What is the final calculated horsepower value given in the example?

What is the final calculated horsepower value given in the example?

• A. 3.2 HP
• B. 4.0 HP
• C. 5.1 HP
• D. 6.8 HP

Answer: (C)

Converting an energy rate in BTU per hour to boiler horsepower uses a standard conversion: 1 boiler horsepower equals 33,475 BTU/hr. So you take the boiler’s input energy rate and divide by 33,475 to get the horsepower. In the example, the input rate is 170,000 BTU/hr. Dividing 170,000 by 33,475 gives about 5.08, which rounds to 5.1 HP. That yields the final calculated horsepower of 5.1. (For reference, mechanical horsepower uses a different conversion, about 2,545 BTU/hr per HP, which is why keeping track of the exact unit matters.)

Converting an energy rate in BTU per hour to boiler horsepower uses a standard conversion: 1 boiler horsepower equals 33,475 BTU/hr. So you take the boiler’s input energy rate and divide by 33,475 to get the horsepower.

In the example, the input rate is 170,000 BTU/hr. Dividing 170,000 by 33,475 gives about 5.08, which rounds to 5.1 HP. That yields the final calculated horsepower of 5.1. (For reference, mechanical horsepower uses a different conversion, about 2,545 BTU/hr per HP, which is why keeping track of the exact unit matters.)