The oven may be protected by an appropriate steel liner and the Dewar vessel housed in a wire mesh cage.

(j) In the case of steel receptacles and composite receptacles with steel liner, the letter "H" showing compatibility of the steel (see 1SO 11114-1:1997); and,

(p) In the case of steel pressure receptacles and composite pressure receptacles with steel liner intended for the transport of gases with a risk of hydrogen embrittlement, the letter "H" showing compatibility of the steel (see 1SO 11114-1:1997).