If the friction loss in 300 feet of hose is 70 psi, what will the friction loss be in 450 feet of the same size hose, flowing the same amount of water?

If the friction loss in 300 feet of hose is 70 psi, what will the friction loss be in 450 feet of the same size hose, flowing the same amount of water?

• A. 70 psi
• B. 105 psi
• C. 90 psi
• D. 120 psi

Answer: (B)

To understand the friction loss for the given scenario, it's important to recognize that friction loss in hoses generally increases in proportion to the length of the hose. A commonly used rule of thumb in fire service is that friction loss increases approximately linearly with the length of hose used when the flow rate and hose diameter remain constant. In this case, if 300 feet of hose results in a friction loss of 70 psi, we can determine the friction loss for 450 feet by first calculating the rate of increased loss per foot of hose. The rate of friction loss for the 300 feet can be considered as: \[ \text{Friction Loss per foot} = \frac{70 \text{ psi}}{300 \text{ feet}} = \frac{7}{30} \text{ psi/foot} \] To find the friction loss for 450 feet, multiply the length of the hose by the friction loss per foot: \[ \text{Friction Loss for 450 feet} = 450 \text{ feet} \times \frac{7}{30} \text{ psi/foot} \] \[ = 105 \text{ psi} \] This calculation confirms that the friction loss in 450 feet of

To understand the friction loss for the given scenario, it's important to recognize that friction loss in hoses generally increases in proportion to the length of the hose. A commonly used rule of thumb in fire service is that friction loss increases approximately linearly with the length of hose used when the flow rate and hose diameter remain constant.

In this case, if 300 feet of hose results in a friction loss of 70 psi, we can determine the friction loss for 450 feet by first calculating the rate of increased loss per foot of hose.

The rate of friction loss for the 300 feet can be considered as:

[ \text{Friction Loss per foot} = \frac{70 \text{ psi}}{300 \text{ feet}} = \frac{7}{30} \text{ psi/foot} ]

To find the friction loss for 450 feet, multiply the length of the hose by the friction loss per foot:

[ \text{Friction Loss for 450 feet} = 450 \text{ feet} \times \frac{7}{30} \text{ psi/foot} ]

[ = 105 \text{ psi} ]

This calculation confirms that the friction loss in 450 feet of