"The information contained in this appendix is not part of this American National Standard (ANS) and has not been
processed in accordance with ANSI's requirements for an ANS. As such, this appendix may contain material that has
not been subjected to public review or a consensus process. In addition, it does not contain requirements necessary
for conformance to the standard."
The following IAPMO Installation Standard is included here for the convenience of the users of the Uniform Plumbing Code. It is not considered as a part of the Uniform Plumbing Code unless formally adopted as such. This Installation Standard is an independent, stand-alone document published by the International Association of Plumbing and Mechanical Officials and is printed herein by the expressed written permission of IAPMO.
The following IAPMO Installation Standard is included here for the convenience of the users of the Uniform Plumbing Code. It is not considered as a part of the Uniform Plumbing Code unless formally adopted as such. This Installation Standard is an independent, stand-alone document published by the International Association of Plumbing and Mechanical Officials and is printed herein by the expressed written permission of IAPMO.
IAPMO IS 31-2014
This Standard specifies requirements for the installation of SDR 9 CTS crosslinked polyethylene (PEX) tubing and fittings, including cold-expansion, crimp, press, and mechanical compression fittings, intended for hot- and cold-water distribution systems within buildings.
This Standards applies to
- SDR 9 CTS PEX tubing complying with ASTM F876 and pressure-rated in accordance with PPI TR-3; and
- PEX fitting systems complying with
- ASTM F877, for mechanical compression fittings and metal or plastic insert fittings with stainless steel press sleeves;
- ASTM F1807 or ASTM F2159, for metal or plastic insert fittings with copper crimp rings;
- ASTM F1960, for cold expansion fittings with PEX reinforced rings; or
- ASTM F2080, for cold expansion fittings with metal compression sleeves.
In this Standard,
- "shall" is used to express a requirement, i.e., a provision that the user is obliged to satisfy to comply with the Standard;
- "should" is used to express a recommendation, but not a requirement;
- "may" is used to express an option or something permissible within the scope of the Standard; and
- "can" is used to express a possibility or a capability.
This Standard refers to the following publications, and where such reference is made, it shall be to the current edition of those publications, including all amendments published thereto.
| ASTM F876 | Standard Specification for Crosslinked Polyethylene (PEX) Tubing |
| ASTM F877 | Standard Specification for Crosslinked Polyethylene (PEX) Hot- and Cold-Water Distribution Systems |
| ASTM F1807 | Standard Specification for Metal Insert Fittings Utilizing a Copper Crimp Ring for SDR9 Cross-linked Polyethylene (PEX) Tubing and SDR9 Polyethylene of Raised Temperature (PE-RT) Tubing |
| ASTM F1960 | Standard Specification for Cold Expansion Fittings with PEX Reinforcing Rings for Use with Cross-linked Polyethylene (PEX) Tubing |
| ASTM F2080 | Standard Specification for Cold-Expansion Fittings With Metal Compression-Sleeves for Cross-Linked Polyethylene (PEX) Pipe |
| ASTM F2159 | Standard Specification for Plastic Insert Fittings Utilizing a Copper Crimp Ring for SDR9 Cross-linked Polyethylene (PEX) Tubing and SDR9 Polyethylene of Raised Temperature (PE-RT) Tubing |
| ASTM F2657 | Standard Test Method for Outdoor Weathering Exposure of Crosslinked Polyethylene (PEX) Tubing |
| AWWA C904 | Cross-Linked Polyethylene (PEX) Pressure Tubing, 1/2 In. (12 mm) Through 3 In. (76 mm) for Water Service |
| IAPMO/ANSI UPC-1 | Uniform Plumbing Code |
| PPI TR-3 | Policies and Procedures for Developing Hydrostatic Design Basis (HDB), Pressure Design Basis (PDB), Strength Design Basis (SDB), and Minimum Required Strength (MRS) Ratings for Thermoplastic Tubing Materials or Tubing |
PEX tubing can be
- pigmented throughout (i.e., with color);
- non-pigmented (e.g., translucent or natural); or
- coated with a pigmented layer.
