Standard Specification for Crosslinked Polyethylene (PEX) Tubing of 0.070 in. Wall and Fittings for Radiant Heating Systems up to 75 psig

ABSTRACT
This specification establishes the requirements for 0.070 in. wall thickness crosslinked polyethylene (PEX) tubing that is outside diameter controlled, and intended for non-potable radiant heating applications for pressures up to 75 psig. It covers requirements and test methods for material, workmanship, dimensions, burst pressure, hydrostatic sustained pressure, bent-tube hydrostatic pressure, environmental stress cracking, stabilizer functionality, excessive temperature and degree of crosslinking, as well as requirements for tubing markings.
SCOPE
1.1 This specification covers 0.070 in. wall thickness crosslinked polyethylene (PEX) tubing that is outside diameter controlled, and intended for non-potable radiant heating applications for pressures up to 75 psig in sizes 5/8 NTS (nominal tubing size) and 7/8 NTS. This specification also includes fittings that are specifically designed for this 0.070 in.-wall PEX tubing. Only maximum 75-psig relief valves shall be used with this tubing. Included in this specification are requirements and test methods for material, workmanship, dimensions, burst pressure, hydrostatic sustained pressure, environmental stress cracking, stabilizer functionality, bent-tube hydrostatic pressure, excessive temperature and degree of crosslinking. Requirements for tubing markings are also given. This specification incorporates an optional middle or outer oxygen barrier layer. This tubing is not intended for field bending at temperatures above 120 ºF (49 ºC).  
1.2 The text of this specification references notes, footnotes, and appendixes, which provide explanatory material. These notes and footnotes (excluding those in tables and figures) shall not be considered as requirements of the specification.  
1.3 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
1.4 The following safety hazards caveat pertains only to the test methods portion, Section 7, of this specification: This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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ASTM F2929-17(2021) - Standard Specification for Crosslinked Polyethylene (PEX) Tubing of 0.070 in. Wall and Fittings for Radiant Heating Systems up to 75 psig
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This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: F2929 − 17 (Reapproved 2021) An American National Standard
Standard Specification for
Crosslinked Polyethylene (PEX) Tubing of 0.070 in. Wall and
Fittings for Radiant Heating Systems up to 75 psig
This standard is issued under the fixed designation F2929; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope* mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
1.1 This specification covers 0.070 in. wall thickness cross-
linked polyethylene (PEX) tubing that is outside diameter
2. Referenced Documents
controlled, and intended for non-potable radiant heating appli-
2.1 ASTM Standards:
cations for pressures up to 75 psig in sizes ⁄8 NTS (nominal
A269/A269M Specification for Seamless and Welded Aus-
tubing size) and ⁄8 NTS. This specification also includes
tenitic Stainless Steel Tubing for General Service
fittings that are specifically designed for this 0.070 in.-wall
A276/A276M Specification for Stainless Steel Bars and
PEX tubing. Only maximum 75-psig relief valves shall be used
Shapes
with this tubing. Included in this specification are requirements
A312/A312M Specification for Seamless, Welded, and
and test methods for material, workmanship, dimensions, burst
Heavily Cold Worked Austenitic Stainless Steel Pipes
pressure, hydrostatic sustained pressure, environmental stress
B16/B16M Specification for Free-Cutting Brass Rod, Bar
cracking, stabilizer functionality, bent-tube hydrostatic
and Shapes for Use in Screw Machines
pressure, excessive temperature and degree of crosslinking.
B61 Specification for Steam or Valve Bronze Castings
Requirements for tubing markings are also given. This speci-
B62 Specification for Composition Bronze or Ounce Metal
fication incorporates an optional middle or outer oxygen barrier
Castings
layer. This tubing is not intended for field bending at tempera-
B140/B140M Specification for Copper-Zinc-Lead (Red
tures above 120 ºF (49 ºC).
