Boiler horsepower - a power unit from the 19th-20th centuries - was used to rate the capacity of a boiler to deliver steam to steam engines.
A common definition of one boiler horsepower is the amount of energy required to produce 34.5 pounds (15.65 kg) of steam per hour at pressure and temperature 0 psig (0 bar) and 212oF (100oC) - with feed water at pressure 0 psig and temperature 212oF. One boiler horsepower is about 33479 Btu per hour (about 9812 watts, 8437 kcal/hr).
Boiler horsepower was used in USA, Australia, and New Zealand and have been calculated in different ways.
PBoHP = A / k (1)
PBoHP = boiler horsepower
A = heat transfer area (ft2)
k = standard area (ft2) - in New Zealand it was common to use 17, in US it was common to use 10 before year 1900 - and more common to use 5 after
Be aware that the a boiler horsepower is not the commonly accepted 550 ft lbf/s and the generally accepted conversion factor of 746 Watts = 1 horsepower does not apply.
Boiler Conversion Ratios
|sq.ft. EDR steam||240||Btu per hr.|
|sq.ft. EDR water||160||Btu per hr.|
|Boiler hp||33.5||MBtu per hr.|
|Boiler hp||140||sq.ft. EDR steam|
|Boiler hp||223||sq.ft. EDR water|
|Boiler hp||34.5||lb. per hr. steam|
|lb. per hr. steam||970||Btu per hr.|
|to||divide by above||from|
Thermodynamics of steam and condensate systems.
The International Boiler and Pressure Vessel Code safety rules governing design, fabrication, and inspection of boilers and pressure vessels, and nuclear power plant components during construction.
Combustion gross and net calorific value.
Steam boilers output can be expressed in Boiler Horsepower, MBTU or in Pounds of Steam delivered per hour.
Classification of boilers according the ASME Boiler and Pressure Vessel Code.
British Horse Power as used for pumps, fans and turbines - and how to convert to other units.
Boiler output vs. feed water temperature.