Section 15256 INSULATED UNDERGROUND PIPING

Section 15256

INSULATED UNDERGROUND PIPING

PART 1 - GENERAL

1.1 DESCRIPTION

A. Scope: This Section specifies pre-insulated liquid piping for direct burial installation. This Section does not provide specifications for insulation for piping installed in galleries, rooms, pipe chases, or exposed to view. Fluid temperatures are limited to the range 40 degrees F to 210 degrees F.

B. Type: Insulation shall be of the factory applied urethane foam type with a polyvinyl chloride (PVC) jacket.

C. Performance and Service Requirements: Insulated piping furnished under this specification shall be suitable for direct burial or installation in pipe trenches. Fluid temperature shall be as listed in Section 15050. Ground temperatures will range from 35 degrees F to 70 degrees F, and the piping may be installed below the water table.

D. Design Requirements: Minimum insulation thicknesses, exclusive of jacket, shall be as follows:

Pipe O.D., Inches	Insulation Thickness, Inches
2 or smaller	1 inch
3 through 6	1-1/2 inches
8 through 12	1-1/2 inches

A minus 15 percent tolerance, on the insulation thicknesses listed above, shall be permitted for manufacturers' standard insulation systems.

1.2 REFERENCES

A. This Section contains references to the following documents. They are a part of this Section as specified and modified. In cases of conflict between the requirements of this specification and those of the listed documents, the requirements of this specification shall prevail.

ANSI B31 70 Code for Pressure Piping

ASTM C591 85 Unfaced Preformed Rigid Cellular Polyurethane Thermal Insulation

ASTM D1784 90 Rigid Poly (vinylchloride); (PVC) Compounds and Chlorinated Poly

(vinylchloride) (CPVC) Compounds

ASTM D234181 Rigid Urethane Foam

1.3 SUBMITTALS

A. The following submittals shall be provided in accordance with Section 01300:

1. Dimensioned shop drawings and location of each expansion loop, including clearances provided for carrier pipe expansion.

2. A complete description of the preinsulated piping and accessories in sufficient detail to demonstrate compliance with these specifications.

3. A copy of this Section with addenda updates, and all referenced sections with addenda updates, with each paragraph check marked to show specification compliance or marked to show deviations.

PART 2 - PRODUCTS

2.1 ACCEPTABLE MANUFACTURERS

A. Preinsulated piping systems shall be Ric-Wil, Thermal Pipe Systems Weldtite, or equal, modified as necessary to provide the specified performance and features.

2.2 MATERIALS

A. Carrier Pipe: Unless otherwise specified, carrier pipe materials shall be as specified in

Section 15050, Piping Systems Specification Sheets, for each piping system.

B. Urethane Foam Insulation: The urethane foam shall conform to ASTM C591, Type II.

C. Insulation Jacket: All PVC shall conform to ASTM D1784, Class 12454-B. The minimum jacket thickness shall be 60 mils and shall be suitable for H-20 highway loading with 2 feet of cover.

D. Shrinkable Sleeves: Shrinkable sleeves for field joints shall be compatible with the PVC jacket. Shrinkable sleeves shall be fabricated from radiation cross-linked semirigid polyethylene, coated on all inside surfaces with thixotropic adhesive designed to flow and provide a complete seal when heated.

2.3 MANUFACTURING

A. General: Pipe sections shall be prefabricated in such a way that the urethane completely fills the annular space between the carrier pipe and the PVC jacket. The exposed insulation at the end of each section shall be sealed with a factory-applied, high temperature, watertight sealant. The carrier pipe shall extend a minimum of 6 inches beyond the insulation for field welding.

B. Anchors: Anchor plates shall be factory fabricated and welded to the carrier pipe. The

PVC jacket shall extend up to the anchor plate and be factory sealed to the anchor plate.

C. Fittings: Fittings shall be factory fabricated and pre-insulated with urethane foam insulation. The insulation shall be protected with a PVC plastic jacket of the same thickness and quality as that of the straight pipe. All miters on the PVC jacket at fittings shall be welded by a thermal set welding process to provide a continuous jacket integrity.

D. Expansion Elbows and Loops: Prefabricated elbows, expansion loops, and tees shall be provided, where specified. All pre-insulated fittings that must provide compensation for pipe expansion and/or contraction shall be installed in a suitably sized jacket and insulated with flexible polyurethane foam insulation. The straight units adjoining expan- sion fittings shall also be insulated with flexible polyurethane foam insulation to compensate for lateral pipe movement.

E. End Seals: End seals shall be provided on ends of each section of preinsulated pipe.

The end seals shall be watertight to protect the exposed insulation.

2.4 PRODUCT DATA

A. The following information shall be provided in accordance with Section 01300:

1. Manufacturer's certification in accordance with Paragraph 15256-3.6.

2. Certification that the jacket meets the requirement of Paragraph 15256-2.2 C.

3. Manufacturer's recommended field installation instructions including pipe jointing techniques, joint insulation, and jacket sealing.

PART 3 - EXECUTION

3.1 GENERAL

A. The preinsulated piping system shall be installed in strict accordance with the manufacturer's recommendations.

3.2 FIELD TESTING

A. Prior to insulating any field joints, individual pipe sections shall be hydrostatically tested at the test pressure and temperature indicated in Section 15050. The Construction Manager shall be notified in writing 48 hours prior to testing. Any leaks shall be repaired, and the system shall be retested until no leaks are detected by the Construction Manager. Field joints shall be insulated after hydrostatic testing has been completed.

3.3 EXPANSION LOOPS AND ELBOWS

A. Prefabricated expansion loops shall be located in the locations shown on the drawings.

Field fabricated expansion loops will not be accepted.

3.4 FIELD JOINTS

A. Carrier pipe field joints shall be as specified in Section 15050. After jointing and pressure testing, rigid urethane insulating material or foamed-in-place urethane of the same density and thickness as the pipe section shall be applied to the joint area. The insulation shall be sealed to the PVC jacket using heat shrinkable sleeves. All material used to insulate and seal field joints shall be supplied by the piping system manufacturer.

3.5 ANCHOR BLOCKS

A. Concrete anchor blocks shall be provided at locations shown on the drawings. Concrete shall comply with Section 03300. Anchor blocks shall be poured against undisturbed soil and shall have minimum dimensions as shown on the drawings. Pipe joints encased in anchor blocks shall be pressure tested prior to pouring anchor blocks. No valves shall be encased in anchor blocks.

3.6 FACTORY REPRESENTATIVE

A. A qualified factory representative of the piping system shall be present during the initiation of the buried piping installation, during major field relocations or changes, and during piping system testing. The factory representative shall supervise the pipe installation, joint insulation process, and installation of the protective jacket at joints during the two days of installation. On completion and testing of the work, the Contractor shall provide a certificate from the manufacturer stating that the installation, including any field relocation or modifications to the system, has been made in accordance with the manufacturer's recommendations.

END OF SECTION