This standard specifies a method for determining the resistance to external blows of thermoplasticspipes with circular cross sections by using theround-the-clock method.The method is intended to be applied to isolatedbatches of pipe. For type testing and audit testing,0 0C and/or一20 0C are applicable.NOTE. Pipes made from polypropylene homopolymer (PP-H)which principally can not conform to impact requirements at0 0C or lower temperatures are permitted to be tested at(23土2) 0C under the condition that PP-H pipes are intendedfor use for soil and waste discharge and bear an additionalmarking indicating that they are not to be installedbelow +5 0C.