State of Technology Report for Force Main Rehabilitation, Final ...

D638) are offered for determining the tensile strength. The minimum value is 9,000 psi (621 bar) as
specified in ASTM F2019, which is the only standard practice for pressure applications.
Wall thickness measurements are also made on the retrieved samples. There is no requirement for
measuring the wall thickness of the in situ liner. Theoretically, this is now possible with the use of a laser
profiler. The inside surface of the original pipe would first be surveyed with the profiler and then the
liner’s inside surface after cure. Assuming the liner hasn’t shrunk away from the inner surface of the
original pipe, the thickness of the liner could then be determined from these two survey measurements.
Ultrasonic tools are also being developed that not only can be used to measure the thickness of the in situ
liner, but also its flexural modulus of elasticity. This could be especially important to an owner who may
want to check on the condition of an old liner to determine if any deterioration (loss of thickness or
modulus) has taken place.
Another QC requirement often required is leak tightness testing, which in the case of a pressure pipe has a
limit of 20 US gallon/inch diameter/mile/day. The recommended pressure level in ASTM F2019 is twice
the working pressure or the working pressure plus 50 psi (3.5 bar), whichever is less.
The last field QC requirement is a visual inspection, usually by CCTV, to check workmanship. No dry
spots, lifts, or delaminations that would affect the liners long-term performance are permitted. Excessive
wrinkles are also not permitted, especially those that impede flow or cleaning equipment.
5.6.2 Long-Term – Qualification Requirements
5.6.2.1 PVC Long-Term QA/QC Requirements. PVC pipe meeting AWWA C900 or C905, or
ASTM D2241 Standard Specification for Polyvinyl Chloride (PVC) Pressure-Rated Pipe (SDR Series) is
subjected to long-term pressure regression testing to establish an HDB for the pipe. Pipes are tested per
ASTM D1598 and the results analyzed in accordance with ASTM D2837. A Hydrostatic Design Stress
(HDS) is determined, which is the maximum tensile stress the material is capable of withstanding
continuously with a high degree of certainty that failure of the pipe will not occur. Fusible PVC and
Duraliner are the only two PVC products made from standard AWWA C900 or C905 stock, so these are
qualified.
Folded PVC
There are no long-term qualification requirements in the folded PVC liner standards. Only one
manufacturer of a folded PVC product, Ultraliner, stipulates that this product could be used for a low
pressure sewer force main renewal. At some point in the future, a requirement similar to that in AWWA
C900 or AWWA C905, where reformed pipes are subjected to long-term pressure regression tests needs
to be established. This would then allow design of a reformed PVC liner to act as a fully structural pipe
for 50 years. At the present time, that information is not available.
5.6.2.2 PE Long-Term QA/QC Requirements. PE pipe meeting AWWA C901 or C906, or ASTM
D3035 is similar to PVC in that these products are also subjected to long-term pressure regression testing.
These tests establish a basis for the long-term pressure rating of the products. There are no other longterm
tests for standard PE pipe.
Deformed PE
PE used for deformed liners under ASTM F1533 is to be made from materials that have a PPI HDB of
either 1,600 psi (110 bar) for PE 3408 or 1,250 psi (86 bar) for PE 2406. However, there is no
requirement for the reformed PE liner to demonstrate that it has a similar HDB rating.
69