What does the symbol refer to?

The symbol in question refers to an eccentric reducer. An eccentric reducer is a fitting that connects two pipes of different diameters, where the centerline of the larger pipe is aligned with the bottom of the smaller pipe. This design allows for a more gradual change in diameter, helping to maintain consistent flow and reduce turbulence, which can be crucial for applications where fluid flow is essential, such as in piping systems for heating, cooling, or other fluid transport systems.

The use of an eccentric reducer is particularly advantageous when dealing with horizontal piping, as it helps to manage the flow of liquid and prevent issues such as air pockets that can occur if a concentric reducer is used. The offset design of the eccentric reducer allows for better drainage and can help in maintaining a more stable flow within the system.

In pipefitting applications, knowing the specific fittings like eccentric reducers is essential for ensuring proper system design and functionality, which can impact the overall efficiency of the piping network. This understanding is crucial for any candidate preparing for the NCCER Pipefitter Certification test.