ASTM F1887-14(2019)
(Test Method)Standard Test Method for Measuring the Coefficient of Restitution (COR) of Baseballs and Softballs
Standard Test Method for Measuring the Coefficient of Restitution (COR) of Baseballs and Softballs
SIGNIFICANCE AND USE
5.1 The ball coefficient of restitution is a ball dynamic property of relative velocity change caused by impact with a rigid wall.
5.2 This test method is suitable for obtaining data in research and development, quality control, and classifying balls by liveliness.
5.3 Sports associations can use coefficient of restitution standards in specifications for official baseballs and softballs.
5.4 This same test procedure can be utilized at impact speeds other then that prescribed in this procedure and so noted in any reported test results.
SCOPE
1.1 This procedure is intended to standardize a method of measuring the coefficient of restitution (COR) of baseballs and softballs.
1.2 This procedure is established to provide a single, repeatable, and uniform test method.
1.3 This procedure is for a ball that is intended for use in the game of baseball or softball.
1.4 The test method is based on ball speed measurements before and after impact with either of two test surfaces: wood or metal.
1.5 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.6 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.
1.7 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.
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Designation: F1887 − 14 (Reapproved 2019) An American National Standard
Standard Test Method for
Measuring the Coefficient of Restitution (COR) of Baseballs
and Softballs
This standard is issued under the fixed designation F1887; 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 baseball and softball, n—any ball defined by the rules
for the game of baseball or softball.
1.1 This procedure is intended to standardize a method of
3.1.2 coeffıcient of restitution (COR), n— a numerical value
measuring the coefficient of restitution (COR) of baseballs and
determinedbytheexitspeedoftheballaftercontactdividedby
softballs.
the incoming speed of the ball before contact with a massive,
1.2 This procedure is established to provide a single,
rigid, flat wall of either wood or metal.
repeatable, and uniform test method.
1.3 This procedure is for a ball that is intended for use in the
4. Summary of Test Method
game of baseball or softball.
4.1 Method A—The strike plate is a rigid metal surface, and
1.4 The test method is based on ball speed measurements
ball speed is measured before and after impact with the strike
before and after impact with either of two test surfaces: wood
plate.
or metal.
4.2 Method B—The strike plate is a rigid wood surface, and
1.5 The values stated in SI units are to be regarded as the
ball speed is measured before and after impact with the strike
standard. The values given in parentheses are for information
plate.
only.
5. Significance and Use
1.6 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
5.1 The ball coefficient of restitution is a ball dynamic
responsibility of the user of this standard to establish appro-
property of relative velocity change caused by impact with a
priate safety, health, and environmental practices and deter-
rigid wall.
mine the applicability of regulatory limitations prior to use.
5.2 This test method is suitable for obtaining data in
1.7 This international standard was developed in accor-
research and development, quality control, and classifying
dance with internationally recognized principles on standard-
balls by liveliness.
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom- 5.3 Sports associations can use coefficient of restitution
mendations issued by the World Trade Organization Technical standards in specifications for official baseballs and softballs.
Barriers to Trade (TBT) Committee.
5.4 This same test procedure can be utilized at impact
speeds other then that prescribed in this procedure and so noted
2. Referenced Documents
in any reported test results.
2.1 ASTM Standards:
E177 Practice for Use of the Terms Precision and Bias in
6. Apparatus
ASTM Test Methods
6.1 Strike Plate, Method A:
E691 Practice for Conducting an Interlaboratory Study to
6.1.1 Material, 5.08-cm (2-in.) thick steel.
Determine the Precision of a Test Method
6.1.2 Size, 61 by 61 cm (24 by 24 in.).
3. Terminology
6.1.3 Mounting, secured flush to a massive rigid wall of
cinder block or concrete, minimally 20.3-cm (8-in.) thick, and
3.1 Definitions of Terms Specific to This Standard:
bolted at all four corners sufficiently secure to prevent move-
ment during ball impact.
