Cov qauv hlau rau cov hulls tau muab faib ua qib zog raws li lawv cov ntsiab lus me me: lub zog dav dav hlau thiab lub zog muaj zog hlau. Nkoj daim hlau xa mus rau kub-kuav los tiag steel daim hlau siv los tsim lub nkoj hull cov qauv tsim ua raws li cov kev cai ntawm kev faib tawm hauv zej zog kev tsim tshwj xeeb. Lub zog ntawm cov qauv steel raws li qhov tshwj xeeb ntawm Tuam Tshoj Classification Society tau muab faib ua plaub qib zoo: a, b, d, thiab e (ie, ccsa, ccsb, ccsc, ccsd); Lub zog muaj zog steel qauv raws li cov kev qhia tshwj xeeb ntawm Tuam Tshoj Classification Society tau muab faib ua peb qib zoo: qib siab, plaub theem zoo.
Lub zog dav dav A thiab B cov nkoj nkoj tuaj yeem ua tau raws li lawv cov txheej txheem thiab kev ua haujlwm ntawm cov khoom siv los ntawm kev dov zoo tib yam, yog li cov txheej txheem tsim khoom kuj yooj yim; thaum lub sij hawm tsim khoom ntawm D, E chav kawm thiab siab zog chav kawm nkoj daim hlau yuav tsum tau ua tiav cov cuab yeej. Raws li cov cuab yeej siv, nws tau paub los ntawm kev tswj cov dov thiab tswj cov txheej txheem txias lossis txheej txheem kev kho cua sov. Nyob rau tib lub sijhawm, qhov yuav tsum tau muaj rau cov khoom siv hlau purity ntawm cov khoom siv steel hlau yog qhov siab, tshwj xeeb tshaj yog cov ntsiab lus ntawm S, P, N, O, H, thiab lwm yam hauv cov hlau yuav tsum tau tswj nruj me ntsis.
Lub koom haum International Kev faib tawm ntawm Kev Xa Khoom (IACS) yog tsim los ntawm lub ntiaj teb cov koom haum tshawb fawb lub nkoj loj. Tam sim no nws muaj 11 tus tswvcuab raug cai thiab 2 tus tswvcuab koom nrog. Cov tswvcuab hauv zej zog yog American Bureau of Shipping (ABS), Bureau Veritas (BV), Tuam Tshoj Classification Society (CCS), Det Norske Veritas (NV), Germanischer Lloyd (GL), thiab Kaus Lim Sau Npe ntawm Shipping. (KR), Labor Classification Society (LR), Nyiv Maritime Association (NK), Polish Register of Ships (PRS), Italian Register of Ships (RINA), Lavxias Register of Ships (RS), hu rau cov koom haum xws li India Classification Society ( IRS), Croatian Register of Nkoj (CRS). Ntau tshaj li 95% ntawm tag nrho cov tonnage ntawm lub ntiaj teb cov tub lag luam nkoj tau dhau los ntawm kev soj ntsuam kev pom zoo los ntawm IACS tso cai rau kev faib cov koom haum.
