Calculating and Estimating RPDP In Rubber-Lined Fire Hose Lines Student Worksheet Refer to the formula for calculating RPDP on page 231 of your textbook for this assignment. 1. Estimate the pump discharge pressure required to provide 50 PSI at the nozzles in the illustrated hose lay. The nozzles are level with the apparatus. Step 1: Determine Friction Loss o Step 1A: To solve this type of problem it is necessary to determine the friction loss in each of the two 1\" lines and pump to the one having the most friction loss. Highest GPM flow is 30 GPM, so flow is _____ GPM. Friction loss for 100 feet of 1\" line is _________PSI. Friction loss for 300 feet of 1\" line is _________PSI. o Step 1B: Determine friction loss on the pump side of the wye Total flow from all nozzles is _____ GPM. Friction loss for 300 feet of 1 inch hose is ____ PSI. o Step 1C. Determine friction loss from appliances 1 appliance in the line creates _____ PSI loss. o Step 1D. Add all friction loss _____ + _____ + _____ = _____ PSI Total Friction Loss Step 2. Determine elevation loss Average difference is 0 feet, so elevation loss is _____. Step 3. Add desired nozzle pressure, friction loss, and elevation loss to determine pump discharge pressure (PDP = NP + FL + EL) ______ + ______ + ______ = ______ PSI 2. Estimate the pump discharge pressure required to provide 80 PSI at the nozzles. One nozzle is level with the apparatus; the other is 20 feet above. Step 1. Determine Friction Loss o Step 1A: To solve this type of problem it is necessary to determine the friction loss in each of the two 1 3/4\" lines and pump to the one having the most friction loss. Friction loss for 100 feet of 1 \" inch hose is ________ PSI. o Step 1B. Determine friction loss on the pump side of the wye Friction loss for _200____feet of 2 inch hose is ____ PSI. o Step 1C. Determine friction loss from appliances _____ PSI loss. o Step 1D. Add all friction loss _____ + _____ + _____ = _____ PSI Total Friction Loss Step 2: Determine elevation loss Average difference is _____ feet, so elevation loss is _____. Step 3. Add desired nozzle pressure, friction loss, and elevation loss to determine pump discharge pressure (PDP = NP + FL + EL) ______ + ______ + ______ = ______ PSI H =GL whe 1120000000000000 G =12 800 L W 8 ThenOOOOOOOOOOOOO H =( 12) (8) =96feet The forward pressure is .5 psi per foot, or F P =( .5) (96) =48psi Now, solve for the required pump discharge pressure. RPDP =NP+FL+BPF P =50+86.06+3548 = 123 .O6psi Note: No loss was allowed for the appliance as the ow was less than 350 QUESTION: A 600-foot length of 5-inch hose has been laid from a pumper into a portable hydrant. Three lines have been taken off the portable hydrant. One is 200 feet of 2-inch hose equipped with a xed- gallonage nozzle owing 175 gpm at 100- psi nozzle pressure. The other two lines are ANSWER: In this problem, the standpipe does not assume the role of an attack pumper, as only one line has been taken off of it. The problem is unusual because it involves both back pressure and forward pressure. The formula required to solve this problem is RPDP=NP+FL+BPFP First, determine the ow from the 11-inch 4 tip. Discharge =29.7D2 I P whe reOOOOOOOOOOOOO D P =50 ThenOOOOOOOOOOOOOO Discharge =( =( 29.7) ( 1.25) ( 1.25) (7.07) =328.09gpm Next, solve for the friction loss in the hose. 230 First, solve for the friction loss in the single 231 l 2 5 -inch line, then for the friction loss in the siamesed lines. H =GL whe 1120000000000000 G =12 800 L W 8 ThenOOOOOOOOOOOOO H =( 12) (8) =96feet The forward pressure is .5 psi per foot, or F P =( .5) (96) =48psi Now, solve for the required pump discharge pressure. RPDP =NP+FL+BPF P =50+86.06+3548 = 123 .O6psi Note: No loss was allowed for the appliance as the ow was less than 350 QUESTION: A 600-foot length of 5-inch hose has been laid from a pumper into a portable hydrant. Three lines have been taken off the portable hydrant. One is 200 feet of 2-inch hose equipped with a xed- gallonage nozzle owing 175 gpm at 100- psi nozzle pressure. The other two lines are FL =CQ2L wher60000000000000 C 328.09 Q W 3 .28 gpm 200 Then00000000000000 FL =( =43.03psi The friction loss formula for the siamesed lines is FL =CQ2L wher60000000000000 C =.5 Q =3.28 L =8 Then0000000000000 FL =( .5) (3.28) (3 =43.03psi The total friction loss in the hose is 43.03 + 43.03 = 86.06 psi. Next, solve for the back pressure. The line is working on the eighth oor, which is seven oors above ground level. Back pressure is 5 psi per oor, or 5 X 7 = 35 psi. Next, solve for the forward pressure