This test method is under the jurisdiction of ASTM Committee F08 on Sports
Equipment, Playing Surfaces, and Facilities and is the direct responsibility of
6.2 Strike Plate, Method B:
Subcommittee F08.26 on Baseball and Softball Equipment.
6.2.1 Material, 10.2-cm (4-in.) thick northern white ash
Current edition approved April 1, 2019. Published May 2019. Originally
wood with moisture content between 10 and 15 % with a flat
approved in 1998. Last previous edition approved in 2014 as F1887 – 14. DOI:
10.1520/F1887-14R19. smooth surface.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F1887 − 14 (2019)
FIG. 1 Test Apparatus
6.2.2 Same as 6.1.2. 8.1.1 Test balls shall be stored in an environmentally
6.2.3 Same as 6.1.3. controlled space for at least 14 days immediately before
testing.
6.3 Ball Throwing Device—A ball throwing device capable
8.1.2 Temperature is to be maintained at 72 6 4°F (22 6
of delivering the ball through the electronic speed monitor at
2°C).
26.82 m/s (60 mph) with a maximum tolerance of 60.30 m/s.
8.1.3 Relative humidity is to be maintained between 40 and
The machine should be calibrated using the electronic speed
60 %.
monitor.
8.1.4 Temperature and relative humidity are to be measured
6.4 Electronic Speed Monitors—An electronic ball speed
and recorded hourly within 60.5°F (60.3°C) and 62% RH
measuring system consisting of two vertical light screens
over conditioning and test duration.
mounted 30.48 cm (12 in.) apart with a tolerance of 60.32 cm,
and a photoelectric sensor located at each screen that triggers
9. Procedure
a timing device on ball passage to measure the time for the ball
9.1 The ball throwing device is set to deliver the ball at
to traverse the distance between the two vertical planes before
26.82 6 0.305 m/s (60 mph). All shots above or below this
and after impact with the strike plate. Resolution shall be
tolerance range will not be used.
60.03 m/s.
9.2 Each ball is shot at the strike plate a minimum of six
6.5 Ball Trajectory Target—A lightweight target with a
times to a maximum of 12 times. A minimum 30-s rest period
30.48-cm (12-in.) diameter circular opening positioned at the
is required between each shot.
second light screen and centered on the ball line of travel
9.3 Only those speed readings for impacts falling within the
between the throwing device and the center of the strike plate.
6-in. target at the strike plate, within the 12-in. target at the
7. Preparation of Apparatus second speed monitor, and thrown within the prescribed speed
range will be used in the calculation of COR.
7.1 Mount the strike plate on a rigid wall such that the
center is approximately 1.22 cm (4 ft) from the floor. Tighten 9.4 The average of the six acceptable COR values for each
all mounting bolts before each test. Torque to 81.35 N-m (60
ball is used to determine the ball COR.
ft-lb) min. 9.4.1 Formulae:
7.2 Position the first speed monitor (light screen) 30.48 6
1 Vb1 Vb2 Vb3 Vb4 Vb5 Vb6
COR 5 Vb/Va 5 1 1 1 1 1 (1)
F G
0.32 cm (12 6 0.125 in.) from the strike plate (see Fig. 1). 6 Va1 Va2 Va3 Va4 Va5 Va6
7.3 Position the second speed monitor (light screen) 30.48
where:
6 0.079 cm (12 6 0.312 in.) from the first speed monitor.
Va = incoming speed, and
Vb = exit speed.
7.4 Position the ball throwing device such that the ball
impacts the strike plate within 15.24 cm (6 in.) of the center
10. Report
and on rebound, passes through the 30.48 cm (12 in.) target
mounted at the second light screen.
