Article 29 -Auxiliary brake in Escalator & Moving walk.
As we mention in article “Escalator & Moving Walk Braking Systems”, all escalators and moving walks must be equipped with an operational break system, but the auxiliary break must be added under the following conditions:
- The connection between the operational brake and the driving sprockets of the steps/pallets is not accomplished by shafts, gear wheels, multiplex chains or when it is accomplished by only a single chain.
- The operational brake does not have an electro-mechanical brake.
- The vertical height of the escalator is more than 6 meters.
The activation of the auxiliary brake must be detected by an electrical safety device or suitable function and the auxiliary brake must become active as below conditions:*
- The speed goes above 1.4 times the nominal speed.
- At any time, the device reverses direction for any abnormal reason.
The auxiliary brake can operate together with the operational brake in case of power failure or an interruption of a safety circuit as well as when the operation of the auxiliary brake is required as mentioned above in *.
The auxiliary braking system must be designed in such a way that when escalators and moving walks with brake load travel downward, it brings the escalator or moving walk to a stop and holds it stationary. Under all operating conditions the downward deceleration must not be more than 1 m/s2.
The auxiliary brakes must be of the mechanical (friction) type and the connection between the auxiliary brake and the driving sprockets of the steps/ pallets must be accomplished by shafts, gear wheels, multiplex chains or more than one single chain. Connection of auxiliary brake to handrail drive shaft is not permitted.
Note: While auxiliary brakes are operating it is not required to consider the stopping distances of operational brakes.
Note: brakes must be designed in a way that they can be released manually by applying continuous pressure.
