Designation: F 491 – 95 An American National Standard

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Reprinted from the Annual Book of ASTM Standards. Copyright ASTM

Standard Specification for

Poly(Vinylidene Fluoride) (PVDF) Plastic-Lined Ferrous
Metal Pipe and Fittings1
This standard is issued under the fixed designation F 491; 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 (e) indicates an editorial change since the last revision or reapproval.

1. Scope Forgings, Carbon Steel, for Piping Components A 105

Forged or Rolled Steel Pipe Flanges, Forged Fittings, and A 181
1.1 This specification covers factory-made poly(vinyl-idene Valves and Parts for General Service
fluoride) (PVDF) plastic-lined ferrous metal pipe and fittings, Carbon Steel Castings Suitable for Fusion Welding for A 216
High-Temperature Service (Grade WCB)
primarily intended for conveying corrosive liquids and gases.
Piping Fittings of Wrought Carbon Steel and Alloy Steel for A 234
Requirements for materials, workmanship, dimensions, design, Moderate and Elevated Temperatures
construction, working pressures and temperatures, test meth- Austenitic Steel Castings for High-Temperature Service A 351
Alloy Steel Castings Specially Heat-Treated for Pressure- A 389
ods, and markings are included. Containing Parts Suitable for High-Temperature Service
Ductile Iron Castings (60-40-18, 64-45-12, 80-55-06) A 536
NOTE 1—This specification does not include products coated with Ferritic Ductile Iron Pressure Retaining Castings for Use at A 395
PVDF nor does it define the suitability of PVDF-lined components in Elevated Temperatures (60-40-18)
chemical environments. Wrought Austenitic Stainless Steel Piping Fittings A 403

1.2 The ferrous piping products shall meet the requirements NOTE 2—The PVDF sealing faces may prevent achievement of the full
of the relevant specification listed in 1.2.1. Nominal sizes from pressure rating of the ferrous housings. For pressure limitations, the
1 through 10 in. in 150 and 300-psi ratings are covered. manufacturer should be consulted.
1.2.1 For Ferrous Pipe: 1.3 The PVDF-lined flanged pipe and fitting assemblies are
ASTM
limited to use from −18 to 135°C (0 to 275°F). For use below
Title of Specification Designation −18°C (0°F) consult the manufacturer. Use in specific aggres-
Pipe, Steel, Black and Hot-Dipped, Zinc-Coated, Welded A 53 sive environments may alter the above temperature range. The
and Seamless (Types E and S)
Seamless Carbon Steel Pipe for High-Temperature Ser- A 106
operating temperature limits shall be established by mutual
vice agreement between the purchaser and the seller.
Electric-Resistance Welded Steel Pipe A 135
Electric-Welded Low-Carbon Steel Pipe for the Chemical A 587 2. Referenced Documents
Industry
Seamless and Welded Austenitic Stainless Steel Pipe A 312
2.1 ASTM Standards:
Electric-Resistance Welded Carbon and Alloy Steel Me- A 513 D 1600 Terminology for Abbreviated Terms Relating to
chanical Tubing Plastics2
1.2.2 For Ferrous Flanges: D 3222 Specification for Unmodified Poly(Vinylidene
Fluoride) (PVDF) Molding, Extrusion and Coating Mate-
ASTM
Title of Specification Designation rials3
Forgings, Carbon Steel, for Piping Components A 105 F 412 Terminology Relating to Plastic Piping Systems4
Forged or Rolled Steel Pipe Flanges, Forged Fittings and A 181 2.2 ANSI Standard:
Valves and Parts for General Service
Forged or Rolled Alloy-Steel Pipe Flanges, Forged Fit- A 182 B 16.5 Steel Pipe Flanges and Flanged Fittings5
tings, and Valves and Parts for High-Temperature Service
Carbon-Steel Castings Suitable for Fusion Welding for A 216
3. Terminology
High-Temperature Service (Grade WCB) 3.1 Definitions—Definitions are in accordance with Termi-
Ferritic Ductile Iron Pressure Retaining Castings for Use at A 395
Elevated Temperatures (60-40-18) nology F 412, and abbreviations are in accordance with Ter-
Ductile Iron Castings (60-40-18, 64-45-12, 80-55-06) A 536 minology D 1600, unless otherwise specified. The abbreviation
for poly(vinylidene fluoride) is PVDF.
1.2.3 For Ferrous Fittings:
ASTM 4. Materials
Title of Specification Designation 4.1 Lining:

1 2
This specification is under the jurisdiction of ASTM Committee F-17 on Plastic Annual Book of ASTM Standards, Vol 08.01.
3
Piping Systems and is the direct responsibility of Subcommittee F17.11 on Annual Book of ASTM Standards, Vol 08.03.
4
Composite. Annual Book of ASTM Standards, Vol 08.04.
5
Current edition approved Sept. 10, 1995. Published November 1995. Originally Available from American National Standards Institute, 11 West 42nd Street,
published as F 491 – 77. Last previous edition F 491 – 93a. 13th Floor, New York, NY 10036.

