This part of ISO 4642 specifies the requirements and test methods for semi-rigid reel hoses for use on fire-fighting vehicles and trailer pumps. The hoses are intended for use at a maximum working pressure of 1,5 MPa for normal pressure hoses (category I) and 4,0 MPa for high pressure hoses (category II). The hoses are further subdivided into types and classes (see Clause 4). This part of ISO 4642 applies to delivery hoses for fire-fighting purposes intended for use at a minimum ambient temperature of -20 °C. Hoses conforming to this part of ISO 4642 should be used with fire hose couplings conforming to the relevant national standards couplings. Requirements are also given for hose assemblies (see 6.12) where these are fitted by the hose manufacturer. NOTE 1 Hoses for use at temperatures lower than -20 °C can be supplied by agreement between the manufacturer and purchaser. NOTE 2 All pressures are expressed in megapascals where 1 MPa = 10 bar.