Polyflow Technical Data Powerpoint
Technical Data and comparisons to other HDPE based Composite pipes
Published on: Mar 4, 2016
Transcripts - Polyflow Technical Data Powerpoint
Robert Gleim Oct. 27th, 2010
Pipe is designed to handle the following load conditions: ◦ A minimum design life of 20 years at MAOP and MAOT ◦ Hydro testing to 1.25x MAOP for 8 hours at MAOT The Hydro test can be performed up to 3 times during the life of the pipe without degrading the 20 year design life Pipe shall have a minimum design life of 1 week when continuously operated at 1.25x MAOP The pipe design strength is based only on the aramid fiber. ◦ No strength is attributed to the plastic.
Base Tube ◦ Plastic is a seal and permeation barrier layer only No strength is attributed to the plastic. ◦ Multi-Layer or Single Layer Tri-axial aramid fiber ◦ Provides the strength to maintain both axial and radial loads ◦ Maximum efficiency of braid Jacket ◦ Used to protect the aramid fiber from damage during handling and installation No strength is attributed to the plastic. Couplings ◦ Provide connections between pipe lengths and retains aramid fiber to prevent slippage.
Fluid Compatibility Liner Material: ◦ Nylon Inert to ◦ HDPE Hydrocarbons Water only Doesn’t Soften and Swell ◦ Nylon Doesn’t Lose Strength Inert to Wet CO2 Water with Not for H2S over 200PPM Hydrocarbons & CO2 ◦ PPS ◦ PPS High H2S environments Water with Jacket Material Hydrocarbons, CO2, & ◦ Nylon for pipe pulls H2S Good abrasion resistance ◦ Polypropylene or nylon for direct bury
Tri-axial fiber reinforcement ◦ Axial fibers sized to carry 100% of axial load and to maintain elongation at less then 1%. ◦ Radial fibers sized to carry 100% of radial load Braid angle optimized to minimize braid consumption and maximize production lengths Neutral Braid Angle = 54.7°
Graphite/Carbon fiber ◦ High strength & good resistance to cyclic loading ◦ Too expensive Aramid fiber ◦ Very similar properties to carbon fiber ◦ Good balance of cost and performance S- Glass fiber ◦ Low cost, high initial strength ◦ Reduced strength in moist environments due to crack growth ◦ Poor cyclic performance
It is necessary to understand the long term behavior of aramids under load. ◦ Strength of the fiber is influenced by load, time and temperature ◦ Product life increases with decreased temperature and load
It is necessary to understand the long term behavior of aramids under load. ◦ Aramid fiber will retain its full strength for more than 80% of its predicted time to failure. ◦ Time to failure is determined by Miners Rule:
See attached chart for example below. At 90°F, the pipe must meet the criteria of 20 year design life and Hydro testing at 1.25x MAOP. ◦ At MAOP, the load in the fiber is only 53.2 % of the short term breaking strength (B.S.). This yields a design life maximum of 50 years. ◦ A 1.25x MAOP hydro test, increases the aramid fiber load to 66.5% of B.S. with a max design life of 1 week. If three - 8 hour, 1.25x hydro tests are performed on the pipe during its life, approximately 14.2% of the pipe life is consumed during the 24 hours of testing (24 out of 168 hr design life) The remaining pipe design life is approximately 34 years ◦ (85.8% of 50 years x 80% of predicted life at full strength)
Long Term Breaking Load of Aramid Fiber in PolyFlow 100 90 1 Week Life @ 1.25 x MAOP 80 66.5% 90°F 70 180°FStatic Load % of BS at 20°C 60 125°F 1.25x 50 53.2 % Design Load @ 40 Approximately a 50 Year Design Life 30 20 10 0 0.0001 0.001 0.01 0.1 1 10 Design life in Years
• A Factor of Safety (FS) is the structural capacity beyond the anticipated applied load. • A FS is used to provide a design margin over the theoretical design capacity to allow for uncertainty in the design process. • The uncertainty could be any one of a number of the components of the design process including calculations, material strengths, manufacture quality, environmental conditions, duty, etc. Accounting for Uncertainties: ◦ Design uncertainties: 2D vs 3D effects & braid efficiencies accounted for by burst testing samples at operating temperature, thus FS=1 ◦ Manufacturing uncertainties: Braid pitch, angle, diameter and wall thickness variations accounted for by burst testing samples at operating temperature, thus FS=1 ◦ Material uncertainties: Braid: varies for temp and design life, typically between FS=2.03 to FS =2.81 ◦ Operating uncertainties: Variability in installation, bend radii, operating pressure & temp, thus FS=1.1 Minimum Factor of Safety for Gathering lines is greater than 2.2