When it comes to examining, testing and recertifying air chain hoists, most companies typically follow the ASME guidelines, which are utilized to ensure maximum efficiency and safety when using lifting equipment.
A proper examination of the air chain hoist follows immediately after the client has returned it. To properly inspect the hoist, the chain is stripped from the hoist and the motor is taken out. The motor veins are reviewed for wear and if none is found, then the motor is lubricated and reinstalled inside the hoist. Next, the break disks are inspected for wear as well. If those also clear inspection, then the chain is placed inside the hoist once again and is ready to be tested.
Testing the air chain hoist is done in two fashions: dynamic and static. Dynamic and static are not vastly different from one another. The main difference is a static-load test comprises of a stationary overload-load test at 125 percent of equipment-rated capacity, which is conducted to verify the structural and mechanical integrity of the lifting equipment.
The technician takes a digital load link, hooks it up to the hoist and tests it to 125 percent of rated and stamped capacity. Once it’s pulled to 125 percent of capacity, the technician waits 10-20 seconds. If there is no failure, then it passes under load testing. This is currently the standard set by OSHA and ANSI. A dynamic-load test consists of performing an overload test at 125 percent of rated capacity and testing the following functions where applicable: hoisting and lowering of the load, and hoist-brake hold.
The same test is performed as the static- load test, except now the hoist is hooked up to a computer that can show a graph of force over time. Once it goes up to 125 percent, the technician can manipulate the hoist up and down to see if there are any deficiencies. It exceeds OSHA and ANSI standards when you can give the customer legitimate proof the hoist is tested to 125 percent and it’s not going to fail. This is the current and most efficient way to prove a hoist is ready to be used again.
Each hoist, depending on the tonnage, will be given a dynamic- or a static-load test. ASME calls for at least a static test to be performed in order to meet its guidelines. Performing a dynamic test is considered beyond its standards.
Although it is not a requirement of ASME, hoists can feature one or two methods of protection. One is an overload clutch, and the other is a Delta P. The Delta P measures the pressure differential that’s coming into the motor and compares it with the pressure that’s exhausting the motor. The differential between pressures is proportional to the load that’s on the hoist. The differential will trip the value and engage the break to protect the hoist.
The other is the overload protection function on air chain hoists. In the U.S., this is considered an accessory to air chain hoists but not a requirement. Some are designed with it, while others are not. Air chain hoists with tonnages of 3-20 will have an overload clutch as a standard on the hoist; hoists with 1-2 tonnages will not, although the Delta P valve is considered an option on the 1/4-2 tons and on hoists of 20 tonnages or higher.
When it comes to any piece of lifting equipment, a proper examination is essential to guaranteeing a successful project. Give each air chain hoist a thorough inspection to meet the standards required for safety and efficiency.
For more information, visit www.lghusa. com/bic or call (800) 878-7305.
