USACE / NAVFAC / AFCESA / NASA UFGS-33 61 00 (April 2008) -------------------------- Preparing Activity: USACE Superseding UFGS-33 61 00 (July 2006) UNIFIED FACILITIES GUIDE SPECIFICATIONS References are in agreement with UMRL dated January 2009 SECTION 33 61 00 PREFABRICATED UNDERGROUND HEATING/COOLING DISTRIBUTION SYSTEM 04/08 NOTE: This guide specification covers the requirements for prefabricated underground distribution system for chilled water, low temperature hot water (less than 95 degrees C (200 degrees F)) or dual temperature water. Edit this guide specification for project specific requirements by adding, deleting, or revising text. For bracketed items, choose applicable items(s) or insert appropriate information. Remove information and requirements not required in respective project, whether or not brackets are present. Comments and suggestions on this guide specification are welcome and should be directed to the technical proponent of the specification. A listing of technical proponents, including their organization designation and telephone number, is on the Internet. Recommended changes to a UFGS should be submitted as a Criteria Change Request (CCR). PART 1 GENERAL NOTE: Provide one or two sump pumps in valve manholes. Units should discharge by buried piping to the nearest storm sewer if possible. Where not economical to discharge to a storm sewer, pumps are to discharge above grade. Plan discharge locations carefully so water will not be discharged over valve manhole tops, sidewalks, etc. Check available NPSH versus required NPSH for pump selected. Coordinate power requirements with electrical designer and provide tell-tale light above ground to indicate sump pump failure. Drawing will show the following: (a) a dedicated circuit (b) lockable switches and circuit breakers that can both be locked "ON" (c) permanent labels at key positions indicated on the drawings so that personnel can understand that the circuit should be left "ON". The label shall be on a corrosion resistant metal plate and shall read as follows: "THIS CIRCUIT SUPPLIES POWER TO THE ELECTRIC SUMP PUMPS IN THE UNDERGROUND HEAT DISTRIBUTION SYSTEM. THIS CIRCUIT MUST BE "ON" AT ALL TIMES, OTHERWISE EXTENSIVE DAMAGE WILL OCCUR TO THE UNDERGROUND HEAT DISTRIBUTION SYSTEM AND PREMATURE FAILURE WILL OCCUR". Where plastic chilled water piping is interconnected with heating system changeover valves, ensure that design includes means to preclude damage to plastic chilled water piping. This can be accomplished either by using changeover valves that ensure tight shut-off or by using enough metal piping on chilled water side of changeover valve to prevent damage to plastic chilled water piping. 1.1 REFERENCES NOTE: This paragraph is used to list the publications cited in the text of the guide specification. The publications are referred to in the text by basic designation only and listed in this paragraph by organization, designation, date, and title. Use the Reference Wizard's Check Reference feature when you add a RID outside of the Section's Reference Article to automatically place the reference in the Reference Article. Also use the Reference Wizard's Check Reference feature to update the issue dates. References not used in the text will automatically be deleted from this section of the project specification when you choose to reconcile references in the publish print process. The publications listed below form a part of this specification to the extent referenced. The publications are referred to within the text by the basic designation only. AMERICAN WATER WORKS ASSOCIATION (AWWA)AWWA C606(2006) Grooved and Shouldered JointsASME INTERNATIONAL (ASME)ASME B1.20.1(1983; R 2006) Pipe Threads, General Purpose (Inch)ASME B16.11(2005) Forged Fittings, Socket-Welding and ThreadedASME B16.18(2001; R 2005) Cast Copper Alloy Solder Joint Pressure FittingsASME B16.22(2001; R 2005) Standard for Wrought Copper and Copper Alloy Solder Joint Pressure FittingsASME B16.26(2006) Standard for Cast Copper Alloy Fittings for Flared Copper TubesASME B16.9(2007) Standard for Factory-Made Wrought Steel Buttwelding FittingsASME B31.1(2007; Addenda 2008) Power PipingASME BPVC SEC IX(2007; Addenda 2008) Boiler and Pressure Vessel Code; Section IX, Welding and Brazing QualificationsASTM INTERNATIONAL (ASTM)ASTM A 105/A 105M(2005) Standard Specification for Carbon Steel Forgings for Piping ApplicationsASTM A 106/A 106M(2008) Standard Specification for Seamless Carbon Steel Pipe for High-Temperature ServiceASTM A 183(2003) Standard Specification for Carbon Steel Track Bolts and NutsASTM A 234/A 234M(2007) Standard Specification for Piping Fittings of Wrought Carbon Steel and Alloy Steel for Moderate and High Temperature ServiceASTM A 53/A 53M(2007) Standard Specification for Pipe, Steel, Black and Hot-Dipped, Zinc-Coated, Welded and SeamlessASTM A 536(1984e1; R 2004) Standard Specification for Ductile Iron CastingsASTM B 62(2002) Standard Specification for Composition Bronze or Ounce Metal CastingsASTM B 75(2002) Standard Specification for Seamless Copper TubeASTM B 75M(1999; R 2005) Standard Specification for Seamless Copper Tube (Metric)ASTM B 88(2003) Standard Specification for Seamless Copper Water TubeASTM B 88M(2005) Standard Specification for Seamless Copper Water Tube (Metric)ASTM C 518(2004) Steady-State Thermal Transmission Properties by Means of the Heat Flow Meter ApparatusASTM C 591(2008) Standard Specification for Unfaced Preformed Rigid Cellular Polyisocyanurate Thermal InsulationASTM D 1384(2005e1) Corrosion Test