1. Raws li cov khoom siv, lub qhov rooj hluav taws tuaj yeem muab faib ua: qhov rooj hluav taws ntoo, lub qhov rooj hluav taws steel, steel - qhov rooj hluav taws kub, thiab qhov rooj hluav taws ua los ntawm lwm cov ntaub ntawv. Feem ntau siv hluav taws qhov rooj yog ntoo thiab steel hluav taws qhov rooj.
2. Raws li kev ua tau zoo ntawm hluav taws kub, qhov rooj hluav taws tuaj yeem muab faib ua: cov qhov rooj hluav taws kub rwb thaiv tsev (Class A), cov qhov rooj hluav taws kub rwb thaiv tsev (Class B), thiab tsis yog- qhov rooj hluav taws kub (Class C).
3. Insulated hluav taws qhov rooj feem ntau muaj peb qhov kev ntsuas hluav taws kub: Chav A (1.5h), Chav B (1.0h), thiab Chav C (0.5h). Cov qhov rooj hluav taws uas ua rau kev khiav tawm cov staircases feem ntau yog Class B qhov rooj hluav taws, uas yuav tsis tawg txawm tias tom qab 60 feeb ntawm kev kub hnyiab.
4. Raws li txoj kev qhib, qhov rooj hluav taws kuj tuaj yeem muab faib ua cov qhov rooj hluav taws uas nquag qhib thiab feem ntau kaw qhov rooj hluav taws.
