How do you calculate the friction loss for dual supply lines?

To calculate the friction loss for dual supply lines, the procedure involves understanding how flow behaves when multiple lines are utilized. Typically, if two lines are being used in parallel, the flow rate can be considered separately through each line, and they effectively share the total flow rate of the incident.

When determining friction loss using the total GPM (gallons per minute), it's essential to recognize that when each line carries an equal amount of water flow, the total GPM effectively is split between the two. Therefore, dividing the total GPM by two applies because each individual line would be experiencing the flow at half the total capacity.

Thus, this division allows you to accurately calculate the friction loss, reinforcing the understanding that friction loss calculations depend directly on flow rates carried by the pipes. By aligning the friction loss calculations to reflect the actual flow in each line, the operator can make more precise adjustments and evaluations regarding pressure needs and overall efficiency in fireground operations.