127Supply of air or vacuum to brakes

127 Supply of air or vacuum to brakes

(1) If air brakes are fitted to a vehicle: (a) the compressor supplying air to the brakes must be able to build up air pressure to at least 80% of the governor cut‑out pressure in not over 5 minutes after the compressed air reserve is fully used up; and (b) for a vehicle with a GVM over 4.5 tonnes—the air storage tanks must have sufficient capacity to allow 5 applications of the service brakes before the air pressure drops below half the governor cut‑out pressure; and (c) there must be an automatic or manual condensate drain valve at the lowest point of each air brake reservoir in the system; and (d) any spring brake fitted to the vehicle must not operate before the warning mentioned in rule 131(4)(a) or 134(3)(a) has been given. (2) If vacuum brakes are fitted to a vehicle, the vacuum supply must be able to build up vacuum: (a) to the level when the warning signal mentioned in rule 131(4)(a) or 134(3)(a) no longer operates within 30 seconds after the vacuum reserve is fully used up; and (b) to the normal working level within 60 seconds after the vacuum reserve is fully used up.