Crane manufacturers design and rate overhead cranes to support a specific load capacity. But in the life of some cranes comes a special occasion: a planned engineered lift – a lift that exceeds the rated crane capacity.
Fred Rau, Crane Reliability Specialist & Modernization Engineer
Exceeding the load rating poses potential, harmful risks. These include damage or failure of critical mechanical and electrical crane components including wire ropes, brakes, hoist components and motor controls. Such failures could or can lead to dropped loads, which may result in property damage, personal injury, and even death.
However, the American Society of Mechanical Engineers (ASME) developed a specification that minimizes these risks. This specification, ASME B30.2-3.2.1.1, “Planned Engineered Lifts,” takes into account special situations when “lifts in excess of the rated load may be required … for specific purposes such as new construction or major repairs.” Consult this specification if you are considering an engineered lift.
ASME’s planned engineered lift specification directs crane users to follow certain guidelines for planned engineered lifts, such as:
- not to exceed 125% of the crane’s rated capacity
- limited to power cranes rated at least 5 tons
- limited to two occurrences on any crane within a 12-month period
In certain special cases, ASME B30.2-3.2.1.1 states, a crane user should consult with the overhead crane manufacturer. These cases include planned engineered lifts that exceed 125% of crane capacity and when a crane user requires more than two planned engineered lifts in 12 months.
The specification further recommends that a business consider uprating a crane’s capacity or replacing the crane with a higher capacity model when more than two engineered lifts are needed within 12 months. I believe that’s a good idea, as such a situation may indicate that the work processes have changed to a degree that would justify increasing crane capacity.
In addition, the ASME specification outlines several procedures that must be followed for planned engineered lifts. These include an inspection of the crane, conducted by a qualified crane professional, before and after a planned engineered lift.
Further, the specification states that the lift must be carried out “under controlled conditions under the direction of a designated person in accordance with a previously prepared lift plan.”
Learn about modernizations to increase lifting capacity
