ring deformation under external loads. Initial ring stiffness is the value obtained in N/m2 that is calculated by the formula below, when the pipe is tested in accordance with ISO 7685 and EN 1228, by applying a deflection of approximately 3%.
S0 = F* f / L * y
f = (1860 + (2500*y/dm))/100000
S0: Stiffness; N/m2
F: Applied Force; N
f: Deflection Factor
L: Sample Length; m
y: Vertical Deflection; m
dm: Average Diameter; m
Non-destructive deflection test with no structural damage
When the pipe sample is tested in accordance with ISO 10466, by implementing the following nominal deflections, it should meet the conditions in the table below.
Minimum test deflection values
Hoop tensile strength
When the samples that are cut out from the pipe are tested as per ISO 8521 and EN 1394, the results should comply with the minimum rating tables ranking in the international standards.
Axial tensile strength
When the samples that are cut out from the pipe in an axial direction are tested as per ISO 8513 and EN 1393, the results should comply with the minimum rating tables ranking in the international standards.
SUPERLIT GRP pipe manufacturing technology comprises a detailed quality control program. Compliance of the pipes and fittings production and their tests to international and local standards is ensured by this program.
Quality Control Tests
Before manufacturing, the raw material is tested. Tests aim to check the compliance, to the standards, of the raw materials and products (pipe, coupling and fittings) manufactured.
A hydrostatic pressure test simulating the operating conditions is applied to pipes with flexible connections and having diameters between 300 mm – 4000 mm.
Coupling Performance Test
Couplings are tested under the conditions specified in EN1119, ISO8639 and ASTM D4161 standart to verify their performance.
- Hydrostatic desing basis (HDB)
- Stress-Corrosion test
- Long-term ring stiffness (under wet condition)
- Long-term ring deflection test
Long-term tests, that take at least 10,000 hours, are performed to generate the design values and to maintain the extrapolation. In other words, the required physical parameters for a defined nominal 50-year design period are designated by using the ISO 10928 methods. In general, a minimum of eighteen samples are prepared and used to obtain a series of data distributed for the duration of the test. By using the least squares method, a logarithmic regression graphic is constituted from the test data. Performance values, corresponding to 50 years of service life for GRP pipes, should comply with the tables in the international standards.