This standard applies to underground structures such as wells, shafts, tunnels, submersibles (boxes), pits, manholes, septic tanks, culverts, culverts, basements, etc., as well as tanks, boilers, and reaction towers where there is a risk of oxygen deficiency. This standard specifies oxygen meters used for measuring, monitoring, and warning oxygen concentrations in ground structures such as hoppers, silos, and warehouses, as well as inside ship holds.