3-BPAttach02 468-2026-028848.pdf

Revised July 2024

SECTION 806

FORM HIGH MODULUS PVC LINER PIPE

806.1 SCOPE

This specification provides for the rehabilitation of gravity flow pipe lines by the insertion of a preheated, folded PVC pipe which is then further heated and progressively unfolded and expanded against the interior surface of the existing pipe. The finished Fold and Form Pipe (FFP) should extend over the installation length in a continuous, tight fitting pipe-within-a-pipe.

806.2 REFERENCE SPECIFICATION

This specification references American Society of Testing and Materials (ASTM) standards F1871 (Standard Specification for Folded/Formed Poly (Vinyl Chlroride) Pipe Type A for Existing Sewer and Conduit Rehabilitation, and F1867 (Standard Practice for Installation of Folded/Formed Poly (Vinyl Chloride) (PVC) Pipe Type A for Existing Sewer and Conduit Rehabilitation.

806.3 MATERIALS

a) The PVC compound used for the FFP shall conform to ASTM D-1784 cell classification 12111 or

32111 with minimum physical properties as listed below:

Tensile Strength ASTM D-638 3,600 psi

Tensile Modulus ASTM D-638 155,000 psi

Flexural Strength ASTM D-790 4,100 psi

Flexural Modulus ASTM D-790 145,000 psi

b) Compounds meeting the above minimum properties that have different cell classifications because one or more properties are greater those of the specified compounds are also acceptable.

c) The minimum length of the FFP shall be that deemed necessary by the Contractor to effectively span the distance between the starting point and the terminating point, unless otherwise specified.

806.4 DESIGN

Liner wall thickness shall be determined in accordance with ASTM 1867, Appendix X1. The Dimensional

Ratio (DR), the Pipe Diameter divided by the Wall Thickness, shall be determined by the Formulae contained in Appendix XI of ASTM F-1216. The long-term (time dependent) Flexural Modulus used in these calculations shall be no greater than 35% of initial, for the cell classifications identified in Section 3.1. Higher values for the long-term Flexural Modulus shall be accepted provided a 3rd party ASTM D2990 Long-term creep test result is submitted. The following table has been prepared in accordance with this requirement.

MAXIMUM SAFE DEPTH FOR FFP

DIMENSIONAL RATIOS

CELL CLASS E-MOD (PSI) 35 41 50

12111 320,000 20' 14' 9'

32111 360,000 22' 16' 10'

Assumptions

Existing pipe is not capable of loading, soil 120 lb/cf, Soil Modulus 700 psi, Ground Water 1/2 total depth, Ovality 2%, Live Load is 16,000 lb./wheel, long-term Modulus of PVC is 35% of initial Modulus per ASTM

D-790. Safety Factor is 2.

806.5 SAFETY

The Contractor shall carry out the operation in strict accordance with all applicable OSHA standards.

Particular attention is drawn to those safety requirements involving entering and working in confined spaces.

806.6 INSTALLATION PREPARATION

a) All debris which would interfere with the installation of the FFP shall be removed.

b) Inspection of pipelines shall be performed by experienced personnel trained in locating and identifying breaks, obstructions and service connections by closed circuit television. The interior of the pipeline shall be carefully inspected to determine the location of any conditions which may prevent proper installation of the FFP into the existing sewer line. Such conditions shall be noted so that these conditions can be corrected prior to installation.

c) The line shall be cleaned of obstructions such as solids, displaced joints, protruding service connections or collapsed pipe that may prevent FFP installation. If the TV inspection reveals an obstruction that cannot be removed by conventional sewer cleaning equipment, a point repair shall be made to remove or repair the obstruction. These preparatory items are incidental to the lining process, and are not additional pay items.

d) Prior to lining, the preliminary video tape of the host pipe shall be reviewed and approved by the

Engineer to assure that the host pipe requires no further protruding tap cutting, point repairs or cleaning in preparation for lining. During this review the Contractor and Engineer will agree on which of the service connections are active and are therefore to be reopened after the lining is complete. Only the active service connections will be reopened.

e) When required, flow of sewage around the section or sections of pipe designated for FFP shall be provided by the Contractor. The bypass shall be made by plugging the line at an existing upstream manhole and pumping or directing the sewage flow into a downstream manhole or adjacent system, if the adjacent system has capacity for the additional flow. The pump and bypass lines shall be of adequate capacity and size to handle the flow. Raw sewage must be pumped back into the sanitary sewer system or disposed of in a manner approved by the City, but such approval shall in no way relieve the Contractor of his responsibility and/or public liability.

f) No service connection operation will be interrupted by construction for more than 12 hours unless the Contractor has made arrangements for the building occupants, such as temporary housing.

Service connection of businesses that require water to function will be separately bypassed to avoid an adverse impact on the operation.

806.7 INSTALLATION

a) The minimum length of the FFP shall be that deemed necessary by the Contractor to effectively span the distance from the starting point to the terminating point, unless otherwise specified.

b) The spool of FFP shall be heated to make the PVC pipe flexible for insertion into the existing pipe.

c) The FFP shall be inserted into the existing pipe using a winch and cable connected to the end of the FFP. The winch shall be equipped with a dynamometer to record the pulling forces required during installation. The maximum force exerted on the FFP shall be a tensile stress of 350 psi (when heated) multiplied times the pipe wall cross sectional area.

d) Thermocouples shall be placed against the pipe at both the upstream and downstream end to monitor the pipe installation temperatures.

a) Once the necessary processing temperature has been achieved the FFP shall be expanded.

Expansion pressure shall be sufficient to unfold the FFP, press it tightly against the wall of the existing pipe and form dimples at the service connections.

g) After the FFP is completely rounded and prior to relieving the pressure holding the FFP against the existing pipe the Contractor shall cool the FFP, using air and/or water, to a temperature below 110 degrees.

806.8 SERVICE CONNECTIONS

After the pressure is removed from the FFP, the Contractor shall re-establish the existing, live service connections. This shall be done without excavation from the interior of the pipeline by means of a CCTV camera and a remote controlled cutting device that fully re-establishes the live service connection. Only active service connections will be reopened. Any inactive service connection which has been inadvertently opened will be sealed closed by the Contractor to the satisfaction of the Engineer.

806.9 WORKMANSHIP

The finished FFP shall be continuous over the entire length of the installation and conform to the contours of the walls of the host pipe. After work is completed the Contractor shall provide to the City a copy of the original video tape and a video of the completed sewer line showing all work completed including all services that were re-connected. All tapes shall be of high quality and clarity and shall show the complete footage of each line, to the satisfaction of the Engineer.

806.10 CLEANUP

After installation of the FFP has been completed and required testing indicates that the FFP is acceptable the project area disturbed by the Contractor's operation shall be restored to its original or better condition in compliance with AR 6.5 as determined by the Engineer.