以水管來說, 澆花澆草的塑料(軟)水管叫a water hose; 埋在地下供應自來水的金屬(硬)管子叫a water pipe.
As far as an oxygen mask is concerned, here is some helpful information:
Hoses or tubing connect an oxygen mask to the oxygen supply. Hose is larger in diameter than tubing and can allow greater oxygen flow. When hose is used it may have a ribbed or corrugated design to allow bending of the hose while preventing twisting and cutting off the oxygen flow.