ASTM F2117-01

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An American National Standard
Designation:F2117–01
Standard Test Method for
Vertical Rebound Characteristics of Sports Surface/Ball
Systems; Acoustical Measurement
This standard is issued under the fixed designation F2117; 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 3.1.1.1 subfloor, n—any structural members found between
the playing surface and the underlying concrete base. Subfloor
1.1 This test method covers the quantitative measurement
systems are typically found in sprung indoor playing surfaces
and normalization of the vertical rebound produced during
and can include but are not limited to: layers consisting of
impacts between athletic balls and athletic surfaces.
sheets of plywood, layers consisting of strips of plywood, and
1.2 Measurements may be conducted on nonathletic sur-
solid-wood members.
faces to test the performance properties of the ball.
3.1.2 athletic surface, n—an athletic surface appropriate for
1.3 Measurementsmaybeconductedusingnonathleticballs
the sport(s) of interest should be selected for testing. The
to test the performance properties of the surface.
surface may be selected from previously installed surfaces and
1.4 The values stated in metric units are to be regarded as
tested in its complete form, or smaller samples may be tested
the standard.The inch-pound units given in parentheses are for
under laboratory settings.
reference only.
3.1.3 coeffıcient of restitution (CR), n—the ratio of rebound
1.5 The methods described are applicable in both laboratory
height to release height. This parameter is useful for nonin-
and field settings.
flated balls that are found to be damaged by impacts with a
1.6 This standard does not purport to address all of the
concrete reference surface. Construction differences and sen-
safety concerns, if any, associated with its use. It is the
sitivity to inflation pressure make this parameter inappropriate
responsibility of the user of this standard to establish appro-
for comparing different playing surfaces based on results
priate safety and health practices and determine the applica-
obtained using inflated sporting balls.
bility of regulatory limitations prior to use.
3.1.4 point elastic surface, n—surface where the energy at
2. Referenced Documents impact is dispersed throughout an area that negligibly exceeds
the impact point (for example, natural turf, artificial turf,
2.1 DIN (Deutsches Institut fur Normung):
poured urethane surfaces). Point elastic surfaces do not pro-
18032 Part II, 1991 Section 5.8
duce noticeable vibrations when impacted.
2.2 British Standards:
3.1.5 reference surface, n—any section of a concrete slab
7044, 1990, Section 2.1
with a smooth uniform, uncracked surface with a minimum
3. Terminology
horizontal dimension of 30 cm (12 in.) that produces a rebound
with minimal horizontal movement.
3.1 Definitions:
3.1.6 sporting ball, n—a sporting ball appropriate for the
3.1.1 area elastic surface, n—surfaces where the energy at
sport(s) of interest should be selected for testing. The test ball
impact is dispersed throughout an area significantly larger than
should be inspected to verify that it is spherical and devoid of
the impact point (for example, sprung wooden basketball
bulges. Bulges indicate structural damage exists within the
floors, poured urethane floors over sprung subfloor). Area
ball, that could affect the testing results. In the case of inflated
elastic surfaces tend to produce a noticeable vibration when
sporting balls, the pressure should conform to manufacturer’s
impacted.
guidelines.
3.1.7 vertical rebound height, n—the highest height
1 achieved by sporting ball during its first rebound after contact-
This test method is under the jurisdiction of ASTM Committee F08 on Sports
ing the surface.
Equipment and Facilities and is the direct responsibility of Subcommittee F08.52 on
Miscellaneous Playing Surfaces.
3.1.8 vertical rebound ratio (VRR), n—the ratio of the
Current edition approved June 10, 2001. Published October 2001. DOI:
rebound on the test surface to the rebound on the reference
10.1520/F2117-01.
2 surface, expressed as a percentage. This parameter may not be
Available from DIN, Burggrafenstrasse 6, D-10787 Berlin, Germany.
Available from BSI, 389 Chiswick High Road, London W4 4AL, UK. appropriate for all sporting balls, as some may experience
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
F2117–01
damage when impacting the reference surface.When reference 7. Testing Conditions
surface rebound measurement is found to be unrepeatable, the
7.1 The following general testing conditions should be
coefficient of restitution should be used instead.
recorded and included in the test report for information
purposes only:
4. Summary of Test Method
7.1.1 All Surfaces:
7.1.1.1 Record temperature (to the nearest 1°C) and relative
4.1 This test method provides a means for evaluating the
humidity (to the nearest 1 %) at an elevation of 30 cm (12 in.)
