Thermal Pipe Systems - Pre-insulated, Gasketed Steam and High Temperature Hot Water Pipe - Super Temp-Tite (CSI Specification Format, Plain Text - Word Processor Format) All square bracket locations [ ] call for a choice to be made or user input:

SPECIFICATION SECTION 15521

UNDERGROUND STEAM PIPING

PART 1 - GENERAL

1.01	SECTION INCLUDES

A.	Extent of underground steam piping work is indicated on drawings and/or schedules and by requirements of this Section.

B.	Types of pipe and fittings specified in this Section include the following:

1.	Piping Materials:

a.	Pre-insulated steel piping system.

2.	Pipe Fittings:

a.	Pre-insulated steel fittings to match pipe.

1.02	QUALITY ASSURANCE

A.	Manufacturer's Qualifications: Firms regularly engaged in manufacture of steam piping products of types, materials, and sizes required, whose products have been in satisfactory use in similar service for not less than 3 years.

B.	Installer's Qualifications: [A firm with at least 3 years of successful installation experience on projects with steam piping work similar to that required for project.][An installer who has been trained and certified by the manufacturer to have demonstrated proficiency in the handling and installation of this piping system.]

C. 	All Materials and installation shall be in conformance with the following:

1.	[Applicable State Code]

2.	ANSI B31.1 "Power Piping".

3.	ANSI B31.9 "Building Service Piping".

D.	Acceptable Manufacturers:

1.	Thermal Pipe Systems, Inc.

2.	Or Engineer's approved equal.

1.03	SUBMITTALS

A.	Product Data: Submit manufacturer's technical product data, dimensioned drawings and installation instructions for steam and condensate piping materials and products.

B.	Federal Approval (STT.GS): 	

1.	[Submit a copy of the current Federal Letter of Acceptability for the pre-insulated steel piping system.]

2.	[The supplier must demonstrate that the proposed product conforms to the criteria as specified in the Federal Agency Prequalification Procedures for Underground Heat Distribution Systems and to CEGS 02552.] 

C.	[Record Drawings: At project closeout, submit record drawings of installed steam and condensate piping and piping products.]

D.	[Maintenance Data: Submit maintenance data and parts lists for steam piping materials and products.  Include this data, product data, shop drawings, and record drawings in maintenance manual.]

1.04	DELIVERY, STORAGE, AND HANDLING

A.	Provide factory-applied plastic endcaps on each length of pipe. Maintain endcaps through shipping, storage, and handling as required to prevent pipe-end damage and eliminate dirt and moisture from inside of pipe.

B.	Where possible, store materials inside and protected from weather.  Where outside storage is necessary, elevate above grade and enclose with durable, waterproof wrapping.

C.	Protect flanges and fittings from moisture and dirt by inside storage and enclosure or by packaging with durable, waterproof wrapping.

PART 2 - PRODUCTS

2.01	UNDERGROUND PIPING SYSTEM

A.	Factory Fabricated Pre-insulated Piping System: The piping system and all of its components shall be designed to operate up to 250 psig at 400ºF, plus typical surges.  The system shall be segmented at 20 foot intervals to preclude the spread of groundwater between pipe lengths. Unless otherwise specified, all pipe, fittings, valves, and accessories shall conform to the requirements of ANSI B31.1 and shall be of proper type for the pressure and temperature of the service.

2.02	STEEL CARRIER PIPE

A.	Carrier pipe shall meet the requirements of ASTM [ERW A53] or [Seamless A53 or A106], Schedule [40] [80] [Std Weight] Grades B. The pipe shall be machined and metallized to provide a satisfactory sealing surface for the sealing rings. The metallizing shall be a high nickel alloy applied to an excess thickness and then machined to the required OD.

2.03	BRONZE COUPLING

A.	The bronze coupling in sizes 3", 4", and 6" shall be made to ASTM B62 and in sizes 8", 10", and 12" to ASTM B61. Bronze couplings shall accommodate all thermal expansion.

2.04	TEFLON SEALING RINGS

A.	The molded and machined Teflon sealing rings shall consist of stainless steel, spring loaded TFE seals.

2.05	RUBBER SEALING RINGS

A.	The secondary rubber sealing rings shall be molded heat resistant Aflas compound.  The ring surfaces shall be smooth and free from all porosity and internal voids.