Brass or Hardware Bronze) Rod, Bar, and Shapes
1.2 The text of this specification references notes, footnotes,
B283 Specification for Copper and Copper-Alloy Die Forg-
and appendixes, which provide explanatory material. These
ings (Hot-Pressed)
notes and footnotes (excluding those in tables and figures) shall
B371/B371M Specification for Copper-Zinc-Silicon Alloy
not be considered as requirements of the specification.
Rod
1.3 The values stated in inch-pound units are to be regarded B584 Specification for Copper Alloy Sand Castings for
as standard. The values given in parentheses are mathematical General Applications
conversions to SI units that are provided for information only B967/B967M Specification for Copper-Zinc-Tin-Bismuth
and are not considered standard. Alloy Rod, Bar and Wire
D618 Practice for Conditioning Plastics for Testing
1.4 The following safety hazards caveat pertains only to the
D792 Test Methods for Density and Specific Gravity (Rela-
test methods portion, Section 7, of this specification: This
tive Density) of Plastics by Displacement
standard does not purport to address all of the safety concerns,
D1505 Test Method for Density of Plastics by the Density-
if any, associated with its use. It is the responsibility of the user
Gradient Technique
of this standard to establish appropriate safety, health, and
D1598 Test Method for Time-to-Failure of Plastic Pipe
environmental practices and determine the applicability of
Under Constant Internal Pressure
regulatory limitations prior to use.
D1599 Test Method for Resistance to Short-Time Hydraulic
1.5 This international standard was developed in accor-
Pressure of Plastic Pipe, Tubing, and Fittings
dance with internationally recognized principles on standard-
D1600 Terminology for Abbreviated Terms Relating to Plas-
ization established in the Decision on Principles for the
tics
Development of International Standards, Guides and Recom-
D2122 Test Method for Determining Dimensions of Ther-
moplastic Pipe and Fittings
This specification is under the jurisdiction of ASTM Committee F17 on Plastic
D2765 Test Methods for Determination of Gel Content and
Piping Systems and is the direct responsibility of Subcommittee F17.61 on Water.
Swell Ratio of Crosslinked Ethylene Plastics
Current edition approved Aug. 1, 2021. Published August 2021. Originally
D2837 Test Method for Obtaining Hydrostatic Design Basis
approved in 2013. Last previous edition approved in 2017 as F2929–17. DOI:
10.1520/F2929–17R21. for Thermoplastic Pipe Materials or Pressure Design Basis
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F2929 − 17 (2021)
for Thermoplastic Pipe Products 3.2.2 crosslinked polyethylene, n—molecular polyethylene
D3895 Test Method for Oxidative-Induction Time of Poly- chains chemically connected through irradiation with high-
olefins by Differential Scanning Calorimetry energy electron beams, or chemical agents such as organic
E18 Test Methods for Rockwell Hardness of Metallic Ma- peroxides or silanes.
terials
3.2.3 hydrostatic design stress (HDS), n—the estimated
F412 Terminology Relating to Plastic Piping Systems
maximum tensile stress the material is capable of withstanding
F1281 Specification for Crosslinked Polyethylene/
continuously with a high degree of certainty that failure of the
Aluminum/Crosslinked Polyethylene (PEX-AL-PEX)
tube will not occur. This stress is circumferential when internal
Pressure Pipe
hydrostatic water pressure is applied. The HDS is equal to the
F2657 Test Method for Outdoor Weathering Exposure of
hydrostatic design basis (HDB) times the design factor (DF)
Crosslinked Polyethylene (PEX) Tubing
for water. For this standard, the design factor is equal to 0.50.
2.2 ANSI Standard:
HDS 5 HDB × DF
B36.10 Standards Dimensions of Steel Pipe (IPS)
5 HDB × 0.05 ~For this standard! (1)
2.3 Federal Standard:
3.2.4 hydrostatic design basis (HDB)—one of a series of
FED-STD-123 Marking for Shipment (Civil Agencies)
established stress values (specified in Test Method D2837) for
2.4 Military Standard:
a plastic compound obtained by categorizing the long-term
MIL-STD-129 Marking for Shipment and Storage
hydrostatic strength determined in accordance with Test
2.5 ISO Standards:
Method D2837.