rebound height produced by a test ball on a test surface. The
above the playing surface. Measurements may be obtained
procedure can be used to evaluate vertical ball rebound
using hand-held commercially available temperature and rela-
performance on a reference athletic surface, evaluate surface
tive humidity sensors.
vertical rebound performance using a reference athletic ball, or
7.1.1.2 The vertical ball rebound should be tested using a
to evaluate the effects of ball-surface interactions. A ball is
1.800-m drop height. Additional drop heights may be tested
released from a known height and allowed to impact the
and should be agreed onby the purchaser and the seller.
reference surface.The release should not impart any horizontal
7.1.2 Wood Playing Surfaces—The wood moisture content
motion. An acoustical measurement system measures the
(%) should be included. Measurements may be obtained using
rebound height obtained on the test surface. The ball is then
hand-held commercially available wood moisture sensors.
released from the same height and allowed to impact the test
7.1.3 Outdoor Playing Surface—The general moisture level
surface, where again, the rebound height is measured. The
of the surface should be included. In general, the surface
vertical rebound ratio, presented as a percentage, is obtained
should be characterized as dry, damp, or wet.
from the ratio of the vertical rebound height on the sporting
7.1.4 Laboratory Sample Sizes:
surface to the vertical rebound height on the reference surface.
7.1.4.1 Area elastic surfaces should be evaluated using a
minimum sample size of 2.0 by 2.0 m (6.5 by 6.5 ft).
5. Significance and Use
7.1.4.2 Point elastic surfaces should be evaluated using a
minimum sample size of 1.0 by 1.0 m (3.3 by 3.3 ft).
5.1 The ball-surface interaction is just one of the important
properties of a sports surface. It may be an indicator of the
8. Procedure
playability or suitability of the surface.
8.1 When the ball and test surface are introduced to a new
5.2 Manufacturers of sporting balls may use this method to
environment, each should be allowed to acclimate. The ball
evaluate the effects of design changes on the rebound height
should be allowed to acclimate to the surroundings for 1 h, and
produced.
the surface should be allowed at least4hto acclimate to the
5.3 Manufacturersofsportssurfacesmayusethismethodto
environment.
evaluate the effects of design changes in the sports surface
8.2 Measure and record ambient temperature to the nearest
system on the rebound height produced.
1°C and the relative humidity to the nearest 1 % at a height of
5.4 The tendency of modern facilities to support multiple
30 cm (12 in.) over the reference surface.
sports on a single surface may require that test surfaces be
8.3 Measure and record ambient temperature to the nearest
testedforseveraltypesofsportingballs.Examplesinclude,but
1°C and the relative humidity to the nearest 1 % at a height of
are not limited to: basketball, soccer, tennis, and baseball.
30 cm (12 in.) over the athletic surface.
5.5 The measurement of rebound height may be affected if
8.4 Locate and document all points to be tested. This
thetemperatureoftheballhasnotreachedequilibriumwiththe
includes points on the reference surface and on the athletic
environment.
surface.
8.4.1 Whentestingunderfieldconditions,includeadiagram
6. Apparatus
of the playing surface and its surroundings and dimensions that
allow the test points to be relocated. Effort should be made to
6.1 Ball-Release Apparatus, capable of releasing the sport-
locate and test rebound properties of the playing surface on
ing ball from a consistent height, without imparting significant
areas representative of the surface conditions present and
spin or horizontal motion to the sporting ball. The ball release
construction methods used in the playing surface. Tests should
apparatus is typically an adjustable-height tripod. The release
also be conducted on areas considered heavy-use and non-use
mechanism may be mechanical, electromagnetic, vacuum, or
areas. Examples include but are not limited to the following:
manual.
8.4.1.1 Natural Turf—Densely covered areas and skinned
6.2 Sound Recording and Analysis System—A system with
areas.
the minimum requirements as follow: acoustic sampling fre-
8.4.1.2 Artificial Turf—Seams in the turf layer, seams in the
quency 11 000 Hz, 8-bit resolution, on a single acoustic
padding layer (if present).
channel. The system must be capable of determining the time
8.4.1.3 Point Elastic Surfaces—Seams in the playing sur-
of the first (t) and second (t ) impacts using the peak acoustic
l 2
face and seams in the padding layer (if present).
signal generated to determine t and t through either the use of
l 2
8.4.1.4 Area Elastic Surfaces—Jointsintheplayingsurface,
hardware or software.
joints in the subfloor layer (if present), joints in the sleeper
6.2.1 Example—Personal computer, sound-card, and micro-
layer (if present), between sleepers (if present), seams in
phone have been found to produce adequate results. padding layer (if present), individual pads (if present).
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