This part of ISO 19013 specifies the requirements for rubber tubing and hoses used in diesel fuel circuits for internal combustion engines. The diesel fuels covered include “bio-diesels” which consist of the methyl ester of rape seed oil at levels up to 20 % by volume in conventional diesel fuels. In addition, this specification may also be applied as a classification system to enable original equipment manufacturers (OEMs) to detail a “line call-out” of tests for specific applications where these are not covered by the main types specified (see example in Annex E). In this case, the hose or tubing would not carry any marking showing the number of this part of ISO 19013 but may detail the OEM's own identification markings as shown on their part drawings.