API 5CT bụ ọkọlọtọ na mkpuchi mmanụ nke American Petroleum Institute, tumadi maka ọkpọkọ mmanụ, tubing na casing.

API 5CT mmanụ casing na-eji mmanụ olulu mmiri, nke a na-ejikarị eme ihe maka ịkụnye na imecha mgbidi ziri ezi nke nkwado ahụ, iji jide n'aka na omume na ịmecha usoro nhazi mgbe arụ ọrụ nkịtị nke olulu mmiri gasịrị.Ihe mkpuchi bụ idobe olulu mmiri na-agba ọsọ ndụ.Dị ka ọnọdụ dị iche iche geological, n'okpuruala mgbagwoju ọnọdụ nrụgide, ịdọrọ, ịpị, na-ehulata, torsional nrụgide na-eme na ngwakọta mmetụta nke tube, nke casing onwe ya, àgwà nke elu chọrọ.Ozugbo casing n'onwe ya mebiri emebi n'ihi ihe ụfọdụ, nwere ike iduga n'olulu mmiri mmepụta dum, ma ọ bụ ọbụna kpochapụ.

Ihe eji arụ ọrụ API 5CT API 5CTỌkpụkpọ igwe anaghị agba nchara: