Kev tawg-pov thawj thiab kev saib xyuas-dawb-carbon aviation obstruction teeb yog tsim rau cov pa phem ib puag ncig, zone 1, zone 2, explosive plua plav ib puag ncig, zone 20, zone 21, zone 22, hauv IIA IIB IIC class explosion-proof gas ib puag ncig, Kub pab pawg T1-T6 ib puag ncig, roj av extraction thiab cia Tshuaj, tshuaj, textile, luam ntawv, tub rog chaw, teeb, chaw txaus ntshai.