Annex B
(normative)
B.1 Principle
Pieces of the hose to be tested are first exposed to fuel for 7 days. Then the test pieces are filled with test liquid and the liquid lost by permeation during time periods of 24 h is determined by weighing for 15 consecutive days or until a peak has been established.
B.2 Sampling
Three test pieces of the hose shall be tested simultaneously. The test pieces shall be approximately 300 mm long.
B.3 Equipment
The test equipment shall be as shown in Figure B.1.
A well-ventilated, draught-free test chamber, temperature controlled to standard laboratory temperature (23 ℃), shall be used for the test.
The glass pipes shown in Figure B.1 shall fit tightly to the inside of the tested hose. The pipe in the lower end of the hose shall be impermeably tight in its lower end. The plug in the upper end of the upper pipe shall have a capillary canal that minimizes ventilation but allows air to replace fuel lost by permeation during the test.
B.4 Test procedure
Fill the test hoses with Test Liquid C, as specified in ISO 1817, and store them for 7 days in air at standard laboratory temperature.
Empty the liquid out and assemble test hoses and glass pipes as shown in Figure B.1 . Refill the hoses and pipes with Test Liquid C, as specified in ISO 1817, up to a level approximately 70 mm above the upper end of the hose.
Fit the plug with the capillary pipe.
Weigh the assembly to an accuracy of 0,01 g. Store the assembly in a vertical position for 24 h at standard laboratory temperature and weigh the assembly again. Record the loss of mass.
Empty the liquid out. Repeat the 24 h permeation test 15 times or until a maximum permeation has been established.
Calculate the average value of the three highest mass loss values recorded. Calculate the permeation rate in grams per square metre hour based on this average mass loss, the inner diameter of the hose and the effective length of the hose between the inner ends of the glass pipes.
