These fittings are used in many different applications, adapting different types and sizes of fittings to each other. They are used to transfer air, gases and fluids.  

The materials of construction of fittings must satisfy certain criteria like as follows:


• The material of construction must be compatible with the other materials in the system.


• It must be compatible with the fluids or solids being transported.


• It should withstand fluctuating temperatures inside and outside of the system.


• It should also be compatible with different pressure levels.


• Fire hazards, earthquakes, and other unforeseen factors also influence fitting materials.


• Fitting material specifications and construction are application dependent.


• For optimization of component selection, user consultation with fitting suppliers is a must.


• The materials of construction should also conform to certain standards like BSP, NPT, ASME, ASTM, DIN, JIC, JIS etc.


• Surface finish is equally important. It is to be noted that all fittings should have a proper finish as fittings are constantly in harsh environments. Corrosion resistant property of the materials is an essential requirement.