SynC™

SynC · SynC Standards

Steel and Stainless Steel Process Piping

Rev1
IssuedOct 12, 2026
Contents

Revision history

Download
Build a datasheet from this standard Start a project with this standard already attached — one click, no setup.
Use in a project

1 Scope

NOTE This standard covers the carbon steel and stainless steel pipe, fittings, joints, linings, coatings, and penetrations of process piping inside the fence of a water, wastewater, or industrial process plant and its pump stations, and the installation and testing of that piping exposed in galleries, buildings, and vaults and buried as yard piping between plant structures. (1.1)
NOTE The boundary of process piping is the plant fence. A buried line between two plant structures is yard piping and belongs here; the same line once it leaves the plant site toward a customer, a well field, or a receiving sewer is a distribution main under Water Distribution PipingSite Water Distribution PipingResolves to the current adopted revision.sync/water-distribution-piping or a sewer or force main under Sanitary Sewer SystemsSanitary Sewer Systems (Site)Resolves to the current adopted revision.sync/sanitary-sewer-systems. Inside a plant building the boundary is the service: a line carrying process water, air, chemical, or sludge is process piping wherever it runs, and the building's own hydronic, steam, domestic water, and tool air stay with their own standards. (1.2)
NOTE Process piping lives in a wetter, more corrosive, more vibration-laden environment than building piping, runs larger, carries solids, and is taken apart for maintenance far more often. Those facts drive the choices this standard records: flanged and coupled joints that can be dismantled, linings matched to the fluid, stainless where the atmosphere or the fluid would consume steel, wall pipes that hold water back through a basin wall, and pressure tests sized to the line rather than to a building code minimum. (1.3)
NOTE The piping schedule is the governing document for every line: its size, service, design pressure, design temperature, material family, and lining or coating designation are read from the piping schedule and are never defaulted by this standard. (1.4)
NOTE Three sibling standards divide process piping by material family, and each owns its own pipe, fittings, joints, linings, coatings, testing, and installation. Ductile iron is under Ductile Iron Process PipingDuctile Iron Process PipingResolves to the current adopted revision.sync/ductile-iron-process-piping, and PVC, CPVC, HDPE, and FRP are under Plastic Process PipingPlastic Process PipingResolves to the current adopted revision.sync/plastic-process-piping. (1.5)
NOTE The following are outside this scope and are governed by the companion standards named. (1.6)
  • Rubber-seated butterfly valves and eccentric plug valves: Butterfly ValvesButterfly ValvesResolves to the current adopted revision.sync/butterfly-valves and Eccentric Plug ValvesEccentric Plug ValvesResolves to the current adopted revision.sync/eccentric-plug-valves.
  • Resilient-seated gate valves: Resilient Seated Gate ValvesResilient-Seated Gate ValvesResolves to the current adopted revision.sync/resilient-seated-gate-valves; process check valves: Process Check ValvesProcess Check ValvesResolves to the current adopted revision.sync/process-check-valves; air release and vacuum valves: Air Release And Vacuum ValvesAir Release and Vacuum ValvesResolves to the current adopted revision.sync/air-release-and-vacuum-valves; valve and gate actuators, extension stems, and floor stands: Valve And Gate ActuatorsValve and Gate ActuatorsResolves to the current adopted revision.sync/valve-and-gate-actuators.
  • Slide gates and stop logs: Slide Gates And Stop LogsSlide Gates and Stop LogsResolves to the current adopted revision.sync/slide-gates-and-stop-logs; process pumps: Horizontal Centrifugal Process PumpsHorizontal Centrifugal Process PumpsResolves to the current adopted revision.sync/horizontal-centrifugal-process-pumps, Vertical Turbine PumpsVertical Turbine PumpsResolves to the current adopted revision.sync/vertical-turbine-pumps, Submersible Solids Handling PumpsSubmersible Solids-Handling PumpsResolves to the current adopted revision.sync/submersible-solids-handling-pumps, and Positive Displacement PumpsPositive Displacement PumpsResolves to the current adopted revision.sync/positive-displacement-pumps.
  • Aeration blowers and overhead cranes and hoists: not yet owned by a SynC standard.
  • Water-retaining concrete structures and their tightness testing: Water Retaining Concrete StructuresWater-Retaining Concrete StructuresResolves to the current adopted revision.sync/water-retaining-concrete-structures; the placement of cast-in items is under Cast In Place ConcreteCast-in-Place ConcreteResolves to the current adopted revision.sync/cast-in-place-concrete.
  • Submerged aeration drop pipes, diffuser headers, and diffuser grids below the basin water surface: not yet owned by a SynC standard.
  • Cathodic protection of buried steel piping: Cathodic ProtectionCathodic ProtectionResolves to the current adopted revision.sync/cathodic-protection; this standard installs the joint bonding that standard specifies where it is indicated.
  • Flame arresters, sediment and drip traps, pressure and vacuum relief, and waste gas burners on digester gas piping: not yet owned by a SynC standard; the digester gas pipe itself is under this standard.
  • Hangers, supports, anchors, guides, and structural attachments: Hangers And SupportsHangers and Supports for Mechanical Piping and EquipmentResolves to the current adopted revision.sync/hangers-and-supports; vibration isolation and seismic restraint: Vibration Isolation And Seismic RestraintVibration Isolation and Seismic RestraintResolves to the current adopted revision.sync/vibration-isolation-and-seismic-restraint.
  • Pipe markers, flow arrows, and valve tags: Mechanical IdentificationMechanical IdentificationResolves to the current adopted revision.sync/mechanical-identification.
  • Field-applied finish coating systems on exposed piping: High Performance CoatingsHigh-Performance CoatingsResolves to the current adopted revision.sync/high-performance-coatings.
  • Insulation and jacketing: Mechanical InsulationMechanical InsulationResolves to the current adopted revision.sync/mechanical-insulation; electric heat tracing: Electric Heat TracingElectric Heat TracingResolves to the current adopted revision.sync/electric-heat-tracing.
  • Trench excavation, dewatering, shoring, and backfill above the pipe zone: EarthworkEarthworkResolves to the current adopted revision.sync/earthwork.
  • Firestop systems at rated assemblies: FirestoppingFirestoppingResolves to the current adopted revision.sync/firestopping.
  • Flow meter straight-run and installation: Flow MeasurementFlow MeasurementResolves to the current adopted revision.sync/flow-measurement; instrument tubing, root valves, and manifolds downstream of the process tap: Instrument Installation And TubingInstrument Installation and Impulse TubingResolves to the current adopted revision.sync/instrument-installation-and-tubing.

2 Referenced Standards

2.1 Materials, fabrication, and installation shall comply with the latest adopted edition of each of the following unless a specific edition is cited.
2.2 Where the Contract Documents, the adopted codes, and a referenced standard differ on the same matter, the most stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.
Standard Title
AMPP SP0188 Discontinuity (Holiday) Testing of New Protective Coatings on Conductive Substrates
ASME B1.20.1 Pipe Threads, General Purpose (Inch)
ASME B16.5 Pipe Flanges and Flanged Fittings, NPS 1/2 through NPS 24
ASME B16.9 Factory-Made Wrought Buttwelding Fittings
ASME B16.11 Forged Fittings, Socket-Welding and Threaded
ASME B16.21 Nonmetallic Flat Gaskets for Pipe Flanges
ASME B16.25 Buttwelding Ends
ASME B16.47 Large Diameter Steel Flanges, NPS 26 through NPS 60
ASME B31.1 Power Piping
ASME B31.3 Process Piping
ASME B31.9 Building Services Piping
ASME B36.10M Welded and Seamless Wrought Steel Pipe
ASME B36.19M Stainless Steel Pipe
ASME BPVC Section IX Boiler and Pressure Vessel Code: Welding, Brazing, and Fusing Qualifications
ASTM A53 / A53M Pipe, Steel, Black and Hot-Dipped, Zinc-Coated, Welded and Seamless
ASTM A105 / A105M Carbon Steel Forgings for Piping Applications
ASTM A106 / A106M Seamless Carbon Steel Pipe for High-Temperature Service
ASTM A139 / A139M Electric-Fusion (Arc)-Welded Steel Pipe (NPS 4 and Over)
ASTM A182 / A182M Forged or Rolled Alloy and Stainless Steel Pipe Flanges, Forged Fittings, and Valves and Parts for High-Temperature Service
ASTM A193 / A193M Alloy-Steel and Stainless Steel Bolting for High Temperature or High Pressure Service and Other Special Purpose Applications
ASTM A194 / A194M Carbon Steel, Alloy Steel, and Stainless Steel Nuts for Bolts for High Pressure or High Temperature Service, or Both
ASTM A234 / A234M Piping Fittings of Wrought Carbon Steel and Alloy Steel for Moderate and High Temperature Service
ASTM A240 / A240M Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip for Pressure Vessels and for General Applications
ASTM A307 Carbon Steel Bolts, Studs, and Threaded Rod 60 000 PSI Tensile Strength
ASTM A312 / A312M Seamless, Welded, and Heavily Cold Worked Austenitic Stainless Steel Pipes
ASTM A358 / A358M Electric-Fusion-Welded Austenitic Chromium-Nickel Stainless Steel Pipe for High-Temperature Service and General Applications
ASTM A380 / A380M Cleaning, Descaling, and Passivation of Stainless Steel Parts, Equipment, and Systems
ASTM A403 / A403M Wrought Austenitic Stainless Steel Piping Fittings
ASTM A409 / A409M Welded Large Diameter Austenitic Steel Pipe for Corrosive or High-Temperature Service
ASTM A536 Ductile Iron Castings
ASTM A774 / A774M As-Welded Wrought Austenitic Stainless Steel Fittings for General Corrosive Service at Low and Moderate Temperatures
ASTM A778 / A778M Welded, Unannealed Austenitic Stainless Steel Tubular Products
ASTM A790 / A790M Seamless and Welded Ferritic/Austenitic Stainless Steel Pipe
ASTM A967 / A967M Chemical Passivation Treatments for Stainless Steel Parts
ASTM F593 Stainless Steel Bolts, Hex Cap Screws, and Studs
AWS A5.4 / A5.4M Stainless Steel Electrodes for Shielded Metal Arc Welding
AWS A5.9 / A5.9M Bare Stainless Steel Welding Electrodes and Rods
AWWA C200 Steel Water Pipe, 6 In. (150 mm) and Larger
AWWA C205 Cement-Mortar Protective Lining and Coating for Steel Water Pipe, 4 In. (100 mm) and Larger, Shop Applied
AWWA C206 Field Welding of Steel Water Pipe
AWWA C207 Steel Pipe Flanges for Waterworks Service, Sizes 4 In. Through 144 In. (100 mm Through 3,600 mm)
AWWA C208 Dimensions for Fabricated Steel Water Pipe Fittings
AWWA C209 Cold-Applied Tape Coatings for Steel Water Pipe and Fittings
AWWA C210 Liquid-Epoxy Coatings and Linings for Steel Water Pipe and Fittings
AWWA C213 Fusion-Bonded Epoxy Coatings and Linings for Steel Water Pipe and Fittings
AWWA C214 Tape Coatings for Steel Water Pipe
AWWA C215 Extruded Polyolefin Coatings for Steel Pipe
AWWA C216 Heat-Shrinkable Cross-Linked Polyolefin Coatings for Steel Water Pipe and Fittings
AWWA C219 Bolted, Sleeve-Type Couplings for Plain-End Pipe
AWWA C222 Polyurethane Coatings and Linings for Steel Water Pipe and Fittings
AWWA C600 Installation of Ductile-Iron Mains and Their Appurtenances
AWWA C606 Grooved and Shouldered Joints
AWWA C651 Disinfecting Water Mains
AWWA M11 Steel Pipe: A Guide for Design and Installation
EJMA Standards Standards of the Expansion Joint Manufacturers Association
MSS SP-58 Pipe Hangers and Supports: Materials, Design, Manufacture, Selection, Application, and Installation

