ISO 13363:2004

ISO 13363:2004 specifies requirements for three types and two classes of hose. The hoses are intended for use in marine-engine wet-exhaust systems (where the exhaust gases are mixed with the discharge of cooling water). The standard does not apply to outboard-motor/personal water craft.
The three types are:

type 1: a softwall hose, made of oil-resistant material, with a synthetic-fabric reinforcement;
type 2: a hardwall hose, made of oil-resistant material, with a synthetic-fabric reinforcement with an helical wire embedded in it;
type 3: a hose or tube (flexible connector), made of oil-resistant material, with or without a reinforcement or cover, intended for use in short lengths in locations where the connector is protected from mechanical damage.

The two classes are:

class A intended for diesel engines;
class B intended for petrol engines, and for diesel engines with a very high exhaust temperature.