Hose fittings are assemblies of separate parts. These parts are the nipple, the socket, the swivel nut or flange, and the sleeve. The nipple is the part that fits the inside diameter of the hose. Nipples have three configurations for the hose-to-tube or component surface-sealing portion. They are the flared,

Figure 5-2.Synthetic rubber hose identification

 flareless, and flanged configurations, as shown in figure 5-3. The socket fits over the outside diameter of the hose and secures one end of the nipple to the hose. The swivel nut or flange secures the other end of the nipple to the mating connection in the fluid system. For Teflon@ hose, some manufacturers have a sleeve in addition to the nipple, socket, and nut or flange. See figure 5-4 for illustrations of Teflon@ hose fittings and sleeves. Individual parts produced by each manufacturer may have unique charac-teristics and tolerances that prevent interchangeability between parts. Do not intermix nipples and sockets from one manufacturer to another. 

Hose fittings are identified by applicable military specification (MS) and manufacturers name or trademark on fittings and nuts. Flared or flareless fittings and nuts are color-coded to show materials or material finishes. See table 5-1.

Figure 5-3.Synthetic hose fittings.



Figure 5-3.Synthetic hose fittingsContinued.



Figure 5-3.Synthetic hose fittingsContinued.



Figure 5-4.Teflon hose fittings.



Figure 5-4.Teflon hose fittingsContinued.

Table 5-1.Hose Fitting Color and Material Code

All hose assemblies are identified by tags, bands, or tapes. Some identifications are permanently marked while others are removable. Removable tags, bands, or tapes should not be installed on hose assemblies located inside fuel and oil tanks or in areas of an aircraft where tags, bands, or tapes could be drawn into the engine intake. Hose assemblies are either commercially manufactured or locally fabricated.