3 Submittals

3.1 Action Submittals

3.1.1 The Contractor shall submit the following for the Engineer of Record's review and return before any process pipe, fitting, flange, coupling, or wall pipe is fabricated or procured:
  • Pipe product data for each material family, size band, and service, identifying the product standard, grade or alloy, manufacture, wall schedule or thickness, and marking
  • Fabricated steel pipe and special data under AWWA C200, including cylinder steel grade, wall thickness design, and the fabricator's quality program
  • Fitting, flange, bolting, and gasket product data, identifying the governing standard, material, pressure class, facing, and gasket compound with its rated temperature
  • Grooved coupling system product data covering couplings, fittings, gaskets, and the grooving method, with the gasket compound and its rated temperature for each service
  • Sleeve-type coupling, dismantling joint, flanged coupling adapter, and restraint harness product data with pressure rating and end-load restraint rating
  • Expansion joint and flexible connector product data, including movement capacity, pressure and temperature rating, and liner and tie-rod arrangement
  • Lining and coating system data for each designation on the piping schedule, with the surface preparation, film thickness, cure, and holiday test the system requires
  • Wall pipe and penetration seal data, including collar type, flange or end configuration, and seal element compound
  • Welding procedure specifications and procedure qualification records under ASME BPVC Section IX for every base metal, filler, and joint configuration, and qualification records for every welder and welding operator
  • Pickling and passivation procedure for stainless steel, naming the process, the chemistry, the neutralization, and the verification test
  • Spool and fabrication drawings showing each shop-fabricated assembly with dimensions, joint types, outlet reinforcement, lining and coating designations, and piece marks
  • A pressure test plan identifying test boundaries, medium, pressure, hold duration, isolation, gauge selection, and the sequence that tests buried and concealed work before it is covered
  • Piping layout drawings at a scale sufficient to resolve conflicts with structure, equipment, valves, and other trades, showing routing, sizes, joint locations, dismantling provisions, and support points
Action Submittals Requiredcheckbox
☑ Pipe product data by material family, size band, and service
☐ Fabricated steel pipe and special data under AWWA C200
☑ Fitting, flange, bolting, and gasket product data
☐ Grooved coupling system product data
☐ Sleeve-type coupling, dismantling joint, and flanged coupling adapter data
☐ Expansion joint and flexible connector product data
☑ Lining and coating system data
☐ Wall pipe and penetration seal data
☑ Welding procedure and welder qualification records
☐ Pickling and passivation procedure
☑ Spool and fabrication drawings
☑ Pressure test plan
☑ Piping layout drawings
3.1.2 Fabrication of an assembly shall not begin until the submittals covering its pipe, fittings, joints, lining, and coating have been returned by the Engineer of Record.
3.1.3 Each submittal shall be internally consistent across pipe, fittings, flanges, gaskets, and couplings, and the Contractor shall bear the cost of resubmission caused by inconsistency within its own submittal.

3.2 Closeout Submittals

3.2.1 The Contractor shall submit the following before the process piping work is accepted:
  • Signed and dated pressure and leakage test reports for every test boundary, recording the medium, pressure, hold duration, observed loss, and the pass determination
  • A weld map and record listing each field weld by location or joint number, the welder identification, the procedure used, and the examination result
  • Nondestructive examination reports for every joint examined beyond visual, with the examiner's certification
  • Passivation records for stainless steel spools and field welds, with the verification test result for each lot
  • Coating and lining inspection records, including surface preparation, film thickness readings, holiday test results, and repairs
  • Disinfection and bacteriological clearance records for finished-water piping
  • Mill test reports and material certifications for pipe, fittings, flanges, and bolting
  • Record drawings showing the installed routing, sizes, joint types, dismantling provisions, wall pipe and penetration locations, and the depth and alignment of buried yard piping
Closeout Submittals Requiredcheckbox
☑ Pressure and leakage test reports
☑ Weld map and record
☐ Nondestructive examination reports
☐ Passivation records
☑ Coating and lining inspection records
☐ Disinfection and bacteriological clearance records
☑ Mill test reports and material certifications
☑ Record drawings

4 Quality Assurance

4.1 Fabricator and Installer Qualification

4.1.1 Fabricated steel pipe and specials under AWWA C200 shall be produced by a fabricator that has furnished pipe to that standard for at least three water or wastewater projects within the preceding five years, and the fabricator shall submit those project references on request.
4.1.2 Shop-fabricated stainless steel spools shall be produced in a shop that maintains a stainless fabrication area separated from carbon steel work.
4.1.3 The contractor installing process piping shall have completed at least three water, wastewater, or industrial process piping installations comparable to this project in size and complexity within the preceding five years, and shall submit those project references on request.
4.1.4 Where the parties disagree whether a submitted reference project is comparable in size and complexity, the Engineer of Record shall make the initial determination.

4.2 Welding Qualification

4.2.1 Welding procedures and welders shall be qualified under ASME BPVC Section IX for each base metal, filler metal, process, position, and thickness range used on the project.
4.2.2 Where the piping schedule designates a line under AWWA C200, field welding of that line shall additionally comply with AWWA C206.
4.2.3 Qualification and continuity records for every welder and welding operator on site shall be kept at the site and available for inspection throughout installation.
4.2.4 A welder whose Section IX continuity has lapsed shall requalify before making any production weld on this project.
4.2.5 Joints made by a welder who was not qualified when the joint was made shall be cut out and remade, and the Contractor shall bear the cost of the removal, the replacement material, the remake, the re-examination, and the repair of any work of another trade disturbed by the removal.

4.3 Stainless Steel Handling Discipline

4.3.1 Stainless steel pipe, fittings, and spools shall be cut, ground, brushed, and handled only with tooling, abrasives, and wire brushes that have never been used on carbon steel.
4.3.2 Stainless steel shall be stored, staged, and transported without contact with carbon steel racks, chains, banding, forks, or fasteners, and shall be separated from carbon steel grinding and welding by distance or by shielding.
NOTE Free iron transferred to a stainless surface from a carbon steel brush, a grinding wheel, or a storage rack rusts in place and starts pitting under the rust bloom. The contamination occurs in the shop or the laydown yard, not in service, and it is invisible until the surface is wet, by which time the pit has begun. In a wastewater plant atmosphere, where hydrogen sulfide and chlorides are already working on the surface, the embedded iron is the point where the attack starts. (4.3.3)
4.3.4 Stainless steel surfaces found to carry embedded iron or rust staining shall be cleaned and repassivated under the Stainless Steel Welding and Surface Treatment section of this standard at the Contractor's cost.

4.4 Grooved Coupling Single Source

4.4.1 Where grooved joints are used, the couplings, grooved fittings, gaskets, and grooving tooling for a given pipe material, size, and service shall be the products of a single manufacturer.
4.4.2 Grooved coupling components of different manufacturers shall not be combined in one joint.
NOTE The groove geometry, the housing, and the gasket cross-section of a grooved joint are a matched set whose seal depends on the gasket being compressed a specific amount by a specific housing against a specific groove. Components that each meet AWWA C606 can still combine into a joint that never reaches its designed compression. (4.4.3)

5 Service Conditions and Design Basis

5.1 Piping Schedule as the Design Basis

5.1.1 The size, service, design pressure, design temperature, material family, and lining and coating designation of each line shall be as indicated on the piping schedule.
5.1.2 No component of a line shall be rated below the design pressure of that line at its design temperature.
5.1.3 Where a component's pressure rating derates with temperature, the rating at the line's design temperature shall govern.
5.1.4 The Contractor shall not substitute a smaller pipe size, a lighter wall, or a lower pressure class than the piping schedule indicates without the written approval of the Engineer of Record.
NOTE A process plant runs raw water at a few psi beside a high-service discharge at two hundred, cold plant water beside blower air at 250°F, and clean water beside sludge that abrades every elbow. One design pressure and one temperature cannot describe that plant, which is why the schedule carries them line by line and this standard reads them rather than asserting them. (5.1.5)

5.2 Governing Design Code

5.2.1 Process piping shall be designed, fabricated, examined, and tested under the code indicated in the datasheet, except where this standard states a more specific requirement.
Governing Design Code for Steel and Stainless Process Pipingselect
ASME B31.3
AWWA C200 and AWWA M11, with field welding under AWWA C206
ASME B31.1
ASME B31.9
NOTE No code is the norm across process plants, because the plant is the sum of lines designed under different traditions. ASME B31.3 is the code written for process service and carries the most complete examination and pressure test rules, so chemical and industrial plants are usually designed to it. AWWA C200 with M11 is the waterworks design basis for large-diameter steel water pipe and settles wall thickness, specials, and field welding without B31.3's examination burden, so water and wastewater plants often cite it for their large lines. ASME B31.1 is the code existing power and industrial facilities carry forward in their specifications. ASME B31.9 covers building services within its pressure and size limits and is the least demanding of the four; its limits are exceeded by the larger and hotter lines in a plant, so it serves only where every line fits inside its scope. (5.2.2)
5.2.3 Where the selected code does not cover a line's size, pressure, or temperature, that line shall be designed under ASME B31.3.

5.3 Blower and Aeration Air Temperature

5.3.1 The design temperature of blower discharge and aeration air piping shall be as indicated in the datasheet.
Blower Discharge Air Design Temperaturerange
°F
120150180200225250275300350400
Per drawings — the blower equipment schedule (deferred by default)
NOTE Compressing air heats it, and the discharge temperature of a blower is set by its pressure ratio, its efficiency, and the inlet air temperature on the hottest day. A positive-displacement blower at the pressures an aeration basin needs discharges well above 200°F, and a multistage centrifugal machine is not far behind. That temperature is a property of the blower selection, which is why it is read from the blower schedule, and it governs the gasket compound, the coupling gasket, the coating, the expansion compensation, and the support material of every foot of pipe between the blower and the basin. (5.3.2)
5.3.3 Every gasket, coupling gasket, flexible connector element, coating, and support component in blower discharge and aeration air piping shall be rated by its manufacturer for continuous service at the air design temperature.

