JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 79

certification
and is estimated for 100,000 hours or 150 million cycles for static or cyclic conditions, respectively. It is usually 0.8-1.0 for cyclic and 0.50-0.56 for static conditions. Thermal expansion is a property that varies in the hoop and axial directions. Typical axial expansion for filamentwound pipe at a 55o winding angle is 1.11.5 x 10-5 inch/inch/oF (approximately twice that of steel). Thermal expansion in piping systems may be accommodated by guides, expansion loops, mechanical expansion joints, anchors or combinations of these. Composite pipes have a very low modulus relative to steel (<5% of steel). This significantly improves the pipe’s ability to handle expansion and contraction loads. ter to the exact strength requirements. Getting the API 15LR specification was a lengthy and rigorous process warranting complete documentation at each and every step, including maintaining a total quality management system as per API (American Petroleum Institute) requirements. This called for a detailed assessment of testing requirements and procurement of specific test equipment tailormade for the purpose. All the testing equipment needed to be calibrated as per the standard norms and the whole facility had to be approved by API from the USA after clearing the thirdparty inspection by reputed agencies. API standards 5B and 5B1 for tubing, threading and gauging of pipes and design standard AWWA M45 for composite pipes were followed. The design template for buried pipes as per AWWA M 45 was also finalized using the MathCAD software. The following routine and type tests are required by API:
Tab. 3: Test methods for mechanical properties for GRE pipes

Long-term type tests: - Long-term hydrostatic design basis (HDB) cyclic pressure test as per ASTM D2992 - Long-term HDB static pressure test as per ASTM D2992 - Long-term beam bending modulus as per ASTM D2925 The API audit certifies the product and its manufacturing facilities at a specific location. EPP Composites created the necessary testing and manufacturing facilities for the complete range of GRE pipes as specified in API 15LR with pipe diameters of 25-600 mm, pressure ranges of 10-70 bar for a pipe length of 4.5/6/9/12 m and a temperature range of -65°C to 120°C. The facilities included a 4-axis CNC filament winding system, a fully automatic hydraulic extractor unit, CADFIL software for accurate winding, a hydro testing machine for pipes and couplers, a 12-m-long curing oven, an ultimate axial tensile strength testing machine, a parallelTab.4 : Test methods for physical properties for GRE pipes

Filament-wound composite pipes – an Indian experience
In view of the crucial need for developing domestic capabilities in composite technology, the Technology Information, Forecasting & Assessment Council (TIFAC), an autonomous organization under the Department of Science & Technology, Govt. of India, launched the Advanced Composites Programme. The programme aims at enhancing the utilisation and application of composites as a major high-performance material in various sectors and at improving laboratoryindustry linkages towards technology development and commercialization. To assess the importance of composite pipes for applications in the oil & gas sector, a project on filamentwound high-pressure glass-reinforced epoxy pipes was launched under the programme in partnership with M/s. EPP Composites Pvt. Ltd., located in Metoda near Rajkot, Gujarat. The project aimed to design GRE pipes as per API 15LR using a 4-axis CNC filament winding system. The use of advanced fabrication techniques such as CNC filament winding results in considerable weight savings with reduced material wastage and would ca-

Mechanical property Burst testing Mill pressure test (1.5 * design) Axial tensile strength Hoop tensile strength Hoop tensile modulus Axial tensile modulus External collapse pressure Initial stiffness factor

Test method
ASTM D1599

Physical property

Test method

Specific gravity Density

ASTM D792

API 15LR ASTM D792

ASTM D2105

Coefficient of thermal expansion Barcol hardness

ASTM D696

ASTM D2290 ASTM D2583

ASTM D2290

ASTM D2105

Degree of cure

API 15LR

ASTM D2924

Glass content Resin content

API 15LR

ASTM D2412

API 15LR

No73 June 2012

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JEC COMPOSITES MAGAZINE - Issue #73 - June 2012

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #73 - June 2012