special specification...

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1993 Specifications CSJ 0683-01-070, etc.

SPECIAL SPECIFICATION 3522

Natural Gas Distribution and Service Pipeline Construction

1. Description. This Item shall govern for materials, equipment and labor necessary for the installation of gas distribution and service pipelines. It includes the properties of steel pipeline and pipe material selection for medium density polyethylene (M.D.P.E.) and high density polyethylene (H.D.P.E.) pipeline, fittings and accessories, transportation, storage, handling, construction method, joining procedure, service connection, testing and minimum contractor requirements for the installation of the natural gas distribution and service lines.

The Contractor shall furnish and install all steel pipe and polyethylene pipe, couplings, valves, valve boxes, stop cocks, anodeless risers, transitional fittings, location tracer wire, test stations and any other materials to complete the installation and testing of the gas facility.

2. Materials. The pipe and fitting material for a new pipeline must be able to maintain its structural integrity under the temperature and environmental conditions that are anticipated during the service lifetime. The material should be compatible with the chemical composition of the gas that it is transporting. The manufacturer should provide certification that their product meets the design specifications or standards for its intended use. The material and manufacturer should come from an approved list as shown in Appendix A. The Contractor will inspect and, if necessary, reject materials if they appear defective and will notify the manufacturer of the defective nature.

(1) Steel Distribution Pipeline, Valves, Fittings and Flanges. The steel pipe should be manufactured in accordance with ASTM A-53, “Pipe, Steel, Black and Hot-Dipped, Zinc Coated, Welded and Seamless,” and ANSI B31.8, “Gas Transmission and Distribution Piping Systems.” Steel fittings should follow ASTM A234, “Pipe Fittings of Wrought Carbon Steel and Alloy Steel for Moderate and Elevated Temperatures,” or ANSI B16.11, “Forged Steel Fitting, Socket Welding and Threaded.” A comprehensive list of standardized steel pipe dimensions can be found in ANSI B36.10. ASTM A-53 lists and defines the three types of steel pipe in Appendix X1: Type F- Furnace Butt Welded or Continuous Welded Type E- Electric Resistance Welded, Grades A and B Type S- Seamless, Grades A and B The bending, flattening, and tensile characteristic requirements, as well as the suggested manufacturing method of these types can be found in ASTM A-53. Dimensions, weights and test pressures for plain end or threaded and coupled pipe are available in

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ASTM A-53, Table X2.2 and Table X2.3, respectively. Basic threading data for steel pipes, 6 in. and lower are shown in Table X3.1.

The pipe should be free of split seams or other defects that could cause leakage.

ASTM A234 specifies the material, manufacturing method, tensile requirements, recommended hardness, dimensions, surface characteristics, inspection, certification, product marking and welding repair for wrought carbon steel and alloy steel fittings that are used in pressure piping and pressure vessel fabrication for service in moderate and elevated temperatures.

The Contractor should obtain the most current list of approved manufacturers from the engineers or owner’s representative prior to construction. (See Appendix A for a list of pipe manufacturers of fittings, flanges, valves and couplings.)

(a) Design of Steel Pipe. Steel pipe must be designed with a sufficient wall thickness and must be buried with adequate protection to be able to withstand external pressures and loads that will be imposed on the pipe during its service life.

The design formula for the steel pipe is:

P = ( 2 * S t / D ) * F * E * T, where:

P = design pressure in pounds per square inch (psi) S = yield strength in psi (§192.107) t = nominal wall thickness of pipe (inches) F = Design Factor (§192.111) E = longitudinal joint factor (§192.113) T = Temperature derating factor (§192.115) The design factors, F * E * T may be approximated to equal (0.32)*(1.00)*(1.00) = 0.32.

(Provided by DOT section in Part 192, Title 49, “Transportation of Natural Gas and Other Gases by Pipeline, Minimum Federal Safety Standards”)

If the steel pipe has been subjected to cold expansion and is subsequently heated to a temperature that either exceeds 900º F, or is held above 600º F for over an hour, then the design pressure is limited to 75% of the design pressure in the above calculation.

(b) Yield Strength. The yield strength for steel pipe depends upon the tensile properties. If the tensile properties are unknown, then the minimum yield strength for the pipe is 24,000 psi. Otherwise, the manufacturer can conduct the following number of tensile tests based on the number of the lengths of pipe that are to be supplied:

10 lengths 1 set of tests for each length 11 to 100 lengths 1 set of tests for each of 5 lengths, but not less than 10 tests Over 100 lengths 1 set of tests for each of 10 lengths, but not less than 20 tests

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If the yield strength to tensile property ratio exceeds 0.85, then the pipe may be used if all external stresses, weight, vibration and thermal expansion have been considered. A safe practice is to choose the lowest value determined by the tensile tests. The specified minimum yield strengths (SMYS) of various grades of seamless and welded pipe are illustrated in the following table:

Specified Minimum Yield Strengths Pipe Grade SMYS in psi Unknown 24,000

A-25 25,000 A 30,000 B 35,000

X-42 42,000 X-52 52,000

(c) Nominal Wall Thickness. The nominal wall thickness may not exceed 1.14 times the smallest measurement taken on the pipe that is 20 in. or less in diameter. See §192.109, Part 192, Title 49, “Transportation of Natural Gas and Other Gases by Pipeline, Minimum Federal Safety Standards”) for measurement procedures for nominal wall thickness.

The following table shows wall thickness for common pipe sizes:

Nominal Wall Thickness of Common Pipe Sizes

Size (in)

Material Specifications

Pipe Wall (in)

O.D. (in)

I.D. (in)

100% SMYS (psig)

20% SMYS (psig)

Class 3 Maximum

Design (psig)

Class4 Maximum

Design (psig)

1” Continuous Butt- API 5L A25 0.133” 1.315 1.049 5,057 1,011 1,517 1,214

1” Continuous Butt- API 5L Grade B 7,080 1,416 2,214 1,771

1 ¼” Continuous Butt- API 5L A25 0.140” 1.660 1.380 4,216 843 1,264 1,011

1 ¼” Continuous Butt- API 5L Grade B 5,902 1,180 1,770 1,416

2” Continuous Butt- API 5L A25 0.154” 2.375 2.067 3,242 648 972 788

2” Continuous Butt- API 5L Grade B 4,538 907 1,361 1,089


3” Continuous Butt- API 5L Grade B 3,120 624 936 749


4” Continuous Butt- API 5L Grade B 2,426 485 727 582

4” Seamless Electric API 5L X-42 2,912 542 1,456 1164

6” Seamless Electric API 5L Grade B 0.188” 6.625 6.249 1,986 397 993 794

6” Seamless Electric API 5L X-42 2,883 476 1,191 953

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(d) Design Factor. The design factor should be used according to the guidelines set in the following table. A class location unit is an onshore area that extends 220 yd. (200 m) in either side of the centerline of any continuous 1 mile (1.6 km) length of pipeline.