5.4 Freeze Protection of Exposed Yard Piping

5.4.1 Process piping exposed outdoors or in unheated structures where the fluid can stand without flow shall be protected against freezing by the method indicated in the datasheet, selected against Site Ambient Temperature MinimumSite Ambient Temperature MinimumParameterEach project supplies its own value.site-ambient-temperature-minimum.
Freeze Protection of Exposed Process Pipingradio
○ Electric heat tracing with insulation
○ Insulation only, relying on continuous flow
○ Drain-down provisions at every low point
○ None required
NOTE Heat tracing with insulation protects a line that stands still, at the cost of a circuit, a controller, and the insulation system it needs to work, and it is the only method that protects a line that must stay full. Insulation alone delays freezing and is enough where the line flows continuously and a brief outage does not drop it below freezing. Drain-down provisions cost the least and suit seasonal or intermittent lines that can be emptied before a freeze, provided someone does it. No protection is the answer where the climate never reaches freezing or where every exposed line is in a heated structure. (5.4.2)
5.4.3 Where electric heat tracing is selected, it shall be furnished and installed under Electric Heat TracingElectric Heat TracingResolves to the current adopted revision.sync/electric-heat-tracing, and the insulation and jacketing under Mechanical InsulationMechanical InsulationResolves to the current adopted revision.sync/mechanical-insulation.
5.4.4 Where the Contractor identifies an exposed routing that can stand without flow and is not covered by the selected method, the Contractor shall notify the Engineer of Record in writing before installing that portion.

5.5 Digester Gas Piping

5.5.1 Digester gas piping shall be of the material family indicated in the datasheet, with every joint welded or flanged and no threaded joint larger than NPS 1.
Digester Gas Piping Materialselect
Type 304L stainless steel
Type 316L stainless steel
Carbon steel, lined and coated as selected for sludge service
NOTE Digester gas is saturated with water and carries hydrogen sulfide, and the condensate that forms on every cool surface is a dilute acid that consumes bare carbon steel from the inside. Type 304L is the usual pipe for the gas header and resists the condensate at the lowest stainless cost; Type 316L is selected where the gas carries enough sulfide and chloride to pit 304L, which is a question of the plant's sludge chemistry; and lined and coated carbon steel serves where the plant has standardized on it and accepts the lining as the barrier. Threaded joints are kept out of gas service above the smallest sizes because a thread is a leak path for a gas that is both flammable and toxic. (5.5.2)
5.5.3 Digester gas piping shall be pitched continuously at not less than 1/8 in. per ft toward the condensate drip traps shown on the digester gas piping plans, with no pockets between traps.
5.5.4 Digester gas piping shall be pressure tested under the Pressure and Leakage Testing section of this standard by the pneumatic method, with every joint soap tested at the test pressure, and shall show no detectable leakage.
NOTE Flame arresters, sediment and drip traps, pressure and vacuum relief devices, and waste gas burners are not yet owned by a SynC standard; this standard provides the pipe, its joints, its pitch, and its test, and the connections those devices require at the locations the drawings show. (5.5.5)

5.6 Seismic Restraint Interface

5.6.1 Process piping shall be braced and restrained under Vibration Isolation And Seismic RestraintVibration Isolation and Seismic RestraintResolves to the current adopted revision.sync/vibration-isolation-and-seismic-restraint wherever that standard requires it for Seismic Design CategorySeismic Design CategoryParameterEach project supplies its own value.seismic-design-category.
5.6.2 Flexible connectors, grooved flexible couplings, and expansion joints shall not be relied upon to resist seismic loads unless the restraint design under Vibration Isolation And Seismic RestraintVibration Isolation and Seismic RestraintResolves to the current adopted revision.sync/vibration-isolation-and-seismic-restraint accounts for them.

6 Carbon Steel Pipe

6.1 Carbon Steel Pipe Product Standards

6.1.1 Carbon steel pipe NPS 12 and smaller shall conform to the product standard indicated in the datasheet, with dimensions and wall schedules under ASME B36.10M.
Carbon Steel Pipe Product Standard, NPS 12 and Smallerselect
ASTM A53 / A53M Grade B
ASTM A106 / A106M Grade B
AWWA C200
6.1.2 Carbon steel pipe NPS 14 and larger shall conform to the product standard indicated in the datasheet.
Carbon Steel Pipe Product Standard, NPS 14 and Largerselect
AWWA C200
ASTM A53 / A53M Grade B
ASTM A139 / A139M Grade B
NOTE ASTM A53 Grade B is the schedule pipe nearly every plant uses for its small and medium lines; it is stocked in every schedule, threads cleanly, and is what the fitting standards are dimensioned to, which is why it is the default below NPS 14. ASTM A106 is a seamless pipe made for elevated temperature and is selected where a blower discharge line or a code requirement calls for seamless pipe with a certified elevated-temperature yield. AWWA C200 is fabricated from plate or coil to the diameter and wall the design needs rather than to a schedule, which is why it is the default from NPS 14 upward, where schedule walls grow heavier than a water line needs and the fabricator can also build the elbows, outlets, and specials to match. ASTM A139 is an electric-fusion-welded pipe produced to a wall rather than a schedule and is the usual product for a large low-pressure air header where C200's waterworks provisions are not needed. (6.1.3)
6.1.4 Carbon steel pipe under ASTM A53 shall be manufactured by the method indicated in the datasheet.
ASTM A53 Carbon Steel Pipe Manufactureradio
● Electric-resistance welded or seamless
○ Seamless only
6.1.5 Galvanized carbon steel pipe shall be used only where the piping schedule designates it.

6.2 Carbon Steel Wall Thickness

6.2.1 The wall schedule for carbon steel schedule pipe NPS 12 and smaller shall be as indicated in the datasheet.
Carbon Steel Wall Schedule, NPS 12 and Smallerselect
Schedule 40
Schedule 80
Schedule 10
Standard weight
NOTE Schedule 40 carries every pressure a plant water line sees with wall to spare for corrosion and for a thread, and it is what the fittings, the grooving tools, and the hanger tables assume, which is why it is the default. Schedule 80 is selected where a threaded small-bore line in chemical or high-pressure service needs the remaining wall at the thread root, or where abrasion from grit or sludge consumes wall over the life of the line. Schedule 10 is light enough to roll-groove and cheap enough to matter on a long low-pressure air header, and it cannot be threaded or cut-grooved. Standard weight equals Schedule 40 through NPS 10 and holds a constant 0.375 in. wall above it. (6.2.2)
6.2.3 Where carbon steel pipe is threaded, the remaining wall at the root of the thread shall satisfy the governing design code's pressure design requirement at the line's design pressure and temperature.
6.2.4 The wall thickness of fabricated steel pipe under AWWA C200 and of pipe NPS 14 and larger shall be as indicated in the datasheet.
Carbon Steel Pipe Wall Thickness, NPS 14 and Largerrange
in.
0.1340.1560.1880.2190.250.2810.3120.3750.4380.50.6250.751
Per drawings — the piping schedule (deferred by default)
NOTE The wall of a large steel line is a design output of internal pressure, surge, external load, vacuum, handling, and the stiffness a buried pipe needs against deflection, computed under AWWA M11 or the governing code by the Engineer of Record, which is why it is read from the piping schedule rather than chosen here. (6.2.5)

6.3 Fabricated Steel Pipe and Specials

6.3.1 Fabricated steel pipe under AWWA C200 shall be made from cylinder steel of a grade that standard permits, with a specified minimum yield strength not less than 36 ksi.
6.3.2 Fabricated elbows, tees, crosses, reducers, outlets, and wyes in steel pipe shall be dimensioned under AWWA C208 and reinforced under AWWA M11 where the outlet or the miter geometry requires it.
6.3.3 Mitered elbows shall have not fewer than the number of segments AWWA C208 requires for the deflection angle and the radius indicated, and single-miter elbows shall not be used for deflections exceeding 22.5 degrees.
NOTE A mitered elbow is the only practical way to turn a large steel line, and its strength depends on the number of segments and the radius. A single sharp miter concentrates stress at the intersection and, on a lined pipe, cracks the lining at the crotch, which is why the segment count rises with the angle. (6.3.4)
6.3.5 Collared or wrapper-reinforced outlets, crotch-plate reinforced wyes, and thrust collars shall be shop fabricated and shown on the spool drawings with the reinforcement dimensions.
6.3.6 Each fabricated piece shall carry a piece mark matching the spool drawings, applied so it remains legible after lining and coating.

6.4 Carbon Steel Fittings

6.4.1 Butt-weld fittings for schedule pipe shall conform to ASME B16.9 of ASTM A234 / A234M Grade WPB material, with a wall matching or exceeding the connecting pipe.
6.4.2 Socket-weld and threaded forged fittings shall conform to ASME B16.11 of ASTM A105 / A105M material, Class 3000 minimum.
6.4.3 Grooved fittings of cast construction shall conform to ASTM A536, and fabricated grooved fittings shall be of the same pipe material and wall as the run.
6.4.4 Gray cast iron threaded fittings shall not be used in process piping.
6.4.5 Reducers on horizontal runs shall be eccentric and oriented flat side up in air and water service and flat side down in sludge service, and reducers on vertical runs shall be concentric.
NOTE Flat side up keeps the top of a water or air line continuous so that air moves along to a vent; flat side down in a sludge line keeps the invert continuous so that solids do not settle behind a step. The same fitting serves both, which is why the orientation is a clause rather than a product selection. (6.4.6)

7 Carbon Steel Linings and Coatings

7.1 Interior Lining

7.1.1 The interior lining of carbon steel pipe and fittings in water, sludge, and chemical service shall be as indicated in the datasheet, applied in the shop by the pipe fabricator or the lining applicator under the standard named for that system.
Carbon Steel Pipe Interior Liningselect
Cement-mortar lining, AWWA C205
Liquid epoxy lining, AWWA C210
Fusion-bonded epoxy lining, AWWA C213
Polyurethane lining, AWWA C222
Unlined
NOTE No lining is the norm across process plants because the choice follows the fluid, the size, and whether the line is buried or exposed. Cement-mortar lining is the waterworks standard for large buried water lines: it is thick, self-healing at small holidays because the alkaline mortar passivates the steel, and tolerant of rough handling, and it adds weight, cannot be grooved, and does not suit small sizes or lines that flex. Liquid epoxy is thin, smooth, and inspectable, suits exposed and smaller lines, and is what most plant piping in buildings carries; it depends on a holiday-free film and a clean, profiled surface. Fusion-bonded epoxy is a shop-applied powder with a harder, more uniform film than liquid epoxy and is selected where the fabricator can apply it and the piece fits an oven. Polyurethane is thicker and more abrasion resistant than either epoxy, cures fast, and is selected for sludge, grit, and other abrasive services. Unlined pipe is the answer for air service and for a few clean services where the design carries a corrosion allowance in the wall instead. (7.1.2)
7.1.3 Air piping shall be unlined unless the piping schedule designates a lining.
7.1.4 Linings shall be continuous through fittings and specials and shall stop at a holdback distance from each field-welded joint that the joint coating method requires, with the holdback completed in the field after welding by the same lining system or by a field-applied liquid epoxy under AWWA C210.
7.1.5 Epoxy and polyurethane linings shall be holiday tested under AMPP SP0188 before shipment, and every holiday shall be repaired and retested.
7.1.6 Cement-mortar lined pipe shall be shipped with the ends sealed to keep the lining moist, and the lining shall be inspected for cracks and disbondment at delivery under the acceptance criteria of AWWA C205.