for Engine Coolants in GlasswareASTM D 1784(2008) Standard Specification for Rigid Poly(Vinyl Chloride) (PVC) Compounds and Chlorinated Poly(Vinyl Chloride) (CPVC) CompoundsASTM D 2000(2008) Standard Classification System for Rubber Products in Automotive ApplicationsASTM D 2241(2005) Standard Specification for Poly(Vinyl Chloride) (PVC) Pressure-Rated Pipe (SDR Series)ASTM D 2564(2004e1) Standard Specification for Solvent Cements for Poly(Vinyl Chloride) (PVC) Plastic Piping SystemsASTM D 2996(2001; R 2007e1) Filament-Wound "Fiberglass" (Glass-Fiber-Reinforced Thermosetting-Resin) PipeASTM D 2997(2001; R 2007e1) Centrifugally Cast "Fiberglass" (Glass-Fiber-Reinforced Thermosetting-Resin) PipeASTM D 3139(1998; R 2005) Joints for Plastic Pressure Pipes Using Flexible Elastomeric SealsASTM D 3350(2008) Polyethylene Plastics Pipe and Fittings MaterialsASTM D 5685(2005) "Fiberglass" (Glass-Fiber-Reinforced Thermosetting-Resin) Pressure Pipe FittingsASTM F 477(2008) Standard Specification for Elastomeric Seals (Gaskets) for Joining Plastic PipeCOPPER DEVELOPMENT ASSOCIATION (CDA)CDA A4015(1994; R 1995) Copper Tube HandbookMANUFACTURERS STANDARDIZATION SOCIETY OF THE VALVE AND FITTINGS INDUSTRY (MSS)MSS SP-73(2003) Brazing Joints for Copper and Copper Alloy Pressure Fittings1.2 SYSTEM DESCRIPTION The system consists of a buried prefabricated [chilled water] [and] [low temperature hot water] [dual temperature] distribution system including service connections to a point 150 mm 6 inches inside of the building. The contract drawings show the specific arrangement of piping, sizes and grades of pipe, and other details. The system is designed for an operating pressure of [_____] kPa psig and an operating temperature of [[_____] degrees C F for hot water] [and] [[_____] degrees C F for chilled water]. 1.3 SUBMITTALS NOTE: Review submittal description (SD) definitions in Section 01 33 00 SUBMITTAL PROCEDURES and edit the following list to reflect only the submittals required for the project. Submittals should be kept to the minimum required for adequate quality control. A “G” following a submittal item indicates that the submittal requires Government approval. Some submittals are already marked with a “G”. Only delete an existing “G” if the submittal item is not complex and can be reviewed through the Contractor’s Quality Control system. Only add a “G” if the submittal is sufficiently important or complex in context of the project. For submittals requiring Government approval on Army projects, a code of up to three characters within the submittal tags may be used following the "G" designation to indicate the approving authority. Codes for Army projects using the Resident Management System (RMS) are: "AE" for Architect-Engineer; "DO" for District Office (Engineering Division or other organization in the District Office); "AO" for Area Office; "RO" for Resident Office; and "PO" for Project Office. Codes following the "G" typically are not used for Navy, Air Force, and NASA projects. Choose the first bracketed item for Navy, Air Force and NASA projects, or choose the second bracketed item for Army projects. Government approval is required for submittals with a "G" designation; submittals not having a "G" designation are for [Contractor Quality Control approval.][information only. When used, a designation following the "G" designation identifies the office that will review the submittal for the Government.] Submit the following in accordance with Section 01 33 00 SUBMITTAL PROCEDURES: _{SD-02 Shop Drawings Distribution System} Detail drawings consisting of fabrication and assembly drawings, for all parts of the work in sufficient detail to check conformity with the requirements of the contract documents, prior to installation. Show in the detail drawings complete piping, wiring and schematic diagrams and any other details to demonstrate that the system has been coordinated and will properly function as a unit. Show on the drawings proposed layout, method of compensation for pipe expansion and contraction, anchorage of equipment and appurtenances, and equipment relationship to other parts of the work including clearances required for maintenance and operation. Clearly identify on the drawings any proposed deviations from the requirements of the contract documents. _{SD-03 Product Data Distribution System} Data composed of catalog cuts, brochures, circulars, specifications and product data, and printed information in sufficient detail and scope to verify compliance with the requirements of the contract documents. _{SD-07 Certificates Distribution System} The manufacturer's or system fabricator's written certification stating that the distribution system furnished meets all the requirements of this specification. _Welding Prior to welding operations, a copy of qualified procedures and a list of names and identification symbols of qualified welders and welding operators. _{SD-10 Operation and Maintenance Data Distribution System}[; _G][; _{G, [_____]}] [Six] [_____] copies of operation and [6] [_____] copies of maintenance manuals for the equipment furnished, 1 complete set prior to performance testing and the remainder upon acceptance. Detail in the operation manuals the step-by-step procedures required for equipment startup, operation, and shutdown. Include in the operation manuals the manufacturer's name, model number, parts list, and brief description of all equipment and their basic operating features. List in the maintenance manuals routine maintenance procedures, possible breakdowns and repairs, and troubleshooting guides. Include in the maintenance manuals piping and equipment layout and simplified wiring and control diagrams of the equipment system as installed. Manuals shall be approved prior to the field performance testing. 