There are several reasons for lifting pipe off of a beam in a pipe rack, with corrosion prevention being the most common.
Right where the pipe touches the beam, water can hide and create corrosion, so many refineries and chemical plants install I-Rods for the pipe to sit on to mitigate corrosion. Before installing the I-Rods, they may go in first to sandblast and repaint where the pipe touches the beam.
Inspecting corrosion under insulation (CUI), is another reason to lift pipe in a pipe rack. When installing new pipe for new construction or removing old pipe during dismantling of a unit, the pipe will need to be lifted to install pipe rollers to ease the pipe in or out of a unit.
The standard ways of lifting pipe in a pipe rack are either mobilizing a crane or climbing in the pipe rack to install chain hoist. Mobilizing a crane involves tying up a crane that could be used for another task, not to mention getting that crane to the unit involves plenty of time and money. The crane is expensive and so is the operator that runs it. Climbing in a pipe rack to install chain-hoists to lift the pipe is inherently dangerous, but can be avoided with the right tools.
Finally there are tools that are specific to the task of lifting pipe off of the beam. Point of Contact pipe lifters from SMP, mount to the I-beam and provide up to 5,500 pounds mechanically or up to 12,000 pounds hydraulically. The Pipe Rack Jack and the BobbyJack respectively, install in minutes and can pay for themselves in one or two uses, saving the plant money and making for a safer workplace.