7.2 Exterior Coating of Exposed Piping

7.2.1 Exposed carbon steel piping shall be shop coated as indicated in the datasheet and field finish-coated under High Performance CoatingsHigh-Performance CoatingsResolves to the current adopted revision.sync/high-performance-coatings.
Shop Coating of Exposed Carbon Steel Pipingselect
Liquid epoxy primer, AWWA C210
Inorganic zinc primer compatible with the field finish system
Shop primer of the field finish system
Bare, with surface preparation and full coating applied in the field
NOTE A shop coat protects the steel between fabrication and finish painting and sets the primer the field system builds on. An AWWA C210 epoxy primer is the natural partner of an epoxy lining and accepts most epoxy and polyurethane field systems. An inorganic zinc primer gives the steel galvanic protection under the finish and is the choice where the finish system is a zinc-epoxy-urethane high-performance system; it demands a near-white blast and cannot be applied over mill scale. Using the field system's own primer in the shop removes any compatibility question at the cost of tying the fabricator to the painting contractor's product. Leaving the pipe bare puts the whole system in one hand in the field and is practical only where the pipe will be blasted and primed before it rusts. (7.2.2)
7.2.3 Blower discharge and aeration air piping in carbon steel shall be coated with a system rated for continuous service at the air design temperature, and a coating system without a published temperature rating at or above that temperature shall not be used on that piping.
7.2.4 Shop coatings shall be held back from field-welded joints by the distance the field joint coating requires and shall be completed in the field after welding.
7.2.5 Shop coating damaged in transit or installation shall be repaired with the shop coating manufacturer's repair procedure before the field finish is applied.

7.3 Exterior Coating of Buried Piping

7.3.1 Buried carbon steel piping shall be shop coated with the system indicated in the datasheet, applied under the standard named for that system.
Exterior Coating of Buried Carbon Steel Pipingselect
Polyurethane coating, AWWA C222
Tape coating system, AWWA C214
Cement-mortar coating, AWWA C205
Liquid epoxy coating, AWWA C210
Fusion-bonded epoxy coating, AWWA C213
Extruded polyolefin coating, AWWA C215
NOTE No buried coating is the norm because soil, handling, and the presence of cathodic protection each push the choice. Polyurethane is thick, tough, and fast curing and has become the usual buried waterworks coating where the fabricator can apply it. Tape systems are applied in the mill at low cost and are reliable in uniform soils, and they are vulnerable to shear in a rocky backfill and to disbondment where cathodic protection is applied over them. Cement-mortar coating is heavy and rigid, protects by alkalinity rather than as a barrier, and suits large lines in benign soils. Liquid epoxy and fusion-bonded epoxy are thin barriers that work well with cathodic protection and depend on a clean blast and a holiday-free film. Extruded polyolefin is a mill-applied, highly impact resistant coating for straight pipe that leaves fittings and field joints to another system. (7.3.2)
7.3.3 Buried coatings shall be holiday tested under AMPP SP0188 before the pipe is lowered into the trench, and every holiday shall be repaired and retested.
7.3.4 Field-welded joints in buried steel piping shall be coated in the field by the method indicated in the datasheet, after the weld has been examined and accepted.
Field Joint Coating for Buried Steel Pipingselect
Heat-shrinkable sleeve, AWWA C216
Cold-applied tape, AWWA C209
Field-applied liquid epoxy, AWWA C210
Field-applied polyurethane, AWWA C222
NOTE A heat-shrink sleeve bonds to the pipe coating on both sides of the joint, tolerates a less than perfect surface, and is the usual joint coating over polyurethane and tape systems. Cold-applied tape needs no heat and suits a tape-coated line, and it depends on the wrap tension and the primer. Field-applied liquid epoxy or polyurethane matches the pipe coating in kind and gives the same barrier at the joint, at the price of a field blast and a cure time before backfill. (7.3.5)
7.3.6 The Contractor shall bear the cost of repairing coating damaged by handling, by the trench, or by backfill, including re-excavation where damage is found after backfill.

8 Stainless Steel Pipe

8.1 Stainless Steel Pipe Product Standards

8.1.1 Stainless steel pipe NPS 12 and smaller shall conform to the product standard indicated in the datasheet, with dimensions under ASME B36.19M.
Stainless Steel Pipe Product Standard, NPS 12 and Smallerselect
ASTM A312 / A312M
ASTM A778 / A778M
ASTM A790 / A790M (duplex)
8.1.2 Stainless steel pipe NPS 14 and larger shall conform to the product standard indicated in the datasheet.
Stainless Steel Pipe Product Standard, NPS 14 and Largerselect
ASTM A778 / A778M
ASTM A312 / A312M
ASTM A409 / A409M
ASTM A358 / A358M
NOTE ASTM A312 is annealed and pickled after welding, which restores full corrosion resistance at the longitudinal seam, and it is the stocked stainless pipe through the schedule range, which is why it is the default in the smaller sizes. ASTM A778 is welded and left unannealed, which costs less and is adequate for the water and air services that make up most plant stainless piping, and the fitting standard A774 is made to match it; it is the usual large-diameter choice because A312 above NPS 12 is a special order. ASTM A409 is a welded large-diameter pipe made to a wall rather than a schedule for corrosive and high-temperature service, and ASTM A358 is a fusion-welded pipe with full radiographic classes for lines where the seam itself must be examined. Duplex pipe under ASTM A790 is selected where chloride stress corrosion cracking is the governing threat and the extra strength lets a thinner wall carry the pressure. (8.1.3)

8.2 Stainless Steel Alloy

8.2.1 The stainless steel alloy for blower discharge, aeration, and channel air piping shall be as indicated in the datasheet.
Stainless Steel Alloy for Air Servicesselect
Type 304L
Type 316L
Duplex 2205
8.2.2 The stainless steel alloy for water, sludge, and chemical services shall be as indicated in the datasheet.
Stainless Steel Alloy for Water, Sludge, and Chemical Servicesselect
Type 316L
Type 304L
Duplex 2205
NOTE Type 304L carries hot, dry air for the life of the plant and is the alloy nearly every aeration header is built from, which is why it is the default for air. In wet service the choice turns on chlorides and on the atmosphere: Type 316L adds molybdenum, which resists the pitting that chlorides, hypochlorite residuals, and the hydrogen sulfide atmosphere of a headworks or a digester building start in Type 304L, and it costs more. Type 304L remains a sound selection for clean water in a clean building. Duplex 2205 resists chloride stress corrosion cracking that neither austenitic grade can and is roughly twice as strong, so it is selected for brine, seawater, high-chloride reuse water, and hot chloride service where 316L has failed. The low-carbon grades are used throughout because the weld heat-affected zone of a standard-carbon grade sensitizes and corrodes along the weld. (8.2.3)
8.2.4 Wrought and forged stainless components in a line shall be of the same alloy family as the pipe, and a Type 304L component shall not be installed in a line designated Type 316L or duplex.

8.3 Stainless Steel Wall Thickness

8.3.1 The wall schedule for stainless steel pipe NPS 2 and smaller shall be as indicated in the datasheet.
Stainless Steel Wall Schedule, NPS 2 and Smallerselect
Schedule 40S
Schedule 10S
Schedule 80S
8.3.2 The wall schedule for stainless steel pipe NPS 2½ through NPS 12 shall be as indicated in the datasheet.
Stainless Steel Wall Schedule, NPS 2½ Through NPS 12select
Schedule 10S
Schedule 40S
Schedule 5S
Schedule 80S
NOTE Stainless steel does not need a corrosion allowance, so the wall is chosen for pressure, for the joint, and for stiffness between supports rather than for metal loss. Schedule 10S carries plant pressures in the mid sizes, roll-grooves, and welds easily, which is why it is the default from NPS 2½ upward. Small-bore stainless is usually threaded or socket welded, and a thread needs the wall of Schedule 40S, which is why that band defaults heavier. Schedule 5S is the thinnest wall that is practical to weld and is selected for large low-pressure air where weight governs. Schedule 80S is selected where a threaded chemical line needs wall at the thread root or where the design pressure is high. (8.3.3)
8.3.4 The wall thickness of stainless steel pipe NPS 14 and larger shall be as indicated in the datasheet.
Stainless Steel Pipe Wall Thickness, NPS 14 and Largerrange
in.
0.1090.1340.1560.1880.2190.250.3120.3750.5
Per drawings — the piping schedule (deferred by default)
8.3.5 Where stainless steel pipe is threaded, the remaining wall at the root of the thread shall satisfy the governing design code's pressure design requirement at the line's design pressure and temperature.

8.4 Stainless Steel Fittings

8.4.1 Butt-weld fittings for ASTM A312 pipe shall conform to ASME B16.9 of ASTM A403 / A403M material in the alloy of the pipe, with a wall matching the connecting pipe.
8.4.2 Butt-weld fittings for ASTM A778 pipe shall conform to ASTM A774 / A774M in the alloy and wall of the pipe.
8.4.3 Socket-weld and threaded forged stainless fittings shall conform to ASME B16.11 of ASTM A182 / A182M material in the alloy of the pipe.
8.4.4 Grooved fittings in stainless lines shall be stainless steel of the alloy of the pipe, and ductile iron grooved fittings shall not be installed in a stainless line.
8.4.5 Fabricated stainless specials, including mitered elbows, reducing outlets, and wall pipes, shall be fabricated from ASTM A240 / A240M plate or from pipe of the same alloy and wall as the run, with mitered elbows segmented as the Fabricated Steel Pipe and Specials article of this standard requires.
8.4.6 The flange construction for stainless steel lines shall be as indicated in the datasheet.
Stainless Steel Flange Constructionselect
Solid stainless steel flange, ASTM A182
Stainless steel stub end with carbon steel backing flange
Stainless steel plate flange, ASTM A240, AWWA C207 pattern
8.4.8 Carbon steel backing flanges shall be coated with the shop coating selected for exposed carbon steel piping and shall be isolated from the stainless stub end by the stub end's own lap, with no carbon steel in contact with the fluid.

9 Stainless Steel Welding and Surface Treatment

9.1 Stainless Steel Welding

9.1.1 Stainless steel butt welds shall be made with a gas tungsten arc root pass, and the root shall be purged with inert gas until the weld has cooled below the temperature at which oxidation forms.
9.1.2 Filler metal shall conform to AWS A5.4 / A5.4M or AWS A5.9 / A5.9M in the low-carbon grade matching the base metal, and a Type 304L line shall be welded with 308L filler, a Type 316L line with 316L filler, and a duplex line with the filler the pipe manufacturer designates.
9.1.3 Welding shall not be performed on a stainless surface that is wet, contaminated with carbon steel, or below the minimum temperature the qualified procedure states.
9.1.4 Weld spatter, arc strikes outside the joint, and grinding marks shall be removed from stainless surfaces by stainless-only tooling.
NOTE An unpurged stainless root grows a sugared, oxidized bead on the inside of the pipe that has lost its chromium to the oxide and corrodes first, and in a sludge or chemical line it also catches solids. The purge costs a few minutes per joint and is the difference between a stainless line and a line that is stainless everywhere but at its joints. (9.1.5)

9.2 Heat Tint Removal and Passivation

9.2.1 Shop-fabricated stainless steel spools and specials shall receive the surface treatment indicated in the datasheet after all welding and fabrication is complete.
Surface Treatment of Shop-Fabricated Stainless Steelselect
Pickled and passivated, ASTM A380 and ASTM A967
Mechanically cleaned to bright metal and chemically passivated, ASTM A967
Electrochemically cleaned at the welds and chemically passivated, ASTM A967
9.2.2 Field welds in stainless steel shall receive the surface treatment indicated in the datasheet after examination and acceptance.
Surface Treatment of Field Welds in Stainless Steelselect
Pickling paste and chemical passivation, ASTM A380 and ASTM A967
Mechanically cleaned to bright metal and chemically passivated, ASTM A967
Electrochemically cleaned and chemically passivated, ASTM A967
NOTE Welding leaves a heat tint beside every stainless weld that is depleted in chromium under its oxide, and the pipe corrodes there first unless the tint is removed and the surface is allowed to rebuild its passive film. Immersion pickling in a shop bath removes the tint and any embedded iron from every surface at once and is the treatment a fabricator applies to a whole spool, which is why it is the shop default. In the field there is no bath: a pickling paste does the same chemistry locally and must be neutralized and rinsed completely, mechanical cleaning with stainless-only abrasives removes the tint without acid and depends on the operator reaching the whole heat-affected band, and electrochemical weld cleaning removes the tint with an electrolyte and a wand and leaves the least residue. All three are followed by a chemical passivation under ASTM A967 to rebuild the film. (9.2.3)
9.2.4 Passivation shall be verified on each lot of shop spools and on each day's field welds by a test method of ASTM A967, and the result shall be recorded.
9.2.5 Pickling and passivation chemicals shall be neutralized and rinsed from the pipe interior and exterior before the pipe is shipped or placed in service, and the rinse water shall be disposed of as the Authority Having Jurisdiction requires.
9.2.6 A stainless surface that fails the passivation verification shall be recleaned, repassivated, and retested at the Contractor's cost.

