ASTM D4726-24

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Designation: D4726 − 18 D4726 − 24 An American National Standard
Standard Specification for
Rigid Poly(Vinyl Chloride) (PVC) Exterior-Profile Extrusions
Used for Assembled Windows and Doors
This standard is issued under the fixed designation D4726; 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*
1.1 This specification establishes requirements for the material properties, including dimensional stability, weatherability, and
extrusion quality, of rigid poly(vinyl chloride) (PVC) exterior profile extrusions used for assembled windows and doors. Methods
for testing and for identifying exterior profile extrusions that comply with this specification are also provided.
1.2 The use of rigid PVC recycled plastic in this product shall be in accordance with the requirements in Section 6.
NOTE 1—Information with regard to application, assembly, and installation should be obtained from the manufacturers of the profiles and of the windows
and doors.
NOTE 2—Refer to Specification D3678 for interior profile extrusions.
1.3 Color-hold guidelines are provided in an appendix for the manufacturer’s product development and quality performance use.
1.4 Color-hold guidelines are presently limited to white, grey, beige, light brown, and dark brown (see Figs. X1.1 through X1.5).
Additional colors will be added as color guidelines are developed.
1.5 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are for information only.
NOTE 3—There is no known ISO equivalent to this standard.
1.6 The text of this standard references notes and footnotes, which provide explanatory material. These notes and footnotes
(excluding those in tables and figures) shall not be considered as requirements of this standard.
1.7 The following safety hazards caveat pertains only to the test methods portion, Section 11, 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.
1.8 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.
This specification is under the jurisdiction of ASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.24 on Plastic Building Products.
Current edition approved Aug. 1, 2018Feb. 1, 2024. Published September 2018April 2024. Originally approved in 1987. Last previous edition approved in 20152018 as
D4726 – 15.D4726 – 18. DOI: 10.1520/D4726-18.10.1520/D4726-24.
*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
D4726 − 24
2. Referenced Documents
2.1 ASTM Standards:
D618 Practice for Conditioning Plastics for Testing
D883 Terminology Relating to Plastics
D1042 Test Method for Linear Dimensional Changes of Plastics Caused by Exposure to Heat and Moisture
D1435 Practice for Outdoor Weathering of Plastics
D1600 Terminology for Abbreviated Terms Relating to Plastics (Withdrawn 2024)
D2244 Practice for Calculation of Color Tolerances and Color Differences from Instrumentally Measured Color Coordinates
D3678 Specification for Rigid Poly(Vinyl Chloride) (PVC) Interior-Profile Extrusions
D3892 Practice for Packaging/Packing of Plastics
D4216 Specification for Rigid Poly(Vinyl Chloride) (PVC) and Related PVC and Chlorinated Poly(Vinyl Chloride) (CPVC)
Building Products Compounds
D4226 Test Methods for Impact Resistance of Rigid Poly(Vinyl Chloride) (PVC) Building Products
E631 Terminology of Building Constructions
E805 Practice for Identification of Instrumental Methods of Color or Color-Difference Measurement of Materials
G147 Practice for Conditioning and Handling of Nonmetallic Materials for Natural and Artificial Weathering Tests
3. Terminology
3.1 General—Definitions are in accordance with Terminologies For definitions of terms pertaining to plastics used in this test
method, refer to Terminology D883 or. For E631 and abbreviations used in this test method, refer to D1600, unless otherwise
indicated.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 color-hold guidelines—target color regions within a three-dimensional model which constitute acceptable appearance
retention levels of color change resulting from weathering of a specific product type and color.
3.2.2 temperate northern climate—in weather testing, a North American metropolitan area testing site located within 73 to 100°
W longitude and 37 to 45° N latitude.
4. Classification
4.1 Color Regions—The color region for a color is determined by measuring the Hunter L, a, b color values for a sample. Use
the integer value (by truncating any fractional results) to determine the color region for the color using the following region
boundaries.
4.1.1 Region 1—Beige:
L = 60 to 87
a = –2.5 to 4.0
b = 6.5 to 23
4.1.2 Region 2—Dark Brown:
L = 13 to 33
a = –1.0 to 6.0
b = 1.0 to 6.5
4.1.3 Region 3—Gray:
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
The last approved version of this historical standard is referenced on www.astm.org.
D4726 − 24
L = 33 to 74
a = –3 to 4
b = –5.5 to 5.5
4.1.4 Region 4—Light Brown:
L = 30 to 60
a = –1.5 to 12.5
b = 3.0 to 12.5
4.1.5 Region 5—White:
L = 83 to 100
a = –4 to 0
b = –5.5 to +5.5
NOTE 4—L,a,b is determined in accordance with the Hunter L,a,b opponent color space system in Test Method D2244.
