This master should be used by designers working on Port of Portland construction projects and by designers working for PDX
tenants (“Tenants”). Usage notes highlight a few specific editing choices, however the entire section should be evaluated and
edited to fit specific project needs.
SECTION 232400 - PREFABRICATED PIPING SYSTEMS
PART 1 - GENERAL
1.1
DESCRIPTION
A.
1.2
This section describes direct buried prefabricated piping systems for high pressure steam,
pumped condensate, and chilled water.
RELATED WORK SPECIFIED ELSEWHERE
A.
Section 015713, Temporary Erosion, Sediment, and Pollution Control
B.
Section 230500, Common Work Results for HVAC
C.
Section 230518, Expansion Compensation
D.
Section 230529, Hangers and Supports for HVAC Piping and Equipment
E.
Section 230553, Identification for HVAC Piping and Equipment
F.
Section 230590, Pressure Testing of HVAC Systems
G.
Section 230719, HVAC Insulation
H.
Section 232000, HVAC Piping
I.
Section 232500, HVAC Water Treatment
J.
Section 312300, Trenching, Backfilling, and Compacting
K.
Section 312319, Dewatering
1.3
REFERENCES
A.
ASTM: American Society for Testing and Materials
1.
ASTM C591: Standard Specification for Unfaced Preformed Rigid Cellular
Polyisocyanurate Thermal Insulation
2.
ASTM D1248: Standard Specification for Polyethylene Plastics Extrusion Materials for
Wire and Cable
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PREFABRICATED PIPING SYSTEMS
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1.4
SUBMITTALS
A.
Product Data: Submit product data for products specified herein.
B.
Installation Manuals: Submit installation manuals for prefabricated piping systems.
C.
Shop Drawings: Submit complete shop drawings for piping systems including elbows, tees,
flanges, coupling locations, anchors. Include cutting lengths and thrust block sizes.
D.
Factory Test Reports: Submit factory test report for each concealed weld location. Identify
each section of piping with a unique number to allow for easy comparison with test report.
E.
Field Piping Tests: Submit report on field piping tests with signatures of the Port and
manufacturer’s representative witnessing.
1.5
QUALITY ASSURANCE
A.
The Contractor shall engage the services of a qualified manufacturer’s representative to provide
instruction on installation procedures for manufacturer’s piping and to be present on site to
assist during critical stages of installation and testing.
B.
Include a report consisting of the installation log indicating actual installed conditions and test
certification signed by the manufacturer’s representative above, the Contractor, and the Port.
Include certification by manufacturer’s representative that the installation is in accordance with
the manufacturer’s recommendations.
PART 2 - PRODUCTS
2.1
ACCEPTABLE MANUFACTURERS
A.
2.2
Multi-Therm 500 by Perma-Pipe/Ricwil, Rovanco, Thermal Pipe, or pre-bid approved equal.
PREFABRICATED HIGH PRESSURE STEAM AND PUMPED CONDENSATE PIPING
SYSTEMS
A.
General: Factory prefabricated insulated pipe conduit housing carrier pipe, with all necessary
fittings, anchors, expansion loops, seals, leak plates and conduit accessories. System shall be
drainable, dryable and testable.
B.
Conduit: Minimum 10-gauge steel. Joints in conduit shall be welded and treated to maintain
integrity of conduit system. Inside of conduit shall be smooth to allow moisture drainage and
removal of inner assembly. Conduit shall be sized to provide adequate annular space between
outer surface of insulation and inner surface of conduit. Outer conduit insulation shall be spray
applied polyurethane foam, 2 pcf density, 1-inch-thick, meeting ASTM C591. Insulation casing
shall be filament-wound fiberglass.
C.
Pipe: Carrier pipe shall be as specified in Section 232000, HVAC Piping, for service indicated.
PREFABRICATED PIPING SYSTEMS
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D.
Pipe Support Guides: Full round insulating support guides shall allow pipe to expand or
contract without stress and shall allow drainage and free air circulation through annular space.
E.
Expansion Loops, Ells and Tees: Prefabricated loops, ells, and tees shall be sized as indicated
on drawings and shall allow for required movement of carrier pipe.
F.
End Seals: Terminal ends of conduits inside building walls shall be equipped with end seals
consisting of a steel bulkhead plate welded to the pipe and conduit. End seals shall be equipped
with drain and vent openings on the vertical centerline, with threaded plugs.
G.
G.Leakplates: Steel plate flange 4 inches larger than conduit O.D., welded to conduit.
H.
Anchors: Prefabricated plate anchors consisting of 3/8-inch steel plate welded to conduit and
carrier pipe.
I.
Insulation: Service pipe insulation shall be as specified in Section 230719, HVAC Insulation,
for service indicated.
2.3
PREFABRICATED CHILLED WATER PIPING
A.
Acceptable Manufacturers: Quik Therm by Perma Pipe/Ricwil, Rovanco, Thermal Pipe, or prebid approved equal.
B.
General: Provide complete prefabricated underground chilled water piping system suitable for
direct burial as indicated on the drawings.
C.
Service Piping:
1.
Integral sealed unit consisting of Type III, Grade P34, Class C Category 5 high density
polyethylene plastic carrier pipe and fittings, in accordance with ASTM D1248, and
polyurethane foam insulation, which completely fills the annular space between the pipe
and jacket. All service piping shall be manufactured to SDR 11 and shall have a pressure
rating of 160 psi.
2.
Provide butt fusion joints on pipe and fittings for chilled water system.
3.
Provide straight sections in 40 foot lengths with piping exposed at each end for field joint
fabrication.
D.
Jacketing:
1.