10 Joints

10.1 Joining Method by Material and Size

10.1.1 The joining method for carbon steel piping NPS 2 and smaller shall be as indicated in the datasheet.
Carbon Steel Joining Method, NPS 2 and Smallerselect
Threaded
Socket welded
Grooved mechanical coupling
Flanged
10.1.2 The joining method for carbon steel piping NPS 2½ through NPS 12 shall be as indicated in the datasheet.
Carbon Steel Joining Method, NPS 2½ Through NPS 12select
Flanged
Grooved mechanical coupling
Butt welded, with flanges at valves and equipment
10.1.3 The joining method for carbon steel piping NPS 14 and larger shall be as indicated in the datasheet.
Carbon Steel Joining Method, NPS 14 and Largerselect
Flanged
Butt welded, with flanges at valves and equipment
Lap-welded bell and spigot
Rubber-gasketed bell and spigot
Bolted sleeve-type couplings
10.1.4 The joining method for stainless steel piping NPS 2 and smaller shall be as indicated in the datasheet.
Stainless Steel Joining Method, NPS 2 and Smallerselect
Threaded
Socket welded
Butt welded
Grooved mechanical coupling
Flanged
10.1.5 The joining method for stainless steel piping NPS 2½ and larger shall be as indicated in the datasheet.
Stainless Steel Joining Method, NPS 2½ and Largerselect
Flanged
Grooved mechanical coupling
Butt welded, with flanges at valves and equipment
NOTE Threading is the small-bore carbon steel joint every plant has made for a century: it needs no hot-work permit and no welder, and its wall and sealant discipline is well understood, which is why it is the default below NPS 2½. Above that size no method is the norm. Flanged joints come apart, mate directly to valves and equipment, and are the waterworks tradition for exposed plant piping; every flange is a gasket, a bolt set, and an alignment to get right. Grooved joints assemble fast without flame, come apart as easily as flanges, and absorb some misalignment and movement, and they put an elastomer at every joint whose compound and temperature rating must suit the fluid. Welded joints are the strongest, tightest, and cheapest per foot on a long run, and they are permanent, so a welded line needs flanges or couplings wherever a valve or a pump will come out. On large steel pipe the bell-and-spigot joints of the waterworks tradition appear: a lap-welded bell and spigot is a self-restrained welded joint made in the trench, and a rubber-gasketed bell and spigot assembles without welding and needs thrust restraint. Bolted sleeve-type couplings join plain ends, absorb a little movement, and are the usual closure and dismantling joint on a buried line. Stainless small-bore is threaded or socket welded where the schedule permits and butt welded where the wall is too thin to thread. (10.1.6)
10.1.7 Joining methods shall not be mixed within a continuous run except at a flange, a coupling, or an adapter listed for both methods and rated for the line's design pressure at its design temperature.
10.1.8 Every line shall have a flanged, grooved, or coupled joint on each side of every valve and at every equipment connection so that the valve or equipment can be removed without cutting pipe.

10.2 Welded Joints

10.2.1 Butt-welded joints shall have ends prepared under ASME B16.25 and shall be full-penetration welds.
10.2.2 Socket-welded joints shall be assembled with the pipe withdrawn approximately 1/16 in. from the bottom of the socket before welding.
10.2.3 Tack welds shall be made by qualified welders using the qualified procedure for the production weld, and shall be fused into the production weld or removed.
10.2.4 Welding shall not be performed when the joint is wet, when the base metal is below the preheat temperature the qualified procedure requires, or when wind or rain prevents the shielding from protecting the arc.
10.2.5 Field welds in lined carbon steel pipe shall be made with the lining held back as the Interior Lining article requires, and the holdback shall be lined in the field after the weld is accepted.
10.2.6 The Contractor shall provide fire watch, shielding, and permits for all hot work, and shall bear the cost of repairing damage caused by spatter, slag, or heat, including damage to linings, coatings, gaskets, and the work of other trades.

10.3 Threaded Joints

10.3.1 Pipe threads shall conform to ASME B1.20.1, cut clean and full, with the burr reamed from the bore before assembly.
10.3.2 Thread sealant shall be a polytetrafluoroethylene tape or a paste sealant rated for the fluid and the design temperature of the line, applied to the male thread only and kept back from the first thread.
10.3.3 Thread sealants containing lead shall not be used, and sealants for finished-water lines shall be certified for potable water contact.
10.3.4 Threaded joints shall not be back-turned to align a fitting after the joint is made up.
10.3.5 Threaded joints in stainless steel shall be made with a sealant or an anti-seize compound that is free of chlorides and of carbon steel particles.
NOTE Stainless threads gall when they are run up dry, and the usual cure, a metallic anti-seize paste, often contains copper or carbon steel flakes that seed corrosion on the stainless surface. A chloride-free, metal-free compound seals the thread and prevents galling without introducing either. (10.3.6)

10.4 Grooved Joints

10.4.1 Grooved joints shall conform to AWWA C606, with grooves roll-formed or cut to the coupling manufacturer's published dimensions for the pipe material and wall and verified with the manufacturer's gauge.
10.4.2 Cut grooving shall be used only on pipe walls for which the coupling manufacturer publishes a cut-groove pressure rating, and roll grooving shall be used on lighter walls.
10.4.3 The grooved coupling gasket compound for each service shall be as indicated in the datasheets below.
Grooved Coupling Gasket Compound, Water and Sludge Servicesselect
EPDM
Nitrile
Fluoroelastomer
Grooved Coupling Gasket Compound, Air Servicesselect
EPDM
Silicone
Fluoroelastomer
Grooved Coupling Gasket Compound, Chemical Servicesselect
EPDM
Fluoroelastomer
Nitrile
NOTE The gasket is the pressure boundary of a grooved joint, so its compound has to match the fluid and the temperature. EPDM is the water and wastewater compound: it resists ozone, hypochlorite residuals, and the dilute chemistry of plant water and sludge, which is why it is the default there, and it swells in petroleum oil and loses its seal above roughly 230°F. In blower discharge air the temperature decides: EPDM serves a low-pressure centrifugal blower that discharges cool, silicone holds its seal to roughly 350°F in dry air and is the usual choice on a positive-displacement blower, and fluoroelastomer extends the limit further and resists most chemistries at the highest cost. In chemical service the compound follows the chemical: EPDM for caustic and most inorganic solutions, fluoroelastomer for acids, oxidizers, and solvents, nitrile where oils and petroleum products are present. (10.4.4)
10.4.5 The gasket compound selected shall be rated by its manufacturer for continuous service in the fluid and at the design temperature of the line.
10.4.6 Gaskets shall be lubricated with the coupling manufacturer's lubricant only, and petroleum-based lubricant shall not be used on an EPDM gasket.
10.4.7 Grooved couplings on straight runs shall be rigid, and flexible couplings shall be used only at locations shown on the piping layout drawings for vibration, movement, or expansion accommodation.
NOTE A flexible grooved coupling permits angular and axial movement at every joint. Placed deliberately where a pump vibrates or a hot line grows, it does useful work; distributed along a run as the ordinary coupling it turns the run into a chain of hinges that wanders under pressure and thermal load and works every gasket. (10.4.8)