5. Significance and Use
5.1 The purpose of this specification is to establish a recognized standard of quality for rigid poly(vinyl chloride) (PVC) exterior
weatherable profile extrusions for use in assembling windows and doors. The information contained in this specification is intended
to be helpful to producers, distributors, and users, and to promote understanding between buyers and sellers. It is also intended
to serve as the basis for specification requirements of exterior windows and doors which are made from rigid PVC profile
extrusions in their construction.
6. Materials and Manufacture
6.1 The profile extrusions used for assembled windows and doors shall be made principally of weatherable, rigid poly(vinyl
chloride) (PVC) compounds meeting or exceeding the requirements of Class 1-20131-13 as defined in Specification D4216.
NOTE 5—Non-PVC materials may be used as a capstock.
6.2 Rigid PVC recycled plastic is acceptable for use in this product if all the requirements in the sections on Terminology (Section
3), Materials and Manufacture (Section 6), Physical Requirements (Section 7), and Performance Requirements (Section 8) are met
by the extrusions containing PVC recycled plastic.
6.3 The PVC compound in the extruded section shall have visual uniform color and be free of any visual surface or structural
changes, such as peeling, chipping, cracking, flaking, or pitting.
6.4 Rework Material—Clean, homogeneous PVC rework material or rework material containing PVC capstock generated from the
manufacturer’s own production of the same class compound is acceptable for use by the same manufacturer providing that the
extruded profiles meet all the requirements of this specification. Clean principally PVC rework material containing non-PVC
capstock is acceptable for use in the substrate of a capstocked product by the same manufacturer, providing that the extruded
profiles meet all of the requirements of this specification.
6.5 The PVC compound shall have successfully met the weathering requirements for six months at each climatic testing site
prescribed in A1.1.1 prior to use in production of exterior-profile extrusions for either market development or sales.
NOTE 6—The six-month-test requirement constitutes a screening process to eliminate catastrophic failure in the marketplace.
7. Physical Requirements
7.1 Dimensions—The size, thickness, and dimensional tolerances of the exterior profiles shall be as agreed upon between the
supplier and the purchaser in the purchase order, or by meet established internal process control standards.
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7.2 Dimensional Stability—The dimensional stability of the exterior-profile extrusions shall be determined in accordance with
11.3. Extrusions over 0.040 in. (1.02 mm) shall have a maximum average shrinkage of 2.2 % for all sides measured, with no single
value exceeding 2.4 %. Extrusions of 0.040 in. (1.02 mm) or less shall have a maximum average shrinkage of 3 %.
7.3 Impact Resistance—Flat sections of the exterior profile extrusion shall have a minimum brittle impact failure of 1.0 in.·lb/mil
(4450 J/m) when tested in accordance with Test Methods D4226, Procedure B, using impactor C.125. Refer to 11.4.
8. Performance Requirements
8.1 Weathering:
8.1.1 The exposures listed in Annex A1 shall be conducted in order to meet the requirements of this specification. All exposures
shall be conducted at an angle of 45° S, plywood-backed, in accordance with Practice D1435 and Practice G147.
8.1.2 After six-month and 1-year exposure times, the minimum mean impact for 20 measurements conducted on the exposed
specimens shall be at least 0.6 in·lb/mil (2670 J/m). Test impact in accordance with 11.4, A1.4, and A1.5.
8.1.3 After each exposure time, the tested specimens shall maintain a visual uniform color and be free of any visual changes in
appearance at the surface, such as peeling, chipping, cracking, flaking, and pitting when tested in accordance with Annex A1.
NOTE 7—It is recommended that manufacturers use the color-hold guidelines in Appendix X1 to ensure quality performance.
8.1.4 Weatherability conformance testing requirements are to reflect performance of a “typical” extrusion system profile
representing a specific PVC compound and a specific extrusion technology. In no case is there an implied requirement for testing
all the various shaped profiles. The lengthy outdoor weatherability testing shall be performed concurrently with market
development of new applications and sales of profiles to existing markets. Completion of weatherability testing prior to marketing
of the product is not required. The profile extrusion producer shall immediately respond in terms of compound change or extrusion
technology change to unsatisfactory weatherability behavior of the profiles under test in any climatic test site at any stage of the
weatherability testing.
9. Workmanship, Finish, and Appearance
9.1 The extrusions shall meet internal process control standards in section, color, and finish. The extrusions shall be substantially
straight and free from defects that might affect appearance or serviceability.
10. Sampling
10.1 Select samples using a statistically acceptable procedure. The samples shall be representative of the compound used.
11. Test Methods
11.1 General—Use the inspection and test procedures contained in this section to determine the conformance of products to the
requirements of this specification. A producer or distributor representing products as conforming to this specification shall use
statistically based sampling plans that are appropriate to each manufacturing process. Keeping essential records are necessary to
document with a high degree of assurance the claim that all of the requirements of this specification have been met. Additional
sampling and testing of the product, as agreed upon between the supplier and the purchaser, is not precluded by this section.
