1.1 This specification covers perforated concrete pipe intended to be used for underdrainage. 1.2 This specification is the SI companion to Specification C 444. 1.3 This standard do This specification covers perforated concrete pipe intended to be used for underdrainage. Pipe manufactured to this specification shall be of two classes, Type 1 and Type 2, describing two arrangements of perforations for pipe manufactured to the stand