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 F 491
4.1.1 Material—The lining shall be made from PVDF Minimum PVDF face
resins conforming to the requirements of Specification D 3222, Nominal pipe size, in. diameter, in.
1 1 7⁄8
except that a maximum of 1 % by weight of additives or 1 1⁄2 2 11⁄16
colorants, or both, is permissible. Organic colorants, if used, 2 3 7⁄16
shall be identified in the manufacturer’s specification. 3 4 5⁄8
4 5 15⁄16
4.1.2 The PVDF lining shall be made from virgin resin or 6 8
clean reworked resin. 8 10 1⁄16
4.1.3 Mechanical Properties—The lining shall have a mini- 10 12 1⁄4
mum tensile strength at yield of 5000 psi and a minimum 6.1.4 Tolerances—Tolerances for pipe, flanges, and fittings
elongation at yield of 8 % when tested in accordance with the shall be as specified in the following table. Bolt holes in both
requirements of Specification D 3222, except that the test flanges on a fixed flange spool shall straddle the same center
specimens shall be obtained from extruded or molded PVDF line to facilitate alignment. Finished lined (plastic face to
liner. The minimum values for tensile strength and elongation plastic face) fabricated fittings shall conform to the nominal
shall apply to both the longitudinal and circumferential direc- face-to-face, etc. as specified in ANSI B 16.5 with the appli-
tions. cable tolerances.
4.2 Ferrous Pipe Fittings: Tolerances for Pipe, Flanges, and Fittings, in.
4.2.1 The mechanical properties of the pipes and fittings Pipe Tolerance
shall conform to the requirements of the appropriate specifi- Length 6 1⁄8
Fixed flange bolt hole alignment 6 1⁄16
cation of 1.2 except as they are influenced by accepted methods Flange perpendicularity (with pipe centerline) 3⁄32 in./ft of diameter

of processing in the industry—for example, Van Stone flaring, Flanges and Fittings
bending, swagging, and welding. The carbon steel pipe and All dimensions in accordance with ANSI
B16.5
wrought fittings shall be welded or seamless steel, Schedule 40
or Schedule 80, except that Schedule 30 pipe may be used in 8 6.2 Flange Construction:
and 10-in. nominal size. 6.2.1 Screw-type flanges shall be secured in position to
4.2.2 Finish—The interior surfaces of all housings shall be prevent inadvertent turning of the flange.
clean and free of mold burrs, rust, scale, or other protrusions 6.2.2 Socket-type flanges shall be fully back-welded to the
that may adversely affect the integrity or performance of the pipe housing and the inside surfaces of the socket flanges shall
lining. be welded and ground smooth.
4.3 Back-Up Gaskets: 6.2.3 Slip-on flanges shall be fully back-welded.
4.3.1 General—Back-up gaskets shall be used to cover the
NOTE 3—No welding shall be done on lined components.
pipe end and gasket face of threaded or slip-on flanges unless
a full radius is provided at the end of the pipe and flange. 6.2.4 Lap-joint (or Van Stone) flanged ends may be manu-
Gaskets may also be required on fittings to provide accommo- factured by standard forming techniques or by using fully
dation or elimination, or both, of sharp corners that could welded stub ends or collars. Lap-joints shall not contain any
damage the lining. cracks or buckles.
4.3.2 Material—Plain gaskets meeting the temperature re- NOTE 4—The use of lap-joint flanges in a piping system may simplify
quirements, or perforated metallic gaskets, may be used. alignment.
6.3 Venting—Each pipe and fitting have a liner thickness
5. Finish
less than that shown in the following table shall be provided
5.1 The outside surface of all lined pipe and fittings, other with a venting system that will release any gases between the
than stainless steel, shall be coated with a corrosion-resistant liner and the housing and will also indicate any leakage
primer over a properly prepared surface. through the liner, in the event of liner failure. Such a system
may consist of a series of 1⁄16 to 5⁄32-in. diameter holes in the
6. Requirements housings.
6.1 Dimensions:
NOTE 5—Vent holes should not be plugged with paint, cement, etc.
6.1.1 Housing—Housing installation dimensions are as re- since this negates the intended purposes listed in 6.3.1.
quired in the specifications listed in 1.2. Minimum Liner Thickness for Non-Vented Piping
6.1.2 Wall Thickness—Fitting linings shall have minimum Nominal pipe size, in. Liner thickness, in.
wall thickness of 3⁄32in. and a uniform face thickness of not less 1 0.100
1 1⁄2 0.120
than 3⁄32 in. Pipe linings shall have a minimum wall thickness 2 0.130
of 0.050 in. and the flared radius and gasket faces shall have a 3 0.150
uniform thickness not less than 80 % of the wall thickness. 4 0.160
6 0.180
6.1.3 PVDF Face Diameter—The outside diameter of the 8 0.180
PVDF covering the gasket face of the flange or the full face of 10 0.180
the lap-joint stub end shall not be less than the diameter 6.4 Workmanship:
specified in the following table. They shall be concentric 6.4.1 Pipe and fitting linings shall show no evidence of
within 1⁄16 in. pinholes, porosity, or cracks when inspected in accordance
PVDF Face Diameter with 6.5.2. The linings shall fit snugly inside the pipe and