PEX tubing is typically available in NTS-1/4 to NTS-3.
Before installation, the installer shall review the tubing markings and verify that
Cold-expansion fittings typically
- are made of brass, stainless steel, or sulfone;
- consist of an insert and a PEX reinforcing ring; and
- are available in NTS-3/8 to NTS-3.
Crimp or press insert fittings typically
- are made of brass, stainless steel, or sulfone;
- consist of an insert and a copper crimp ring or a stainless steel press ring
- are available in NTS-3/8 to NTS-2.
Compression (i.e., transition) fittings typically
- are made of brass; and
- consist of
- a nut, a compression ring, and an insert; or
- an O-ring brass insert with a compression sleeve
- are available in NTS-1/4 to NTS-3.
Only fittings systems marked on the tubing shall be used for installation with that particular tubing.
Tools and tool accessories (e.g., tool heads) used
for the installation of PEX tubing systems shall
be in accordance with the manufacturer's specifications and written instructions.
PEX tubing passing through drilled or notched
metal studs or metal joists, or hollow-shell
masonry walls shall be protected from abrasion
by elastomeric or plastic sleeves or grommets.
Steel-plate protection shall be installed in accordance with the local plumbing code.
When receiving PEX tubing shipments, the receiver shall inspect and inventory each shipment, ensuring that there has been no loss or damage. In addition:
- At the time of unloading, the markings of all tubing, fittings, and accessories shall be verified to ensure that all items have been manufactured in accordance with the applicable product Standard and appropriately certified.
- An overall examination of the shipment shall be made. If the shipment is intact, ordinary inspection while unloading shall be sufficient to ensure that the items have arrived in good condition.
- If the load has shifted, has broken packaging, or shows evidence of rough treatment, each item shall be carefully inspected for damage.
- The total quantities of each shipment (e.g., tubing, gaskets, fittings, and accessories) shall be checked against shipping records.
- Any damaged or missing items shall be noted on the delivery slip. The carrier shall be notified immediately and a claim made in accordance with its instructions.
- No damaged material shall be disposed of. The carrier shall recommend the procedure to follow.
- Shortages and damaged materials are normally not reshipped without request. If replacement material is needed, it shall be reordered from the manufacturer, the distributor, or a manufacturer's representative.
PEX tubing and fittings shall be stored indoors
and in its original packaging until the time of
installation. Appropriate precautions to protect
the tubing from damage, impact, and punctures
shall be taken.
Accumulative exposure time to UV radiation during storage and installation shall not exceed the UV exposure limits recommended by the manufacturer or specified in ASTM F876.
Note: ASTM F876 has four categories for UV-resistance, ranging from untested to 6 months of continuous exposure, as listed in the material designation code.
Note: ASTM F876 has four categories for UV-resistance, ranging from untested to 6 months of continuous exposure, as listed in the material designation code.
PEX tubing and fittings shall not be exposed to
open flames
PEX tubing shall not be exposed to temperatures exceeding 93°C (200°F).
Chemical compatibility (e.g., with common
construction materials) shall be verified with
the manufacturer prior to direct contact.
In general, petroleum- or solvent-based chemicals (e.g., paints, greases, pesticides, or
sealants) shall not be allowed to come in direct
contact with PEX tubing or fittings.
Thermal expansion and contraction forces on suspended horizontal runs of PEX tubing that can experience a 22°C (40°F) or greater change in temperature (operating temperature compared to ambient temperature) shall be controlled by a means of mitigating temperature-induced stresses to other parts of the water distribution system. Means for controlling thermal expansion and contraction include
- loops;
- offsets;
- arms with rigid anchor points; and
- supporting the tubing with continuous runs of CTS support channels with
- rigid anchor points installed every 20 m (65 ft); and
- proper strapping (e.g., 27 kg (60 lb) straps or equivalent) spaced 1 m (3 ft) and rated for the maximum temperature and UV exposure of the PEX tubing application.
