How many pounds per hour is 1 boiler horsepower?

One boiler horsepower is commonly taken as 34.5 pounds of steam per hour on the from-and-at 212°F basis.

How many BTU/hr are in one BHP?

One boiler horsepower is commonly taken as about 33,475 BTU/hr. Some references round slightly, so minor differences can appear between tables.

Can I convert BHP directly to kW?

Yes for heat output comparison: BHP × 33,475 ÷ 3412.142 gives kW. This is a capacity conversion, not electrical motor horsepower.

Why does the calculator show feedwater GPM?

The same steam mass flow must be replaced by feedwater, before blowdown and control factors. The GPM estimate is useful when moving from boiler capacity to feed pump sizing.

Is boiler horsepower the same as mechanical horsepower?

No. Mechanical horsepower is a power unit equal to 550 ft-lbf/s or about 746 watts. Boiler horsepower is a steam generation capacity unit based on evaporation.

Engineering

Boiler HP to Lbs/Hr Calculator

Convert boiler horsepower to steam production in lb/hr and kg/hr, with energy output and feedwater flow estimates for quick boiler sizing work.

What does boiler horsepower mean?

Boiler horsepower is a traditional capacity unit for steam boilers. The common conversion is 1 BHP = 34.5 lb/hr of steam and about 33,475 BTU/hr on the from-and-at 212°F basis.

Clayton Industries gives the same technical definition of BHP as 33,475 BTU/hr derived from 34.5 lb/hr of steam, which is the basis used by this calculator.

Worked example

100 BHP × 34.5 = 3,450 lb/hr steam 3,450 lb/hr × 0.45359237 = 1,564.9 kg/hr 100 BHP × 33,475 = 3,347,500 BTU/hr 3,347,500 ÷ 3412.142 = 981.0 kW

This conversion is useful for comparing boiler capacity, estimating feedwater flow, and checking whether a boiler size is in the right range before a detailed steam balance.

Why actual steam output can differ

Real boiler evaporation depends on feedwater temperature, operating pressure, blowdown, boiler efficiency, steam quality, and firing conditions. For process design, use an enthalpy balance instead of relying only on nominal BHP.

Common questions

One boiler horsepower is commonly taken as 34.5 pounds of steam per hour on the from-and-at 212°F basis.
One boiler horsepower is commonly taken as about 33,475 BTU/hr. Some references round slightly, so minor differences can appear between tables.
Yes for heat output comparison: BHP × 33,475 ÷ 3412.142 gives kW. This is a capacity conversion, not electrical motor horsepower.
The same steam mass flow must be replaced by feedwater, before blowdown and control factors. The GPM estimate is useful when moving from boiler capacity to feed pump sizing.
No. Mechanical horsepower is a power unit equal to 550 ft-lbf/s or about 746 watts. Boiler horsepower is a steam generation capacity unit based on evaporation.