1926.1426(b) Preventing Boom Free Fall

Where the use of equipment with a boom that is designed to free fall (live boom) is prohibited, the boom hoist must have a secondary mechanism or device designed to prevent the boom from falling in the event the primary system used to hold or regulate the boom hoist fails, as follows:

A friction clutch and, in addition, a braking device, to allow for controlled boom lowering.

A secondary braking or locking device, which is manually or automatically engaged, to back-up the primary brake while the boom is held (such as a secondary friction brake or a ratchet and pawl device).

Hydraulic drums must have an integrally mounted holding device or internal static brake to prevent boom hoist movement in the event of hydraulic failure.

Neither clutches nor hydraulic motors must be considered brake or locking devices for purposes of this subpart.

Hydraulic boom cylinders must have an integrally mounted holding device.