Class

Location* Description of Class Location F

1 Crossing R.O.W. of unimproved pavement without casing 0.72

2 Crossing without casing or making parallel encroachment of R.O.W. 0.60

3 Supported by vehicular, railroad or pedestrian bridge 0.50

4 Used in a fabricated assembly or used within 5 pipe diameters in any direction from the last fitting of a fabricated assembly 0.40

* Class Restrictions:

• Classes 1 and 2 shall use a design factor of 0.50 or less, if the steel pipe is used in a compressor station, regulating station or measuring station or

located on a platform that is offshore or on inland navigable waters.

• Class 2 shall use a design factor of 0.50 or less for uncased pipe that crosses the rights-of-way of a hard surfaced road, a highway, a public street or

a railroad.

(e) Longitudinal Joint Factor. The longitudinal joint factor to be used in the design formula should be in accordance with the following table:

Specification Pipe Class Longitudinal Joint Factor, E

ASTM A 53 Seamless 1.00 Electric resistance welded 1.00 Furnace butt welded 0.60 ASTM A 106 Seamless 1.00 ASTM A 333 Seamless 1.00 Electric resistance welded 1.00 ASTM A 381 Double submerged arc welded 1.00 ASTM A 671 Electric-fusion-welded 1.00 ASTM A 672 Electric-fusion-welded 1.00 ASTM A 691 Electric-fusion-welded 1.00 API 5 L Seamless 1.00 Electric-fusion-welded 1.00 Electric-flash-welded 1.00 Submerged arc welded 1.00 Furnace butt welded 0.60 Other Pipe over 4 in. 0.80 Other Pipe under 4 in. 0.60

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(f) Temperature Derating Factor. The temperature derating factor can be determined from the table below:

Gas Temperature

In Degrees Fahrenheit

Temperature Derating Factor, T

250 1.00

(g) Valves for Steel Gas Pipe. Each valve must meet minimum requirements of API 6D, “Pipeline Valves (Gate, Plug, Ball and Check Valves)” or an equivalent specification.

The valve must have a maximum service pressure rating for temperatures that are equal to or exceed the maximum service temperature. As part of the manufacturing process, the valve must be tested for leakage to a pressure of at least 1.5 times the pressure rating. Test pressure during a ‘seat test’ must be applied to each side of the closed valve, leaving the other side open. Any valves with ductile iron shall not have pressure ratings that exceed 80% of the pressure rating for steel valves that are comparable and can be used only if: 1) Welding is not used on the ductile iron elements; 2) No ductile iron will be used in assemblies for compressor stations; and 3) The temperature-adjusted service pressure does not exceed 1,000 psig.

Valves must be placed on solid foundation to prevent settling and shall be installed in such a way to eliminate strains. Valve boxes shall be installed in an upright position properly located over the valve stem. The valve box shall be properly separated from the valve and/or piping. The top of the valve shall be located slightly above grade.

Valves along the distribution line should be located where there is more than adequate access and freedom for adjusted movement. There should also be ample space around the valve to be able to inspect for connection adequacy or leakage.

(h) Flanges and Other Fabricated Assemblies. The flange or flange accessory must meet the minimum requirements of ASME/ANSI B16.5 or an equivalent specification. The flange and steel butt-welded fitting must have a maximum service pressure rating for temperatures that are equal to or exceed the maximum service temperature. The actual bursting strength of the fitting must be at least equal to the bursting strength of the pipe and a prototype must be tested.

The Contractor should not force flanges together by springing or jacking the pipe.

Bolts and insulating sleeves must fit freely in the boltholes. The Contractor should comply with tightening requirements to prevent excessive strain. The bolts should be tightened in a criss-cross pattern after the flanges are snugly placed together. Gasket leaks should not be stopped by trying to tighten the bolts more than required, but by replacing the gasket or flange.

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The Contractor shall meet 2 flat-faced flanges together using a full-face gasket. Raised face flanges should be met together using a ring gasket. Gasket ratings must match the ratings of the flanges. Stud bolts and/or cap screws (machine bolts) shall be of the proper grade, diameter and length. The length of stud bolts shall allow for the end of the bolt to be flush with the nut or extend beyond the nut a maximum of 2 or 3 threads. Stud bolts should engage an equal amount of threads on each end. Cap screws used with tapped fittings shall penetrate the fitting to a depth not less than the cap screw diameter.

Taps for instrument piping, control lines, and gauges shall be located away from welds and fittings where turbulent flow may cause false readings. Taps shall be located where the possibility of damage from outside sources is minimized.

All piping and fittings should be thoroughly cleaned of dirt, rust, weld slag and other substances produced from fabrication. The completed station and above ground piping should be painted with a primer and 2 coats of enamel. All below ground piping should be wrapped with a protective tape and/or coated with mastic.

(i) Coating of Steel Pipe. The steel pipes and connections for gas distribution should all be coated. All pipe, pipe joints, fittings to be coated should be clean, dry, and free of rust, mill scale, grease, oil, soap, or other substances. Slag from arc welding on both sides of the cover pass at the junction of weld metal and pipe metal shall be removed from the circumference of the weld joint prior to priming and tapping. Excessive buildup of weld metal at the twelve-o’clock point of the cover pass should be filed down to match the reinforcement of the surrounding weld. The Contractor should insure that filing down the excessive weld metal, weld spatter or burrs does not damage the pipe wall.

The manufacturer should coat the sections before transport and the Contractor should coat the field joints before installation. Upon inspection, or as instructed by the Engineer or owner representative, the Contractor should replace or repair any defective coatings of pipe sections and report this finding to the Engineer.

If the pipes are coated with TGF-3 coal tar enamel, the coating on the pipe must be cut back a distance of 8 to 12 in. from the joint. In locations where the coal tar is bonded to field coating, the Kraft outerwrap should be removed a minimum of 4 in. from the edge of the coating. Edges of the enamel and felt wrapping should be feathered to assure a firm bond between the original coating and the field coating. In locations where the field coating is to be bonded to tape coated or extruded coated pipe, the outerwrap should be removed a minimum of 6 in. from the edge of the tape coating.

The Contractor should hand coat a primer the bare ends of the pipe joints as well as in all locations of field welding. After the primer has become tacky, the Contractor should spirally tape the surface of the joint or field weld a minimum of 1/4 overlap under a constant tension and the underside of the tape shall be free of voids. Extra tape shall be wrapped around field welds and junctions of mill coating. The last turns of tape shall be double wrapped without tension and carried 2 in. over the mill coat or taped coat. Narrow tape should be used over service-tees, couplings,

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valves, and other special fittings without the appearances of voids, holidays or pockets.

When the pipe is ready to be lowered into the trench, the Contractor should inspect for holidays, or voids within the coating surface. If a holiday is found, the area around the holiday to be repaired should be approximately 4 in. from the edge and all the way around the holiday. Once the primer and field coat have been applied to the repaired surface, the area should be spirally wrapped with a tape coat 2 in. on each side of the holiday.

Field coating on fusion bond epoxy coated pipe can include employing heat shrink sleeves to the pipe joints with either a formulated mastic sealant or a liquid epoxy primer. Guidelines, provided by the manufacturer, establish what type of equipment contractors can use to insert heat shrink sleeves during construction.

(2) Thermoplastic Pipe, Fittings and Valves. Thermoplastic pipe and fittings must comply with ASTM D-2513, “Standard Specification for Thermoplastic Gas Pressure Pipe, Tubing, and Fittings.” The pipe and fittings must be tested for long-term failure in accordance with ASTM D-1598, “Standard Method for Time-To-Failure of Plastic Pipe Under Constant Internal Pressure,” §A1.5, Requirements for Pipe and Fittings.

