1.1 This specification covers perforated concrete pipe intended to be used for underdrainage. 1.2 This specification is the inch-pound companion to Specification C 444M; therefore, no SI equivalents are presented in the This specification covers perforated concrete pipe intended to be used for underdrainage. The pipes shall be of two classes: Type 1 which shall have circular perforations and Type 2 which shall have slotted perforations. The joints shall be of such des