a composite hose for use in automotive air conditioning systems employing &# 34 ; refrigerant 12 &# 34 ; including an innermost three - ply tube having an elastomer inner tube ply , a middle tube ply of a thermoplastic polymer bonded to the inner tube ply , and an outer tube ply of an elastomer bonded to the middle tube ply . at least one textile yarn , cord or fabric reinforcement layer surrounds the three - ply tube and a specially compounded elastomer cover overlies the textile reinforcement . suitable adhesives maybe applied between the inner and middle tube and between the middle and outer tube to provide a consolidated , co - acting tube element . a hose fitting is attached to an end of the composite hose to form a hose assembly .