1.4 QUALITY ASSURANCE NOTE: If need exists for more stringent requirements for weldments, delete the first bracketed statement. [Weld piping in accordance with qualified procedures using performance qualified welders and welding operators. Qualify procedures and welders in accordance with ASME BPVC SEC IX. _Welding procedures qualified by others, and welders and welding operators qualified by another employer may be accepted as permitted by ASME B31.1. Notify the Contracting Officer 24 hours in advance of tests performed at the work site, if practicable. The welder or welding operator shall apply the personally assigned symbol near each weld made as a permanent record. Weld structural members in accordance with Section 05 05 23 WELDING, STRUCTURAL.] [Welding and nondestructive testing procedures are specified in Section 43 02 00 WELDING PRESSURE PIPING.] 1.5 DELIVERY, STORAGE, AND HANDLING After delivery to the jobsite, protect all materials and equipment from anything which could cause damage to the material or equipment. Seal piping at each end to keep the interior clean and free of dirt and debris. Keep fittings together and keep their interior surfaces clean at all times. Insulation shall be kept dry and clean. PART 2 PRODUCTS 2.1 STANDARD PRODUCTS Provide system components which are standard products of a manufacturer regularly engaged in the manufacture of the product and that essentially duplicate items that have been in satisfactory use for at least 2 years prior to bid opening. The system shall be supported by a service organization that is, in the opinion of the Contracting Officer, reasonably convenient to the site. 2.2 PIPING AND CASING MATERIALS 2.2.1 General Metallic pressure pipe, fittings, and piping accessories shall conform to the requirements of ASME B31.1 and shall be types suitable for the temperature and pressure of the water. 2.2.2 Piping NOTE: Designer will eliminate only the materials which are not satisfactory for his design. All carrier pipe is acceptable for chilled water systems. All carrier pipe except PVC is acceptable for low temperature hot water. Do not allow Reinforced Thermosetting Resin Pipe (RTRP) in locations where heating water temperature cannot be assured to be less than 93 degrees C (200 degrees F). 2.2.2.1 Steel Pipe Piping shall conform to ASTM A 53/A 53M, Grade B, standard weight, black or to ASTM A 106/A 106M, Grade B, standard weight. 2.2.2.2 Copper Tubing Copper tubing shall conform to ASTM B 88M ASTM B 88, Type K or L. 2.2.2.3 Reinforced Thermosetting Resin Pipe (RTRP) RTRP pipe shall conform to [ASTM D 2996][ASTM D 2997]. 2.2.2.4 Polyvinyl Chloride (PVC) Pipe NOTE: PVC carrier pipe is limited to 24 degrees C (75 degrees F) service. Pressure rating of plastic piping varies with temperature and must be considered in design. PVC pipe with SDR 26 is rated for 1100 kPa (160 psi) working pressure at 23 degrees C (73 degrees F). PVC pipe shall conform to ASTM D 2241 with a Standard Thermoplastic Pipe Dimension Ratio (SDR) of 26 and PVC 1120 or 1220 as the material. 2.2.2.5 Joints and Fittings for Copper Tubing Wrought copper and bronze solder-joint pressure fittings shall conform to ASME B16.22 and ASTM B 75M ASTM B 75 . Cast copper alloy solder-joint pressure fittings shall conform to ASME B16.18. Cast copper alloy fittings for flared copper tube shall conform to ASME B16.26 and ASTM B 62. Brass or bronze adapters for brazed tubing may be used for connecting tubing to flanges and to threaded ends of valves and equipment. Extracted brazed tee joints produced with an acceptable tool and installed as recommended by the manufacturer may be used. Grooved mechanical joints and fittings shall be designed for not less than 862 kPa 125 psig service and shall be the product of the same manufacturer. Grooved fitting and mechanical coupling housing shall be ductile iron conforming to ASTM A 536. Gaskets for use in grooved joints shall be molded synthetic polymer of pressure responsive design and shall conform to ASTM D 2000 for circulating medium up to 110 degrees C 230 degrees F. Grooved joints shall conform to AWWA C606. Coupling nuts and bolts for use in grooved joints shall be steel and shall conform to ASTM A 183. 2.2.3 Casings 2.2.3.1 Polyvinyl Chloride (PVC) Casing PVC casings shall conform to ASTM D 1784, Class 12454-B with a minimum thickness equal to the greater of 1/100 the diameter of the casing or 1.50 mm 60 mils. 2.2.3.2 Polyethylene (PE) Casing NOTE: If the distribution system is to be installed when the temperature is cold, the polyethylene casing is less susceptible to cracking from the cold. Polyethylene casings shall conform to ASTM D 3350, Type III, Class C, Category 3 or 4, Grade P 34 with thickness as follows:                Casing Diameter               Minimum Thickness                    (in mm)                        (in mm)                250 and smaller                       3                250 to 450                            4                450 to 600                            5                over 600                              6                Casing Diameter               Minimum Thickness                  (in inches)                     (in mils)                10 and smaller                      125                10 to 18                            