ASTM F1839-01(2007)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: F 1839 – 01 (Reapproved 2007)
Standard Specification for
Rigid Polyurethane Foam for Use as a Standard Material for
Testing Orthopedic Devices and Instruments
This standard is issued under the fixed designation F 1839; 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 2. Referenced Documents
1.1 This specification covers rigid unicellular polyurethane 2.1 ASTM Standards:
foam for use as a standard material for performing mechanical C 273 Test Method for Shear Properties of Sandwich Core
tests utilizing orthopedic devices or instruments. The specifi- Materials
cation is applicable to sheets or blocks of foam, or foam that is D 1621 Test Method for Compressive Properties Of Rigid
made by the user using a two-part liquid mixture. Cellular Plastics
1.2 This specification covers polyurethane foam material D 1622 Test Method forApparent Density of Rigid Cellular
that is used in the laboratory for mechanical testing, as Plastics
described in 1.1. These materials are not intended for implan- E4 Practices for Force Verification of Testing Machines
tation into the human body. F 543 Specification and Test Methods for Metallic Medical
1.3 The foam described herein possesses mechanical prop- Bone Screws
erties which are on the order of those reported for human
3. Terminology
cancellous bone. See Appendix X1 Rationale for further
information regarding the appropriateness of using the speci- 3.1 Definitions:
3.1.1 final form—the condition of the foam product when
fied foam as a model for human cancellous bone.
1.4 This specification covers compositional requirements, used by the end user to perform tests of orthopedic devices or
instruments. The condition of the foam product of which all
physical requirements, mechanical requirements, and test
methods for rigid polyurethane foam in the solid final form. physical and mechanical tests required by this specification are
performed.
1.5 This specification provides qualification criteria for
3.1.1.1 solid—the foam is in a uniform solid form, such as
vendor or end-user processes and acceptance criteria for
individual material lots. a slab, plate, or block.
3.1.2 foam rise direction—the nominal direction that the
1.6 Thisspecificationprovidesmechanicalpropertiesoffive
different grades of foam in the solid final form. A foam that foam rises during the polymerization (“foaming”) process,
either at the suppliers production facilities for the solid
does not meet the specified mechanical properties shall be
identified as an ungraded foam. supplied foam, or at the end-users facilities for foam produced
from the liquid supplied form. The foam rise direction shall be
1.7 Unless otherwise indicated, the values stated in SI units
are to be regarded as standard. The values in parentheses are marked on the foam block or indicated in the shipping
documentation for foam that is supplied in the solid form.
given for information only.
1.8 The following precautionary statement pertains to the 3.1.3 grades—The grade designation refers to the nominal
density of the foam, in its solid final form, expressed in units
test method portion only, Section 8, of this specification: This
3 3
standard does not purport to address all of the safety concerns, of kg/m (lbm/ft ). Five grades of foam have been defined in
this specification. Their nominal densities are given below:
if any, associated with its use. It is the responsibility of the user
3 3
of this standard to establish appropriate safety and health
Grade 10: 160.2 kg/m (10.0 lbm/ft )
3 3
Grade 12: 192.2 kg/m (12.0 lbm/ft )
practices and determine the applicability of regulatory limita-
3 3
Grade 15: 240.3 kg/m (15.0 lbm/ft )
tions prior to use.
3 3
Grade 20: 320.4 kg/m (20.0 lbm/ft )
3 3
Grade 40: 640.7 kg/m (40.0 lbm/ft )
This specification is under the jurisdiction of ASTM Committee F04 on
Medical and Surgical Materials and Devices and is the direct responsibility of For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Subcommittee F04.21 on Osteosynthesis. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Current edition approved Oct. 1, 2007. Published October 2007. Originally Standards volume information, refer to the standard’s Document Summary page on
approved in 1997. Last previous edition approved in 2001 as F 1839 – 01. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
F 1839 – 01 (2007)
TABLE 2 Grade Designation and Density
3.1.4 supplied form—the condition of the foam product
when received from the supplier by the end user. Minimum Density, Maximum Density,
Grade
3 3 3 3
kg/m (lbm/ft ) kg/m (lbm/ft )
3.1.4.1 solid—the foam is in a uniform solid form, such as
10 144.2 (9.0) 176.2 (11.0)
a slab, plate, or block.
12 176.2 (11.0) 208.2 (13.0)
3.1.4.2 liquid—two liquid components (base and activator)
15 224.3 (14.0) 256.3 (16.0)
thatcanbemixedbytheendusertoproducearigid,unicellular
20 304.4 (19.0) 336.4 (21.0)
40 624.7 (39.0) 656.8 (41.0)
foam slab.
