30OZ110.pdf

mg rover group engineering standards issue no:mgr es: title: page 1 of 2 date: - printed copy is uncontrolled - check issue is current - 5 ozone resistance after ageing and flexing february 1993 30.oz.110 contents 1scope4procedure 2apparatus5assessment 3 specimen preparation 1scope 1.1this standard is applicable to all plastic or rubber materials. note:test conditions shall be in accordance with bs 903 part a43 unless otherwise specified herein. 2apparatus 2.1air circulating oven capable of maintaining 100c 2c. 2.2refrigerator capable of maintaining -40c. 2.3jig for applying strain. 2.4 ozone apparatus in accordance with bs 903, part a43. 3specimen preparation 3.1cut a specimen 12,5 mm wide; in the case of wrapped hoses test the whole section; in the case of internally reinforced hoses, remove reinforcement and lining from the cover. 3.2condition and strain the specimen as in clauses 4.1 to 4.5. 3.3coat the specimen with hypalon paint or other suitable material on the ends adjacent to the clamps and on cut edges. 4procedure 4.1age the specimen in the oven for 72 hours at 100c 2c. 4.2flex the specimen by bending through 1800 six times by hand after cooling to 20c. 4.3age for two hours at -40c. 4.4after allowing the specimen to attain room temperature, apply a strain of 10 per cent of the specified elongation at break for the material, up to a maximum of 20 per cent strain. 4.5age at -40c for 24 hours. 4.6set the ozone apparatus to produce an ozone concentration of 50 parts of ozone per hundred million unless otherwise specified, at a temperature of 40c 1c and a velocity of ozonised air over the specimen of 14 mm/s 10%. mg rover group engineering standards issue no:mgr es: title: page 2 of 2 date: - printed copy is uncontrolled - check issue is current - 5 ozone resistance after ageing and flexing february 1993 30.oz.110 4.7immediately place the conditioned specimen in the ozone test apparatus for a period of 72 hours, unless specified otherwise. 4.8 on completion of the test period r