10.5 Flanged Joints

10.5.1 Flanges for carbon steel piping NPS 12 and smaller shall be of the standard and class indicated in the datasheet.
Carbon Steel Flange Standard and Class, NPS 12 and Smallerselect
ASME B16.5 Class 150
ASME B16.5 Class 300
AWWA C207 Class D
AWWA C207 Class E
10.5.2 Flanges for carbon steel piping NPS 14 and larger shall be of the standard and class indicated in the datasheet.
Carbon Steel Flange Standard and Class, NPS 14 and Largerselect
AWWA C207 Class D
AWWA C207 Class B
AWWA C207 Class E
AWWA C207 Class F
ASME B16.5 Class 150 through NPS 24, ASME B16.47 Series A above
NOTE ASME B16.5 Class 150 is the flange every small and medium plant line and every valve in those sizes is drilled to, which is why it is the default below NPS 14, and Class 300 is selected where the design pressure at temperature exceeds the Class 150 rating. AWWA C207 is the waterworks flange: it is a flat-faced ring, hub, or blind flange drilled to the same bolt circle as Class 125 cast iron and Class 150 steel through NPS 24, so it mates to ductile iron valves and fittings, and its classes are pressure ratings for water service rather than pressure-temperature curves. Class D at 150 to 175 psi matches the ductile iron fittings beside it and is what most plant water lines use, which is why it is the default from NPS 14 upward; Class B at 86 psi serves low-pressure large lines and air headers; Class E at 275 psi and Class F at 300 psi serve high-service and surge-prone lines. ASME flanges above NPS 24 move to B16.47, whose Series A bolt pattern matches C207 Class E and F and whose Series B does not match anything in the waterworks catalog. (10.5.3)
10.5.4 Flanges for stainless steel piping shall be of the construction selected in the Stainless Steel Fittings article and of the class and bolt pattern matching the mating component.
10.5.5 Carbon steel flanges under ASME B16.5 shall be of ASTM A105 / A105M material, and the attachment type shall be as indicated in the datasheet.
ASME B16.5 Flange Attachment Typeselect
Slip-on
Weld neck
Lap joint with stub end
NOTE A slip-on flange slides over the pipe and is fillet welded inside and out, costs the least, and aligns its bolt holes by rotating before it is welded, which is why it is the flange nearly every plant line carries. A weld neck flange is butt welded to the pipe through a tapered hub, carries the highest bending and fatigue rating, and is selected on blower discharge lines, high-pressure lines, and lines designed under a code that requires it. A lap joint flange is a loose ring over a welded stub end and is selected where the bolt holes must rotate to align after the stub end is welded, or where the pipe is stainless and the ring can be carbon steel. (10.5.6)
10.5.7 Flanges under AWWA C207 shall be ring, hub, or blind flanges of the flange type and facing that standard provides, welded to the pipe as AWWA C207 and AWWA C206 require, and ring flanges shall be welded both inside and out.
10.5.8 Where a steel flange mates to a cast iron or ductile iron flange, the joint shall use a flat-faced steel flange and a full-face gasket.
NOTE A raised-face steel flange bolted to a flat-faced iron flange bends the iron over the edge of the raised face as the bolts are drawn up, and iron has almost no ductility to absorb that bending. The crack appears in the valve body or the pump casing, not in the flange the installer was watching. (10.5.9)
10.5.10 The flange gasket material for each service shall be as indicated in the datasheets below.
Flange Gasket Material, Water and Sludge Servicesselect
EPDM rubber, full face
SBR rubber, full face
Non-asbestos compressed fiber
Polytetrafluoroethylene
Flange Gasket Material, Air Servicesselect
Non-asbestos compressed fiber
Flexible graphite
High-temperature EPDM rubber, full face
Spiral wound, stainless steel and graphite
Flange Gasket Material, Chemical Servicesselect
Polytetrafluoroethylene
EPDM rubber, full face
Fluoroelastomer
Non-asbestos compressed fiber
NOTE A full-face rubber gasket is the waterworks gasket for flat-faced C207 and iron flanges: it fills the whole face, seats at low bolt load, and tolerates the slight misalignment of large flanges, and SBR is its lowest-cost compound where the water carries no oxidizer while EPDM resists hypochlorite residuals and ozone. Non-asbestos compressed fiber is the ring gasket for raised-face ASME flanges in water and is selected in air service where a rubber compound cannot hold the temperature; flexible graphite holds far higher temperatures and seals a hot air header through thermal cycles at a higher cost; a high-temperature EPDM compound serves an air header that stays below its rating; and a spiral-wound gasket is selected where a blower discharge flange sees both high temperature and a bending load. In chemical service PTFE is inert to nearly everything and creeps under bolt load, so it suits a full-face flat flange better than a raised face; EPDM serves caustic and most inorganic solutions; fluoroelastomer serves acids and oxidizers; and compressed fiber serves the mild chemistries where its binder is not attacked. (10.5.11)
10.5.12 Flange gaskets shall conform to ASME B16.21 for nonmetallic flat gaskets and shall be rated by their manufacturer for the fluid and the design temperature of the line.
10.5.13 Flange bolting for exposed piping shall be of the material indicated in the datasheet.
Flange Bolting Material, Exposed Pipingselect
ASTM A307 Grade B, zinc plated
ASTM A193 Grade B7 bolts with ASTM A194 Grade 2H nuts
Type 304 stainless steel, ASTM F593 or ASTM A193 Grade B8
Type 316 stainless steel, ASTM F593 or ASTM A193 Grade B8M
10.5.15 Flange bolting in submerged, buried, wet-well, and chemical-area locations shall be Type 316 stainless steel regardless of the material selected for exposed piping, unless the piping schedule designates otherwise.
10.5.16 Stainless steel bolts shall be assembled with a chloride-free anti-galling compound on the threads.
10.5.17 Flange bolts shall be tightened in a crossing pattern in at least three passes to the torque the gasket manufacturer publishes, and the bolts of a flange in hot air service shall be retorqued after the first thermal cycle.
10.5.18 Flange joints shall be aligned before bolting, and bolts shall not be used to draw misaligned flanges together.

10.6 Sleeve-Type Couplings, Dismantling Joints, and Flanged Coupling Adapters

10.6.1 Bolted sleeve-type couplings, flanged coupling adapters, and dismantling joints shall conform to AWWA C219 and shall be rated for the design pressure of the line.
10.6.2 A dismantling joint shall be installed at each location shown on the piping layout drawings where a valve, meter, or item of equipment must be removed from a flanged line.
NOTE A flanged line with no axial play cannot release a valve: the valve is clamped between flanges that will not move. A dismantling joint is a flanged coupling adapter with a tied, adjustable length that closes the gap on installation and opens it on removal, and it is the difference between a valve change that takes an hour and one that takes a cutting torch. (10.6.3)
10.6.4 Sleeve-type couplings and flanged coupling adapters shall be restrained against the end thrust of the line by the method indicated in the datasheet, except where the piping on both sides is independently anchored.
Restraint of Sleeve-Type Couplings and Flanged Coupling Adaptersselect
Tie rods and lugs across the coupling
Integral restraint of the coupling, rated by its manufacturer
Anchorage of the piping on each side, with no restraint at the coupling
NOTE A sleeve-type coupling seals on two gaskets and holds no axial load by itself, so a line that is not otherwise anchored pushes the coupling apart at the first pressure test. Tie rods across the coupling are the traditional restraint and are sized by the engineer for the thrust at test pressure; an integrally restrained coupling grips the pipe with wedges or a harness built into the housing and is rated by its manufacturer for a stated end load; and anchorage of the piping on each side removes the load from the coupling entirely and is the arrangement where the coupling is a closure between two restrained runs. (10.6.5)
10.6.6 Coupling gaskets shall be of the compound selected for grooved coupling gaskets in the same service, and coupling bolts shall be of the material selected for flange bolting in the same exposure.
10.6.7 Coupling and adapter housings in buried service shall be coated with the buried pipe coating system or with a fusion-bonded epoxy under AWWA C213, and shall be wrapped or encased as the manufacturer requires after installation.

10.7 Expansion Joints and Flexible Connectors

10.7.1 Thermal growth in blower discharge, aeration, and other hot or long process lines shall be absorbed by the method indicated in the datasheet, at the locations shown on the piping layout drawings.
Expansion Compensation in Process Pipingselect
Stainless steel bellows expansion joints
Fabricated expansion loops and offsets
Flexible grooved couplings in a designed sequence
Rubber expansion joints
NOTE A stainless bellows joint absorbs the most movement in the least length and is the usual device on a hot air header, where it is tied or hinged so that pressure thrust does not stretch it, and it is the least forgiving of misalignment and of a missing anchor. A fabricated loop or offset uses the pipe's own flexibility, needs no device and no maintenance, and costs run length and the space to route it. A sequence of flexible grooved couplings between guides absorbs growth a little at each joint and suits a grooved line, and it depends on the engineer locating the guides so the movement goes where it is intended. A rubber expansion joint absorbs movement and vibration at a pump or a blower inlet in cool service, and its temperature limit removes it from a hot discharge. (10.7.2)
10.7.3 Bellows expansion joints shall be designed and manufactured under the EJMA Standards for the movement, pressure, temperature, and cycle life the application requires, and shall be furnished with internal liners in air service and with tie rods or hinges where the joint is not anchored on both sides.
10.7.4 A flexible connector shall be installed at every blower discharge and every pump suction and discharge connection, rated for the fluid, the design pressure, and the design temperature, and restrained against pressure thrust by control rods or by the anchorage of the piping.
10.7.5 Anchors and guides shown for the expansion design shall be installed before the line is placed in service and shall not be relocated or omitted without the written approval of the Engineer of Record.
NOTE An expansion joint is one element of a force path between two anchors, and a relocated anchor changes the movement every guide and every joint between it and the next anchor was sized for. The relocation is an engineering decision, not a field one. (10.7.6)

11 Wall Pipes and Penetrations

11.1 Wall Pipes Through Water-Retaining Walls

11.1.1 Every pipe passing through a wall, floor, or slab that retains water or separates a wet space from a dry one shall pass through a wall pipe of the same material family as the line, cast into the concrete with the collar indicated in the datasheet.
Wall Pipe Collar Typeselect
Integral seep ring, welded continuously both sides
Integral thrust and seep collar, sized for the line thrust
Puddle flange
NOTE A seep ring is a plate collar welded around the wall pipe at mid-wall that lengthens the path water would have to travel along the outside of the pipe through the concrete, and it is what nearly every wall pipe in a basin wall carries, which is why it is the default. A thrust collar is a heavier ring sized to transfer the line's axial thrust into the wall and is selected where the wall pipe is the anchor of a run. A puddle flange is a flange set at the wall face rather than within it and serves a thin wall or a slab where there is no depth for a ring. (11.1.2)
11.1.3 Wall pipes shall be fabricated from pipe of the wall thickness of the line or from ASTM A240 plate in stainless lines, with the end configuration on each face matching the joint selected for the line.
11.1.4 Wall pipes in carbon steel shall be lined and coated as the line is, with the coating omitted only from the embedded length.
11.1.5 Wall pipes shall be furnished to the concrete trade in time to be set before the wall is placed, with the location and elevation of each wall pipe as shown on the process mechanical plans, and shall be set and secured under Cast In Place ConcreteCast-in-Place ConcreteResolves to the current adopted revision.sync/cast-in-place-concrete so that they do not move during placement.
11.1.6 Wall pipes shall not be cored or cut into a water-retaining wall after the concrete is placed except with the written approval of the Engineer of Record and a sealing detail the Engineer of Record accepts.

11.2 Sleeves and Penetration Seals Through Dry Walls and Floors

11.2.1 Process piping passing through a wall, floor, or slab that does not retain water shall pass through a sleeve sized for the pipe, its coating, and the seal or firestop that closes the annulus.
11.2.2 The annular space at penetrations through below-grade walls, slabs on grade, and other locations that must remain watertight shall be sealed by the method indicated in the datasheet.
Penetration Seal at Watertight Dry-Side Penetrationsselect
Modular mechanical sleeve seal
Cast-in sleeve with waterstop collar and modular mechanical sleeve seal
Grouted annulus with elastomeric sealant
NOTE A modular seal is bolted up from the dry side after the pipe is set, holds rated pressure, and can be taken apart to replace the pipe, which is why it is the default. A waterstop collar on the sleeve closes the second path, between the sleeve and the concrete, and matters wherever the wall sees a sustained head. A grouted annulus with sealant costs the least and serves a wall above the water table where the penetration will never be opened again. (11.2.3)
11.2.4 Modular mechanical sleeve seals shall be selected from the manufacturer's chart for the actual sleeve inside diameter and pipe outside diameter, shall be rated for not less than the hydrostatic head at the penetration and not less than 20 psig, and shall have seal elements of EPDM or of a compound compatible with the pipe contents where EPDM is not.
11.2.5 Penetrations of fire-resistance-rated assemblies shall be firestopped under FirestoppingFirestoppingResolves to the current adopted revision.sync/firestopping.
11.2.6 Pipe shall be centered in its sleeve or wall pipe and independently supported on each side of the penetration so that the penetration carries no pipe load.

12 Dissimilar Metal Isolation

12.1 Where stainless steel piping connects to carbon steel or ductile iron piping, valves, or equipment in wet service, the connection shall be isolated as indicated in the datasheet.
Isolation at Stainless-to-Ferrous Connections in Wet Serviceradio
○ Insulating flange kit at every connection
○ No isolation
NOTE Stainless steel is noble to carbon steel and ductile iron in plant water, so the ferrous side corrodes faster at an uninsulated joint, concentrated at the bolt circle and the first few inches of the iron. The effect is small where the iron is lined and the water is low in conductivity, and it is severe in chloride water and wherever bare iron is wetted beside a large stainless surface. (12.2)
12.3 An insulating flange kit shall comprise a full-face insulating gasket, insulating sleeves on every bolt, and insulating washers under every nut and bolt head on one side of the joint.
NOTE An insulating kit that omits the bolt sleeves leaves every bolt as a metallic bridge across the gasket, so the joint is electrically continuous and the isolation the kit was bought for does not exist. The omission is invisible after assembly, which is why the sleeve count belongs in the specification. (12.4)
12.5 Insulating flange kits shall be rated for the design pressure and temperature of the line, shall be tested for electrical isolation after assembly, and shall be installed where they remain accessible.