(a) Design of Plastic Pipe. Thermoplastic piping, intended as a carrier for compressed natural gas, should be buried or encased in a shatter resistant material. All types of pipe failure should be considered before calculating a resistance. The nature of the material, pressure, pipe and fitting dimensions, and gas chemical behavioral characteristics are all elements that should be considered when manufacturing shatter resistant pipe.

Pressure design calculations are based on the following formula, which relates stress of the pipe wall to internal pressure:

P = 1

2−SDR

S * DF * F * DFT, where:

S = long term hydrostatic strength (psi) (1600 psi for High Density Polyethylene (H.D.P.E.))

P = Internal pressure. (The burst and sustained pressure, Pb and PS, can be substituted into this equation with the corresponding yield stress, Sy, and fiber stress, Sf.

SDR = Standard Dimension Ratio (equivalent to D/t, or outside diameter/wall thickness)

DF = Design Factor (0.32 for dry natural gas) (See PPI TR-9/2000, “Recommended Design for Pressure Applications of Thermoplastic Pipe Materials.”

F = Service Factor, usually = 1.00

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The design pressure shall not exceed a gauge pressure of 100 psig for H.D.P.E. pipe in distribution systems or by the design pressures shown in the following table:

DESIGN PRESSURE GUIDELINES

Size CTSIPS SDR Wall

Thickness OD ID Max Design

Pressure (psig)

Max Design Pressure (psig)

Anodeless Risers PE 3408 High Density Mains at

73.4ºF 120ºF 140ºF ½” CTS 7 .090 .625 .455 100 100 85 ¾” CTS 10 .090 .875 .695 100 71 57 1” CTS 12.5 .090 1.125 .945 89 56 45

1 ¼” IPS 11 .151 1.660 1.358 100 64 51 2” IPS 11 .216 2.375 1.943 100 64 51 3” IPS 11 .318 3.5 2.864 100 64 51 4” IPS 11 .409 4.5 3.682 100 64 51 6” IPS 11 .602 6.625 5.349 100 64 51

Temperature Design Factors, DFT

The standard temperature is 73º F. In locations of higher temperature, the manufacturer should be consulted to obtain a correct temperature design factor. In most conditions, DFT = 1.00.

PPI TR-9/2000, “Recommended Design for Pressure Applications of Thermoplastic Pipe Materials.”

*See PPI, TN-18, “Long-Term Strength (LTHS) By Temperature Interpolation.”

(b) Thermoplastic Fittings. H.D.P.E. Fittings

Various P.E. fittings intended for use with the corresponding outside diameter of P.E. pipe shall meet the requirements of the following specifications:

Butt-type fittings ASTM D-3261 Electrofusion type fittings ASTM F-1055

(c) Transition Fittings. Polyethylene Transition Fittings.

Plastic to steel connections must be made with a transitional fitting that is designed to be butt-fused at the plastic end and welded on the steel end. Compression fittings are not permitted. For a P.E. to cast iron pipe connection, a transition between steel to P.E. should be assembled first. Then a transition can occur between the steel and the cast iron with an appropriate coupling.

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(d) Valves for Thermoplastic Pipelines. Thermoplastic pipelines require valves that are designed to protect the plastic material against torsional or shear forces or other induced stresses occurring during the operation of the distribution line.

(3) Test Stations. The Contractor shall provide all labor and materials necessary for the installation of a test station as detailed in the plans at locations shown in the plans.

(4) Transportation, Handling and Defects. Hauling and Stringing

All trucks used for the transport of coated and plastic pipes should be padded and have secure straps with padded chains around the pipe to prevent movement and damage. The pipe must be hoisted by crane onto the ground and not dropped from the truck or trailer. The trucks should also have enough padded supports so that the plastic pipe does not sag during transport.

During loading and unloading of plastic pipe, 2 men shall be used to carry the pipe to the desired position while preventing damage to the pipe. The pipe should be strung on the ground free from rocks or other projections causing damage.

Coated pipe shall be strung using slings or wide, padded tongs of a type designated to protect the coating. Pipe 2 in. or smaller may be unloaded by hand. Strung pipe should not be placed in direct contact with rocky or rough terrain that could cause damage to the coating. Hooks that could damage pipe bevels or root faces, or cause “out of roundness” shall not be used. Cable, narrow tongs, hooks or other devices are prohibited from coming in direct contact with coated pipe.

Coated pipe should be stacked in a pyramid fashion and nested on 12 in. wide padded skids, placed on flat, solid ground and spaced not more than 20 ft. apart. The following table shows the maximum number of layers in which the given sized pipe can be stacked:

Pipe Size Number of Layers

Up to 1 1/4” Twenty (20) 2” Fifteen (15) 4” Nine (9) 6” Seven (7)

8” to 10” Six (6) 12” Five (5) 14” Four (4) 16” Three (3) 20” Two (2)

When stacking coated pipe suitable means must be used to prevent joints from rolling or avalanching. All hauling and stringing operations shall be conducted in such a manner as to minimize interference with normal use of land, roads, streets, and/or highways.

Polyethylene pipe (P.E.) can be stored in sunlight no longer than 120 days. Plastic pipe in general should be protected from excessive heat or harmful chemicals. Cleaning

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solutions, detergents, solvents, alcohols, etc., should not be allowed to come into contact with the pipe surface. All pipe should be visually inspected both inside and out at the construction site before installation to insure that no damage has occurred to pipes during transportation, handling and/or storage that could impair its serviceability. A second visual inspection shall be made before lowering the pipe into the trench.

Any pipe that has gouges, dents or other damage shall be repaired by removal of the defective section and replacing with a new section of pipe.

3. Equipment. The Engineer or owner’s representative may disallow the use of any specialty tool or equipment that does not meet owner’s standards for such usage.

(1) Pressure Test Equipment. The Contractor should furnish all equipment necessary for standard or high pressure testing. The Contractor should furnish all pipe pigging equipment, temporary pig traps and launchers and all other equipment that is needed during high pressure testing.

(2) Radiographic Inspection. The Contractor shall provide all equipment that is required for radiographic testing, including all film and processing equipment, and all film identification, recording, filing and storage equipment. The Contractor should also provide all barriers, warning systems, film badges, documentation and records needed to protect and monitor the qualified personnel conducting this procedure near radiation sources.

(3) Tapping into an Existing System. The Contractor should furnish all equipment, instrumentation and materials necessary to insure that the final tie-in welds or fusions between new and existing systems are performed safely. Equipment to perform this work may include pneumatic air movers, combustible gas indicators (CGI’s), oxygen monitors, fire extinguishers, fire-retardant clothing for construction personnel and self contained breathing apparatus, among other items.

4. Construction Methods and Testing.

Construction methods shall conform to the pertinent requirements of the following items:

Item 400, “Excavation and Backfill for Structures” Item 402, “Trench Excavation Protection” Item 403, “Temporary Special Shoring” Item 476, “Jacking, Boring or Tunneling Pipe”

In addition to the referenced specifications, the following items are especially relevant to installing gas distribution pipelines.

