Lub qhov rooj hluav taws 2-teev yog lub qhov rooj tua hluav taws tshwj xeeb uas tsim los rau cov chaw tshwj xeeb thiab cov chaw tshwj xeeb nrog lub sijhawm hluav taws kub txog li 120 feeb. Piv nrog rau cov pa hluav taws-resistant qhov rooj ntawm 0.5-1.5 teev, cov khoom xaiv thiab cov txheej txheem ntau lawm yog nruj dua thiab siab-tus qauv.