10.1 Report the following information:
10.1.1 Name of the test facility and test operator,
8. Conditioning
10.1.2 Test date,
8.1 Ball Conditioning and Test Room Conditions: 10.1.3 Hourly measurements of test conditions, including:
F1887 − 14 (2019)
TABLE 1 COR
10.1.3.1 Relative humidity and temperature of the ball
conditioning and test room environments,
MATERIAL Xbar sr sR r R
10.1.3.2 Number of hours ball was in conditioning environ-
AS1 0.39667 0.00179 0.00438 0.00500 0.01226
AS2 0.46814 0.00274 0.00548 0.00767 0.01535
ment.
AS3 0.48080 0.00283 0.00573 0.00793 0.01604
10.1.4 Test equipment used for this test method,
AS4 0.39850 0.00196 0.00516 0.00550 0.01444
10.1.5 Test ball information, model, weight tested, and any
AS5 0.44961 0.00137 0.00374 0.00382 0.01047
AS6 0.54680 0.00177 0.00429 0.00496 0.01202
other pertinent data such as condition of the ball,
AB1 0.55502 0.02148 0.02148 0.06015 0.06015
10.1.6 For each event impact (including invalid impacts),
AB2 0.56559 0.00211 0.00571 0.00591 0.01598
ball inbound speed, rebound speed,
AB
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: F1887 − 14 F1887 − 14 (Reapproved 2019) An American National Standard
Standard Test Method for
Measuring the Coefficient of Restitution (COR) of Baseballs
and Softballs
This standard is issued under the fixed designation F1887; 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 procedure is intended to standardize a method of measuring the coefficient of restitution (COR) of baseballs and
softballs.
1.2 This procedure is established to provide a single, repeatable, and uniform test method.
1.3 This procedure is for a ball that is intended for use in the game of baseball or softball.
1.4 The test method is based on ball speed measurements before and after impact with either of two test surfaces: wood or metal.
1.5 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.6 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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.7 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.
2. Referenced Documents
2.1 ASTM Standards:
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 baseball and softball, n—any ball defined by the rules for the game of baseball or softball.
3.1.2 coeffıcient of restitution (COR), n— a numerical value determined by the exit speed of the ball after contact divided by
the incoming speed of the ball before contact with a massive, rigid, flat wall of either wood or metal.
4. Summary of Test Method
4.1 Method A—The strike plate is a rigid metal surface, and ball speed is measured before and after impact with the strike plate.
4.2 Method B—The strike plate is a rigid wood surface, and ball speed is measured before and after impact with the strike plate.
5. Significance and Use
5.1 The ball coefficient of restitution is a ball dynamic property of relative velocity change caused by impact with a rigid wall.
5.2 This test method is suitable for obtaining data in research and development, quality control, and classifying balls by
liveliness.
5.3 Sports associations can use coefficient of restitution standards in specifications for official baseballs and softballs.
This test method is under the jurisdiction of ASTM Committee F08 on Sports Equipment, Playing Surfaces, and Facilities and is the direct responsibility of Subcommittee
F08.26 on Baseball and Softball Equipment.
Current edition approved May 1, 2014April 1, 2019. Published June 2014May 2019. Originally approved in 1998. Last previous edition approved in 20092014 as
F1887 – 09.F1887 – 14. DOI: 10.1520/F1887-14.10.1520/F1887-14R19.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F1887 − 14 (2019)
FIG. 1 Test Apparatus
5.4 This same test procedure can be utilized at impact speeds other then that prescribed in this procedure and so noted in any
reported test results.
6. Apparatus
6.1 Strike Plate, Method A:
6.1.1 Material, 5.08-cm (2-in.) thick steel.
6.1.2 Size, 61 by 61 cm (24 by 24 in.).
6.1.3 Mounting, secured flush to a massive rigid wall of cinder block or concrete, minimally 20.3-cm (8-in.) thick, and bolted
at all four corners sufficiently secure to prevent movement during ball impact.
6.2 Strike Plate, Method B:
6.2.1 Material, 10.2-cm (4-in.) thick northern white ash wood with moisture content between 10 and 15 % with a flat smooth
surface.
