A proof load test is done on various rigging and lifting elements to make sure that they can resist the maximum design load in both lateral and longitudinal directions without unacceptable failure or deformation (yielding). To ensure that lifting devices are manufactured with the most stringent industrial safety standards, they’re subjected to a load testing rigor designed to yield to a 400,000-pound pullup. The rig is hydraulically controlled and connected to the appropriate pulling apparatus, which typically includes an overhead crane or a forklift. The device collects the design forces as the pull moves it and then applies it to the apparatus with corresponding forces. The design forces can be applied in either lateral or longitudinal directions. In either direction, the testing apparatus must show that the design forces can be produced and maintained with minimal deformation or breaking of the device.
To perform a proof load test on lifting cylinder assemblies, load cells are placed inside the assembly. As the assembly moves in various directions, the load cells generate force against them. A weight array is then placed inside the assembly, and the individual components are installed on the array. This forces each component to yield to both the horizontal and vertical forces, resulting in superior performance.
While these tests provide the verification that the designs are safe for use, the actual application is driven by strict industrial safety standards. For example, OSHA requires all heavy lifting machinery and equipment that produce power-driven loads to have continuous positive air pressure (CPAP) to prevent pulmonary disease and aspiration. Likewise, the crane used to place loads should meet or exceed the maximum limits for tension and tensile strengths stipulated by OSHA and other governing agencies. Additionally, the proof load test assures manufacturers that their products are strong enough to withstand the types of adverse conditions that are common in the workplace.
There are many reasons to perform a proof load test on your heavy lifting equipment. Perhaps you’ve had a piece of equipment fail on you because it exceeded the limits of safety. Or maybe your last inspection wasn’t thorough enough to record any issues. Regardless, of why you need to know how well your equipment performs under different conditions, performing a pre-test inspection can help ensure you have passed all necessary inspections.
OSHA requires two types of proof load test required for all machines and pieces used to lift human weight. The first type is a pull test, which verifies that the loads are safely distributed over a large surface area. The second type of inspection is a tilt test, which verifies that the loads are evenly and safely distributed over a smaller surface area. Both types of inspections are performed during the manufacture of your machines and other heavy lifting equipment. If these tests are not properly performed, OSHA may fine your company.
Safety guidelines for the test include the following: The test is divided into two phases. The first phase is completed with a static test that includes a swing test and a bottom-out test. After the static test is complete, the second phase will begin with a hydraulically-assisted test (also called an accelerated test) that verifies that the machine and hydraulic cylinders are working according to manufacturers’ recommendations. Both the swing and bottom-out tests must be completed in accordance with OSHA requirements.
The second phase of the proof load test, the accelerated test, verifies that the equipment is operating according to the specifications specified by OSHA. In this phase, the inspectors evaluate the speed, acceleration, operating condition, and angle of attack of the lifting device. These parameters are important factors when it comes to determining the safe use of a crane for lifting and the placement of materials on the device. The inspectors will also evaluate the loading and unloading speeds as well as the time required for the complete process.
The purpose of the proof load testing is to determine whether or not lifting devices are safe for the workers and the environment. This helps the organization to maintain or obtain a certification that demonstrates compliance with OSHA regulations. In order for businesses to successfully qualify for a certification, they must perform the necessary tasks as outlined by the guidelines of OSHA. There are several ways to perform these activities, but the most popular way is to hire a third-party lab. Hiring a third-party lab to perform these heavy duty proof load tests can help businesses reduce their potential liabilities, cut down on the time needed for the tests, and improve their overall safety program.