Page 117 - Trenchless Technology Piping Installation and Inspection

Existing Pipeline Renewal and Replacement Methods 83

II. Pressure limited due to stress

15 × q × ⎜ ⎛ 1 + q ⎞ ⎟ × DR 2 – 05 × ⎜ ⎛ 1 + q ⎞ ⎟ × DR = S
.
.
×
100 ⎝ 100 ⎠ ⎝ 100 ⎠ P PN
where S = flexural strength of liner, psi = 4,500 psi
Solve for t,
.
.
70 5 24 48
– = 432 7
.
t 2 t
2
432.7t + 24.48t – 70.5 = 0
t = 0.376 in. (maximum compressive hoop stress)
III. Select minimum CIPP thickness

Thickness Limitations
0.878 in. : External pressure buckling
0.376 in. : Maximum compressive hoop stress
Minimum design thickness = 0.88 in. (22.3 mm)
Design case: External pressure buckling

2.8 Sample Specifications for CIPP
This section presents sample specifications for CIPP.
1. Intent
1.1 It is the intent of this specification to provide for the recon-
struction of pipelines and conduits by the installation of a
resin-impregnated flexible tube, which is tightly formed
to the original conduit. The resin is cured using either hot
water under hydrostatic pressure or steam pressure
within the tube. The cured-in-place pipe (CIPP) will be
continuous and tight fitting. The work shall be completed
within (to be determined) calendar days from the “Notice
to Proceed.”
2. Referenced documents
2.1 This specification references standards from the American
Society for Testing and Materials, such as: ASTM F1216-09
(Rehabilitation of Existing Pipelines and Conduits by the
Inversion and Curing of a Resin-Impregnated Tube), ASTM
F1743-08 (Rehabilitation of Existing Pipelines and Conduits
by Pulled-in-Place Installation of Cured-in-Place Thermoset-
ting Resin Pipe [CIPP]), ASTM D5813-04 (Cured-in-Place
Thermosetting Resin Sewer Pipe), ASTM D790-07 (Test
Methods for Flexural Properties of Un-reinforced and