Setting up a Hydrotest for Thermoflex
The FPS Onshore team will work with your project team to decide to either test the full system or sections of it based on length and volume of line, whether the section of pipe is used to reduce water requirement or limit longitudinal expansion and reduce pressure change during testing. Testing in sections allows for construction to continue while testing completed.Construction should never occur near a line under testing.
In low-stress applications application the pipeline will be unrestrained on surface or buried, while high-stress applications will be buried with all transition below grade. The ends of the pipe being tested should be secured to ensure that in the event of a leak or failure, personnel and the environment are not harmed by forces sudden pipe movement.
Before testing begins, isolate the Thermoflex pipe from all low pressure components. The pipe to be tested is then filled with water and all trapped air is bled away or removed by pigging. The valve opening and closing sequence will be done in a way that ensures the prevention of water hammer and the creation of a vacuum inside the pipe. Pressure measurement will be taken at the lowest elevation in the whole test section. When this is not possible, correction to the test pressure must be made for the hydrostatic head; to ensure the pipe will not be over-pressurized. The temperature will be monitored for large temperature swings, which could cause erroneous pressure measurements.
Preconditioning and Stabilization
Low Stress Applications
For surface applications, the pipe is first inspected for visible signs of damage as part of the pre-hydro conditioning steps. The pipe is repositioned at any location where expansion during pressurization may contact surface structures or cause the pipe to kink.
Starting the low stress preconditioning phase, the pipe is pressurized up to target pre-conditioning pressure (𝑃𝑃). The pressure ramp-up rate should be no more than 50 psi per minute.In surface applications, visually inspect the pipe to make sure it has not elongated and contacted other structures on site. If this occurs, depressurize the line and reposition the pipe.
The pre-conditioning pressure is maintained within +0 psi/-10 psi for a period of four hours.
For high-stress applications, the Thermoflex pipe is buried. A trench is first fully backfilled and compacted according to requirements in Section 9.4.3 before pressurization. After filling the line with water, the pipe is pressurized at a rate no more than 50 psi per minute to 35%of the target pre-conditioning pressure(𝑃𝑃).
The line is then locked down by closing valve(s), which isolates it from the pump and other components to hold pressure for 10 to 12 hrs., typical performed overnight.
The pressure is then increased in steps until 100%of the target pre-conditioning pressure(𝑃𝑃)is reached. Now, the test can begin.
Thermoflex Pipe Hydrotest
Thermoflex pipe should be pressurized to Test Pressure (PT) and, locked down by isolating it from the pump and other components. If the test pressure remains above 95% of the hydrotest pressure(𝑃𝑃) for four (4)hours, up to (8) eight hours if desired, with no indication of leakage then installation is verified. The pipe can now be depressurized at a rate no more than 50 psi per minute.
Pneumatic Pressure Testing can be performed on Thermoflex, but the line must meet special requirements, contact a Baker Hughes FPS-Onshore Technical Service Engineer for the special requirements and the pneumatic testing procedure.
Hydrotesting is critical to successful Thermoflex pipe installation. Contact us to get started.