ASTM F2117-10(2017)

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: F2117 − 10 (Reapproved 2017) An American National Standard
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. Terminology
1.1 This test method covers the quantitative measurement 3.1 Definitions:
and normalization of the vertical rebound produced during
3.1.1 area elastic surface, n—surfaces where the energy at
impacts between athletic balls and athletic surfaces.
impact is dispersed throughout an area significantly larger than
the impact point (for example, sprung wooden basketball
1.2 Measurements may be conducted on nonathletic sur-
floors, poured urethane floors over sprung subfloor). Area
faces to test the performance properties of the ball.
elastic surfaces tend to produce a noticeable vibration when
1.3 Measurementsmaybeconductedusingnonathleticballs
impacted.
to test the performance properties of the surface.
3.1.1.1 subfloor, n—any structural members found between
1.4 The methods described are applicable in both laboratory
the playing surface and the underlying concrete base. Subfloor
and field settings.
systems are typically found in sprung indoor playing surfaces
1.5 The values stated in metric units are to be regarded as
and can include but are not limited to: layers consisting of
the standard.The inch-pound units given in parentheses are for
sheets of plywood, layers consisting of strips of plywood, and
reference only.
solid-wood members.
1.6 This standard does not purport to address all of the
3.1.2 athletic surface, n—an athletic surface appropriate for
safety concerns, if any, associated with its use. It is the
the sport(s) of interest should be selected for testing. The
responsibility of the user of this standard to establish appro-
surface may be selected from previously installed surfaces and
priate safety and health practices and determine the applica-
tested in its complete form, or smaller samples may be tested
bility of regulatory limitations prior to use.
under laboratory settings.
1.7 This international standard was developed in accor-
3.1.3 coeffıcient of restitution (CR), n—the ratio of rebound
dance with internationally recognized principles on standard-
height to release height. This parameter is useful for nonin-
ization established in the Decision on Principles for the
flated balls that are found to be damaged by impacts with a
Development of International Standards, Guides and Recom-
concrete reference surface. Construction differences and sen-
mendations issued by the World Trade Organization Technical
sitivity to inflation pressure make this parameter inappropriate
Barriers to Trade (TBT) Committee.
for comparing different playing surfaces based on results
2. Referenced Documents
obtained using inflated sporting balls.
2.1 DIN (Deutsches Institut fur Normung):
3.1.4 point elastic surface, n—surface where the energy at
18032 Part II, 1991 Section 5.8
impact is dispersed throughout an area that negligibly exceeds
2.2 British Standards:
the impact point (for example, natural turf, artificial turf,
7044, 1990, Section 2.1
poured urethane surfaces). Point elastic surfaces do not pro-
2.3 EN (European Committee for Standardization):
duce noticeable vibrations when impacted.
EN 12235 Surfaces for sports areas - Determination of
3.1.5 reference surface, n—any section of a concrete slab
vertical ball behaviour
with a smooth uniform, uncracked surface with a minimum
horizontal dimension of 30 cm (12 in.) that produces a rebound
This test method is under the jurisdiction of ASTM Committee F08 on Sports
with minimal horizontal movement.
Equipment, Playing Surfaces, and Facilities and is the direct responsibility of
Subcommittee F08.52 on Miscellaneous Playing Surfaces.
3.1.6 resting time constant (K ), n—a time constant that
r
Current edition approved April 1, 2017. Published April 2017. Originally
corrects for the duration that the ball is in contact with the
approved in 2001. Last previous edition approved in 2010 as F2117 – 10. DOI:
10.1520/F2117-10R17. surface.
Available from DIN, Burggrafenstrasse 6, D-10787 Berlin, Germany.
3 3.1.7 sporting ball, n—a sporting ball appropriate for the
Available from BSI, 389 Chiswick High Road, London W4 4AL, UK.
