In car air-conditioning installations freon hoses made of the highest quality rubber compounds are used. They have a thin layer of nylon (polyamide) in the inner layer of synthetic rubber (BARRIER type) to reduce freon permeation down to the minimum. The hoses are manufactured in compliance with standards, e.g. SAE J2064. Typical freon hoses used in cars have inner diameters of: 8, 10, 13 and 16 mm and textile reinforcement. There are two freon hose versions manufactured: a thick wall standard version and the latter – LW version with thinner wall. Hoses of bigger sizes (with inner diameters 22, 28 or 35 mm) usually have steel braid and are used in larger installations e.g. in buses. The working pressure of freon hoses is usually up to 35 bar, temperature from -40°C to +135°C.
The car air-conditioning hoses for freon must be mounted with special fittings. They are available in car service stations as a complete hose assembly assigned to a particular type of a car. However, they can be sometimes fixed or replaced, but always with the highest degree of accuracy and care.
Special thermoplastic hoses for freon (inner layer – polyamide) can be employed in industrial freon cooling installations. Likewise, to recharge and test car installations or (smaller diameters) for cooling installations with carbon dioxide. The thermoplastic hoses for freon should be fitted with standard hydraulic fittings and hoses of smaller diameters (for testing and recharging) with special fittings assigned for the hose.