2.06	FIBERGLASS CASING PIPE

A.	The casing for the piping system shall be reinforced thermosetting resin plastic (RTRP) pipe manufactured by the filament winding process.  The casing pipe shall be wound to meet ASTM D2310 classified RTRP-12E.  Thickness shall be not less than 0.187" for pipe sizes 3" & 4" diameter and not less than 0.250" for pipe sizes 6" through 12" diameter.

2.07	RUBBER END SEALS: End seals for the pre-insulated pipe system shall be [EPDM (STT)] [HSN (STT.GS)].

[The end seals for STT shall be an ethylene propylene diene monomer (EPDM) heat resistant compound. The rings shall be molded using a properly vulcanized compound. The ring surface shall be smooth and free from all porosity and internal voids.]

[The end seals for STT.GS shall be a highly saturated nitrile (HSN) heat resistant compound. The rings shall be molded using a properly vulcanized compound. The ring surface shall be smooth and free from all porosity and internal voids.]

2.08	INSULATION

A.	Insulation shall consist of an inner layer of high temperature calcium silicate and an outer layer of polyisocyanurate foam.

1.	Calcium Silicate Insulation: The calcium silicate insulation shall be a hydrous material satisfactory for temperatures to 1200?F. Insulation shall conform to ASTM C-533 and Mil Spec Mil-1-2781.  

2.	Polyisocyanurate Foam Insulation: Polyisocyanurate foam insulation shall meet the following specifications:

Type:  				Two component isocyanurate.
Compressive Strength: 		35 psi parallel minimum at 5% compression.
Shrinkage:  			None at 70ºF
Free Rise Density: 		2.0 to 3.0 lbs/cubic foot
Aged "K" (70ºF - 72 hours): 	0.140 BTU-in/hr-ft²-ºF
Closed Cell Content: 		90%
		
3.	Insulation Thickness shall be as shown in table below:

	Carrier Pipe	------ Insulation Thickness (in.) ------ 
	Size (in.)		Calcium Silicate		Polyisocyanurate	

	3			1.00				1.25		
	4			1.00				1.25		
	6			1.50				1.25		
	8			2.00				1.75		
	10			2.50				1.18	
	12			2.50				1.18	

4.	Insulation concentricity: Carrier pipe shall be concentric to casing pipe. The allowable maximum deviation from center line of carrier pipe shall be plus or minus 1/4 inch at the casing center point and plus or minus 1/16 inch at the end seals.

2.09	INSULATED FITTINGS

A.	Fittings shall be pre-insulated by manufacturer using the same insulation thickness and casing as the pipe.

2.10	WALL PENETRATION SLEEVES

A.	Provide wall penetration sleeves where piping passes through masonry or concrete walls. Sleeves in outside walls below and above grade shall be schedule 40 or standard weight coated black steel pipe or as specified by the Design Engineer. Sleeves shall be held securely in proper position and location during construction. Sleeves shall be of sufficient length to pass through entire thickness of walls or slabs.  Refer to typical detail of wall penetration as shown. In existing concrete manholes or building walls, penetrations may be made using the "core drilling" method, providing care is taken to drill the holes to the size needed and square to the line of the pipe.

2.11	WALL PENETRATION SEALS

A. 	All wall penetrations shall be sealed to prevent water from entering the building or manhole. 

1.	Mechanical Sleeve Seals: Modular, mechanical type, consisting of interlocking synthetic rubber links shaped to continuously fill the annular space between the pipe and sleeve, connected with bolts and pressure plates which cause rubber sealing elements to expand when tightened, providing watertight seal and electrical insulation.
	
2.	Manufacturer:  Subject to compliance with requirements, provide mechanical
sleeve seals of the following:

a.	Thunderline Corp.

b.	Proset

PART 3 - EXECUTION

3.01	GENERAL

A.   	Installation of the piping system shall be done in accordance with the appropriate publications, including ANSI B31.1 and the following specifications and instructions.  A manufacturer's field representative shall conduct a pre-installation clinic to prequalify contract personnel in the proper procedures for the installation. [Certification of instruction and competence shall be issued to those personnel so trained and only those so certified shall be permitted to perform work on the pipe.]  Good workmanlike procedures shall be followed.

B.	Unless otherwise indicated, all piping shall be pitched with a grade of not less than 1 inch in 20 feet in the direction of the steam flow.

C.	Open ends of pipe lines and equipment shall be properly capped or plugged during installation to keep dirt or other foreign matter out of the system.

