OSHA Guide – Cranes and Derricks in Construction

Section 1426 – Free Fall and Controlled Load Lowering

Free Fall Generally Prohibited

Some older cranes are designed with a “live boom,” where the rate of lowering the boom can only be controlled by a brake. Failure of the brake can lead to free fall of the boom and a risk of death or serious injury to workers near the crane. This standard prohibits the use of equipment with a live boom unless:

  • The equipment was manufactured before October 31, 1984, or
  • The equipment is a floating crane/derrick or a land crane/derrick on a vessel/flotation device

Free Fall Specifically Prohibited

Even in the two situations where the equipment may have a live boom, the equipment may not be used in the following circumstances:

  • An employee is in the fall zone of the boom or load
  • An employee is being hoisted
  • The load or boom is directly over a power line, or over any part of the area extending the Table A of section 1408 clearance distance to each side of the power line; or any part of the area extending the Table A clearance distance to each side of the power line is within the radius of vertical travel of the boom or the load
  • The load is over a shaft, except where there are no employees in the shaft
  • The load is over a cofferdam, except where there are no employees in the fall zone of the boom or the load
  • Lifting operations are taking place in a refinery or tank farm

Backup Protection

In the situations listed above where the use of equipment with a 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:

  • Friction drums must have:
    • 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 backup 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 may be considered brake or locking devices for purposes of this subpart
  • Hydraulic boom cylinders must have an integrally mounted holding device

Preventing Uncontrolled Retraction

Hydraulic telescoping booms must have an integrally mounted holding device to prevent the boom from retracting in the event of hydraulic failure.

Load Line Free Fall Prohibited

In each of the following circumstances, controlled load lowering is required and free fall of the load line hoist is prohibited:

  • An employee is directly under the load
  • An employee is being hoisted
  • The load is directly over a power line, or over any part of the area extending the Table A of 1926.1408 clearance distance to each side of the power line; or any part of the area extending the Table A of 1926.1408 clearance distance to each side of the power line is within the radius of vertical travel of the load
  • The load is over a shaft
  • The load is over a cofferdam, except where there are no employees in the fall zone of the load