Boiler Room Formulas

Reduce your business’s operating costs by increasing boiler room system efficiency. Before targeting a specific area for improvement, ensure you understand the primary conversion factors and formulas. Boiler room formulas are among the most valuable tools in boiler room management. Calculate the ideal steam boiler size, determine your water softener’s requirements and know the capacity you need to heat your water.

Boiler Room Conversion Factors

The most critical conversion factors when using boiler room formulas are:

• Pounds of steam (water) per hour (PPH): Boiler horsepower (BHP) x 34.5
• BHP: PPH ÷ 34.5
• Gallons of water evaporated per minute: BHP x 0.069
• British thermal units (BTU) per hour: BHP x 33,479
• Square feet of equivalent direct radiation (EDR): BHP x 139
• Gallons of water per minute (GPM): EDR x 0.000496 or lbs/hr x 0.002 
• Feet of water: Pounds of water per square inch (PSI) x 2.307
• PSI: Feet of water x 0.4335
• Gallons of water: Cubic feet of water x 7.48
• Pounds of water: Gallons of water x 8.345
• Pounds of water per minute (lbs/min): Cubic feet per minute x 62.43
• Gallons per hour (GPH): Cubic feet per minute x 448.8
• Parts per billion of oxygen: Cubic centimeters per liter of oxygen x 1400

Essential Formulas for Boiler Room Management

Several of the most critical formulas needed for successful boiler room management include:

Water Softener Formulas

Use these formulas to determine your water softener’s workload:

• BHP x 0.069 = GPM
• GPM x 60 minutes x hours of operation = Gallons per cycle
• Gallons per cycle x grains of hardness = Total grains requiring filtering

Calculating the BTU Needed to Heat Water

Verify the power you need with these calculations:

• GPH x temperature rise x 8.5 = BTU
• BTU ÷ 970 = PPH
• GPM x 8.5 x 60 = BTU
• BTU of boiler ÷ BTU = Temperature rise

Sizing Feedwater Pumps

A receiver tank should have the capacity to hold 10 minutes of condensate for boilers over 200 BHP and five minutes of condensate for boilers under 200 BHP. Enter the correct information into this formula: 

• BHP x .069 x minutes of storage x 1.33 = Receiver size, in gallons

Determining Cubic Feet of Gas

Use these equations to determine the necessary volume of gas:

• BHP x 42.175 = Standard cubic feet per hour (SCFH)
• BHP x 33,475 = BTU output
• BTU output x 1.25 = BTU input
• 100 cubic feet = 1 therm
• 1 therm = 100,000 BTU

Discover More With Smith Hughes Today

If you want to learn more about formulas for boiler room management and how they apply to your operation, the professionals at Smith Hughes can assist you. Since 1946, we have been a national leader in providing boiler products, rentals and services in the hot water boiler and process steam markets. Connect with our team online today to request pricing or obtain more information on our products and services.