3.02	RECEIVING AND HANDLING SHIPMENTS

A.	Inspection: Each shipment shall be inspected with care on its arrival.  It is the responsibility of the installation contractor to ascertain whether there has been any loss or damage.  Any pipe or equipment that arrives damaged or is lost in shipment shall be reported by the contractor. Make overall inspection of the load.  If the load has shifted or end packing has been damaged, then inspect each piece carefully for damage.  The ends shall be inspected for scars, nicks, etc. Other obvious defects shall be cause for rejection. Check total quantities of each item against tally sheet (pipe, fittings, etc). Any damaged or missing items shall be noted on the delivery receipt and receipt returned to the carrier.  Notify the carrier immediately and make claim in accordance with the carrier's instructions.  Do not dispose of damaged material; follow procedure as directed by the carrier.

B.	Unloading Instructions: The means by which the pipes are unloaded in the field shall be the decision and responsibility of the installation contractor.  To prevent the possibility of the core pipe from shifting within the casing pipe, do not stand a length on one end or raise it vertically.  Under no condition shall a pipe be dragged along the ground.  Do not lift fitting or pipe by inserting a bar, pipe, etc., inside of the core, since damage to the pipe may result.  If any pipe is damaged in unloading and handling, mark the damaged area and set it aside.  A factory representative shall determine whether damaged casing can be repaired in the field and, if so, shall determine exact method for repair and instruct contractor in making repair.

C.	Storage: Store pipe on a flat surface so as to support the barrel evenly. Store random lengths separately where they will be readily available.  Individual lengths of pipe shall be stacked in piles no higher than 5 feet.
			
D.	Loading Transfer Trucks: Use trucks with long bodies so that pipe lengths do not overhang.  Make certain truck bed is smooth, without cross-strips, bolt heads, or other protrusions that could damage the pipe.  Short body trucks may be used if fitted with racks that properly support the pipe in a horizontal position. The rack shall have supports spaced every 3 feet or less along the pipe lengths. Pad the contact areas to avoid damage to the pipe.
	
3.03	DISTRIBUTING PIPE ALONG TRENCH

A.	Pipe lengths may be strung along the line of the trench so as to minimize additional handling during installation.  Do not remove protection materials from the pipe ends until the pipe is lowered into the trench and ready for assembly.

3.04	EXCAVATION
	
A.	Excavation shall take into account the need for the thrust blocks at all fittings that are direct buried in the ground.  The trench bottom shall give uniform support along the entire length of any pipeline. Where several pipelines are located in a common trench, the trench shall be wide enough to maintain the specified distances between adjacent lines.  The excavation shall be in a straight line except where fittings are located.

3.05	TRENCHING

A.	The trench depth shall allow for a minimum cover height of 36" over the top of the casing pipe.  Keep excavations free of water during construction.  If the Contractor determines it is necessary to remove unsuitable material to a depth greater than specified, refill excavation carried below the depths indicated or directed with specified bedding material and compact in 6" lifts to 95% of maximum density in accordance with ASTM D1557, Method D.  Excavate and replace soil disturbed and weakened by the Contractor's operations or soils permitted to soften from exposure to weather, with bedding material and compact it with a plate-type vibratory compactor.

B.	The width of the trench at the top of the pipe shall be held to the minimum required for efficient and proper installation. The minimum trench width at the top shall be one foot greater than the outside diameter of the casing. Where two or more pipes are in the same trench, the trench must be wide enough to maintain the specified distances between adjacent lines, generally a minimum of 6" in pipe sizes up to 6" diameter, and 12" minimum in sizes 8" and up. The excavation should be in a straight line.

3.06	PLACING PIPE IN THE TRENCH

A.	The pipe shall be mechanically passed into the trench. The latest state and federal safety regulations shall be understood and observed. If slings are necessary, use only canvas straps; no cable or chain slings shall be used.

3.07	BEDDING

A.	Bedding material shall be sand, pea gravel or other materials free of sharp objects, heavy clods, boulders, or frozen lumps as specified by the design engineer. The approved bedding shall be used 6" under, around and over the pipe. Utilize the best professional practices that apply to buried pressure piping.
                                  
3.08	ASSEMBLY OF THE COUPLINGS

A.	Comply with manufacturer's directions for assembly of couplings and installation of piping system in trench.

3.09	TESTING

A.	All carrier pipe joints shall be tested in accordance with the Contract Specifications.  Test shall be hydrostatic test of 150 psi or 1-1/2 times working pressure, whichever is greater, for a period of two hours.

