BS EN ISO 7840 pdf free download

BS EN ISO 7840 pdf free download.Small craft- Fire-resistant fuel hoses.
5.5 Volume change in test liquids Determine the change in volume of the hose (tube and cover) by the procedure described in ISO 1817. Place the test pieces in test liquids as specified in 5.2 at a temperature of40 °C士2 °C for 40 days. If the hose is made of a homogeneous compound (with or without reinforcement), the swelling shall not exceed 35 % by volume, as measured by displacement in water. For hose with an inner layer of fuel- resistant material and a cover of another material, mainly intended for weather and ozone resistance, the increase in volume shall not exceed 35 % for the tube and 120 % for the cover. 5.6 Mass reduction of test hose Determine the reduction in mass of the inner layer by the procedure described in ISO 1817. Fill three hoses or submerge test pieces from the hoses with test liquids, as specified in 5.2, and store them for 40 days in air at a temperature of40 °C+ 2 °C. The reduction in mass of the inner layer shall not exceed 8 % of the initial mass of the test pieces. NOTE A reduction in mass of 8 % corresponds to a decrease in volume of approximately 10 %. 5.7 Fire resistance Test the hose in accordance with the method described in Annex A. 5.8 Effect of ozone The hose shall be tested as described in ISO 7326:2006, Method 1. The sample shall show no visible cracks at x7 magnification.5.10 Cold-flex test For straight hoses of 19 mm inside diameter and less, condition three hose samples for 5 h at -20 °C士2 °C. Flex in the cold chamber through 180° from the centreline to a diameter of 10 times the maximum outside diameter of the hose. The flexing shall take place within 4 s and the hose shall not fracture or show any cracks, checks or break in the tube or cover. For straight hoses larger than 19 mm inside diameter and all pre-formed hoses, prepare three samples (100士5)mmx[6士1)mmfromthewholehosewallandconditionthemfor5hat-20°C士2°Cin an unrestrained loop, positioned between two jaws 50 mm wide and 64 mm apart. While in the cold chamber, bring the jaws together rapidly until they are 25 mm apart. The samples shall not fracture or show any cracks, checks or breaks. 5.11 Abrasion test一38 mm and larger fuel-fill hose with helical wire embedded reinforcement Hose samples of 38 mm inner diameter shall be selected for the test. Larger bore hose sizes to be qualified by the test shall not have a cover thickness or construction less than those of the test samples. Three identical 38 mm bore hose samples shall be tested. Condition hose for at least 24 hat23 °C+2°C and 50 %士5 % relative humidity. The test hose shall be mandrel- (core-) supported and rotated at a constant speed of 80 r/min土2 r/min. Subject hose to a laterally moving abrasive surface, i.e. 80 grit aluminium oxide (Al2O3) emery cloth, parallel to the longitudinal axis of the hose. The abrasive surface shallbe (25土5) mm x (75土5] mm affixed to a hard surface which will cycle back and forth 75 mm士5 mm in each direction while loaded with a constant normal force of45 N土5 N. One test cycle shall equal one 360° rotation of the outside diameter of the hose and one back and forth movement of the abrasive surface. After 1 000 cycles, the three test samples shall have no helical wire reinforcement exposed at the point of contact with the abrasive surface.BS EN ISO 7840  pdf download.