Document wrR8r5zEv8qGDYkrXqYXm0qo3

TABLE A-3. SUMMARY OF DYNAMOMETER TEST PROCEDURES FOR FMVSS 121 (tractors, trucks, buses trailers) Sequence Burnish brake linings (all vehicles) Brake effectiveness/ retardation factor (trailers only) Fade and recovery (all vehicles) Procedure Evaluation Criteria Make 200 stops from 40 mph at 10 ft/sec/sec Make 200 additional stops from 40 mph at 10 ft/sec/sec Make 7 consecutive stops from 50 mph with increasing brake air chamber pressure Decelerate from 50 mph to 15 mph at 9 ft/sec/sec at 72 second intervals deceleration rate; repeat 10 times Hot stop from 20 mph at 14 ft/sec/sec Make 20 consecutive stops from 30 mph at 12 ft/sec/sec deceleration rate. (at 60 second Intervals) Brake temperatures, T 315 F < T < 385 F Brake temperatures, T 450 < T < 550 Calculated brake retardation force force at each air chamber pressure Service air pressure must'be below 100 psi No pressure limit . Service air pressure must be below 85 psi and above 20 psi