Why are steam lines larger than condensate lines?

Steam lines are larger than condensate lines primarily because steam requires more volume due to pressure. In a steam system, steam is generated and distributed under high pressure, and as it travels through the lines, it needs to maintain its energy and velocity, which often requires a larger diameter to accommodate these factors. The larger diameter helps reduce pressure drop and allows for efficient transfer of heat and energy throughout the system.

The physical properties of steam, which is less dense than water, do contribute to the design of the piping system; however, this alone doesn't dictate the sizes of the lines the way the pressure and volume requirements do. While condensate lines do need to be sized appropriately to ensure that water can drain efficiently and avoid risks of water hammer, their flow requirements are different due to the fluid's density and state compared to steam. Safety regulations are also important but serve more as guidelines to ensure proper operation rather than being the primary reason for the size difference between steam and condensate lines.