Fire flow calculations is an important part of architectural design and Pro Draft can help you with that. When the fire department shows up, you might think they just open a hose and start spraying. But manually extinguishing a fire needs proper quick calculation to make sure there’s enough water and pressure to do the job. Otherwise, it’s like using a lawn sprinkler.
Whether new construction or remodeling an existing structure, fire flow calculations are as important as other building considerations.
Definition
Seconds count when a fire breaks out, firefighters need to know they have the resources available to handle a fire when they arrive at the scene.
The International Fire Code defines fire flow as the “flow rate of a water supply, measured at 20 psi (138 kPa), that is available for firefighting.” The Fire Flow Calculation Area is “the floor area, in square feet (m2), used to determine the required fire flow.”
What a fire flow calculation is not is the amount of water needed for a sprinkler system. That’s an entirely different calculation, especially since sprinklers aren’t installed in every house or building. Fire flow and sprinkler systems are independent of each other, and the available water must supply the greater of the two, the manual firefighting.
The term “fire flow” is a number used to measure and calculate the available quality water supply for a manual firefighting operation. Finding that number isn’t difficult in an established area. But determining that number for new construction in an undeveloped area can be difficult, since verifying the number requires testing the flow site at the location.
Formulas For Fire Flow Calculations
Because it’s not an exact science, there are several formulas for fire flow calculations available, including:
• The Iowa State University (ISU) formula, was created in the 1950s following multiple fire studies in enclosed spaces. The ISU ideal rate of flow is:
o Required fire flow (gallons per minute (gpm)) = V ÷ 100
o V = the volume of the space that is burning
• The National Fire Academy Formula is similar to the ISU method, but with a simpler formula:
o Required fire flow (gpm) = (length x width) ÷ 3
• The International Fire Code, widely used in the US, only requires that an approved water supply be “capable of supplying the required fire flow” provided to buildings.
This tool at Calculator Academy can give a rough estimate of a fire flow calculation but should not be used for an actual calculation for construction.
Verification Of Fire Flow Calculations
The best way to do this is simply to do an onsite flow test. But testing around new construction in a newly developed area may not be possible.
When a fire flow calculation test can’t be done onsite, it’s possible to do calculations on paper. Running a hydraulic calculation of the flow from the water supply (pump, water tower, or reservoir) to the project site can offer an estimate of an available fire flow. Once the construction is completed, it’s best to follow up with an onsite flow test.
Let Pro Draft Design Your Next Building Project
Pro Draft has been helping bring ideas to life in Maui for 30 years. We’re ready to help with drawings, interior design, “green design” with LEED certification, project management, and permit expedition.
We can help with architecture, drawings, blueprints, and permits, and answer all of your questions before the first day of construction. We’re happy to help, and will work to ensure your project is exactly the way you envision.
Call Pro Draft today at (808) 579-9050 or 1-800-499-4699 from the Mainland
