Lub qhov rooj ntoo hluav taws yog ua los ntawm cov ntoo uas muaj hluav taws kub, thiab lub qhov rooj ntawm lub qhov rooj muaj cov khoom siv hluav taws kub uas tsis muaj tshuaj lom thiab tsis muaj teeb meem rau tib neeg lub cev, txuag hluav taws xob thiab kev tiv thaiv ib puag ncig, thiab yog nruab nrog cov khoom siv hluav taws xob tiv thaiv hluav taws. Tom qab lub qhov rooj ntoo fireproof tau tsim, txhuam cov roj hauv qab ib zaug kom tsis txhob raug damped thiab deformed.