150                18 through 24                       200                over 24                             225 2.2.3.3 Reinforced Thermosetting Resin Pipe (RTRP) Casing RTRP casing shall be of the same material as the pipe, with casing thickness as follows:                Casing Diameter               Minimum Thickness                    (in mm)                        (in mm)                200 and smaller                      1.2                     250                               2                     300                             2.7                     350                             2.9                  400 to 450                           3                     500                             3.2                     600                             3.9                Casing Diameter               Minimum Thickness                  (in inches)                     (in mils)                8 and smaller                         70                      10                              80                      12                             105                      14                             115                   16 to 18                          120                      20                             125                      24                             155 2.3 PIPING CONNECTIONS 2.3.1 Steel Pipe Steel pipe smaller than 19 mm 3/4 inch may be threaded; otherwise, all steel pipe shall be welded. Steel welding fittings shall conform to the requirements of ASTM A 105/A 105M or ASTM A 234/A 234M. Welding fittings shall also conform to ASME B16.9 for buttweld fittings and ASME B16.11 for socket-weld fittings. Long radius buttwelding elbows conforming to ASME B16.9 shall be used whenever space permits. Pipe Threads shall conform to ASME B1.20.1 . Pipe to be threaded shall be schedule 80. 2.3.2 Copper Pipe Copper pipe shall be brazed or connected using an insulated pipe coupling. Wrought copper or cast copper alloy solder joint pressure fittings shall conform to MSS SP-73. Insulated pipe couplings for copper pipe shall be cast bronze containing an O-ring seal on each end and shall be jacketed and sealed to act as an expansion joint. 2.3.3 Plastic Pipe a. Pipe, fittings, flanges, and couplings shall have end connections of the adhesive bell and spigot type. Threaded piping, including pipe, fittings, flanges, and couplings, will not be permitted. b. Flanged Connections: Flat face flanged connections shall be provided between plastic piping and metal piping. Plastic flanges shall be suitable for connection to ASME Class 150 flanges. c. RTRP Piping Sizes: When piping sizes other than 50, 75, 100, 150, and 200 mm 2, 3, 4, 6, and 8 inches are indicated, the next larger piping size shall be provided. The connecting system piping shall be of the same size or increased to meet the next size of RTRP piping. 2.3.3.1 General Plastic fittings shall be made of the same type and grade of material as the piping to which they will be connected and shall be furnished by the manufacturer who supplies the pipe. Fittings shall have temperature and pressure ratings not less than those of the connecting piping. 2.3.3.2 Polyvinyl Chloride (PVC) Polyvinyl chloride (PVC) pipe shall be solvent welded or connected using bell and spigot connections. The solvent used to connect fittings and pipe shall conform to the requirements of ASTM D 2564. Bell and spigot joints utilizing elastomeric seals shall conform to the requirements of ASTM D 3139. The elastomeric seals shall conform to ASTM F 477 . 2.3.3.3 Reinforced Thermosetting Resin Plastic (RTRP) Reinforced thermosetting resin plastic pipe shall be joined using fittings and adhesive furnished by the pipe manufacturer in accordance with ASTM D 5685. 2.4 END SEALS 2.4.1 General Each preinsulated section of piping shall have a complete sealing of the insulation to provide a permanent water and vapor seal at each end of the preinsulated section of piping. Preinsulated sections of piping modified in the field shall be provided with an end seal which is equivalent to the end seals furnished with the preinsulated section of piping. End seals must be tested and certified in accordance with paragraph Casing and End Seal Testing and Certification. 2.4.2 Types End seals provided shall be one of the following types: a. Carrying the outer casing over tapered pipe insulation ends and extending it to the carrier pipe. Sufficient surface bonding area shall be provided between the casing and the carrier pipe. b. Using specially designed molded caps made of polyethylene or rubber of standard manufactured thickness. A minimum 40 mm 1-1/2 inch surface bonding area shall be provided between the cap and both the casing and carrier pipe. c. Using elastomer-ring end seals designed and dimensioned to fit in the annular space between the casing and the carrier pipe. d. Using a waterproof mastic seal vapor barrier over the exposed insulation ends. e. Shrink sleeves. 