(a) Excavation. The width of the work area shall be kept to the minimum width necessary. When clearing the work area, the Contractor shall consider the soil stability, protection of material vegetation and adjacent resources, as well as minimum disruption of pedestrian walkways, roads, and other structures in the area. Care should be taken during grading operations to minimize the removal of ground cover (vegetation) and/or topsoil outside of the trench. The Contractor shall stabilize disturbances to the surrounding soil during grading operations as soon as possible to avoid erosion.

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The bottom of the trench shall be uniformly graded with no sags or ridges so that the pipe will be continuously supported. Voids under the pipe shall be filled with stabilized backfill and bank sand should be placed over the pipeline where proposed utilities are anticipated. When rock ledge, hardpan or boulders are encountered, the trench bottom shall be undercut at least 4 in. and the undercut refilled with good-bearing small-particle-size soil, rounded and ½ in. or less in diameter.

The minimum trench width should include the outside diameter of the pipe plus:

4 in. for 2 in. and smaller pipe 8 in. wide for 4 in. pipe and larger

It shall be the sole obligation of the Contractor to contact one-call (where available) and to take all other steps necessary to determine the exact location of all underground utility facilities prior to any excavation. The Contractor shall give at least 48 hours advance notice to the owners of other pipelines and utilities in and around the excavation area.

All excavation in close proximity to underground utilities or other structures shall be done by hand. Extreme caution shall be exercised whenever excavating to avoid striking, hooking, gouging or scraping to utilities inside the work area. Nearby utilities shall be protected as necessary to protect against damage and supported if the excavation extends below them in order to maintain their line and grade.

The design of the separation between existing and proposed utilities within TxDOT highway and street rights-of-way should comply with the TxDOT Utility Accommodation Policy or with local agency requirements if in another agency’s jurisdiction. If boring is impractical and the presiding agency approves open cut construction within the right-of-way of paved roads, the trench should not exceed the width of the casing plus 4 in. for pipe 2 in. and smaller and 8 in. for pipe 4 in. and larger.

The trench shall be of sufficient depth to provide a minimum cover of 36 in. from ground surface to the top of the pipe. Depth of cover shall be measured from the lowest side of the trench. When the trench is located less than 5 ft. from, or crosses a ditch, the depth of cover shall be measured from the flow line of the said ditch. In areas to be graded after installation, the finished grade shall be 36 in. below the finish grade. If the pipeline is located in rocky terrain, the trench cover should be at least 24 in. from the ground surface to the top of the pipe. If the line traverses sand the minimum cover shall be 60 in. from the top of the pipe to the surface elevation.

During the course of construction, the Contractor should make sure that the natural gas pipeline is free from debris, water, animals or trash. If the ends of the pipe are left unattended, the pipe ends shall be securely closed until work is resumed. The Contractor is responsible for assuring the Engineer or owner’s representative that the line is clean, coated and protected after installation prior to joining ends of pipe.

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In addition all plastic pipe and plastic service lines shall be installed with sufficient clearance, or should be insulated, to protect them from any source of heat that would affect the serviceability of the system.

(2) Joining Procedures. No welding shall be done when the quality of the weld may be adversely affected by weather conditions. Rain, blowing sand, windstorms and other inclement weather shall be cause to cease welding operations. Wind shields may be used during windy weather.

(a) Steel Pipe. Joining sections of steel pipe are primarily accomplished with butt-welds. All welding on steel distribution facilities shall be performed in accordance with established Company Standard Welding Procedures.

Pre-heating and post-heating shall be used when the ambient temperature is below 32º F. Frost on steel pipe shall be driven away from the bevel a minimum of 4 in. before arc welding takes place. Electrodes or rods that have damaged coating or are not clean shall not be used.

The Contractor should clean the surface to be welded to a bright metal finish free of debris or other material that might be detrimental to the weld. The Contractor shall take extra precautions during bevel cleaning operations to preserve the original bevel and root face configuration. Field cut ends on 6 in. pipe and larger shall be beveled by machine held torch. The original bevel and root face of the pipe should be preserved at a 30º angle. High-low condition shall not exceed 1/16 in. on any quadrant. Hammering of the pipe to reduce high-low shall not be permitted. If the wall thickness of one pipe is greater than 3/32 in. (0.94 ft.) of the other pipe then:

The thicker walled pipe should be taper-bored to match the thinner wall (through 12in. in size) or turned down (larger than 12 in.) to match if a notch is likely to occur at junction of cover pass and base metal; or

Have a transitional insert pipe with an intermediate wall thickness that is welded between them.

The Contractor should seek the Engineer’s or owner representative’s approval for the method of connecting the two differing sections. During the welding procedure the pipe is not to be moved until the beading process is complete. If movement is required after string bead completion (raising or lowering onto skids), it shall be done with the utmost care to prevent undue stressing of the stringer bead. If a slight change in direction is needed which does not require a cold bend or the use of a weld fitting, the entire weld shall be completed before it is stressed.

The weld should alternate 180º between the horizontal alignment of the longitudinal seam from one section to the next. Girth welds should be done on a fixed horizontal position and at a minimum of 16 in. above the ground. If welding is completed in the trench, then the bellhole shall be large enough to provide the welder ready access to the joint.

Completed welds should be free from surface defects and undercutting. Visual examinations by the Contractor, Engineer, or owner’s representative should be

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done in accordance with API, Section 3.3, “Visual Examination.” See later sections for welding procedures during hot tapping.

Each welder working on the pipeline shall have a distinctive mark, which shall be placed on the pipe coating with lumber pencil near each weld made. In the event more than one welder on a single weld, every welder should place their mark near the portion they have welded. The mark for the stringer pass shall be placed on top the hot pass immediately underneath, and in sequence for each succeeding pass. The mark shall be identical with the number appearing on the welder’s identification card. Welders should make a distinctive mark on the pipeline placed on, but not damaging, the pipe coating.

Selected welds may be subject to random testing, either by destructive means, X-Ray, radiograph or ultrasonic methods. Removing the weld and replacing the removed section of pipe with a ‘pup’ joint at least 3 ft. long is a destructive test. Sections that are tested shall be cut and tested in accordance with the latest revision of API 1104, Standard of Destructive Testing.

Should the weld fail the destructive test, the second weld by the same welder shall be tested immediately. Failure of the second weld will be sufficient cause to remove a welder from the project. If the second weld fails a third weld should be tested. If the third weld fails then all welds made by the welder on the project shall be removed and replaced.

Welds tested by radiography or X-Ray shall meet the acceptability limits in Section 6 and Section 8 of the latest revision to API Standard 1104. A defective weld determined by these tests shall be repaired with one attempt. If the repair is unsuccessful, i.e. fails the second examination by radiography or X-Ray, then the weld should be removed from the pipeline and replaced.

(3) Thermoplastic Pipe. A representative of the owner or contractor shall qualify the persons, performing heat-fusion welding on distribution facilities.

Fusion of thermoplastic pipe should follow the owner’s operations guide and should comply with the specifications set in the Department of Transportation (DOT) Regulations, Title 49, Part 192, §281, §283, §285 and §287. “Transportation of Natural and Other Gas by Pipeline: Minimum Federal Safety Standards.”