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 F 491
fitting housings. Any bulges or other obvious indication of poor 7.2.2.2 Close off steam.
contact with the housing shall be cause for rejection. 7.2.2.3 Vent and introduce air to purge the specimens for a
6.4.2 The gasket face of the PVDF linings shall be free of minimum of 1 min.
surface defects that could impair sealing effectiveness. 7.2.2.4 Circulate water at a maximum temperature of 25°C
Scratches, dents, nicks, or tool marks on the gasket surface (77°F) until the ferrous housing skin temperature adjacent to
shall not be deeper than 10 % of the wall thickness. the flange at the outlet end of the test specimen measures 50°C
6.5 Performance: (122°F) maximum.
6.5.1 Qualification—PVDF-lined pipe and fittings must be 7.2.2.5 Drain, then introduce air to purge the specimens for
capable of meeting the requirements specified in Section 7. a minimum of 1 min, making certain that specimens are
6.5.2 Inspection: completely drained.
6.5.2.1 Each lined pipe and fitting, prior to shipment, shall 7.2.3 There shall be no evidence of leakage from the venting
be subjected to a hydrostatic test or an electrostatic test, or system or the flanges during the 100 cycles. At the completion
both, as specified in 8.1 or 8.2. The test or tests to be used shall of the test, the liner shall show no evidence of buckling,
be at the option of the manufacturer, unless otherwise specified cracking, or crazing.
by the purchaser. 7.2.4 At the conclusion of the testing specified in 7.2.2,
6.5.2.2 Each lined pipe and fitting shall subsequently be subject the PVDF-lined pipe or fitting to the hydrostatic test
visually inspected prior to shipment to verify conformance to specified in 8.1 or, after drying, to the electrostatic test
the design and dimensional requirements of 6.4. specified in 8.2.
6.5.2.3 Each lined pipe and fitting shall bear an inspection 7.3 Vacuum Test:
verification impression stamp on the housing to indicate 7.3.1 Test representative production samples of PVDF-lined
compliance with the requirements of this specification. pipe and fittings to determine the vacuum ratings of the lined
components. Test a minimum of two pipe spools, tees, and
7. Qualification Tests 90-deg elbows in each size. Conduct tests at room temperature,
7.1 Temperature Test: at the manufacturer’s maximum recommended service tem-
7.1.1 Cycle representative production samples of PVDF- perature, and at one intermediate temperature if a full vacuum
lined pipe and fittings in an oven from room temperature to 135 rating cannot be achieved at the maximum recommended
6 3°C (275 6 5°F) to determine the ability of the lined service temperature. Full vacuum is defined as 29.6 in. Hg
components to withstand heat aging and temperature cycling. corrected.
Test a minimum of two pipe spools, tees, and 90-deg elbows in
NOTE 6—Vacuum-temperature ratings should be published in the
each size.
manufacturer’s literature.
7.1.2 Install companion flanges at the manufacturer’s rec-
ommended torque value, and affix a thermocouple to the 7.3.2 For pipe spools, specimen length shall be at least 10
ferrous housing to measure the temperature. Pipe spools shall pipe diameters. Install a flange incorporating a sight glass at
be at least 3 ft long. After 3 h in an oven at 135°C (275°F) as one end and a blind flange suitable for drawing a vacuum at the
indicated by the thermocouple, air cool the lined components other end. Make provision for measuring the ferrous housing
to 50°C (122°F) maximum. Repeat this test for a total of three temperature.
cycles. 7.3.2.1 Heat the specimens uniformly externally with the
7.1.3 Inspect PVDF-lined pipe and fittings after each cycle sight glass end visible. Begin the test after the desired ferrous
for distortion or cracks in the PVDF lining. At the completion housing temperature has been reached. Hold a selected initial
of the third cycle, subject specimens to either the hydrostatic or vacuum level for 24 h and if no failure occurs, increase the
electrostatic test described in 8.1 or 8.2. vacuum by 2 in. Hg. Repeat this every 24 h until failure or full
7.2 Steam-Cold Water Cycling Test: vacuum is reached. Failure is defined as any buckling or
7.2.1 Subject representative production samples of PVDF- collapse of the liner. If failure occurs at the initial vacuum level
lined pipe and fittings to steam-cold water cycling to determine selected, test a new test specimen at a lower vacuum level to
the ability of the lined components to withstand rapid tempera- determine the failure threshold. The vacuum failure threshold
ture changes. Test a minimum of two pipe spools, tees, and is defined as 1 in. Hg below that at which failure occurs.
90-deg elbows in each size. NOTE 7—The external pressure method to simulate higher than full
7.2.2 Assemble PVDF-lined pipe and fittings with suitable vacuum can be used to establish the failure threshold when full vacuum is
blind flanges having provision for the introduction of steam, achievable. With the use of pressure taps, an external pressure is applied
air, or cold water, and for drainage. Install the flanges using the between the liner outside diameter and the pipe inside diameter.
manufacturer’s recommended torque value. Pipe spool length 7.3.3 The vacuum rating shall be 80 % of the failure
shall be 10 ft minimum. Mount the test specimens in such a threshold value.
manner as to permit complete drainage and then subject them 7.3.4 At the test completion and after the vacuum rating is
to 100 steam-cold water cycles, each of which shall consist of established, heat a duplicate specimen to the test temperature.
the following in the sequence given: Apply the rated vacuum to the specimen after the desired skin
7.2.2.1 Circulate 30 6 2 psig saturated steam through the temperature has been reached. Achieve the rated vacuum
specimens until the ferrous housing skin temperature adjacent within 2 min and apply continuously for 48 h. If no liner
to the flange at the outlet end of the test specimen has been buckling or collapse occurs, the vacuum rating shall be
maintained at the maximum stabilized temperature for 30 min. considered acceptable.