3.10	BACKFILLING

A.	Backfilling of trenches shall progress as rapidly as construction, testing, and acceptance of work permits.  Uniformly compact and grade bottom of trenches.  After installation of bedding material and pipe, place backfilling as follows:

1.	Place initial backfill to a depth of 12" over the top of pipe casing.

2.	Compact the material to a density equivalent to the surrounding undisturbed soil or up to 90% of maximum density (ASTM D1557, Method D), whichever is greater.

3.	Backfill remainder of trench in 1 ft. lifts and compact as above.

4.	For trenches excavated in roads and streets located under structures, place backfill in 6" layers to top of trench and compact each layer to at least 95% maximum density (ASTM D1557, Method D).
	
3.11	FLANGED JOINTS

A.	Flanged joints shall be faced true, provided with gaskets, and made perfectly square and tight.

3.12	THRUST BLOCKS

A.	Thrust blocks shall be installed wherever the pipe line changes direction, as at tees and elbows; changes size, as at reducers and some crosses and tees; stops as a dead end; and develops thrust, as at a valve or similar equipment.  The above situations may occur either where the fittings, etc., are directly buried in the soil or where they are located in a manhole.

B.	Thrust blocks shall be designed for maximum anticipated test pressure. Size and type of thrust blocks depend on pressure, pipe size, and the type of soil.

C.	Thrust blocks shall be installed using a concrete having a compressive strength of not less than 3000 psi minimum ultimate 28 days compressive strength, air entrained, with water reducing admixture.  The table below gives the thrust load at any fitting.  Dead end and anchor loads are equal to TEE shown below.  Thrust blocks shall be poured on and against undisturbed soil or soil tamped to 95% proctor density.

1.	Thrust at Fittings for Concrete Thrust Blocks in pounds at 100 psi:
										
	Size (in.)	TEES		90º Elbow	45º Elbow		 
	
	3	 	962		1,361	 	736
	4		1,590		2,249	 	1,217		
	6		3,447		4,875		2,638	 
	8		5,843		8,263		4,472
	10		9,076		12,836	6,946
	12		12,768	18,056	9,771

2.	For pressure other than 100 psi, increase loads proportionately (example: for 150 psi, multiply by 1.5; for 200 psi, multiply by 2.00; etc.).

D.   	Safe Bearing Loads: The approximate safe bearing loads of various soils given in the following table are for horizontal thrusts when the depth of cover over the top of the pipe exceeds 2 ft.

SOIL						SAFE BEARING LOAD
						 (lbs./sq. ft.)					

Soft Clay						1,000
Sand							2,000
Sand and Gravel					3,000
Sand and Gravel Cemented with Clay		4,000	
Hard Shale						10,000

E.	Pre-insulated fittings shall be provided with thrust plates designed to transfer thrust from the steel pipe to the concrete thrust blocks. The entire surface of the steel plates shall be coated. During manufacture steel plates shall be sealed against FRP casing.

3.13	STARTUP PROCEDURE

A.	Startup procedure shall conform to generally accepted practices and be done in a workmanlike manner. Startup should be done in the presence of the manufacturer's field representative.

B.	The following startup procedure should be followed:

1.	Open drip leg valves on all trap assemblies, taking precautions to keep personnel clear of these areas for at least one hour, or whatever time is required to achieve a "dry" free blow.

2.	Slowly open steam valves to allow steam to enter line and blow through open valves in drip leg until steam is flowing "dry". Six-inch valves and smaller may be cracked open. Eight inch and larger valves should be brought up to pressure by means of a 1" bypass line installed around the valve.  Pressure build up should not exceed 15 psig during this free blow period.

3.	At the end of one hour, check all free blow points to see if "sputter free" steam has been achieved.  Continue at 15 psig until all such sputtering has stopped, at which time all drip leg valves should be closed. 

4.	Allow steam pressure to reach 30 psig (approximately 275ºF) and remain at or near this pressure level for a minimum period of 4 hours.

5.	At the end of 4 hour period, the system may be brought up to operating pressure in increments of 50 psig per hour.

C.	Manufacturer's Written Certification: After testing and prior to start-up of the system, the manufacturer must certify in writing that the system was installed per the manufacturer's installation instructions.

END OF SECTION

UNDERGROUND STEAM PIPING
15521-1