3.1.5 ungraded—foam that does not fit into one of the five
grades specified in 3.1 because of the foam not meeting one or
4.5 Dimensional Stability—The material in the solid final
more of the physical or mechanical requirements of Section 4.
form shall have an average percentage thickness of change less
4. Physical and Mechanical Requirements
than 1.0 %, when tested according to the method described in
4.1 Composition—The material shall be supplied either in
8.3.
solid or liquid form. The solid or combined liquid parts shall
4.6 Compressive Strength—The material in the solid final
produce a foam consisting of polyether polyurethane.
formshallmeetthecompressivestrengthrequirementsgivenin
4.2 Appearance:
Table 3, when tested according to the method described in 8.4.
4.2.1 Solid Supplied Form—The solid foam slab shall be
All specimens shall meet this requirement. The values inTable
3 3
free of obvious extraneous matter, and appear to the unaided
3 are stated at 616.0 kg/m (61.0 lbm/ft ) around each grade’s
eye to be uniform throughout the slab in color and porosity.
nominal density.
4.2.2 Liquid Supplied Form—The two liquid components
4.7 Compressive Modulus—The material in the solid final
shall appear to the unaided eye throughout its volume to be
form shall meet the compressive modulus requirements given
uniformandfreefromobviousextraneousmatterorparticulate
in Table 4, when tested according to the method described in
debris.
8.4. All specimens shall meet this requirement. The values in
3 3
4.2.3 Solid Final Form—The solid foam slab shall be free
Table 4 are stated at 616.0 kg/m (61.0 lbm/ft ) around each
of obvious extraneous matter, and appear to the unaided eye to
grade’s nominal density.
be uniform throughout the slab in color and porosity.
4.8 Shear Strength—The material in the solid final form
4.3 Void Content—The material in the solid final form shall
shall meet the shear strength requirements given in Table 5,
meet the requirements of Table 1 for voids, cracks and
when tested according to the method described in 8.5. All
nonuniform areas, when examined using the procedures de-
specimens shall meet this requirement. The values in Table 5
3 3
scribed in 8.1. All specimens shall meet this requirement.
are stated at 616.0 kg/m (61.0 lbm/ft ) around each grade’s
4.4 Density—The material in the solid final form shall have
nominal density.
a density within the ranges specified in Table 2, according to
4.9 Shear Modulus—The material in the solid final form
thefoam’sgradespecification.Thedensityshallbedetermined
shall meet the shear modulus requirements given in Table 6,
using the method described in 8.2. All specimens shall meet
when tested according to the method described in 8.5. All
this requirement.
specimens shall meet this requirement. The values in Table 6
3 3
are stated at 616.0 kg/m (61.0 lbm/ft ) around each grade’s
TABLE 1 Requirements for Voids, Cracks, and Nonuniform Areas
nominal density.
Defects Requirements
4.10 Screw Pullout—The material in the solid final form
Voids
shall meet the screw pullout requirements given in Table 7,
when tested according to the method described in 8.6. All
Void depth (measured perpendicular Void depth shall be less than 50 % of
specimens shall meet this requirement.
to slab’s transverse plane) the slab thickness, and less than
6.35 mm (0.250 in.)
5. Significance and Use
Void diameter (measured parallel to
slab’s transverse plane) 5.1 This specification describes the compositional require-
ments, physical requirements, mechanical requirements, and
Larger than 6.35 mm (0.250 in.) None allowed in any grade
test methods for rigid unicellular polyurethane foam for use in
testing orthopedic devices or instruments.
Between 3.18 mm (0.125 in.) No more than 1 allowed per 230
2 2
and 6.35 mm (0.250 in.) cm (36 in. ) surface area for Grades
5.2 This foam described in this specification is not intended
10, 12, and 15. None allowed in
to replicate the mechanical properties of human or animal
Grades 20 and 40.
bone. The requirements of this specification are intended to
Between 1.57 mm (0.062 in.) No more than 6 allowed per 230
2 2
and 3.18 mm (0.125 in.) cm (36 in. ) surface area for Grades
10, 12, and 15. No more than 3 TABLE 3 Requirements for Compressive Strength
allowed in Grades 20 and 40.
Minimum Compressive Maximum Compressive
Grade
Strength, kPa (psi) Strength, kPa (psi)
Cracks None allowed
10 2095 (304) 2895 (420)
Nonuniform areas Concentrated areas of poor 12 2895 (420) 3790 (550)
construction, irregular cells, and hard 15 4280 (620) 5315 (770)
and soft spots shall not exceed 10 % 20 7000 (1015) 8245 (1195)
of the visible surface area 40 22 410 (3250) 24 300 (3525)
F 1839 – 01 (2007)
TABLE 4 Requirements for Compressive Modulus
are described in 8.1-8.6. Test specimens are required for each
Minimum Compressive Maximum Compressive grade and formulation.
Grade
Modulus, kPa (psi) Modulus, kPa (psi)
7.2 Test specimens shall be solid foam blocks. The short-
10 56 300 (8165) 76 700 (11 125)
transverse direction of the specimens shall coincide with the
12 76 700 (11 125) 99 200 (14 390)
foam rise direction of the original foam bun.
