Quality Asuurance Quality Control

Quality and Standards

Subor’s approach to the quality concept is not limited to the production process and its product. Subor’s management conception in all activities is an insight that considers the satisfaction of all stakeholders, especially the customers and it adopts occupational health and safety as the fundamental policy.Having established its management system upon such foundation, Subor has obtained certificates for ISO 9001 Quality, ISO 14001 Environment, and OHSAS 18001 Occupational Health and Safety Management Systems.

All relevant tests as required in the scopes of international standards as listed above are performed in Subor’s laboratories, which are accredited with regards to conformity to ISO 17025: General Requirements for the Competence of Testing and Calibration laboratories.

Subor manufacturing process has been designed to meet the requirements of the most fundamental and extensive international standards of the industry as given below:

AWWA C-950	ASTM D 3754	ASTM D 3517	ASTM D 3262	ISO 10639	ISO 10467	ISO 25780	EN 1796	EN 14364	DIN 16868
Fiberglass Pressure Pipe	Standard Specification for Sewer and Industrial Pressure Pipe	Standard Specification for Pressure Pipe	Standard Specification for ‘‘ Fiberglass’’ (Glass-Fiber-Reinforced Thermosetting-Resin) Sewer Pipe	Plastics piping systems for pressure and non-pressure water supply - Glass-reinforced thermosetting plastics (GRP) systems based on unsaturated polyester (UP) resin	Plastics piping systems for pressure and non-pressure drainage and sewerage - Glass-reinforced thermosetting plastics (GRP) systems based on unsaturated polyester (UP) resin	Plastics piping systems for pressure and non-pressure water supply, irrigation, drainage or sewerage - Glass-reinforced thermosetting plastics (GRP) systems based on unsaturated polyester (UP) resin - Pipes with flexible joints intended to be installed using jacking techniques	Plastics piping systems for water supply with or without pressure - Glass-reinforced thermosetting plastics (GRP) based on unsaturated polyester resin (UP)	Plastics piping systems for drainage and sewerage with or without pressure - Glass-reinforced thermosetting plastics (GRP) based on unsaturated polyester resin (UP) - Specifications for pipes, fittings and joints	Glass fibre reinforced unsaturated polyester resin (UP-GF) pipes

Production Control Test

Tests are performed in order to inspect and measure performance of the product. The results of tests are recorded and they can be accessed easily. The conducted tests cover the entire process; from the entrance of raw materials to the shipment of the final products.

Raw materials are delivered with supplier certification demonstrating their compliance with Subor quality requirements; in addition, raw material samples are subjected to incoming control tests in Subor laboratories prior to their use.

All pipes are subjected to the following control checks in Subor laboratories and on production lines during production.

Visual Inspection
Barcol Hardnes
Dimensional Checks (Pipe Length, Diameter, Wall Thickness)
Hydrostatic Leak Tightness Test (for pressure pipes)

On a sampling basis, the following control checks are performed.

Determination of Pipe Stiffness
Deflection without damage or structural failure
Axial Tensile Strength Tests
Circumferential Tensile Strength Tests
Composition Test

Certificates

Advantages of GRP

The abrasion resistance of the pipe is tested according to CEN/TR 15729. The method for this test has been released by Darmstadt University. The test is carried out by adding a gravel mixture with water inside the pipe sample and cycling it within certain times to determine the abrasion level of liner layer of the pipe.

This practice is useful for establishing the hoop stress or internal pressure versus time-to-failure relationships, under selected internal and external environments which simulate actual anticipated product end-use conditions, from which a design basis for specific piping products and materials can be obtained. This test is applied in accordance with ASTM D 2992 standard.

Various joint qualification tests are applied according to international standards such as EN 1119 and ASTM D 4161, to find out the performance of the joint.

The test is applied for determining the ring creep properties for glass-reinforced thermosetting plastics (GRP) pipes. Properties include the wet creep factor and the long-term specific creep stiffness. This test is applied in accordance with ISO 10468 standard.

Long term ring bending strain test method determines the long-term ring- bending strain of pipe when deflected under constant load and immersed in a chemical environment. It has been found that effects of chemical environments can be accelerated by strain induced by deflection. This test is applied in accordance with ASTM D 5365 standard.

In addition to in-process product and performance tests, Subor also performs short and long term tests in order to determine qualification, pipe design criteria and monitor the long term material condition. The long term monitoring is carried out for more than 10.000 hours in the “Subor Long Term Test Laboratory” and aim at reviewing the performance of pipes over 50 years.

Subor performs the following tests:

Strain Corrosion Testing
Hydrostatic Design Basis (HDB)
Long Term Ring Bending Strain
Long Term Specific Ring Stiffness
Abrasion Resistance
Joint Qualification Tests
Water Jetting Resistance Testing

The method evaluates the effect of a chemical environment on the pipe when in a deflected condition. It has been found that the effects of chemical environments can be accelerated by strain induced by deflection. This test is performed by applying sulphuric acid solution in accordance with ASTM D 3681 standard.

During the service life, the sewer lines need to be cleaned with high pressurized water. Therefore the pipe has to have strength against high pressurized water jetting cleaning applications. This test is applied in accordance with DIN 19523 standard.