A steam boiler must have two means of feed water makeup if over how many square feet?

• A. 500 ft²
• B. 1000 ft²
• C. 200 ft²
• D. 50 ft²

Answer: (A)

The key idea is redundancy in water supply for bigger boilers. When a boiler grows large, it uses more makeup water and the impact of losing a single feedwater source becomes much greater. To prevent the boiler from running dry if one path fails or is shut down for maintenance, codes require two independent means of providing makeup water. This safety approach protects against dry firing, overheating, and potential damage, by ensuring there is always a backup route to add water.

In practice, the rule is tied to the boiler’s size, using heating surface as the measure of how large the boiler is. Once it crosses that size threshold, two separate makeup water paths are mandated, not just one. So the option that reflects that standard size category is the correct choice.