Raws li qhov sib txawv ntawm qhov hluav taws kub ntawm steel qhov rooj, lawv qhov hluav taws kub kuj tuaj yeem muab faib ua peb qib: A, B thiab C. Steel qhov rooj hluav taws ntawm cov qib sib txawv tuaj yeem siv rau ntau qhov chaw.

hluav taws qhov rooj Hoobkas,hlau pem hauv ntej qhov rooj xim,hluav taws qhov rooj 1 teev, hlau hollow qhov rooj,fireproof qhov rooj, 20 feeb hluav taws nyob qhov rooj,hluav taws qhov rooj xauv,

hluav taws kub ntsuas hlau qhov rooj tsum,hlau pem hauv ntej qhov rooj xim,txhim kho qhov hluav taws kub nyob hauv qhov chaw nres tsheb, hluav taws kub ntsuas hlau qhov rooj jambs,fireproof qhov rooj,hlau pem hauv ntej qhov rooj,20 feeb hluav taws ntsuas qhov rooj,

Thaum muaj xwm ceev hluav taws kub tawm qhov rooj, khoom siv thaum muaj xwm ceev qhov rooj,hlau pem hauv ntej qhov rooj xim,Hluav taws kub resistant qhov rooj rau tsev, hluav taws kub resistant qhov rooj rau flats,fireproof qhov rooj,hluav taws tawm qhov rooj qhov ntev,20 feeb hluav taws ntsuas qhov rooj