ISO 1167 Thermoplastics pipes, fittings and assemblies for
3.2.4.1 Discussion—A listing of HDB and HDS values are
the conveyance of fluids -- Determination of the resistance
contained in PPI publication PPI TR-4.
to internal pressure -- Part 1: General method
ISO R 161-1690 Pipes of Plastic Materials for the Transport
3.2.5 hydrostatic strength equivalency (HSE), n—a pressure
of Fluids (Outside Diameters and Nominal Pressures) Part
testing evaluation methodology where hydrostatic testing is
1, Metric Series
conducted on PEX tubing that is constructed with a barrier
ISO 17455 Plastics piping systems -- Multilayer pipes --
layer in the middle or outside wall of the tubing, and is
Determination of the oxygen permeability of the barrier
constructed with PEX material that has an established HDB.
pipe
HSE methodology is applied where the barrier layer reduces
the thickness of the HDB rated PEX material in the wall such
2.6 PPI Standards:
that the PEX wall thickness excluding the barrier layer(s) is
PPI TR-3 Policies and Procedures for Developing Recom-
slightly less than 0.070 in. (1.78 mm).
mended Hydrostatic Design Basis (HDB), Strength De-
sign Basis (SDB), Pressure Design Basis (PDB) and
3.2.6 HSE-DR, n—an identifying term for the tubing where
Minimum Required Strength (MRS) Ratings for Thermo-
the minimum PEX wall thickness falls below 0.070 in. (1.78
plastic Piping Materials or Pipe
mm), yet the tubing, as constructed, still meets the pressure
PPI TR-4 PPI Listing of Hydrostatic Design Basis (HDB),
rating requirements of this specification as demonstrated by
Strength Design Basis (SDB), Pressure Design Basis
HSE evaluation testing.
(PDB) and Minimum Required Strength (MRS) Ratings
3.2.7 pressure rating (PR)—the estimated maximum water
for Thermoplastic Piping Materials or Pipe
pressure the tube is capable of withstanding continuously with
a high degree of certainty that failure of the tube will not occur.
3. Terminology
5 7
3.2.7.1 Discussion—If both ⁄8 NTS and ⁄8 NTS tubing are
3.1 Definitions—Definitions are in accordance with Termi-
used in the same system, the pressure rating of the system is
nology F412, and abbreviations are in accordance with Termi-
limited to the pressure rating of the ⁄8 NTS tubing.
nology D1600, unless otherwise specified. The abbreviation for
crosslinked polyethylene is PEX. 3.2.8 relation between dimensions, hydrostatic design
stress, and pressure rating—the following expression, com-
3.2 Definitions of Terms Specific to This Standard:
monly known as the ISO equation, 6 is used in this specifica-
3.2.1 barrier layer, n—a very thin polymeric film within the
tion to relate dimensions, hydrostatic design stress, and pres-
tube wall or around the circumference of the tubing, which
sure rating:
provides a means for greatly reducing the transmission of
oxygen from the atmosphere and into the fluid within the tube. 2S⁄P 5 D ⁄ t 2 1
~ !
O
or
2S⁄P 5 R 2 1 (2)
Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
4th Floor, New York, NY 10036, http://www.ansi.org.
where:
Available from DLA Document Services, Building 4/D, 700 Robbins Ave.,
S = hydrostatic design stress, psi (MPa),
Philadelphia, PA 19111-5094, http://quicksearch.dla.mil.
P = pressure rating, psi (or MPa),
Available from International Organization for Standardization (ISO), ISO
Central Secretariat, BIBC II, Chemin de Blandonnet 8, CP 401, 1214 Vernier,
D = average outside diameter, in. (mm),
O
Geneva, Switzerland, http://www.iso.org.
t = minimum wall thickness, in. (mm), and
Available from Plastics Pipe Institute (PPI), 105 Decker Court, Suite 825,
R = dimension ratio, DR.
Irving, TX 75062, http://www.plasticpipe.org.