6.2.2 Same as 6.1.2.
6.2.3 Same as 6.1.3.
6.3 Ball Throwing Device—A ball throwing device capable of delivering the ball through the electronic speed monitor at 26.82
m/s (60 mph) with a maximum tolerance of 60.30 m/s. The machine should be calibrated using the electronic speed monitor.
6.4 Electronic Speed Monitors—An electronic ball speed measuring system consisting of two vertical light screens mounted
30.48 cm (12 in.) apart with a tolerance of 60.32 cm, and a photoelectric sensor located at each screen that triggers a timing device
on ball passage to measure the time for the ball to traverse the distance between the two vertical planes before and after impact
with the strike plate. Resolution shall be 60.03 m/s.
6.5 Ball Trajectory Target—A lightweight target with a 30.48-cm (12-in.) diameter circular opening positioned at the second
light screen and centered on the ball line of travel between the throwing device and the center of the strike plate.
7. Preparation of Apparatus
7.1 Mount the strike plate on a rigid wall such that the center is approximately 1.22 cm (4 ft) from the floor. Tighten all mounting
bolts before each test. Torque to 81.35 N-m (60 ft-lb) min.
7.2 Position the first speed monitor (light screen) 30.48 6 0.32 cm (12 6 0.125 in.) from the strike plate (see Fig. 1).
7.3 Position the second speed monitor (light screen) 30.48 6 0.079 cm (12 6 0.312 in.) from the first speed monitor.
7.4 Position the ball throwing device such that the ball impacts the strike plate within 15.24 cm (6 in.) of the center and on
rebound, passes through the 30.48 cm (12 in.) target mounted at the second light screen.
8. Conditioning
8.1 Ball Conditioning and Test Room Conditions:
8.1.1 Test balls shall be stored in an environmentally controlled space for at least 14 days immediately before testing.
8.1.2 Temperature is to be maintained at 72 6 4°F (22 6 2°C).
F1887 − 14 (2019)
8.1.3 Relative humidity is to be maintained between 40 and 60 %.
8.1.4 Temperature and relative humidity are to be measured and recorded hourly within 60.5°F (60.3°C) and 62 % RH over
conditioning and test duration.
9. Procedure
9.1 The ball throwing device is set to deliver the ball at 26.82 6 0.305 m/s (60 mph). All shots above or below this tolerance
range will not be used.
9.2 Each ball is shot at the strike plate a minimum of six times to a maximum of 12 times. A minimum 30-s rest period is
required between each shot.
9.3 Only those speed readings for impacts falling within the 6-in. target at the strike plate, within the 12-in. target at the second
speed monitor, and thrown within the prescribed speed range will be used in the calculation of COR.
9.4 The average of the six acceptable COR values for each ball is used to determine the ball COR.
9.4.1 Formulae:
1 Vb1 Vb2 Vb3 Vb4 Vb5 Vb6
COR 5 Vb/Va 5 1 1 1 1 1 (1)
F G
6 Va1 Va2 Va3 Va4 Va5 Va6
where:
Va = incoming speed, and
Vb = exit speed.
10. Report
10.1 Report the following information:
10.1.1 Name of the test facility and test operator,
10.1.2 Test date,
10.1.3 Hourly measurements of test conditions, including:
10.1.3.1 Relative humidity and temperature of the ball conditioning and test room environments,
10.1.3.2 Number of hours ball was in conditioning environment.
10.1.4 Test equipment used for this test method,
10.1.5 Test ball information, model, weight tested, and any other pertinent data such as condition of the ball,
10.1.6 For each event impact (including invalid impacts), ball inbound speed, rebound speed,
10.1.7 Average ball COR in accordance with Section 9 of this standard,
10.1.8 Any and all unique observations, including but not exclusively, any damage to the ball, and
10.1.9 Calibration certificate numbers for measurement devices and velocity timers.
11. Pre
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