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 F 491
7.4 Retest—When a test specimen fails to meet the require- 9.1.1 Nominal pipe size,
ments of 7.1, 7.2, or 7.3, the cause of failure shall be sought 9.1.2 Liner material identification (“PVDF”),
and corrected. Repeat the temperature test specified in 7.1, the 9.1.3 Manufacturer’s name (or trademark),
steam-cold water cycling test specified in 7.2, and the vacuum 9.1.4 This ASTM designation “ASTM F 491,”
test specified in 7.3, using double the number of test speci- 9.1.5 Length (on pipe only), and
mens. 9.1.6 Other information such as order numbers, part num-
bers, item numbers, etc., which shall be provided at the
8. Inspection Tests purchaser’s request.
8.1 Hydrostatic Pressure Test—The internal test pressure 9.2 Pipe liner identification shall be provided on a band
shall be 425 psi minimum. Conduct the test at ambient containing the raised letters “PVDF.” One band is required on
temperature. Completely fill the pipe and fitting with clean fittings and on pipe lengths up to 6 ft; two bands are required
water and bleed the system free of all air prior to the for pipe lengths over 6 ft. The band will typically be located
application of pressure. Reach full test pressure within 1 min near the flange.
and maintain for a further 3 min. Observe the pressure gage
and the venting system in the test specimen throughout the test 10. Packaging
for any evidence of leakage, which shall be cause for rejection. 10.1 The gasket face of each lined pipe and each fitting shall
8.2 Electrostatic Test—Conduct the test with a nondestruc- be protected by end plates or other suitable protective means,
tive high-voltage tester at an output voltage of 10 kV. A visible such as individual boxing.
or audible spark (or one that is both), that occurs at the probe
when electrical contact is made with the housing because of a 11. Quality Assurance
defect in the liner, shall be cause for rejection. 11.1 When the product is marked with this designation,
F 491, the manufacturer affirms that the product was manufac-
9. Marking tured, inspected, sampled, and tested in accordance with this
9.1 Marking on the pipe and fitting shall include the specification and has been found to meet the requirements of
following: this specification.

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if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards
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