Which of the following are types of expansion joints?

Expansion joints are crucial components in piping systems designed to absorb movement, accommodate temperature changes, and reduce stress on the connections. Among the choices provided, bellows and slip joints are specifically recognized types of expansion joints.

Bellows are flexible devices made from metal or other materials that can expand and contract. They help absorb thermal expansion or contraction of pipes or other structural components, allowing for movement without causing damage. Their design enables them to withstand pressure and vibrations while providing the necessary flexibility to accommodate changes in length due to thermal effects.

Slip joints, on the other hand, are used to allow for axial movement between sections of pipe. They permit the connected pipe sections to slide relative to one another as they expand and contract with temperature changes, effectively managing the dynamics of temperature-induced movement.

In contrast, the other options contain terms that do not typically refer to expansion joints or describe types of expansion joints. Recognizing that bellows and slip joints both serve the purpose of managing movement and accommodating thermal expansion clarifies why this combination is identified as types of expansion joints.