Qhov sib txawv ntawm lub qhov rooj hluav taws kub thiab cov qhov rooj ntoo thiab cov hlau hluav taws kub yog tias lawv tau ntim nrog thaj tsam loj ntawm cov iav hluav taws kub, uas yog qhov tsim nyog rau cov tsev so high-end, chav siv thiab lwm qhov chaw. Tom qab lub qhov rooj iav fireproof tau raug kub siab, lub pob tshab jelly-zoo li fireproof nplaum txheej nyob rau hauv nruab nrab ntawm lub iav yuav harden sai heev los tsim ib tug opaque fireproof rwb thaiv tsev board.