13 Delivery, Storage, and Handling

13.1 Pipe, fittings, and spools shall be delivered with the manufacturer's markings and piece marks intact and legible, and with every open end capped or sealed.
13.2 Lined and coated pipe shall be handled with wide fabric slings, padded forks, or end hooks that bear on the pipe interior, and shall not be handled with chains, bare cables, or forks against the coating.
13.3 Pipe shall be stored off the ground on padded supports, in a manner that prevents standing water inside the bore, prevents permanent bending between supports, and keeps the coating out of contact with the ground.
13.4 Stainless steel pipe, fittings, and spools shall be stored separately from carbon steel and shall not contact carbon steel racks, chains, banding, or fasteners.
13.5 Cement-mortar lined pipe shall be kept with its ends sealed until the joint is made, and the lining shall be kept from freezing and from drying in direct sun.
13.6 Gaskets, coupling gaskets, seal elements, and sealants shall be stored within the temperature range their manufacturer publishes, out of sunlight, and shall not be used after their marked expiration date.
13.7 Open piping at the end of each work period shall be capped, plugged, or taped closed.
13.8 The Contractor shall bear the cost of cleaning, recoating, or replacing material damaged or contaminated by improper storage or handling.

14 Exposed Piping Installation

14.1 Routing and Alignment

14.1.1 Piping shall be installed along the routing and at the elevations shown on the process mechanical plans and on the accepted piping layout drawings.
14.1.3 Horizontal water and sludge lines shall be pitched to the drain connections shown on the piping layout drawings, and air headers shall be pitched to the drain connections at their low points.
NOTE A blower discharge header carries the moisture the blower drew in with the air, and that moisture condenses in the header when the blower stops and the pipe cools. A header pitched to a drain empties itself; one with a sag at a coupling holds water against the gasket and corrodes a carbon steel line from the inside. (14.1.4)
14.1.5 Piping shall not be sprung, forced, or pulled into position to meet an equipment nozzle, a valve flange, or a support.
14.1.6 Piping shall be installed so that every valve operator, every flange, every coupling, every drain, and every instrument tap can be reached from a floor, a platform, or a permanent ladder without removing permanent construction.
14.1.7 Where the parties disagree whether a component is reachable for the operation it requires, the Engineer of Record shall make the initial determination.

14.2 Support Interface

14.2.1 Hangers, supports, saddles, stands, anchors, guides, and structural attachments for process piping shall be furnished and installed under Hangers And SupportsHangers and Supports for Mechanical Piping and EquipmentResolves to the current adopted revision.sync/hangers-and-supports and MSS SP-58, selected for the material, size, temperature, and weight of the line including its fluid.
14.2.2 Support components in wet, washdown, chemical, and corrosive-atmosphere locations shall be of the corrosion-resistant material and finish Hangers And SupportsHangers and Supports for Mechanical Piping and EquipmentResolves to the current adopted revision.sync/hangers-and-supports requires for that exposure, and support components in contact with stainless steel piping shall be stainless steel or shall be separated from the pipe by a nonmetallic isolator.
14.2.3 Supports for blower discharge and aeration air piping shall accommodate the thermal growth of the line between anchors and shall be rated for the air design temperature.
14.2.4 Supports shall not bear on a lining, a coating that is not rated for point loading, or an expansion joint.
14.2.5 Process piping shall not be supported from equipment, from other piping, or from the work of other trades.

14.3 Equipment and Valve Connections

14.3.1 Every connection to a pump, blower, meter, or item of process equipment shall be made through a flexible connector where this standard requires one, and through a flanged, grooved, or coupled joint that permits the equipment to be removed without cutting pipe.
14.3.2 Piping at an equipment connection shall be supported independently of the equipment so that no pipe weight, thermal load, or test load is carried by the equipment nozzle.
14.3.3 Piping shall be aligned to the equipment nozzle before the connection is made, and the connection shall not be used to draw the piping into alignment.
NOTE A pump casing and a blower discharge flange carry a published allowable nozzle load, and a misaligned pipe applies a moment to that nozzle every hour the machine runs. The bearing failure that follows is blamed on the machine. (14.3.4)
14.3.5 Valves shall be installed with the straight run, the operator orientation, and the support the valve standard requires, and the piping shall provide the flanged or grooved joint on each side of every valve that the Joining Method article of this standard requires.
14.3.6 Flow meters shall be installed with the upstream and downstream straight run Flow MeasurementFlow MeasurementResolves to the current adopted revision.sync/flow-measurement requires, and the piping shall provide that straight run without a fitting, a valve, or a tap within it.

14.4 Instrument and Sample Taps

14.4.1 Process connections for instruments and sample lines shall be provided at the locations shown on the process and instrumentation diagrams, as a welded outlet, a forged half coupling, or a flanged nozzle of the material and rating of the line.
14.4.2 Taps on a horizontal water or air line shall be taken from the top or the side of the pipe, and taps on a horizontal sludge line shall be taken from the side with the tap bore flush with the pipe interior.
NOTE A tap on the bottom of a sludge line fills with solids and reads nothing; a tap on the top of a water line vents air into the instrument. The side tap, flush with the bore, is the one that stays open in sludge. (14.4.3)
14.4.4 The root valve, the tubing, and the manifold downstream of the process connection are furnished under Instrument Installation And TubingInstrument Installation and Impulse TubingResolves to the current adopted revision.sync/instrument-installation-and-tubing, and this standard requires the connection and its location.

14.5 Identification and Finish Interfaces

14.5.1 Pipe markers, flow arrows, and valve tags shall be furnished and installed under Mechanical IdentificationMechanical IdentificationResolves to the current adopted revision.sync/mechanical-identification after the finish coating is complete.
14.5.2 Field finish coating of exposed carbon steel piping, and of stainless steel piping where the piping schedule designates it for coating, shall be applied under High Performance CoatingsHigh-Performance CoatingsResolves to the current adopted revision.sync/high-performance-coatings after the pressure test of that piping has passed.
14.5.3 Stainless steel piping shall be left uncoated unless the piping schedule designates a coating for it.
14.5.4 Insulation and jacketing on process piping, where the piping schedule designates it, shall be applied under Mechanical InsulationMechanical InsulationResolves to the current adopted revision.sync/mechanical-insulation after the pressure test of that piping has passed, and insulation in contact with stainless steel shall meet the chloride limits that standard requires for austenitic stainless surfaces.
14.5.5 Personnel protection against contact with blower discharge and aeration air piping in areas where it can be reached shall be provided by the method indicated in the datasheet.
Personnel Protection on Hot Air Pipingradio
○ Insulation and jacketing under the mechanical insulation standard
○ Expanded metal or perforated guards at reachable locations
○ Warning identification only
NOTE Insulating a hot header protects everyone who passes it and keeps heat out of the blower room, and it hides the pipe from inspection and traps moisture against a carbon steel surface if the jacket leaks. A guard at the reachable locations leaves the pipe open to inspection and costs less, and it protects only where it is placed. Warning identification alone is the answer where the header runs overhead out of reach and the Owner accepts that no one touches it. (14.5.6)

15 Buried Yard Piping Installation

15.1 Trench, Bedding, and Backfill

15.1.1 Trench excavation, dewatering, sheeting and shoring, and backfill above the pipe zone shall be performed under EarthworkEarthworkResolves to the current adopted revision.sync/earthwork.
15.1.2 The pipe zone, from the trench bottom to 12 in. above the top of the pipe, shall be bedded and backfilled by the Contractor installing the piping with the material indicated in the datasheet, placed and compacted in lifts not exceeding 6 in. on each side of the pipe simultaneously.
Pipe Zone Bedding and Backfill Material for Buried Steel Pipingselect
Sand or fine granular material free of stones larger than 3/4 in.
Crushed stone or gravel graded to 3/4 in. maximum
Controlled low-strength material
Native excavated material screened of stones larger than 3/4 in.
NOTE A coated steel pipe is only as good as the coating that survives the backfill, which is why the pipe zone is a separate material from the rest of the trench. Sand bedding cradles the pipe uniformly and does the least harm to a coating, and it migrates into a wet trench with open-graded material beside it. Crushed stone drains and holds its shape under traffic, and its angular faces scar a tape or thin epoxy coating unless the coating is rock-shield wrapped. Controlled low-strength material flows under the haunch without compaction effort, which is where a large pipe is hardest to compact, and it costs more and floats the pipe unless the pipe is weighted or filled. Screened native material costs the least where the native soil is a sand or a loam and is wrong in a rocky or clay soil. (15.1.3)
15.1.4 The trench bottom shall be shaped or bedded so that the pipe bears uniformly along its length and not on its joints, couplings, or collars.
15.1.5 Buried piping shall be installed to the depth of cover shown on the yard piping plans and profiles and not less than Frost DepthFrost DepthParameterEach project supplies its own value.frost-depth below finished grade for any line that can stand without flow.
15.1.6 A detectable warning tape shall be placed in the backfill 12 in. above the top of the pipe along the full length of every buried process line.

15.2 Thrust Restraint and Joint Bonding

15.2.1 Buried steel piping with welded joints shall be restrained by the continuity of its welds, and buried piping with gasketed bell-and-spigot joints or sleeve-type couplings shall be restrained at every bend, tee, reducer, dead end, and valve by the thrust restraint shown on the yard piping plans and thrust restraint details.
15.2.2 Thrust restraint on a buried gasketed steel line shall be by harnessed joints, by restrained couplings, or by concrete thrust blocks bearing against undisturbed soil, as the drawings indicate for each location.
15.2.3 Where cathodic protection, test stations, or electrical continuity is indicated on the yard piping plans, every gasketed joint and every coupling in buried steel piping shall be bridged by a welded or exothermically bonded jumper of the size the drawings show, and the bond shall be coated after it is made.
NOTE Cement-mortar coated and welded steel lines are electrically continuous; a rubber-gasketed joint or a sleeve coupling is not. A cathodic protection system drives current to every foot of pipe it can reach and leaves unprotected every foot beyond a break in continuity, and the bond is what makes the line one conductor. The cathodic protection system itself, with the bond cable size and the connection method, is under Cathodic ProtectionCathodic ProtectionResolves to the current adopted revision.sync/cathodic-protection; this standard installs the bonds it depends on. (15.2.4)

15.3 Buried Pipe Coating Protection

15.3.1 Coated pipe shall be inspected for coating damage after it is lowered into the trench and before the pipe zone is backfilled, and holidays found shall be repaired and retested under AMPP SP0188 before backfill.
15.3.2 Where the pipe zone material is crushed stone, buried pipe with a tape, epoxy, or polyurethane coating shall be wrapped with a rock shield before backfill.
15.3.3 Buried pipe shall not be backfilled until the field joint coating has cured for the time its manufacturer publishes at the trench temperature.
15.3.4 Pipe installed in a trench shall be laid with the bell or the coupling facing the direction of laying, with the interior cleaned of soil and debris as each joint is made, and with the open end plugged whenever laying stops.

