A space is a 'permit-required confined space' when it is large enough to enter, has limited means of entry/exit, is not designed for continuous occupancy, AND:

Giải thích

A permit-required confined space adds at least one serious hazard—hazardous atmosphere, engulfment, an inwardly converging/entrapping configuration, or another recognized hazard—to the basic confined-space criteria. Being outdoors, small, or well-ventilated does not define a permit space; the presence of a serious hazard does.