Butt Fusion is forcing two butted ends of pipe together using a heating or melting applicator and holding the surfaces together until the joint cools naturally.

Equipment and tools, which are specifically manufactured for the fusion process, should be used. The heating tools should be capable of maintaining uniform surface temperature within the manufacturer’s specified melting temperature range. The heating elements should be electrical which can be thermostatically controlled. The Contractor should use a crayon temperature indicator to verify that the heating element temperature is correct prior to fusion. Manufacturing heat fusion standards should be available from the owner’s offices or regional district offices.

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One of the primary advantages for using P.E. pipe is that 1) The fused locations along the pipe have no leakage; and 2) The joint area becomes as strong as or stronger than the pipe itself in tensile and bending properties. In heat fusion the resin molecules interlock together during the heating process. Molten beads develop around the pipe joints, but these beads can be removed if they are too large as to restrict the pipe cross-sectional area.

The butt fusion machines used in this operation are available for pipes having 5/8 in. to 72 in. diameters. Smaller machines for 4 in. and smaller are lever operated. In cases where the fusion beads grope into the cross section area of the pipe a debeader can be applied during pull back to maximize the pipe’s cross sectional area, its holding capacity, but this procedure is usually somewhat expensive.

Electrofusion is a fusion method when resin molecules interlock with each other just as in butt fusion. The primary difference is the heat source for the sections of pipe. The electrofused joints are clamped together and heated internally either by internal heating coils or a conductive polymer. An electric current is supplied to the conductor.

Each welder shall place a distinctive mark on the pipe with a felt-tip pen near each respective weld. The mark should be the same number appearing on the Welder’s Qualification Card. The color of the ink’s mark should be distinguishable from the color of the pipe.

Selected welds may be tested to destruction or tested by ultrasonic methods. For a destructive test, the Contractor will remove the weld to be tested and replace the removed section of the pipe with a ‘pup’ joint at least 3 ft. long.

Should the weld fail the destructive test, the second weld by the same welder shall be tested immediately. Failure of the second weld will be sufficient cause to remove a welder from the project. If the second weld fails a third weld should be tested. If the third weld fails then all welds made by the welder on the project shall be removed and replaced.

Ultrasonic weld tests shall search for any voids or imperfections of the weld, which would impair its serviceability.

(4) Corrosion Control and Cathodic Protection for Steel Pipe. Anode lead wires should be attached to the pipe by means of the thermite welding process, using a No. 15 (15 gram) cartridge. All coating and primer on the pipe surface should be removed down to the base metal at the connection. Wire connections, no larger than a number 6 AWG wire, should be connected to the pipe. If a wire is larger than number 6 AWG, then it should be stranded and the strands should be bundled no larger than a number 6 AWG wire and should be attached separately. Brazing between the wire and the pipe is prohibited. The anode lead wire should be securely tied around the pipe prior to welding the lead wire. The Contractor should test the weld by hammering the connection.

Insulators and couplings should be installed per manufacturer recommendations. Insulating sleeves, when required, shall be installed in flanges without the sleeves

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undergoing any strain. Refer to owner standards for the testing of insulating assemblies.

Couplings, which are sealed with rubber gaskets, should be bonded. Couplings that are not required to insulate shall have bonds made to both joints of pipe and to the middle ring or barrel of the fitting. Couplings that are required to isolate one section of the pipeline from the other shall have bonds made to the middle ring or barrel of the fitting and to the pipe on the non-insulated side. Bonds shall be made by thermite welding No. 6 AWG, or No. 8 AWG-RHW 600 Volt wire to the pipe and fitting.

All cathodic protection devices must be controlled so as to not damage the pipe’s protective coating.

(5) Gas Distribution Pressure Control Devices. A pipeline system should incorporate a pressure control device in the event that the maximum allowable pressure is exceeded because of a failure in the system. A pressure control device would activate as a result of accidental over-pressuring.

A gas distribution system that maintains an operating pressure under 60 psig and has a regulator does not require such a device. Regulators are defined in the next paragraph.

Regulators are smaller pressure control devices that can stabilize the downstream pressure in order to limit the build up of pressure within the pipe that would create an unsafe distributed gas operation. An abrasive resistant regulator with a single port valve at the inlet is capable of reducing the distribution line pressure to a pressure recommended for household appliances. Pipe connections to the regulator should not exceed 2 in. in diameter. If a regulator varies from this description, and the pipeline exceeds 60 psig, then the gas distribution system needs other pressure control devices, such as relief valves or automatic shut-off controls.

Relief valves can be operated alone at pressures that do not exceed the manufacturers safe working pressure of a regulator and should act with another regulator(s) for higher pressures. The relief valve is vented to the outside atmosphere but should be controlled so that it does not exceed a safe pressure value around customer usage. Their locations within the system should follow valve specifications for accessibility.

(6) Steel Bends. Pipe bends should conform to one of these three methods:

1. Cold bending with Company approved bending shoe or other device.

2. Forged steel ells, trimmed to fit. Elbows may not be used for change in direction of pipe less than 2 in. unless the arc length is at least 1 in.

3. Miter joint deflections should be limited to a 30º turn and should not be used in systems designed for pressures over 100 psig. Miter joints should be spaced at least one diameter of pipe distance between each other as measured from the crotch of each joint. They are prohibited in pipes that are 8 in. and larger. Any angle weld that corrects a pipe misalignment of 3º or less shall not be considered a miter joint.

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Pipes, larger than 4 in. in diameter, should not be bent in places where there is a 2.5% or greater difference at the bend between maximum and minimum diameters. Also, there should be no bends within 12 in. of a circumferential weld. When field cold bending, the Contractor shall not deflect the longitudinal axis of the pipe more than 1 1/2 º in any length along the pipe axis equal to the diameter of the pipe. The longitudinal weld seam must be as near as possible to the neutral axis of the bend. All bends should be free from buckling, cracks or other evidence of mechanical damage.

(7) Lowering. After welding and coating has been completed, the line shall be lowered into the trench. Prior to lowering the pipe, the trench bottom should be cleared of all skids, brush, chips, rock or other debris. The pipe should be handled with padded thongs which are raised a minimum amount to prevent coating disbanding or pipe wall buckling.

Plastic pipe must be handled with care when lowered into the ditch. It should not be subject to unnecessary strains from bending or twisting. The pipe should be laid on the trench bottom in such a manner as to snake the pipe from one side of the trench to the other with one cycle approximately every 40 ft.

(8) Location Devices for Plastic Pipe. An electronically conductive trace wire that is magnetically detectable must be installed with plastic pipe so the pipe can be located after its installation. The wire, with all of its connections, should be insulated and protected by no less than 2-5 lb. anodes attached at the farthest ends of the pipe. Should there be a possibility of damage to the pipe by future excavation, a suitable covering or warning device shall be installed.

The warning tape shall be placed above the pipe with a 12 in. layer of backfill, separating it from the pipe. Tape in no instance should take the replacement of tracer wire, but may be used as an additional safety factor. The wire shall be separated from the pipe by four to six in. if the pipe is not encased. The wire may be inserted with the pipe at bored crossings and when inserted into another old line. As an alternative to the latter, a steel pipe can be used as the locator provided that all sections of the old pipe are bonded together electrically and that the old pipe used as casing is not tied electrically into an active steel system.