11.2 Conditioning of Specimens—Condition the test specimens in accordance with Procedure A of Practice D618. For the purpose
of quality control testing, the minimum conditioning time shall be four hours.
11.3 Dimensional Stability:
11.3.1 Determine the dimensional stability in accordance with Test Method D1042, except that one or more specimens shall be
exposed to either of the following test cycles:
11.3.1.1 30 min immersed in water maintained at 180 6 2°F (82 6 1 °C), or
D4726 − 24
11.3.1.2 30 min conditioned in a forced-ventilation oven at 180 6 2°F (82 6 1 °C).
11.3.2 Specimens shall condition for no less than 1 h in accordance with Procedure A of Practice D618, prior to measurement.
If a specimen were to fail, select and retest two additional specimens.
11.4 Impact Test—Determine the impact strength in accordance with Test Methods D4226, Procedure B, using the C.125 impactor.
12. Packing, Packaging, and Package Marking
12.1 The exterior profile extrusions shall be packaged in such a manner as to provide reasonable protection against damage in
ordinary handling, transportation, and storage.
12.2 Provisions of Practice D3892 shall apply to this specification.
12.3 Marking on each package of extruded profile extrusions shall include the following:
12.3.1 Manufacturer’s name or trademark;
12.3.2 Identity of code number of extrusion profiles;
12.3.3 Class of compound (SpecificationCell classification as defined D4216) usedper Specification D4216in profiles;;
12.3.4 The designation ASTM D4726, affirming that the product so marked has been qualified to all the provisions of this
specification, andspecification.
12.3.5 The date and any other relevant information, such as factory, machine, production shift, and so forth, either directly or all
or partly coded.
13. Keywords
13.1 color-hold guidelines; doors; exterior-profile extrusions; poly(vinyl chloride) (PVC); recycled plastic; windows
ANNEXES
(Mandatory Information)
A1. WEATHERABILITY PROCEDURE
A1.1 Summary of Procedure of Determining
Weatherability
A1.1.1 Flat section specimens cut from finished product lineals or laboratory extruded samples are exposed in accordance with
Practice D1435 and Practice G147 at 45° S, plywood-backed, in a hot, dry (desert) climate; a hot, humid climate; and in a northern
temperate climate for periods of six months, one year and two years.
A1.1.2 Degree of retention of the original impact strength due to weather exposure in each exposure site is measured after
six-months and one-year exposure.
A1.1.3 The acceptability of color uniformity, and surface changes resulting from weathering at each test site and each exposure
frequency is determined by visual observation in comparison to the unexposed specimens.
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A1.2 Significance
A1.2.1 The processing of poly(vinyl chloride) (PVC) compounds has influence on impact retention and some influence on
appearance retention. For this reason samples prepared for impact retention must be processed in a manner similar to the
commercial product while still permitting the use of laboratory scale equipment.
NOTE A1.1—It is recommended that manufacturers use the color-hold guidelines in Appendix X1 to ensure quality performance.
A1.2.2 Poly(vinyl chloride) compounds undergo complex changes when exposed to the weather. Changes in appearance are
caused by chemical changes in the PVC, additives, or pigments. Changes in appearance are caused by selective erosion of some
pigments faster than others. Changes in impact strength are due to chemical changes in the PVC or additives, or due to physical
changes on the surface as a result of erosion and crazing.
A1.3 Sampling and Specimen Preparation
A1.3.1 Select samples using a statistically acceptable procedure. The samples shall be representative of the product to be qualified.
A1.3.2 If commercial parts are used, cut them into sections so that flat test specimens at least 1.5 in. (38 mm) wide can be obtained.
The back surface of the specimen must lay as flat as possible on the specimen support anvil. Cut the flat sections such that there
are no ridges or raised areas remaining on the back surface of the specimen that would make contact with the specimen support
anvil. The specimens shall be free of obvious imperfections, grooves, ribs, and so forth. Material prepared in the laboratory by a
similar process is an alternate to a commercial part. If the commercial product is extruded, the laboratory specimen must be
extruded; if the commercial product is a laminate of two materials, the laboratory specimen must be laminated with the two
materials, and so forth.
A1.3.3 The number of specimens or the size of the specimen must be sufficient to obtain at least 20 impact locations of the dropped
dart for each weathering interval.
A1.3.4 The thickness of any test specimen must differ from the average test specimen by no more than 10 %.
A1.4 Conditioning
A1.4.1 Condition the test specimens, including specimens removed from the weather exposure, at 73.4 6 3.6°F (23.0 6 2.0 °C)
and 50 6 10 % relative humidity for not less than 24 h before testing. In no case shall weathered specimens be oven-dried before
testing.
NOTE A1.2—The operational fluctuations are allowable deviations from the specified temperature and relative humidity settings. They do not imply that
these settings can be higher or lower than that specified. If the operational fluctuations are greater than
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