2.4.3 Casing and End Seal Testing and Certification Testing and certification procedures by an independent testing laboratory shall demonstrate that casings and end seals are capable of resisting penetration of water into the casing and insulation. The test shall be performed on the type of prefabricated system to be furnished. If more than one type of prefabricated system is to be used, then the tests shall be performed on each type. The test shall consist of hot and cold cycle testing followed by immersion in a water filled chamber with a head pressure. The hot and cold cycle testing shall consist of 14 days of temperature cycling. A fluid with a temperature of 5 degrees C 40 degrees F shall circulate through the carrier pipe alternating every 24-hours with a fluid with a temperature of 95 degrees C 200 degrees F circulating through the carrier pipe for a low temperature hot water or dual temperature service or 24 degrees C 75 degrees F for a chilled water service. While the hot and cold cycle test is being performed, the test sample is either buried or encased in dry bedding sand with a minimum of 300 mm 12 inches of sand all around the test sample. The carrier pipe size of the test sample shall be 80 mm 3 inches in diameter and shall be restrained during the test period. The insulation thickness shall not exceed the maximum thickness provided for the piping in the project. Transition time for temperature cycle testing shall not exceed 15 minutes in going from cold to hot and 30 minutes in going from hot to cold. The fluid in the carrier pipe may be water, oil or heat transfer fluid. Following the hot and cold cycling test, the test sample shall be immersed in a water filled chamber. The pressure on the highest point of the test sample shall not be less than 60 kPa 20 feet of water head pressure subjected over the entire length of the 2.4 m 8 foot test sample of prefabricated pipe. The water shall contain a dye penetrant, which will be used to check for end seal leakage. The pressure in the chamber must be held for not less than 48 hours. Upon completion of this pressure test, the test sample shall be cut open. With the use of a light that will readily show the presence of the dye that was in the water, the test sample shall be inspected. Evidence of the dye inside the test sample shall indicate that the end seal is not acceptable and cannot be certified. 2.5 INSULATION Comply with EPA requirements in accordance with Section 01 62 35 RECYCLED / RECOVERED MATERIALS. 2.5.1 Factory Applied Insulation NOTE: An insulation thickness of 20 mm (0.9 inch) is normally sufficient for these systems. However, in cases where the cost of energy used for these systems is high, a life cycle cost analysis should be performed to determine whether additional insulation is cost effective. Prefabricated pipe and fittings shall be insulated in the factory. Foam insulation for prefabricated insulated pipe and fittings shall be polyurethane foam meeting the requirements of ASTM C 591 having a density not less than 32 kg per cubic meter 2 pounds per cubic foot (pcf). The polyurethane foam shall completely fill the annular space between the carrier pipe and the casing. Insulation thickness shall be a minimum of [20] [_____] mm [0.9] [_____] inches. The insulation thermal conductivity factor shall not exceed the numerical value of 0.02 W/mK 0.15 Btu-inch/square foot-degree F-hour at 24 degrees C 75 degrees F, when tested in accordance with ASTM C 518 . Manufacturer shall certify that the insulated pipe is free of insulation voids. 2.5.2 Field Applied Insulation Field applied insulation for fittings, and field casing closures, if required, and other piping system accessories shall be polyurethane matching the pipe insulation. Thickness shall match adjacent piping insulation thickness. Buried fittings and accessories shall have field applied polyurethane insulation to match adjacent piping and shall be protected with a covering matching the pipe casing. Shrink sleeves with a minimum thickness of 1.3 mm 50 mils shall be provided over casing connection joints. 2.6 CONCRETE VALVE MANHOLES NOTE: Valve manholes must be detailed on the drawings with complete concrete structural details including details of any waterproofing. Concrete valve manholes shall be provided in accordance with Section 33 60 01 VALVES, PIPING AND EQUIPMENT IN VALVE MANHOLES and manufactured in accordance with Section 03 40 00.00 10 PLANT-PRECAST CONCRETE PRODUCTS FOR BELOW GRADE CONSTRUCTION. 2.7 PIPING AND EQUIPMENT IN VALVE MANHOLES Piping and equipment in valve manholes shall be provided in accordance with Section 33 60 01 VALVES, PIPING, AND EQUIPMENT IN VALVE MANHOLES. 2.8 TREATED WATER NOTE: If freeze protection for chilled water is not required, this paragraph should be deleted. When a glycol system is used, the size of the HVAC systems should be corrected due to changes in specific heat and viscosity. ASHRAE's "HVAC Systems and Equipment Handbook" should be consulted for the appropriate calculation procedures. Ethylene glycol should be used for HVAC systems. However, if the heat transfer media has the possibility of mixing with a potable water system, propylene glycol should be used. The required concentration should be entered based upon the anticipated ambient or operating temperature. A [_____] percent concentration by volume of industrial grade [ethylene] [propylene] glycol shall be provided for the system. Glycol shall be tested in accordance with ASTM D 1384 with less than 0.013 mm 0.5 mils penetration per year for all system metals. The glycol shall contain corrosion inhibitors. Silicate based inhibitors shall not be used. The solution shall be compatible with pump seals, other elements of the system, and water treatment chemicals used within the system. PART 3 EXECUTION 3.1 EXAMINATION After becoming familiar with all details of the work, verify all dimensions in the field and advise the Contracting Officer of any discrepancy before performing the work. 3.2 INSTALLATION For all preinsulated, prefabricated systems, obtain the services of a trained representative of the pipe system manufacturer to instruct the Contractor's work forces in the installation procedures to ensure that the system is installed in accordance with the manufacturer's published instructions and the plans and specifications. The manufacturer's representative shall be a person who regularly performs such duties for the manufacturer. Furnish the Contracting Officer a list of names of personnel trained and certified by the pipe system manufacturer in the installation of this system. Only personnel whose names appear on the list will be allowed to install the system. The list shall not be more than 1 year old. 3.3 PIPING SYSTEMS 3.3.1 Buried Insulated Systems Buried insulated systems shall consist of carrier pipe, insulation, casing, end seals, fittings and accessories as specified. 