ASTM_F_1881_-_11.pdf

Designation:F1881 11An American National StandardStandard Test Method forMeasuring Baseball Bat Performance Factor1This standard is issued under the fixed designation F1881;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method defines a method for determining batperformance by measuring the bat-ball coefficient of restitution(BBCOR),deriving the bat performance factor(BPF),andcalculating batted-ball speed(BBS).It is applicable to baseballbats of any construction or material.The test method providesa quantitative measure of bat dynamic performance that may beused for comparison purposes.1.2 The BBCOR,BPF,and BBS are each calculated frommeasurements taken in the laboratory on test equipmentmeeting the requirements defined in this test method.1.3 The values stated in inch-pound units are to be regardedas standard.The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.4 This standard does not purport to address all the safetyconcerns,if any,associated with its use.It is the responsibilityof the user of this standard to establish appropriate safety andhealth practices and to determine the applicability of regula-tory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2F1887 Test Method for Measuring the Coefficient of Resti-tution(COR)of Baseballs and SoftballsF1888 Test Method for Compression-Displacement ofBaseballs and SoftballsF2398 Test Method for Measuring Moment of Inertia andCenter of Percussion of a Baseball or Softball Bat3.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 balance point,ndistance to the center of mass of abat when measured from the distal end of the bat knob.3.1.2 bat-ball coeffcient of restitution(BBCOR),nCORof a specific ball colliding with a bat as defined in this testmethod.See coeffcient of restitution(COR).3.1.3 bat performance factor(BPF),nratio of BBCOR toball COR in accordance with this test method.3.1.4 center of percussion(COP),nalso known as thecenter of oscillation,length of a simple pendulum with thesame period as a physical pendulum,as in a bat oscillating ona pivot.Forces and impacts at this location will not induceaxial reactions at the pivot point.3.1.5 coeffcient of restitution(COR),nmeasure of impactefficiency calculated as the relative speed of the objects afterimpact divided by the relative speed of the objects beforeimpact.3.1.6 moment of inertia(MOI),nmeasure of mass distri-bution relative to an axis of rotation.It is the product of themass multiplied by the square of the distance to the mass,summed over the entire bat.4.Significance and Use4.1 This test method offers a laboratory means to comparethe relative performances of baseball bats.4.2 Use of this test method can provide sports governingbodies a means to compare calculated batted-ball speed andother physical properties of the bats.5.Apparatus and Equipment5.1 Test BallsOfficial balls approved for play and tested inaccordance with the following procedures.Perform ball com-pression test of Test Method F1888 prior to ball COR test ofTest Method F1887.5.1.1 Compression300 to 375 lb at 0.25-in.deflection(1135 to 1668 N at 6.4 mm deflection).Compression valuesdetermined in accordance with Test Method F1888.Balls to belabeled with compression value.1This test method is under the jurisdiction of ASTM Committee F08 on SportsEquipment and Facilities and is the direct responsibility of Subcommittee F08.26 onBaseball and Softball Equipment.Current edition approved Nov.1,2011.Published November 2011.Originallyapproved in 1998.Last previous edition approved in 2009 as F1881 09.DOI:10.1520/F1881-11.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.1Copyright.ASTM International,100 Barr Harbou r Dr.PO box C-700 West Conshohocken,Pennsylvania 19428-2959,United States Copyright ASTM International 5.1.2 Weight5.00 to 5.25 oz(142 to 149 g),balls to belabeled with weight value.5.1.3 Size9.00 to 9.50-in.circumference(228.6 to 241.3mm),balls to be labeled with size value.5.1.4 COR0.525 to 0.555,balls to be labeled with CORand test speed in ft/s.5.2 Bat-Ball COR Test Apparatus:5.2.1 Ball CannonA device capable of shooting a ball ata speed of 88 ft/s(26.8 m/s).The ball shall not have a spin ratein excess of 10 rpm.Typical pitching machines cannot yield theaiming accuracy required by this test method.Cannon exhaustair must not cause motion of the bat in the absence of animpact.The cannon shall not blow out a match located in theimpact location when it is dry-fired(fire