The outer casing protective jacket shall be high density polyethylene to the same
specifications as the service pipe. The jacket shall be manufactured to a minimum
thickness of SDR 32.5. Jackets made from PVC, tape materials or thin walled
polyethylene shall not be allowed. Fittings shall not be jacketed or insulated.
2.
Both ends of each length of piping shall have a polyethylene disk between the service
pipe and the jacket. The disk shall be recessed approximately 1/2 inch from the end of
the pipe. End seals shall not be mastic, rubber, shrink end caps or other non-polyethylene
materials.
E.
Insulation:
1.
Provide rigid, 90 to 95 percent closed cell polyurethane with a 1.9 to 2.1 pound per cubic
foot density and an aged coefficient of thermal conductivity (K) of .13 BTU/(HR*F/IN.)
at 73ºF.
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2.
Apply insulation to the following minimum thickness:
Nominal Pipe
Minimum Insulation
Jacket Size
Size in inches
Thickness in inches
in inches
2"
3"
4"
6"
8"
10"
12"
14"
16"
3.
4.
0.92"
0.86"
0.86"
1.73"
1.67"
1.19"
1.13"
1.43"
1.49"
4"
5"
6"
10"
12"
14"
16"
18"
20"
Jacket Thickness in
inches
0.14"
0.17"
0.20"
0.33"
0.39"
0.43"
0.49"
0.49"
0.62"
Joints and fittings shall be uninsulated.
Support guides shall be factory installed, to assure equal thickness of insulation around
the pipe.
F.
Field joints: All joints shall be joined by one of the following methods:
1.
The joints shall be thermal butt fusion welded. The service pipe and the jacket shall be
simultaneously welded so as to maintain the pressure rating of both the service pipe and
the jacket. Field joints may be made either inside the trench or on top of the trench.
2.
The service pipe shall be thermal butt fusion welded. The exposed field joint shall be
sealed, with a sleeve of the same wall thickness as the jacket, by means of extrusion
welding. Heat shrinkable adhesive backed wrap or hot air welding shall not be allowed.
3.
Weld pressures, temperatures, and time shall be in accordance with the manufacturer’s
recommendations. The pipe manufacturer shall supply all butt fusion or extrusion
welding equipment.
G.
Accessories: Provide all required accessories including anchor plates, wall sleeves, and
miscellaneous materials as required for attachment to steel pipe at ends and as required and
detailed to a complete and total installation.
PART 3 - EXECUTION
3.1
PREPARATION
A.
Measurements, Lines and Levels:
1.
Check dimension at the building site and establish lines and levels for the work specified
in this section.
2.
Establish all inverts, slopes and manhole elevations by instrument, working from an
established datum point. Provide elevation markers for use in determining slopes and
elevations.
3.
Use established grid and area lines for locating trenches in relation to building and
boundaries.
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3.2
PIPING JOINTS
A.
Prefabricated high pressure steam and pumped condensate pipe, conduit, and fittings shall be
joined using methods and materials specified in Section 232000, HVAC Piping, and in
accordance with manufacturer’s recommendations.
B.
Prefabricated chilled water piping shall be joined as specified herein and in accordance with
manufacturer’s recommendations.
3.3
ADJUSTING AND CLEANING
A.
3.4
Adjust and clean according to Section 232000, HVAC Piping and Section 232500, HVAC
Water Treatment.
PREFABRICATED PIPE INSTALLATION
A.
Install all piping as to vent and drain to building.
B.
Utility Marking: Install utility warning tape and location wire over the entire length of the
underground piping utilities in accordance with requirements of Section 312300, Trenching,
Backfilling, and Compacting.
C.
Field welds at conduit closures shall be tested for leaks. Pressurize with compressed air at
5 psig. Check with soap suds.
D.
Anchors shall be installed within 5 feet of each end of prefabricated piping. Concrete shall be
cast over the anchorplate and conduit and shall be large enough for firm anchorage into
undisturbed soil. Concrete block shall be a minimum 30 inches in length and shall extend at
least 9 inches above and below prefabricated piping.
3.5
TESTING
A.
Carrier and service piping shall be tested according to requirements of Section 230590, Pressure
Testing of HVAC Systems, and in accordance with the manufacturer’s recommendations,
except as specified below.
B.
High density polyethylene plastic pipe shall be tested hydrostatically using the following
“Monitored Make-Up Water Test” procedure:
1.
Piping system shall be filled with water and allowed to stabilize at ambient temperature.
2.
Care shall be taken to bleed any trapped air from the test section.
3.
Test procedure shall consist of an initial 3-hour expansion followed by a 1-, 2-, or 3-hour
test phase. During the initial expansion phase, the test section shall be pressurized to the
system test pressure and enough make-up water shall be added each hour for 3 hours to
return test system to test pressure.
4.
The test phase shall follow immediately and may be 1, 2, or 3 hours.
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5.
At the end of the above 1-, 2-, or 3-hour test phase, the test section shall be returned to
test pressure by adding a measured amount of water. If the amount of water does not
exceed the value indicated in Table 1, then leakage is not indicated.
TAB L E 1 : T ES T PH A S E M AK E - UP AM O UN T
Nominal Pipe Size
(inches)
2
3
4
6
8
10
12
14
16
18
20
Make-Up Water Allowance
(U.S. Gallons/100 Ft. of Pipe)
1 Hour Test
0.07
0.10
0.13
0.3
0.5
0.6
1.3
1.4
1.7
2.2
2.3
2 Hour Test
0.11
0.15
0.26
0.6
1.0
1.3
2.3
2.8
3.3
4.3
5.5
3 Hour Test
0.19
0.25
0.40
0.9
1.5
2.1
3.4
4.2
5.0
6.5
8.0
END OF SECTION 232400
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