FAQ >> Crane Overloads and Crane Test Loads

Crane Overloads and Crane Test Loads

Crane Overloads - What is allowed?

On a routine basis, the amount of load a crane can "legally" lift, as a percent of its rated capacity, is 100.0000%, with a tolerance of +.000%/-100% (get the idea?). All kidding aside however, ASME B30.2 does provide for what is termed "planned engineered lifts" where it is necessary to make very occasional lifts (generally 2 lifts/year) in excess of rated capacity(cranes 5 ton capacity and above). The procedure varies depending on whether the lift is over 125% of the rated capacity, but generally includes a written plan, engineering analysis if over 125%, pre-lift and post-lift inspections of the crane, permanent record keeping, etc. In cases where the heavy lift occurs more frequently, ASME suggests a permanent rerating of the crane, which of course requires a formal engineering study and load test. It is noted here that OSHA 29CFR1910.179 does not, in fact, provide for or mention anything relative to such planned engineered lifts, however, in a letter of interpretation from OSHA concerning these types of lifts, the ASME procedure was deemed acceptable (reference OSHA web site).

Crane Test Loads - Acceptable tolerance

In the past, crane test loads were specified at 125% of rated capacity by both OSHA and ASME. Neither standard, however, would specify an acceptable tolerance over or under the 125% figure. The only reference to such a tolerance was given in an interpretation by ASME B30.2. Though not considered a part of the standard, this interpretation suggested a toleranceof +0%/-4% on the weight of the test load. In effect, this suggested a test load weighing between 120% and 125% of the rated crane capacity (ie: 125% - 125% x .04 = 120%). It is interesting to note here, however, that recent revisions to both the OSHA and ASME standards now suggest that the test weight be no less than 100% of rated capacity and no more than 125% of capacity. In other words, test loads equal to the rated capacity are now considered adequate. This would seem to indicate a major change in the requirements for load testing of cranes, which previously dictated a test weight of 125% of the capacity.

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