16 Pressure and Leakage Testing

16.1 Test Boundaries and Medium

16.1.1 Every portion of the process piping shall be pressure tested before it is coated in the field, insulated, buried, concealed, or connected to equipment that cannot withstand the test.
16.1.2 Liquid-service piping shall be tested hydrostatically with clean water, and air-service piping shall be tested by the method indicated in the datasheet.
Pressure Test Method for Air Pipingradio
○ Pneumatic test with clean dry air or nitrogen
○ Hydrostatic test with clean water
NOTE Water stores almost no energy under pressure, so a hydrostatic test is the safer test and is the baseline for every liquid line. A large air header was not designed or supported to hold the weight of water, and filling it would overload its supports and leave water in a line that must stay dry, which is why air piping is usually tested pneumatically at its own modest design pressure with the precautions this standard requires. A hydrostatic test of an air line remains available where the supports and the drains can take it and the Owner prefers the safer medium. (16.1.3)
16.1.4 A pneumatic test shall be preceded by a preliminary test at not more than 25 psig to find gross leaks by sound and soap solution, shall be raised in steps of not more than one-quarter of the test pressure, and shall not exceed the lowest pressure rating of any component within the boundary.
16.1.5 Personnel not essential to a pneumatic test shall be excluded from the test area while the system is pressurized.
16.1.6 Every test boundary shall be recorded on the pressure test plan before the test, with the components isolated or removed from the boundary because their rating is below the test pressure.
16.1.7 Where the calculated test pressure exceeds the rating of a valve, a flexible connector, an expansion joint, or an instrument within the intended boundary, that component shall be isolated or removed and tested separately at its own rated pressure.

16.2 Test Pressure, Duration, and Acceptance

16.2.1 The hydrostatic test pressure of each liquid line shall be the design pressure of that line on the piping schedule multiplied by the factor indicated in the datasheet, and not less than the minimum indicated in the datasheet.
Hydrostatic Test Pressure Factorrange
× design pressure
1.251.5
Hydrostatic Test Pressurerange
psig
5075100125150200250
16.2.2 The pneumatic test pressure of each air line shall be the design pressure of that line on the piping schedule multiplied by the factor indicated in the datasheet.
Pneumatic Test Pressure Factorrange
× design pressure
1.11.251.5
NOTE A hydrostatic test at 1.5 times design pressure is the factor ASME B31.3 and most plant specifications carry, and it is what the flanges, couplings, and wall pipes are expected to see once; AWWA practice for large steel water pipe accepts 1.25 times where the pipe wall was designed to a lower allowable stress. The minimum pressure floor catches a low-pressure gravity or siphon line whose design pressure times the factor would prove nothing. Pneumatic tests store energy in proportion to pressure, which is why the code factor for a pneumatic test is 1.1 and the higher factors are reserved for lines whose rupture would reach no one. (16.2.3)
16.2.4 The test pressure shall be held for not less than the duration indicated in the datasheet.
Test Hold Durationrange
hours
124824
Default: Not less than 2 hours
16.2.5 Exposed piping shall show no visible leakage and no pressure drop over the hold period, after the test medium has reached the temperature of the piping.
16.2.6 The leakage criterion for buried piping with gasketed joints or sleeve-type couplings shall be as indicated in the datasheet.
Leakage Criterion for Buried Gasketed Steel Pipingradio
○ No pressure drop and no makeup water over the hold period
○ Makeup water not exceeding the AWWA C600 allowance for the joint count and diameter
NOTE A welded or flanged line holds pressure without makeup and is tested to zero loss. A rubber-gasketed bell-and-spigot line of waterworks pattern weeps a small, calculable volume at its joints while the gaskets seat, and the waterworks tradition tests it against a measured makeup volume rather than against a gauge, using the AWWA C600 allowance written for gasketed mains. Where every joint in the buried run is welded, the zero-loss criterion applies. (16.2.7)
16.2.8 Every joint, weld, flange, coupling, wall pipe, and valve body within the boundary shall be inspected during the hold period, and visible leakage at any joint shall fail the test regardless of the measured pressure or makeup.
16.2.9 A failed test shall be followed by repair of the cause, restoration of the boundary, and a complete repeat of the test from the beginning.
16.2.10 The Contractor shall bear the cost of the repair, the retest, the test medium, the re-excavation of buried piping, and the repair of any work of another trade damaged by the failure or by the water released.
16.2.11 Test gauges shall be calibrated within the preceding twelve months, shall have a full-scale range between 1.5 and 2 times the test pressure, and shall be located at the low point of the test boundary.

16.3 Weld Examination

16.3.1 Every welded joint shall be visually examined after completion and before it is coated, lined in the field, insulated, buried, or otherwise made inaccessible, and shall show full profile, complete fusion, and freedom from cracks, undercut, overlap, and surface porosity.
16.3.2 Nondestructive examination beyond visual shall be performed by the method indicated in the datasheet.
Nondestructive Examination Method for Welded Jointsselect
Visual examination only
Visual examination and random radiographic examination
Visual examination and random ultrasonic examination
Visual examination and liquid penetrant examination of stainless welds
16.3.3 Where a random examination method is selected, the proportion of welded joints examined shall be as indicated in the datasheet, distributed across welders and across each day's production.
Random Examination Rate for Welded Jointsrange
%
51020100
NOTE Visual examination is the baseline the governing codes require for the pressures a plant runs, and a project that adds radiography or ultrasonic examination is buying confidence beyond the minimum where the line is buried, cast into a wall, or carries a chemical whose release would hurt someone. Radiography records the joint on film and finds internal voids; ultrasonic examination finds the same defects without a radiation exclusion zone and depends more on the operator. Liquid penetrant examination of stainless welds finds the surface cracks and porosity that heat tint hides, and it is the examination most often added to stainless chemical lines. (16.3.4)
16.3.5 A joint that fails examination shall be repaired or cut out and remade and re-examined by the same method at the Contractor's cost, and where more than ten percent of the examined joints of any welder fail, every joint made by that welder since the last passing examination shall be examined at the Contractor's cost.

16.4 Test Documentation

16.4.1 The pressure test shall be witnessed by the party indicated in the datasheet, and the Contractor shall give that party not less than five business days notice of a scheduled test.
Pressure Test Witnessselect
Engineer of Record or the Engineer's representative
Owner's representative
Contractor's quality control representative
NOTE The Engineer of Record witnesses the test on most plant projects because the test is the only proof the piping will ever offer before it is buried or coated. An Owner's representative witnesses where the Owner staffs its own inspection. A Contractor's quality control representative witnesses alone only where the contract carries a quality control program the Owner has accepted in place of witnessing. (16.4.2)
16.4.3 A signed and dated test report shall be prepared for every test boundary, recording the date, the boundary, the medium, the test pressure, the hold duration, the starting and ending pressure, the makeup volume where measured, the name and signature of the Contractor's representative, and the name and signature of the witness.
16.4.4 A test report shall not record a conditional or qualified pass, and a boundary in which a repair was made shall be recorded on a new report covering the complete repeat test.

17 Disinfection of Finished-Water Piping

17.1 Process piping that will carry finished or potable water shall be disinfected after it has passed its pressure test and before it is placed in service, by the method of AWWA C651 indicated in the datasheet.
Disinfection Method for Finished-Water Process Pipingselect
Continuous-feed chlorination
Slug chlorination
Tablet or granule method
NOTE Continuous feed meters a chlorine solution into the fill water until the whole line holds a stated residual for a stated contact time, works on any size and any configuration, and is the method most plant lines receive. Slug chlorination pushes a short, highly concentrated slug slowly through a long line and suits a long buried run where filling the whole line with a treated volume is impractical. The tablet or granule method places calcium hypochlorite in the pipe as it is laid and fills the line slowly, needs no feed equipment, and is limited to lines that can be kept dry and clean until they are filled. (17.2)
17.3 The disinfecting solution shall be held in the line for the contact time AWWA C651 requires for the method and the residual applied, and the line shall then be flushed until the residual matches the plant's finished water.
17.4 Chlorinated flush water shall be dechlorinated before discharge where the Authority Having Jurisdiction or the receiving water requires it, and shall be disposed of as the Authority Having Jurisdiction requires.
17.5 Bacteriological samples shall be collected and analyzed as AWWA C651 requires, and the line shall not be placed in service until the samples pass.
17.6 A line that fails bacteriological testing shall be redisinfected, reflushed, and resampled at the Contractor's cost.
NOTE Building domestic water piping is disinfected under Disinfection Of Water SystemsDisinfection of Domestic Water SystemsResolves to the current adopted revision.sync/disinfection-of-water-systems and distribution mains outside the plant under Water Distribution PipingSite Water Distribution PipingResolves to the current adopted revision.sync/water-distribution-piping; this article covers the finished-water process lines inside the plant that neither of those standards reaches. (17.7)

18 Warranty

18.1 The Contractor shall warrant the process piping work, including pipe, fittings, joints, welds, flanges, couplings, wall pipes, linings, coatings, passivation, and penetration seals, against defects in materials and workmanship for the period indicated in the datasheet, measured from the date of substantial completion.
Contractor Installation Warranty Periodrange
years
1235
Default: Not less than 1 years
18.2 Where the contract General Conditions specify a longer warranty period than the datasheet, the longer period shall govern.
18.3 Any leak, joint failure, lining or coating failure, or corrosion attributable to the materials or the installation discovered within the warranty period shall be repaired by the Contractor at no cost to the Owner.
18.4 The Contractor shall bear the cost of draining and isolating the line, excavating buried piping, removing and reinstating insulation and finish work, and repairing damage caused by the failure or by the repair itself.
NOTE The unassigned cost in a process piping warranty is not the joint. It is the basin that has to be taken out of service, the yard that has to be reopened, and the equipment the leak reached first. Naming those costs here is what makes the warranty enforceable without an argument. (18.5)
18.6 A repaired or replaced portion of the piping shall carry a warranty running for a full new term from the date the repair is accepted or for the remainder of the original term, whichever ends later, and shall be pressure tested under this standard before the repair is accepted.

19 Spare Parts

19.1 The Contractor shall furnish spare flange gaskets and spare coupling gaskets of each size and compound installed, in the quantity per size indicated in the datasheet, delivered to the Owner before substantial completion.
Spare Gaskets per Size and Compoundrange
each
24612
19.2 Spare parts shall be the products of the manufacturers of the installed components, packaged and labeled with the size, compound, and service they fit, and listed on a receipt signed by the Owner's representative.

Edit this page

SynC Standards are reference material provided for informational purposes only and as a guide. They are not engineering, architectural, or legal advice and are not a substitute for the judgment of a licensed design professional. It is the responsibility of the user to determine the applicability of any standard to a specific project and to verify all requirements against the governing codes, manufacturer data, and project conditions. SynC does not render professional services and forms no professional relationship by publishing this content. Provided "as is," without warranty of any kind, including fitness for a particular purpose. See our Terms of Use for the complete terms. Moderation log.

This standard is published by SynC and licensed under Creative Commons Attribution-ShareAlike 4.0. You may share and adapt it, including commercially, provided you give credit, link to the license, indicate any changes, and license your adaptations under the same terms. Keep the attribution and notice below with any copy — it includes the warranty disclaimer the license requires you to retain.

Attribution & reuse notice — keep this with any copy:
"Steel and Stainless Steel Process Piping." SynC Standards. Licensed under CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0/). Source: https://synergyinconstruction.com/wiki/sync/steel-and-stainless-process-piping — reference material only; not professional engineering advice and provided without warranty. Verify against governing codes and have a licensed professional review before use.