Thermal expansion and contraction forces on vertical runs of PEX tubing that pass through more than one floor and can experience a 22°C (40°F) or greater change in temperature (operating temperature compared to ambient temperature) shall be controlled by installing
- a riser clamp at the top of every other floor; and
- mid-story guides to maintain the alignment of the vertical tubing.
Adequate clearance shall be provided between
PEX tubing and the building structure (e.g.,
using bored holes and sleeves) to allow for free
longitudinal movement of the tubing.
Note:
LB = C × √(D × ΔL)
where
| LB | = | length of flexible arm |
| C | = | material constant (12 for PEX) |
| D | = | nominal outside diameter of tubing |
| ΔL | = | thermal expansion length |
FIGURE 1
EXPANSION ARMS
(See Sections 6.4.1 and 7.3)
EXPANSION ARMS
(See Sections 6.4.1 and 7.3)
Expansion arms shall be installed as illustrated
in Figure 1.
Note:
LB shall be calculated as specified in Figure 2 and divided in to three sections, as follows :
L B = L1 + (2 × L2)
where
L1 = LB + 5; and
L2 = L1 × 2.
FIGURE 2
EXPANSION LOOPS
(See Sections 6.4.2 and 7.3)
EXPANSION LOOPS
(See Sections 6.4.2 and 7.3)
Expansion loops shall be installed at the mid-point between anchors, as illustrated in Figure 2.
The minimum length of expansion loops shall be calculated using the equation in Section 6.4.1.2; however, the distance LB shall be divided into three sections, as illustrated in Figure 2, where
L1 = LB ÷ 5; and
L2 = L1 × 2
L1 = LB ÷ 5; and
L2 = L1 × 2
Vertical PEX tubing shall
- be supported at each floor or as specified by the water-distribution system designer to allow for expansion and contraction; and
- have mid-story guides.
Unless otherwise authorized by the authority having jurisdiction, suspended horizontal runs of PEX tubing
- NTS-1 and smaller shall be supported every 0.8 m (32 in), unless continuously supported by metallic CTS or V channels that
- are supported at intervals not exceeding 1.8 m (6 ft);
- have a maximum cantilever, measured from the support to the end of the CTS support channel, of 0.5 m (1.5 ft); and
- NTS-11/4 and larger shall be supported every 1.2 m (4 ft), unless continuously supported by metallic CTS or V channels that
- are supported at intervals not exceeding 2.4 m (8 ft); and
- have a maximum cantilever, measured from the support to the end of the CTS support channel, of 0.5 m (1.5 ft).
Anchors shall be
- used to restrict PEX tubing movement;
- made of materials that provide rigidity to the support system and utilize pipe clamps designed for plastic tubing capable of restraining the tubing; and
- installed in accordance with Figures 1 or 2, as applicable (i.e., anchor distances and size of arms and offsets).
The procedure for making joints shall be as
specified by the manufacturer.
PEX tubing systems manufactured in accordance with the applicable standards referenced
in Section 2 are deemed manufactured joints
and may be installed in concealed spaces without the need for access panels.
Except when the PEX tubing is protected with
fiberglass or closed-cell insulation or the
recessed light is IC-rated, the clearance between
recessed light fixtures and PEX tubing shall be
at least 300 mm (12 in).
When in direct view of the light source, the
clearance between fluorescent lighting and PEX
tubing shall be at least 1.5 m (5 ft). If the minimum clearance cannot be achieved, the PEX
tubing shall be protected with a UV-blocking
sleeve.
Hot-work joints (e.g., soldering, brazing, welding, and fusion-welding) shall be
- made at least 500 mm (18 in) from PEX tubing in the same water line; and
- performed prior to completing the PEX joints.
The free (unsupported) bending radius for PEX
tubing, measured at the outside of the bend,
shall be not less than six times the actual outside diameter of the tubing, unless otherwise
specified by the PEX manufacturer. Supports
should be used to facilitate rigid bends and to
alleviate stress on PEX joints when bends are
needed in close proximity to such joints.
Tighter bends may be used when the PEX tubing is uniformly bent (supported) around a
curved bracket or other rigid fixture. In this
case, the minimum outside radius of the supported bend shall be as specified by the PEX
manufacturer.