F2929 − 17 (2021)
3.2.9 tubing material designation code—The tubing mate- determined in accordance with procedures no less restrictive
rial designation code shall consist of the abbreviation for the than those of PPI TR-3. See Appendix X1 for additional
type of plastic (PEX) followed by four Arabic digits that information on PPI hydrostatic stress ratings.
describe short-term properties in accordance with applicable
NOTE 1—HDB values at 73 ºF (23 ºC) and 180 ºF (82 ºC) may be
ASTM standards and as shown in Table 1.
published in PPI TR-4. The HDB at an intermediate temperature, such as
3.2.9.1 Discussion—The first digit is for chlorine resistance,
120 ºF (49 ºC), is determined by arithmetic interpolation.
which is not applicable for radiant tubing applications, but is NOTE 2—Tubing produced by crosslinking by peroxides, Azo
compounds, or silane compounds in extrusion, or by electron beam after
mentioned here for information purposes.
extrusion have met the requirements of Section 6. There are several other
3.2.9.2 Discussion—The second digit is for demonstrated
processes for producing crosslinked polyethylene tubing. However, each
UV resistance of PEX material when tested in accordance with
process must be established as meeting the requirements of this specifi-
Test Method F2657. For radiant heating, it shall be one of the
cation.
classification digits from Table 1 for the nominal exposure time
5.1.2 Barrier Layer—A barrier layer to reduce oxygen
period from Table 1 of Test Method F2657 where the UV-
diffusion is optional for this tubing. Tubing incorporating an
exposed samples meet the requirement of 7.10 Stabilizer
optional layer shall meet the requirements of 6.14 and 6.15 and
Functionality. The UV resistance shall be demonstrated on
all other requirements of this specification.
representative pipe samples for the original validation of pipe
5.1.2.1 Polymeric oxygen barrier layer materials shall be
made from a particular PEX material, that material being the
compatible with PEX and meet the requirements of this
combination of PEX resin and its additive system.
specification.
3.2.9.3 Discussion—The last two digits are the hydrostatic
NOTE 3—EVOH (Ethylene vinyl alcohol), which is the typical material
design stress for water at 73 °F (23 °C) in units of 100 psi with
used for the barrier layer, is defined by the mole % ethylene content: lower
any decimal figures dropped. Where the hydrostatic design
ethylene content grades have higher oxygen barrier properties.
stress code contains less than two figures, a zero is used before
5.1.2.2 Bonding or tie layer(s) material (if present) shall be
the number. Thus, a complete material designation code for
compatible with both PEX and barrier layer providing for
PEX tubing shall consist of the three letters “PEX” and four
permanent bonding between layers to meet layer adhesion
digits.
requirements of 6.14. A bonding/tie layer containing a colorant
3.2.10 0.070 in. wall radiant heating system—PEX tubing
shall be acceptable.
with a 0.070 in. thickness, and corresponding fittings designed
5.1.2.3 All barrier tubing sizes in this specification are
for 0.070 in. wall tubing, used for radiant heating applications.
pressure rated equivalent to DR of the PEX tubing. Tubing that
has PEX material minimum wall thickness equal to or greater
4. Tubing Classification
than 0.070 in. (1.78 mm) is pressure rated as that DR using the
4.1 General—This specification covers tubing for 0.070 in.
design equation (3.2.8), and is marked with that DR. Tubing
wall radiant heating that is classified using the tubing material
having a barrier layer that has PEX material minimum wall
designation code for PEX tubing.
thickness that is less than 0.070 in. (1.78 mm) is pressure rated
using hydrostatic strength equivalency (HSE) testing (6.3.2.3),
5. Materials
and is marked “HSE-DR.”
5.1 Tubing—Crosslinked polyethylene tubing, meeting the
5.2 Fittings—The fittings shall be made from one of the
requirements of this specification, is primarily defined by
following metals:
means of three criteria, namely, (1) nominal density, (2) degree
5.2.1 Cast Copper Alloys—Cast copper alloy fittings shall
of crosslinking, and (3) long-term strength tests. There is a
strong correlation between nominal density and results of be made from material meeting t
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