ITF

9 PART A – THE BALL 1. REGULATIONS FOR THE TESTING OF TENNIS BALLS FOR ITF APPROVAL The properties of tennis balls are specified by the International Tennis Federation to generate uniformity, and consistency in performance. Special testing facilities and apparatus are necessary to accurately measure these properties, and this section details the required test conditions and procedures. The following notes are provided as additional information for those involved in the testing or evaluation of tennis balls and should be read in conjunction with the specification for a tennis ball, as described in Rule 3 and Appendix I of the Rules of Tennis. 1.1 General Considerations With the exception of Stage 3 moulded foam and cut foam types, a tennis ball consists of a hollow rubber core (which may or may not be pressurised) covered by a textile material composed of wool, nylon and cotton. Because the properties of the rubber core and its internal gas are affected by temperature, the properties of the cover by atmospheric moisture, and the effective internal pressure by the external atmospheric pressure, it is important that ball testing is carried out in a controlled atmosphere where at least temperature and humidity are standardised. While it is not practical to control atmospheric pressure, it is desirable that any testing station should be at or near sea level so that test data are comparable. In any case, atmospheric pressure should always be recorded when ball tests are made. The following conditions are specified for testing by the ITF (the "Controlled Environment"): Temperature 20 ± 2C (68F) Relative humidity 60 ± 5% Atmospheric pressure 102 ± 3 kPa (30 inches Hg) Other Controlled Environment standards may be fixed for localities where one or more of the average temperature, humidity and average barometric pressure at which the game is being played differ materially from 20º Celsius (68º Fahrenheit), 60% relative humidity and 102 kPa (30 inches Hg) respectively. Applications for such adjusted standards may be made by any National Association to the ITF and, if approved, shall be adopted for such localities.

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