1. Inner cleanliness requirements: the weight of removable insoluble impurities ≤ 0.27g/m2；maximum size ≤ 200um.
  2. Tension test: more than 2500N
  3. Burst test：high-pressure cooling pipe burst pressure ＞ 14.7Mpa；Low-pressure cooling pipe burst pressure＞9.8Mpa.
  4. Hose vacuum resistance characteristic: OD change cannot be more than 20% camparing with nature condition. 
  5. Hose length variation：Under certain pressure, length variation is between -4% to +2% after test.
  6. O-zone resistance:：Under 8X magnification glass, no visible cracking on hose surface.
  7. Hose Volume variation ratio：rubber material hose volume variation ratio is between -5% and +35%;
?  8. hose tightness：Allowed max tolerance of R134a, nominal bore diameter≤2.0g/md，nominal bore diameter>3.0g/md

Auto conditioning pipeline can be devided into high-pressure pipe and low-pressure by pressure level, and devided into gaseous pipe and hydraulic pipe according to cooling condition. Auto conditioning pipe is consist of aluminum tube, joint, conditioner rubber hose, conditioner bellows, aluminum bushing, filling nozzle, pressure switch, O-ring, plastic fitting.