Available from ANSI, 1819 L Street, Washington, DC 20036, USA. sport(s) of interest should be selected for testing. The test ball
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F2117 − 10 (2017)
should be inspected to verify that it is spherical and devoid of apparatus is typically an adjustable-height tripod. The release
bulges. Bulges indicate structural damage exists within the mechanism may be mechanical, electromagnetic, vacuum, or
ball, that could affect the testing results. In the case of inflated manual.
sporting balls, the pressure should conform to manufacturer’s
6.2 Sound Recording and Analysis System—A system with
guidelines.
the minimum requirements as follow: acoustic sampling fre-
3.1.8 vertical rebound height, n—the highest height
quency 11 000 Hz, 8-bit resolution, on a single acoustic
achieved by sporting ball during its first rebound after contact-
channel. The system must be capable of determining the time
ing the surface, as measured from the bottom of the ball to the
of the first (t) and second (t ) impacts using the peak acoustic
l 2
top of the surface.
signal generated to determine t and t through either the use of
l 2
hardware or software.
3.1.9 vertical rebound ratio (VRR), n—the ratio of the
6.2.1 Example—Personal computer, sound-card, and micro-
rebound on the test surface to the rebound on the reference
phone have been found to produce adequate results.
surface, expressed as a percentage. This parameter may not be
appropriate for all sporting balls, as some may experience
7. Testing Conditions
damage when impacting the reference surface.When reference
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 65cm(12
rebound height produced by a test ball on a test surface. The
6 2 in.) above the playing surface. Measurements may be
procedure can be used to evaluate vertical ball rebound
obtained using hand-held commercially available temperature
performance on a reference athletic surface, evaluate surface
and relative 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 6 0.005-m (71 6 0.2-in.) drop height, as measured from
released from a known height and allowed to impact the
the bottom of the ball to the top of the test surface. Additional
reference surface.The release should not impart any horizontal
drop heights may be tested and should be agreed on by the
motion. An acoustical measurement system measures the
purchaser and the seller.
rebound height obtained on the test surface. The ball is then
7.1.2 Wood Playing Surfaces—The wood moisture content
released from the same height and allowed to impact the test
(%) should be included. Measurements may be obtained using
surface, where again, the rebound height is measured. The
hand-held commercially available wood moisture sensors.
vertical rebound ratio, presented as a percentage, is obtained
7.1.3 Outdoor Playing Surface—The general moisture level
from the ratio of the vertical rebound height on the sporting
of the surface should be included. In general, the surface
surface to the vertical rebound height on the reference surface.
should be characterized as dry, damp, or wet.
7.1.4 Laboratory Sample Sizes:
5. Significance and Use
7.1.4.1 Area elastic surfaces should be evaluated using a
5.1 The ball-surface interaction is just one of the important
minimum sample size of 2.0 by 2.0 m (6.5 by 6.5 ft).
properties of a sports surface. It may be an indicator of the
7.1.4.2 Point elastic surfaces should be evaluated using a
playability or suitability of the surface.
minimum sample size of 1.0 by 1.0 m (3.3 by 3.3 ft).
5.2 Manufacturers of sporting balls may use this method to
8. Procedure
evaluate the effects of design changes on the rebound height
produced.
8.1 When the ball and test surface are introduced to a new
environment, each should be allowed to acclimate. The ball
5.3 Manufacturers of sports surfaces may use this method to
evaluate the effects of design changes in the sports surface should be allowed to acclimate to the surroundings for 1 h, and
the surface should be allowed at least4hto acclimate to the
system on the rebound height produced.
environment.
5.4 The tendency of modern facilities to support multiple
8.2 Measure and record ambient temperature to the nearest
sports on a single surface may require that test surfaces be
testedforseveraltypesofsportingballs.Examplesinclude,but 1°C and the relative humidity to the nearest 1 % at a height of
30 cm (12 in.) over the reference surface.
are not limited to: basketball, soccer, tennis, and baseball.
5.5 The measurement of rebound height may be affected if 8.3 Measure and record ambient temperature to the nearest
1°C and the relative humidity to the nearest 1 % at a height of
thetemperatureoftheballhasnotreachedequilibriumwiththe
environment. 30 cm (12 in.) over the athletic surface.
