Steam is measured in which units?

• A. Cubic meters per hour.
• B. Liters per second.
• C. Pounds per hour.
• D. Gallons per minute.

Answer: (C)

Measuring steam flow is about mass flow rate rather than volume flow because the energy delivered by steam depends on how much mass is moving, not just the space it occupies. The density of steam changes with pressure and temperature, so a given volume can contain very different amounts of energy. Using a mass-based measure like pounds per hour directly reflects how much steam (and thus energy) is being supplied, regardless of the steam’s state. The other options describe volumetric flow rates (how much volume passes per unit time), which would vary with pressure and temperature and don’t consistently represent the energy transported by the steam. That's why pounds per hour is the standard way to quantify steam flow.