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Crane Safety, Subpart N


Introduction to Cranes

A crane is a machine that consists of a rotating structure that is used to hoist and move heavy objects. There are several different types of cranes, including:

– Mobile– Hydraulic– Overhead– Gantry– Tower



The primary difference between each crane type is in the boom hoist, load line controls, and load charts. These differences are significant enough that crane operators must receive specific training on each type of crane they are expected to operate.



• Hoist - A hoist is used to lift and lower the load. • Boom - A boom is an incline spar, strut, or other

long member supporting the hoisting tackle.• Boom Stops - Boom stops are devices used to

limit the angle of the boom at its highest position. • Boom Angle Indicator - A boom angle indicator

is an accessory device that measures the angle of the centerline of the boom base section to horizontal.



• Block - Blocks are sheaves or grooved pulleys in a frame with the hook, eye, and strap.

• Jib - A jib is an extension attached to the boom point which provides added boom length for lifting specified loads.

• Load - A load is the weight of the object being lifted by the crane. This weight includes the load block and hook, wire rope, rigging, boom attachments, and ancillary attachments.


Crane Accidents

Hazards associated with cranes include:– Improper load rating.– Excessive speeds.– No hand signals.– Inadequate inspection and maintenance.– Unguarded parts.– Unguarded swing radius.– Working too close to power lines.– Improper exhaust system.– Shattered windows.– No steps, guardrails, or walkways.– No boom angle indicator.– Not using outriggers.


Crane Accidents

The four major types of crane accidents are: • Contact with power lines.• Overturns.• Falls.• Mechanical failures.

Among the causes of crane accidents, contact with power lines occurs the most often and is considered to be the most dangerous.


Crane Accidents

Crane accidents are most commonly caused by:• Instability of the crane.• Lack of communication between the operator

and jobsite workers.• Improper training of operators and jobsite

workers.• Inadequate maintenance or inspection of the

crane.


Who’s At Risk

• Among those who are at risk in crane accidents are the crane operators and anyone working at the crane site.

• Crane operators and all personnel working with cranes must receive proper training. They also must maintain regular equipment inspections to identify any existing or potentially hazardous conditions. In addition, precautionary maintenance must be performed as required by the crane manufacturer and/or supplier to ensure the crane is operating safely.


Planning for Crane Usage

Check and inspection procedures: • Level the crane and ensure the support surface is firm and able to

support the load.• Contact power line owners to determine any and all precautions.

Know the location and voltage of the over head power lines before beginning work.

• Know the basic crane capacities, limitations, and job site restrictions, such as the location of power lines, unstable soil, or high winds.

• Make other personnel aware of hoisting activities.• Barricade areas within the swing radius.• Ensure that there is proper maintenance and inspections.• Determine the safe areas to store materials and place machinery.


Crane Inspections

What to inspect and maintain:• Tires are properly inflated with the correct air pressure

and no leaks.• Clearance for swing radius.• Wire rope wear and sheaves.• Load capacity.• Secure guardrails and guards.• Efficient rigging equipment.• Physical damage to the crane.• Loose or missing hardware, nuts, or bolts.• Fluid leaks.


Crane Inspections: Loading

• A crane operator must know all the limitations, loading capacities, warnings, and instructions before operating a crane. Another factor to pay attention to when operating a crane is to know the weight of the load. Unknown load weight can lead to an overturned crane.

• To avoid these conditions, ensure that the load is within load chart ratings for boom length and the load radius of the crane. Also make sure the crane is rated by the maximum weight it will lift at a minimum radius and minimum boom length –the further from its center point, the less it will lift.


Lifting Principles

There are four basic principles that cover a crane’s mobility and safety during lifting operations. They are:

– Center of Gravity.– Leverage.– Stability.– Structural Integrity.


Power Line Precautions

• OSHA standards require that you stay at least 10 feet away from power lines.

• When crane work requires being near power lines, all electrical distribution and transmission lines must be de-energized and visibly grounded at every point of work. They also must be grounded and de-energized where insulating barriers, not attached to the crane, have been erected to prevent physical contact with the power line.


Power Line Precautions

Equipment or machines shall operate near power lines only in compliance with the following:

– For lines rated 50 kV. or below, minimum clearance shall be 10 feet between the lines and any part of the crane or load.

– For lines rated over 50 kV., minimum clearance shall be 10 feet between the lines and any part of the crane or load plus 0.4 inches for each 1 kV., or twice the length of the line insulator, but never less than 10 feet.

– In transit with no load and the boom lowered, the equipment clearance shall be a minimum of 4 feet for voltages less than 50 kV., 10 feet for voltages over 50kV., up to and including 345 kV., and 16 feet or voltages up to and including 750 kV.

– A person shall be designated to observe clearance of the equipment and give a timely warning for all operations where it is difficult for the operator to maintain the desired clearance by visual means.


Crane Operator Qualifications

Crane operators must be qualified on specific crane types and have on-the-job training. They are required to pass a practical operating examination, which is limited to the specific type of equipment he/she can operate.



Operators are required to meet these physical qualifications:

– Have vision of at least 20/30 Snellen in one eye, and 20/50 in the other, with or without glasses.

– Be able to distinguish red, green, and yellow, regardless of the position of the colors, if color differentiation is required for operation.

– Must have adequate hearing, with or without hearing aids, for the specific operation.



Cranes should only be operated by the following personnel:

– Designated operators.– Learners under the direct supervision of a designated operator.– Maintenance and test personnel, when it is necessary in the

performance of their duties.– Inspectors.


Hand Signals

• It is required that a poster be posted at the jobsite with an illustration of the hand signals that every operator and personnel working with or around cranes must know.

• Hand signals for crane and derrick operators should be those set by the American National Standard Institute customized for the type of crane in use.

copyright © 2008 crane safety, subpart n

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