15 111 200 (16 130) 136 650 (19 820)
20 178 100 (25 830) 207 800 (30 140)
40 539 600 (78 260) 582 800 (84 530)
8. Procedure
8.1 Determination of Void Content:
8.1.1 Use the foam block specimens described and specified
TABLE 5 Requirements for Shear Strength
in 8.2-8.6.
Minimum Shear Strength, Maximum Shear Strength,
Grade
8.1.2 Examine all of the surfaces and edges of test speci-
kPa (psi) kPa (psi)
mens for voids and nonuniform areas with the unaided eye.
10 1650 (240) 2170 (315)
12 2170 (315) 2725 (395) Measure the dimensions of the void or nonuniform areas using
15 3000 (435) 3620 (525)
an instrument capable of measuring 60.025 mm (0.001 in.).
20 4590 (665) 5275 (765)
8.2 Determination of Foam Density:
40 12 340 (1790) 13 240 (1920)
8.2.1 Prepare three specimens, 25.4 by 25.4 by 25.4 mm (1
by 1 by 1 in.) from solid foam.
TABLE 6 Requirements for Shear Modulus
8.2.2 Determine the apparent density of the three foam
3 3
specimens, in kg/m (lbm/ft ), in accordance withTest Method
Minimum Shear Modulus, Maximum Shear Modulus,
Grade
kPa (psi) kPa (psi)
D 1622.
10 20 820 (3020) 27 680 (4015)
8.2.3 Calculate the average apparent density of the three
12 27 680 (4015) 35 100 (5090)
foam specimens.
15 39 000 (5655) 47 130 (6835)
8.3 Determination of Dimensional Stability:
20 60 160 (8725) 69 400 (10 060)
40 167 170 (24 245) 179 470 (26 030)
8.3.1 Prepare three specimens, 25.4 by 25.4 by 12.7 mm (1
by 1 by 0.5 in.) from solid foam.
8.3.2 Condition the specimen for 24 h at 21 6 2.8°C (70 6
TABLE 7 Requirements for Screw Pullout
5°F) and 50 6 10 % relative humidity. Measure the specimen
Minimum Pullout, Maximum Pullout,
thickness near the center of the length to 60.025 mm (0.001
Grade
N (lb) N (lb)
in.) and mark the location of the measurement.
10 335 (75) 415 (95)
8.3.3 Place the specimen on a 6.35-mm (0.25-in.) thick
12 400 (90) 545 (125)
15 485 (110) 675 (150) aluminum plate and apply a minimum vacuum pressure of 508
20 670 (150) 800 (180)
mm (20 in.) of mercury under a vacuum bag or diaphragm.
40 2455 (550) 2755 (620)
Place this assembly in a circulating forced-air oven for 2 h
minimum at 121 6 2.8°C (250 6 5°F). Remove the assembly
andallowtocoolto49°C(120°F)orlesswhilemaintainingthe
provide a consistent and uniform material with properties on vacuum.
the order of human cancellous bone to use as a test medium
8.3.4 Recondition and remeasure the thickness at the
when testing various orthopedic devices, such as bone screws. marked location in accordance with 8.3.2. Calculate the per-
cent thickness change.
6. Apparatus
8.3.5 Calculate the average percent thickness change of the
three specimens.
6.1 Analytical Balance or Scale—capableofweighingfoam
specimens to the nearest 60.1 %. 8.4 Determination of Compressive Strength and Modulus:
6.2 Micrometer Dial Gage or Caliper—capable of measur- 8.4.1 Prepare five specimens, 50.8 by 50.8 by 25.4 mm (2
ing dimensions of the foam specimens to 60.1 %. by 2 by 1 in.), from solid foam, with the thickness of the
specimen parallel to the foam rise direction. Measure the
6.3 Conditioning Oven—Forced-air circulating oven ca-
pable of maintaining 121 6 2.8°C (250 6 5°F) for 24 h. dimensions within 60.025 mm (60.001 in.). The specimens
shall be conditioned at 24 6 2.8°C (75 6 5° F) for 3 h prior to
6.4 Desiccator—containing desiccant with high affinity for
water vapor (anhydrous calcium chloride or equivalent). testing.
6.5 Vacuum—capableofapplyingavacuumpressureof508
8.4.2 Test in accordance with Test Method D 1621 at 24 6
mm (20 in.) of mercury to foam specimen for dimensional 2.8°C (75 6 5°F). The specimens shall be oriented such that
stability test.
the axis of the compressive load is applied parallel to the foam
6.6 Atesting machine and load cell conforming to Practices rise direction.
E4 and capable of applying tensile and compressive loads at a
8.4.3 Determine the compressive strength using Procedure
constant displacement rate. A of Test Method D 1621 and the maximum compressive
modulus for each specimen.
7. Sampling and Test Specimens
8.4.4 Calculatetheaveragecompressivestrengthandmodu-
lus of the five specimens.
7.1 The number of test specimens and the specimen sizes
required for physical characterization and mechanical testing 8.5 Determination of Shear Strength and Modulus
...