3.3.2 Buried Uninsulated Systems NOTE: Buried uninsulated piping systems shall be used only where justified by a life cycle cost analysis that includes the decreased initial cost of the distribution system, increased operating energy cost due to the heat gain or heat loss in the piping system, leakage and the cost of any increased heating or cooling equipment capacity. Buried uninsulated steel pipe must have a protective coating in all cases and cathodic protection where required by soil conditions. Buried uninsulated systems shall consist of carrier pipe, fittings and accessories as specified. 3.4 VALVE MANHOLES AND PIPING EQUIPMENT IN VALVE MANHOLES Valve manholes and piping and equipment in valve manholes shall be installed in accordance with Section 33 60 01 VALVES, PIPING, AND EQUIPMENT IN VALVE MANHOLES. 3.5 THRUST BLOCKS NOTE: Designer will indicate dimensions and locations of required thrust blocks on the drawings. Blocks will be sized for specific fittings and for allowable in situ soil pressures. Thrust blocks shall be designed for the maximum test pressure specified. Install thrust blocks at the locations shown or recommended by the pipe system manufacturer. Thrust blocks may not be required on all systems, and the need for thrust blocks shall be as recommended by the system manufacturer. Thrust blocks, if necessary, shall be installed at all changes in direction, changes in size, valves and terminal ends, such as plugs, caps and tees. Thrust blocks shall be concrete having a compressive strength of not less than 14 MPa 2000 psi after 28 days and shall be in accordance with Section 03 31 00.00 10 CAST-IN-PLACE STRUCTURAL CONCRETE. Thrust blocks shall be placed between solid ground and the fitting to be anchored. Unless otherwise indicated or directed, the base and the thrust bearing sides of the thrust blocks shall be poured directly against undisturbed earth. The sides of the thrust blocks not subject to thrust may be poured against forms. Thrust blocks shall be placed so that the joints for all fittings will be accessible for repair wherever possible. No pipe joint shall be embedded in concrete unless the assembly has previously been hydrostatically tested. The thrust blocks shall provide for transfer of thrusts and reactions without exceeding the allowable stress of the concrete and shall be installed in accordance with pipe manufacturer's instructions. In muck or peat, all thrusts shall be resisted by piles or tie rods to solid foundations or by removal of peat or muck which shall be replaced with ballast of sufficient stability to resist thrusts. 3.6 INSTALLATION OF PIPING SYSTEMS Install the piping system furnished in accordance with the piping system manufacturer's instructions. Piping shall be installed without springing or forcing other than what has been calculated for cold spring. Pipe ends shall have burrs removed by reaming and shall be installed to permit free expansion and contraction without damage to joints or hangers. Nonmetallic pipe cut in the field shall be machined to fit couplings or joints and shall be coated or treated to match standard factory coated ends. Copper tubing shall not be installed in the same trench with ferrous piping materials. When nonferrous metallic pipe (e.g., copper tubing) crosses any ferrous piping material, a minimum vertical separation of 300 mm12 inches shall be maintained between pipes. Connections between different types of pipe and accessories shall be made with transition fittings approved by the manufacturer of the piping system. 3.6.1 Pitching of Horizontal Piping Horizontal piping shall be pitched at a grade of not less than 40 mm in 1 m1 inch in 20 feet toward the drain points unless otherwise indicated. 3.6.2 Open Ends Open ends of pipelines and equipment shall be properly capped or plugged during installation to keep dirt and other foreign matter out of the system. 3.6.3 Cutting Prefabricated Piping Sections Where prefabricated pipe sections are field cut, new end seals similar to the factory applied end seal shall be provided and installed in accordance with the manufacturer's instructions. 3.6.4 Joints 3.6.4.1 Welded Joints Welded joints between sections of pipe and between pipe and fittings shall be provided where specified or indicated. 3.6.4.2 Threaded Joints Threaded joints shall not be used belowground. Joints shall be made tight with polytetrafluoroethylene tape applied to the male threads only. Not more than 3 threads shall show after the joint is made up. 3.6.4.3 Grooved Mechanical Joints Grooves shall be prepared according to the coupling manufacturer's instructions. Grooved fittings, couplings, and grooving tools shall be the products of the same manufacturer. Pipe and groove dimensions shall comply with the tolerances specified by the coupling manufacturer. The diameter of grooves made in the field shall be measured using a "go/no-go" gauge, vernier or dial caliper, narrow-land micrometer, or other method specifically approved by the coupling manufacturer for the intended application. Groove width and dimension of groove from end of pipe shall be measured and recorded for each change in grooving tool setup to verify compliance with coupling manufacturer's tolerances. Grooved joints shall not be used in concealed locations. 