"But they told us we had permission to overload it twice per day. We have it in writing”.
We were amazed to hear our customer thought it was okay to overload their bridge crane. This is a dangerous proposition, and to be clear, it is never okay to overload your bridge crane. By definition, overloading means to lift a heavier weight than the rated capacity of the crane.
The customer in this case was large and busy enough to hire three different vendors, including Shupper-Brickle, to service their hoists and cranes. In one of the customer's buildings, a 10-Ton, 60 foot span, double-girder bridge crane of 1990 vintage had been recently upgraded to 15-tons. However, the customer later realized they wanted to perform a pick of 17 tons, twice per day.
When the end-user asked our competitor if they could perform the 17-Ton pick twice per day they were told that “permission” was granted. They received an explicit approval to lift more than the rated capacity or overload the crane and trolley hoist by two tons. Unfortunately, this advice disregards all standards and best practices, and it put the end-user at risk for a very serious accident.
Be advised that there are no OSHA, ANSI, ASME, CMAA or HMI guidelines allowing cranes or hoists to be overloaded. On the contrary, these industry groups specifically prohibit lifting more than the rated load on any piece of equipment. Any "permission" to irregularly lift or intentionally overload a bridge crane seriously jeopardizes the equipment and the operators.
Shupper-Brickle was given an order by the customer to perform an engineering study to examine the design of the runway and bridge. This is the only way to determine the true capacity and proceed safely. To be clear, it is never okay to overload a crane.