This International Standard specifies the material for and the dimensions of rotary core diamond drilling equipment, system C. NOTE 1 Cutting materials other than diamond may be used. It applies to — single- and double-tube core barrels, including diamond core bits, reaming shells, core lifters, core-lifter cases, core tubes (outer and inner) and heads; — drill rods and couplings; — casing tubes and couplings. The casing tubes are not designed for drilling, and the casing string is only employed for casing-off the hole. The range of equipment covers diamond core drilling of holes from 35 mm to 112 mm in diameter (outer bit diameter) with the corresponding core diameters from 21 mm to 92 mm. Single- and double-tube core barrels provide a means of coring compact rocks (types M and DM core barrels), fissured and fractured rocks (types T and DT core barrels) and fractured and broken-down rocks (type DP core barrels).