The location wire shall be soldered at all wire connections. Tee splices should be made with a minimum of 4 turns wrapped tightly around the bared portion of the main tracer. The Contractor should protect the main tracer wire from getting cut. The Contractor should make line splices crossing two bare sections of wire with a minimum of 4 turns in opposite directions.

Other Construction Recommendations for soldering the location wire connections are as follows:

a. The finished connection should be soldered using a No. 1 welding tip with a soft-non-carbonizing flame and No. 60/40 rosin core solder.

b. Acid core solder is not permitted.

c. Only enough heat needed to smooth the solder joint is recommended.

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d. Heat should be applied to the wire, not to the solder.

e. Heat the connection for a few seconds and touch the end of the solder to the joint. When the proper temperature is achieved, the solder will melt and flow freely around the connection.

f. Allow the wire to cool and do not move the wire while cooling.

g. Insulate by applying several turns of the electrical tape around the soldered joint. Extend the electrical tape well over the wire insulation in all directions.

h. As an alternative, “splice kits” that were specifically designed to protect the connections from the underground environment may be used.

(9) Cutting of Plastic Pipe. When it is necessary to cut the pipe, it shall be cut with special plastic pipe cutters, with a fine-toothed handsaw or hacksaw. The pipe ends shall subsequently be faced in order to obtain a clean, square end, free of burrs for joining.

(10) Clearing of Obstructions in Pipe. In order to prevent small animals, water or other debris into the pipeline, the Contractor shall insure that all open ends of the pipe are closed at the end of each day’s work, and shall not be reopened until the adjacent pipe section is ready to be welded. Any debris found in the pipe, either before or after welding has occurred, should be removed.

A pipe that has been strung along the right-of-way should be swabbed with a wire brush, cloth or rubber pig, prior to welding. Once a specified length of pipe is complete, the Contractor should install a pig catcher at each end of the length and run a pig, or pipeline scraper, twice through the line. The catcher shall be secured to the pipe to prevent it from blowing away during the pigging operation, which is controlled by the movement of air.

(11) Connections to Existing Lines. Excavations done in the vicinity of existing lines in service shall be done in a carefully controlled environment. The Contractor should provide a sufficiently large trench to complete the connection to an existing line. Welders making hot taps should be of an approved rated experience level. Contractors when hot tapping to existing service, should comply with the owner’s procedural standards and is subject to inspection at any time. Exposed pipelines should be adequately supported to withstand the vibrations of weight and tapping equipment. Sufficient time should be allowed to let the pipe contract and assume ground temperature.

(12) Supports and Anchors. The Contractor should make sure that each pipeline has enough anchor and support to prevent undue strain on the pipe or accessory equipment, resist longitudinal forces caused by bends or offsets, protect against forces due to weight, thermal expansion and internal pressures, and prevent excessive vibrations. However, the supports should not prevent the pipe from expanding or contracting after installation.

Bridge supports that are used when a pipeline operates at 50% of SMYS should not be welded to the pipe unless the weld totally encircles the pipe circumference. Anchors for

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underground pipelines are recommended when the pipe is attached to a fixed pipeline or surface. The pipeline should also have freedom of some allowable movement.

When P.E. pipe is used in lieu of cast iron, it is necessary to anchor the P.E. at both ends to prevent pullout of cast iron joints. Anchoring should prevent any excessive tension on the cast iron pipe.

(13) Backfill. Backfill material should comply with Item 400, “Excavation and Backfill for Structures”. In addition, the clean backfill material should surround the pipe for at least 4 in. above the pipe and may not be mounded over the pipe but shall be level from one side of the trench to the other side. The Contractor shall tamp the backfill in 9 in. layers and using company approved compaction tools. During compaction the Contractor should protect the coating around the pipe. Compacting with heavy equipment is not permitted, unless the pipe has 24 in. of cover and the pipe has more than 15 psig of internal pressure. Finally, the Contractor should reinforce the pipe bearings into the trench soil if the Contractor decides to flood the trench to consolidate the backfill.

(14) Boring or Horizontal Directional Drilling. The Contractor shall seek approval from TxDOT for all street or highway crossings prior to the Contractor beginning of the work. Minimum interruptions should be made to the normal traffic use of the street or highway.

Boring or horizontal drilling is the preferred method for crossing a street or highway and adjacent railroad rights-of-way. The method of boring shall be approved by TxDOT prior to construction. The size of the bore should be a maximum of 2 in. larger than the pipe or casing. Care shall be exercised to prevent damage to nearby pavement.

The Contractor shall insure that any uncoated casing is painted with two coats of bitumastic enamel and that the casing is separated from the pipeline with casing insulators. The casing insulators should be sealed with casing seals or bushings. The pipe should be inserted into the casing so that the pipe coating and casing insulators are not damaged. Two vents should be placed on one end from the top of the pipe and from the other end at the bottom of the pipe. Holes for vents shall be cut and welds for vent connections to casing shall be made prior to the insertion of the pipe. Vent markers shall be coated to an aboveground level. Markers should be attached to the vents and should have clear visibility.

The Contractor should insure a relatively constant horizontal and vertical alignment that meets the satisfaction of the Engineer. The Contractor should take special care of insuring that the natural gas pipe is not damaged as it is being either inserted into a borehole or pulled back through a directional bore. When it is anticipated that the borehole will have significant deflections, the borehole dimension should increase to two nominal sizes larger than the natural gas pipe. In a directional bore, a fusible length, approximately 2 ft. in length and one size larger than the gas pipe diameter, should be used between the pull head and the natural gas pipe to protect the natural gas pipe.

(15) Service Line. A service line is a line that transports gas from a main or pipeline to a customer meter set assembly without regard to location or ownership.

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(a) Trench and Cover. The service line, after being properly supported, should have a minimum 12 in. depth below the ground at the meter and 18 in. in areas leading up to the property line or in alleys, easements, streets or roads. Any condensation or liquid must drain towards the main, so there must be a uniform positive grade towards the property line. Should the meter location be at the property line, minimum cover shall be 18 in. Each service line shall be properly supported on undisturbed or well-compacted soil.

(b) Service Line Connections. Each service line connection shall be made at the top of the main and be complete if connected to a meter. The connection shall be made with forged, fabricated or molded service tee. The service shall terminate in a screwed stop approximately 15 in. above existing or immediate future grade. A stub service line shall terminate at the property line or easement line and should be suitably capped for future testing. There should be no less than 5 ft. of service line between the service tee and the beginning of the steel riser. If necessary, this distance can be obtained by varying the location of the service connection along the main.

(c) Installation. Lateral changes in direction should not exceed an angle of 22 1/2 degrees and should be installed with forged fittings for welding steel pipe. However, if the pipe is less than 1 in. in diameter, it can be bent with manufacturer approved pipe-bending equipment. Coating and holiday repair procedures apply to service lines as well and should be complete before placing into the trench.