3.6.4.4 Brazed Joints Brazed joints for copper pipe and fittings shall conform to CDA A4015. Brazing alloys melting above 593.3 degrees C 1100 degrees F shall be utilized. 3.6.4.5 Nonmetallic Pipe Joints Nonmetallic pipe joints shall be installed in accordance with the written instructions of the manufacturer. 3.6.5 Expansion Loops NOTE: In the design for expansion compensation, strive to use L- and Z-bends in lieu of expansion loops wherever possible. If expansion compensation is needed, expansion loops and expansion bends (Z- and L- type) shall be factory fabricated of casing, insulation, and carrier piping identical to that furnished for straight runs. Expansion loops and bends shall be properly designed in accordance with the allowable stress limits indicated in ASME B31.1 for the type of pipe used. Expansion loops and bends shall be shipped to the jobsite in the maximum size sections feasible to minimize the number of field joints. The expansion loops and bends casing and insulation where applicable, shall be suitably sized to accommodate pipe movement. Field joints shall be made in straight runs of the expansion loops and bends, and the number shall be kept to a minimum. For steel pipe, cold springing shall not be allowed when sizing the expansion loops and bends, but piping shall be cold sprung one-half the calculated maximum operational expansion during field assembly. Pipe stress in expansion loops and bends shall conform to the requirements for expansion loops specified in ASME B31.1. 3.6.6 Anchors Anchor design shall be in accordance with the published data of the manufacturer and for prefabricated systems shall be factory fabricated by the prefabricated system manufacturer. In all cases, the design shall be such that water penetration, condensation, or vapor transmission will not wet the insulation. 3.6.7 Field Casing Closures NOTE: Whether or not to insulate the exposed section of pipe and cover with a casing at the joint between the sections of the pipe must be determined by a life cycle cost analysis. Factors to consider include heat loss/heat gain through the uninsulated section, cost to insulate and cover the uninsulated section, and the usage per year of the prefabricated system. Normally the exposed section is insulated and covered. The joint between the sections of pipe must be protected from corrosion. Field insulation and encasement of joints shall be accomplished after the visual and pressure tests specified are completed. Field insulation and encasement shall be in accordance with the manufacturer's written instructions. Thickness dimensions of the insulation and casing materials shall not be less than those of the adjoining prefabricated section. Insulating material shall be foamed in place polyurethane. Care should be taken to ensure that field closures are made under conditions of temperature and cleanliness required to produce a sound, continuous vapor barrier. A standard polyethylene heat shrink sleeve shall be installed over the casing and shall have a 150 mm 6 inch minimum overlap at each end. 3.6.8 Underground Warning Tape NOTE: Select the proper tape for the project. Tape with metallic core is utilized for nonferrous pipe systems to locate piping with pipe location devices. Underground warning tape shall be buried above the piping during the trench backfilling and shall be buried approximately 300 mm12 inchesdeep. Tape shall be [0.1 mm 0.004 inch thick polyethylene tape] [polyethylene tape with metallic core]. Tape shall be 150 mm 6 inches wide and be printed with repetitive caution warnings along its length. Tapes shall be yellow in color with black letters. Tape color and lettering shall not be affected by moisture or other substances contained in the backfill material. 3.6.9 Markers for Underground Piping NOTE: Indicate the location of the markers on the drawings for projects that require markers. Delete the paragraph if not needed in the project. Markers for underground piping shall be placed as indicated approximately 600 mm 2 feet to the right of the _{distribution system} and referenced to the flow direction in the supply line. The marker shall be concrete 150 mm 6 inch square or round section [600] [900] mm [2] [3] feet long. The top edge of the marker shall have a minimum 13 mm 1/2 inch chamfer all around. The letters [CHW] [LHW] [DTW] shall be impressed or cast on the top of the markers to indicate the type of system that is being identified. Each letter shall be formed with a V-shaped groove and shall have a width of stroke at least 6 mm 1/4 inch at the top and depth of 6 mm 1/4 inch. The top of the marker shall protrude not more than [25] [50] [75] [100] mm [1] [2] [3] [4] inches above finished grade. 3.7 EARTHWORK Earthwork shall be performed in accordance with Section 31 00 00 EARTHWORK. 3.8 ELECTRICAL WORK Electrical work shall be performed in accordance with either Section 33 70 02.00 10 ELECTRICAL DISTRIBUTION SYSTEM, UNDERGROUND or Section 33 71 01 OVERHEAD TRANSMISSION AND DISTRIBUTION. 