Directional fittings (e.g., 90° and 45° elbows) should only be installed where necessary.
Note: The flexible nature of PEX tubing allows for sweeping bends resulting in less fittings and joints.
PEX tubing and fittings may be used in direct burial applications when allowed in the manufacturer's written installation instructions.
Note: AWWA C904 should be consulted for water service applications.
Note: AWWA C904 should be consulted for water service applications.
Manufacturer's installation instructions shall be
consulted prior to installation of PEX tubing in
fire resistive constructions. PEX tubing penetrating a wall or floor-and-ceiling fire-rated assembly shall include a means of passive fire
protection in accordance with the local codes.
PEX tubing shall be sized in accordance with IAPMO/ANSI UPC 1.
Note: Potable water piping sizing is addressed in Section 610.0 and Appendix A of IAPMO/ANSI UPC 1—2012.
Note: Potable water piping sizing is addressed in Section 610.0 and Appendix A of IAPMO/ANSI UPC 1—2012.
Flow velocities through the water distribution system, used for calculating flush tank and flush valve fixture units depending on the tubing sizes (see Table 1), shall not exceed
- 3.0 m/s (10 ft/s) for cold-water distribution systems; and
- 2.4 m/s (8 ft/s) for hot-water distribution systems.
| NOMINAL TUBING SIZE | FLOW VELOCITY: 3.0 m/s (10 ft/s) | FLOW VELOCITY: 2.4 m/s (8 ft/s) | ||||
|---|---|---|---|---|---|---|
| FLOW VOLUME, L/min (gpm) | FLUSH TANK FIXTURE UNITS | FLUSH VALVE FIXTURE UNITS | FLOW, L/min (gpm) | FLUSH TANK FIXTURE UNITS | FLUSH VALVE FIXTURE UNITS |
|
| 1/2 | 20.8 (5.5) | 6 | — | 16.7 (4.4) | 4 | — |
| 3/4 | 41.6 (11.0) | 15 | — | 33.3 (8.8) | 11 | — |
| 1 | 68.9 (18.2) | 26 | — | 55.3 (14.6) | 20 | — |
| 11/4 | 103.0 (27.2) | 46 | 10 | 82.5 (21.8) | 33 | 5 |
| 11/2 | 143.5 (37.9) | 77 | 24 | 114.7 (30.3) | 54 | 13 |
| 2 | 246.1 (65.0) | 200 | 91 | 196.8 (52.0) | 135 | 52 |
| 3 | 533.0 (140.8) | 590 | 495 | 426.2 (112.6) | 443 | 310 |
Hot-water recirculation systems shall
- be balanced to maintain adequate system temperatures; and
- have flow velocities that do not exceed 0.6 m/s (2 ft/s) (see Table 2); and
- use only PEX tubing designated for hot, chlorinated water recirculation systems and rated for the maximum percentage of time during which the system is intended to be operated at elevated temperatures, in accordance with ASTM F876.
| NOMINAL TUBING SIZE | FLOW VELOCITY m/s (ft/s) |
FLOW VOLUME L/min (gpm) |
FRICTION LOSSES AT 49 °C (120°F) kPa/m (psi/ft) |
|---|---|---|---|
| 1/2 | 0.6 (2) | 4.2 (1.1) | 0.4411 (0.0195) |
| 3/4 | 0.6 (2) | 8.3 (2.2) | 0.2850 (0.0126) |
| 1 | 0.6 (2) | 13.6 (3.6) | 0.2081 (0.0092) |
| 11/4 | 0.6 (2) | 20.4 (5.4) | 0.1629 (0.0072) |
| 11/2 | 0.6 (2) | 28.4 (7.5) | 0.1335 (0.0059) |
| 2 | 0.6 (2) | 48.8 (12.9) | 0.0950 (0.0042) |
Installation of PEX water distribution systems may be tested with air when
- expressly allowed in the written instructions of the manufacturers of all plastic pipe and fittings installed at the time the PEX piping system is being tested; and
- compressed air or other gas testing is not prohibited by the authority having jurisdiction.