A protector sleeve should be installed over the service line connection to the service tee. This sleeve shall be made from a straight section of 1 1/4 in. plastic pipe and 30 in. long. The sleeve shall be tied to the service tee to prevent sliding down the service line during backfill and compaction. Prior to backfilling, the Contractor should install a strong chord around the service tee and through a hole drilled in the side of the wall of the protector sleeve near one end. This should be accomplished after the sleeve has been tested. Tape is prohibited as a means of tie down. The sleeve should be slipped over the service line before the service line is connected to the service tee.

Prior to making the service connection the pipe should be allowed to cool and assume ground temperature. Backfill material should be free of stones and other debris and be placed during the coolest part of the day as possible. Backfill should be tamped or compacted and should continuously support the service line. The Contractor shall insure that the service line is not damaged during backfill.

(d) Clearing of Obstructions in Service Line. The service line should be free of any obstacles or dirt that may clog the line. The Contractor should apply air pressure at the meter end to blow the material out the main end prior to making connection.

(e) Service Line Testing. A service line, before it is tapped into a distribution system and after welding is complete, should be tested at all welding fusion points under appropriate pressure requirements for 30 min. if an indicating gauge is used or 5 min. if a Dragnet indicator is used. Time shall begin when the pressure in the facility stabilizes.

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(f) Service Line Location Device. An electrical conductive locator wire is required for service lines. The wire should be insulated and connected to the main locator wire on one end and the anodeless service wire on the other. This wire should be placed as to avoid any contact to the service line. The wire or tape, if used, should be placed at a minimum of 9 in. above the pipe. All wire joints are to be soldered. “Splice kits”, if available may be used. The locator wire shall be connected to the service riser with 2 double half-hitches, and avoiding electrical contact with the riser.

(16) Other Testing Requirements

(a) Test Procedure. Air and Nitrogen are the preferred test media. The temperature of the plastic pipe must never exceed 100ºF due to the compressed air or other sources. At higher pressures and for longer periods of time, nitrogen may be a more representative of the carried product. If nitrogen is used, the Contractor should follow the carrier’s guidelines for testing and purging procedures. After the test media has been purged from the new line, normal test procedures shall be followed, except when repairing leaks.

When repairing leaks in steel pipe, the Contractor must remove the defect down to the clean metal surface and the segment of pipe must be preheated. Flame cutting of leaking welds should not be permitted. Prior to rewelding , the line shall be completely purged with inert gas. Otherwise, the Contractor shall maintain the flow of gas and ignite it before welding.

Several other testing requirements are recommended as useful tools that insure maximum quality construction standards.

(b) Radiographic Inspection. All radiographic inspections shall be performed in accordance with Section 8.2 of API Standard 1104. The Contractor should provide a written copy of the radiographic procedure to the Engineer or owner’s representative.

When radiographic inspection is specified on the plans, the additional latest standards and codes are recommended for the Contractor:

Department of Transportation, 49 CFR Part 192, “Transportation of Natural and Other Gas by Pipeline: Minimum Federal Safety Standards.”

Radiographic certification shall be through a qualification and certification program, which incorporates the requirements stipulated in the Recommended Practice No. SNT-TC-1A, Supplement A, “Radiographic Testing Method”, and should be performed in accordance with Section 8.7 of API Standard 1104.

ANSI B31.8, “Gas Transportation and Distribution Piping Systems.”

ASME Code Section V, “Nondestructive Examination.”

United States Nuclear Regulatory Commission, Title 10, Chapter 1, CFR- Energy and other federal, state and local regulations for protection against radiation.

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The Contractor shall notify the Engineer if any welds fail to meet radiographic inspection requirements. Any defective welds will be replaced and tested again.

All film identification and methods should be made available to the Engineer or owner’s representative and the procedure should be in accordance with Section 8.6 of API Standard 1104. Radiographic reports should be made available to the Engineer or owner’s representative upon request.

(c) Standard Pressure Testing. Pressure test requirements shall be indicated on the plans or coordinated prior to issuance of work. The Contractor should demonstrate the test in accordance to the federal standards in 49 CFR Part 192 and take precautions to insure the safety of the construction personnel and the public during the course of the test. The minimum test pressure shall be 1.5 times the maximum operating pressure, or 90 psig, whichever is greater. The Contractor will demonstrate to the satisfaction of the Engineer or owner’s representative that the entire piping system installed does not leak and safely operates at the specified maximum allowable pressure, using a dial type pressure gauge. Any joints that tie in segments of pipe that have been tested previously should be soap tested at the operating pressure and repaired by the Contractor if appearing defective. The Contractor should obtain all necessary permits to conduct any testing that so requires.

The standard air test is required for any pipeline designed to operate at 60 psig or less. The test pressure will be at a minimum of 90 psig and a maximum of 120 psig. If air is used as the testing media, the air shall remain in the pipe for 8 hours at the minimum test pressure. The Contractor will issue a statement at the completion of the test to the Engineer that the test was successful.

(d) High Pressure Test. Pipelines with design test pressures that are greater than 90 psig should undergo high-pressure tests with nitrogen. The Contractor should coordinate with the Engineer or owner’s representative, to review the following requirements for pressure tests:

a. Optimum direction and injection rate for filling the pipe section with nitrogen while minimizing air entrapment.

b. Optimum direction and discharge location for safely draining the pipe system, as well as de-nitrifying procedures, when the test is complete.

c. Type, quantity and condition of pipeline pigs.

d. Installation and use of any temporary pig launchers and/or receivers.

e. Capacities of nitrogen equipment.

f. Pressurization procedures.

g. Written test documentation.

h. Limitations to discharge of test nitrogen, when the test has not been validated, and retesting is needed.

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i. Temperature stabilization of test nitrogen when pipe is full (24 hours after pipe has been filled).

Temperature measurements should be taken every 30 min. during the stabilization period if the test lasts longer than 2 hours. If the test duration is less than 2 hours, measurements should be recorded every 15 min. The Contractor should seek approval from the Engineer or owner’s representative prior to depressurizing the pipeline. At that time the Contractor will clean and dry the pipeline before tapping occurs.

The test pressure shall be maintained at or above the minimum test pressure for the periods shown in the following table: Time shall begin when the pressure in the facility has stabilized.

Length Time in Hours by Size

2” 4” 6”-8” 10”-12” 14”-20” Over 20” 100’ or less 1* 1* 2* 2 4 8 101’ to 150’ 2* 2* 3 8 16 16

501’ to 2,000’ 2* 3 12 24 24 30 2,001’ to 10,000’ 4 12 24 30 36 48

Over 10,000’ 8 16 24 36 48 48

*Test with Dragnet Detector may be substituted

(e) Method of Test. A recording gauge shall be used on all test of facilities which will operate at 100 psig or more. A Dragnet indicator may be substituted, as indicated in the preceding table for testing a facility to operate at less than 100 psig.

(f) Safety During Test. Every reasonable precaution shall be taken to protect workers and the general public during testing. No direct connections will be permitted from the new line to any existing gas lines unless they are physically separated. Suitable steps shall be taken to keep persons not involved in the test procedure out of the testing area during the test.

(g) Test Documentation. Contractor shall prepare a record of each facility test as part of the test procedure. The record may be on the back of the recording chart, on the order under which the work is done or on a separate piece of paper. All testing documentation required by the owner shall include the following information:

a. Company name.

b. Name of person responsible for test (directly).

c. Test fluid used.

d. Test pressure.

e. Test duration.

f. Leaks and failure noted and their disposition.