3.9 TESTING Conduct tests before, during, and after installation of the system. Provide all instruments, equipment, facilities, and labor required to properly conduct the tests. Test pressure gauges for a specific test shall have dials indicating not less than 1.5 times nor more than 2 times the test pressure. It is the Contractor's responsibility to make the pipe system workable at no cost to the Government. 3.9.1 Metallic Pipe Welds NOTE: Where welding of piping is not required or there are no prior experiences which may warrant radiographic inspection of the welded joints this entire paragraph should be deleted. An approved independent testing firm or firms regularly engaged in radiographic testing shall perform a radiographic examination of the field welds. The radiographic testing shall be performed in accordance with ASME B31.1. All radiographs shall be reviewed and interpreted by a Certified Level III Radiographer employed by the testing firm. Any welds found to be unacceptable shall be removed, rewelded and radiographically reexamined in accordance with the above criteria. Such repair and reexamination shall be accomplished at no cost to the Government. 3.9.2 Carrier Pipe Cleaning and Testing Distribution piping shall be tested as required before backfilling and with all joints exposed. The area between joints may be backfilled as necessary to prevent pipe movement. 3.9.2.1 Cleaning Carrier Pipe Prior to testing, the interior of the carrier pipe shall be cleaned of foreign materials by thorough flushing with clean water. Water shall be circulated at a velocity between 2 and 3 m/s (7 and 10 feet per second) for a minimum of 4 hours. If required, temporary and/or supplementary pumps shall be provided to ensure that required velocity is achieved. System strainers shall be cleaned after the flushing operation is complete. Temporary strainers shall be installed as required. After flushing, the water shall remain in the piping system for testing of the system. All air shall be removed from the system prior to starting the tests. 3.9.2.2 Hydrostatic Pressure Cycling and Tests Hydrostatic pressure cycling shall have 4 cycles. Each cycle shall consist of a 10 minute period at 1000 kPa 150 psig followed by a 5 minute period at a pressure less than 350 kPa 50 psig. The next cycle shall begin immediately following the completion of the previous cycle. Pressure rise and drop shall not exceed 690 kPa 100 psi per minute. The pressure gauge shall be located and the pressure measured at the opposite end of the system from where the pressure is applied. After completion of the hydrostatic pressure cycling, the first hydrostatic pressure test shall be performed. During the first hydrostatic pressure test, the system shall be proven tight at a pressure of 1.5 times the working pressure up to 1000 kPa 150 psig. This pressure shall be held for a minimum of 1 hour. The method of pressurizing the system shall be disconnected from the system before starting the 1 hour pressure holding period. If the pressure cannot be held for the specified length of time, the cause of pressure loss shall be determined, corrected and the hydrostatic pressure cycling and first hydrostatic pressure test shall be repeated until the system can hold the required pressure for at least 1 hour. After successful completion of the first hydrostatic pressure test, the water shall be drained out of the piping system and the piping system filled with treated water as defined in paragraph TREATED WATER for the remaining tests and for permanent operation of the system. The hydrostatic pressure cycling and tests shall be repeated after the system has been filled with treated water, using the same test conditions and criteria. 3.9.2.3 Operational Test Operational test shall be performed on the complete system or testable portions thereof. The test shall be conducted with full design flows and operating temperatures in all runs of piping as if in service, to demonstrate satisfactory function and operating effectiveness. The operational test will have two cycles. Each cycle shall consist of a 6-hour period with treated water in the system at the maximum operating temperature of [_____] degrees C F and maximum flow rate, and a period of at least 6-hours with no flow. For dual temperature systems, the first cycle shall use the heating temperature of [_____] degrees C F and the second cycle the cooling temperature of [_____] degrees C F of the designed system. Supply temporary pumps, piping connections, boilers, chillers and the gauges required to circulate the water at the desired temperatures and flow rates. Water shall be circulated through supply lines and returned through the return piping to demonstrate that the pressure drop is compatible with the flow rate and size of pipe and to show that obstructions do not exist in the piping system. Any unusual indicated pressure drop will be investigated and any obstructions removed. Any leaks found shall be repaired. After any obstructions have been removed and any leaks repaired, the operational test shall be repeated until successfully passed. 3.9.2.4 Final Hydrostatic Test After successful completion of the operational test, the system shall be pressurized to 1-1/2 times the working pressure up to 1000 kPa 150 psig. This pressure shall be held for a minimum of 4 hours. Means of pressurizing shall be disconnected prior to the start of the 4-hour pressure holding period. If the pressure cannot be held for the specified length of time, the cause of the pressure loss shall be determined, corrected, and all of the hydrostatic pressure cycling and tests repeated.