8.4 Locate and document all points to be tested. This
6. Apparatus
includes points on the reference surface and on the athletic
6.1 Ball-Release Apparatus, capable of releasing the sport- surface.
ing ball from a consistent height, without imparting significant 8.4.1 Whentestingunderfieldconditions,includeadiagram
spin or horizontal motion to the sporting ball. The ball release of the playing surface and its surroundings and dimensions that
F2117 − 10 (2017)
allow the test points to be relocated. Effort should be made to tested surface. Record five rebound measurements following
locate and test rebound properties of the playing surface on the methods in 8.7 and calculate the average time between
areas representative of the surface conditions present and rebounds (t ) and the average rebound height for the
ref-2
construction methods used in the playing surface. Tests should reference surface (h ).
ref-2
also be conducted on areas considered heavy-use and non-use
8.12 Record the inflation pressure of the ball, when
areas. Examples include but are not limited to the following:
appropriate,attheconclusionofevaluatingtheplayingsurface.
8.4.1.1 Natural Turf—Densely covered areas and skinned
The inflation pressure is for information purposes only and can
areas.
be obtained using a low-pressure gage of the type available at
8.4.1.2 Artificial Turf—Seams in the turf layer, seams in the
automotive stores.
padding layer (if present).
8.4.1.3 Point Elastic Surfaces—Seams in the playing sur- 9. Calculations
face and seams in the padding layer (if present).
9.1 Rebound height is approximated using the time duration
8.4.1.4 Area Elastic Surfaces—Joints in the playing surface,
(∆t) between the first (t) and second (t ) impacts of the ball
l 2
joints in the subfloor layer (if present), joints in the sleeper
with the surface, with ∆t, t and t measured to the nearest
l 2
layer (if present), between sleepers (if present), seams in
0.001 s (t, and t are obtained from the moment of maximum
l 2
padding layer (if present), individual pads (if present).
sound intensity generated during the impact).
8.4.2 When testing under laboratory conditions, include a
∆t~s! 5 t 2 t (1)
2 1
descriptionoftheoverallsystemconstructionandadescription
9.2 The average time between the first and second impacts
of construction details present at all test points.
excluding the maximum and minimum time differences should
8.5 Set the drop height to the nominal desired height. The
be computed to the nearest 0.001 s for each point {i} tested on
actual drop height should be measured and recorded to the
the playing surface (∆t) and for each test {j} on the reference
i
nearest 0.005 m (0.2 in.). The surface/ball system should be
surface (∆t ).
ref{j}
evaluated using a nominal drop height of 1.800 6 0.005 m (71
∆t 1∆t 1∆t 1∆t 1∆t
6 0.2 in.) and any additional drop heights considered useful. 1 2 3 4 5
∆t 5 (2)
$i%
8.6 Perform ball inspection; verify that construction is still
9.3 The average time between the first and second impacts
sound. When appropriate, verify that the inflation pressure is
of the ball with the playing surface is then converted to vertical
within manufacturer’s specifications and record actual pres-
rebound height for each point {i} and drop {j} on the playing
sure.
surface (h ) and for each point {k} and drop {j} on the
{i}
8.7 Evaluate the rebound height from the desired point on
reference surface (h ) in metres. Calculate the average
ref{k,j}
thereferencesurfacebyrecordingfiveverticalreboundheights
reboundheightforeachpoint {i}ontheplayingsurfaceandfor
produced from the specified testing height on the reference
each point {k} on the reference surface. Apply the correct
surface to the nearest 0.005 m (0.2 in.), calculate the time
resting time constant for the ball used during testing. Select
between impacts (t ) and the rebound height (h ) for all
ref-1 ref-k
resting time constants have been supplied in Table 1. Studies
five drops and the average rebound height for the reference
using balls not included in Table 1 should consult the govern-
surface (h ). Sporting balls without inflation valves (such as
ref-1
ing body of the respective sport for guidance.
golfballs,racquetballs,andsoforth)arereleasedfromthedrop
h 5 1.23~∆t 2 K ! (3)
height with a random orientation. Sporting balls with inflation $i,j% r
valves(soccerballs,basketballs,andsoforth)arereleasedwith
9.4 When appropriate, calculate the vertical rebound ratio
the inflation valve pointing away from the impact surface.
(VRR{i}) to the ne
...