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The Contractor will date and sign the report before sending it to one or more of the following parties: the appropriate supervisor, inspector, Engineer or owner’s representative.

The Contractor should coordinate with the Engineer, owner and/or owner’s representative, other contractors in the area and the permitting local agency (if required) when ready to activate or tap the new line into the gas distribution system. This coordination shall be done during design in order to phase the tie-in or purge at the owner’s determination in order to minimize service interruption during peak customer usage. The test period needed to determine the serviceability of the pipeline (usually one calendar year) shall be determined by the owner or owner representative, If failure occurs during that test period, all repairs and tests shall completed at the expense of the Contractor.

(17) Purging, Disconnection and Abandonment. Each facility to be abandoned in place shall be disconnected from all sources and supplies of gas. The system should be completely purged of gas using air or inert gas. If air is used, it should be released into one end in a smooth and continuous flow. If there is an insufficient amount of air that can eliminate the formation of a hazardous mixture, a slug of inert gas shall be released into the line before the air. A slug shall be sufficient to fill approximately 100 lineal ft. of line. A test shall be performed to insure no air is left in the system that could become a combustible mixture after purging. The Contractor shall seal or cap all openings to the facility.

(18) Clean Up. The Contractor shall be responsible for leaving the surrounding area clear of any rubble and debris. The Contractor shall restore all removed landscaping and repair all damaged drives, walks and other structures. All restoration shall be equal to or better than the original condition of the area. Careful examination should be made of the original condition in order to record damages done by construction.

In rural areas, backfill shall be mounded and waterways cut to permit run off.

5. Measurement. Measurement of completed and accepted work as described herein will be as follows:

(a) The installation of a gas pipeline, of the type and size specified, being placed in an open trench or in a previously installed casing pipe will be measured by the linear foot of pipe installed.

(b) The installation of a gas pipeline, of the type and size specified, being placed by boring will be measured by the linear foot of pipe installed in the bore.

(c) Steel pipe casing of the size specified for a service line or gas main installed in an open trench, will be measured by the linear foot of casing installed. This does include the pipe installed in the casing.

(d) Boring of a steel pipe casing of the size specified on the plans, will be measured by the linear foot of bore. This does not include the pipe installed in the casing.

(e) Valves of the type and size specified on the plans, will be measured by the each.

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(f) New service stubs for 1-in. through 4 in. diameter pipes placed in open trench, either connected to an existing or proposed gas pipeline, will be measured as each location as shown on the plans and as directed by the Engineer. New welded service tees and valves will be measured for the welding required to install each fitting for a 1 1/4 in. service tee and 2 or 4 in. valve.

(g) Relocating or lowering service connection will be measured as each location shown on the plans or as directed by the Engineer.

(h) Extending or shortening, connecting and pump testing an existing service line will be measured as each location shown on the plans or as directed by the Engineer. Adjusting an existing service line will usually utilize the existing service tee and valve, so welding required for relocating the service tee and valve should be added.

(i) Test stations of the type shown on the plans will be measured as each location shown on the plans.

6. Payment. The work performed and materials furnished in accordance with this Item and measured as provided under “Measurement” will be paid for at the unit price bid for the items of work hereinafter described. These prices will be full compensation for furnishing all materials, labor, equipment, testing, accessories and incidentals necessary for the installation of the natural gas pipelines as shown in the plans. This will include all excavation and backfill, pipe bedding materials, repair of existing pavements, concrete and curb and gutter and abandonment of existing gas pipes being taken out of service. Trench safety will be paid for in accordance with Item 402, “Trench Excavation Protection”.

(1) Payment for gas pipeline will be made at the unit price bid for “Gas Pipeline” of the type and size specified when installed in an open trench or in a previously installed casing pipe, complete in place.

(2) Payment for gas pipeline will be made at the unit price bid for “Gas Pipeline (Bore)” of the type and size specified when installed by boring, complete in place.

(3) Payment for steel pipe casing installed in an open trench will be made at the unit price bid for “Gas Pipeline Casing” of the size specified, complete in place.

(4) Payment for steel pipe casing installed by boring will be made at the unit price bid for “Gas Pipeline Casing (Bore)” of the size specified, complete in place.

(5) Payment for valves, of the type and size specified, will be made at the unit price bid for “Valves”, complete in place.

(6) Payment for new service stubs for 1 in. through 4 in. diameter pipes will be made at the unit price bid for “Service Stub”, complete in place.

(7) Payment for relocating or lowering an existing service connection will be made at the unit price bid for “Adjust Service Connection”, complete in place.

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(8) Payment for extending or shortening an existing service line, including connecting and pump testing, will be made at the unit price bid for “Adjust Service Line”, complete in place.

(9) Payment for test stations of the type shown on the plans will be made at the unit price bid for “Test Station”, complete in place.

Testing of natural gas pipelines for leakage, including all labor, materials and equipment necessary to perform the tests, will not be paid for directly but shall be considered subsidiary to the various natural gas pipeline pay items.

APPENDIX A

Various steel pipe manufacturers are shown in the table below:

Type and Schedule Manufacturer Bentler Steel C F & I Dalmine Mannesmann (V&M) Nippon Steel North Star Steel NKK Siderca (DST Group) Tamsa (DST Group) Vallourec (V&M)

Carbon Steel & Low Temp Carbon Seamless, STD-XXH

Voest Alpine Ipsco Kawasaki Lone Star Steel Maverick Newport Nippon Steel SAW Pipes Sumitomo Tex Tube

Carbon Steel ERW/DSAW Welded Pipe 0.156”W-STD 0.375”W-1.5”W

U.S. Steel Laclede Sawhill Carbon Steel Fusion Coated ERW

0.156”W-STD Wheatland Lone Star Steel Tex Tube Epoxy Fusion Bonded

(0.188) 6“ Maverick Tube

Various valve, coupling, flange and fitting manufacturers are shown in the table below:

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Type and Schedule Manufacturer

Bebitz Boltex Coffer National Flange Piping Products Texas Metal Works Western Forge

Carbon, Stainless & Chrome-Moly Forged Flanges 150# - 600#

Wilhelm Geldbach Alloy Piping Products Canadoil Closebend Custom Alloy Dynamic Products Interfit (Vallourec) Mills Iron Works Steel Forgings Trinity Tube Forgings (TFA)

Carbon Steel, Stainless & Chrome-Moly Weld Fittings STD-XXH

Wilhelm Geldbach Bonney Forge Capitol/Camco Grinnell Mills Iron Works Penn Machine Phoenix Forge WFI International Ward Manufacturing

Forged Fittings, O-Lets, Nipples, Swages, Couplings, MI Fittings

Westbrook Mfg. Barton Co., Inc. Bonney Forge Grinnell, Inc. Nordstrom Valve, Inc. Milwaukee Valve Co.

Valves

Pacific Valves

Various polyethylene pipe manufacturers are shown in the table below:

Pipe Material Manufacturer Phillips

Poly Pipe H.D.P.E. 3408 Plexco-Yellowstripe

UPONOR Plexco-Yellowstripe M.D.P.E. 2406

Poly Pipe

special specification...

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