Presentation on theme: "Driver Recert 2012 Topics Update on Fire Hose Friction Loss Coefficients Fire Flow Through Long LDH Supply Lines Rural Water Supply Flow Rates Booster."— Presentation transcript:
1 Driver Recert 2012 TopicsUpdate on Fire Hose Friction Loss CoefficientsFire Flow Through Long LDH Supply LinesRural Water Supply Flow RatesBooster Tank Fill Rate DataEngine Deck Gun Flow Rate DataTower Monitor Flow Rate DataRescue 351 TopicsOther Stuff in General
2 Fire Hose Friction Loss Calculation Changes Are On the Way Fire Protection Research Foundation (supports the NFPA)Project: “Developing Friction Loss Coefficients For Modern Fire Hose”Start: Jun Expected Completion: Fall 2011 Summary: Current baseline friction loss coefficients used to calculate fire hose pressure loss were derived using 50 year-old hose design technology. Modern fire hose has substantially less friction loss and different performance characteristics than the hose on which these coefficients were originally based. Calculating pressure loss in modern fire hose cannot be done with reasonable accuracy using currently recognized friction loss coefficients. Pressures that are calculated with these current coefficients are typically higher than those which occur in practice In some cases this could result in elevated and potentially dangerous nozzle pressures.Research Objective: This project will develop baseline friction loss coefficients for the types of fire hose commonly used by today’s fire service, and identify any additional performance characteristics that should be considered for friction loss calculations.Affected NFPA Documents: This project directly addresses a topic specifically covered by NFPA 1961, Standard on Fire Hose (2007 edition). The friction loss characteristics of fire hose are an important consideration in the selection of fire hose but are not currently included in NFPA The next revision of this standard will address the friction loss characteristics to include updated values for the friction loss coefficients for modern fire hose.
3 Overall objective of research project was to develop friction loss char of modern fire hose and use new FL data to support the revision of the FL coefficientsCurrent FL coefs based on old hose mfg technology are considered to be outdated and overly conservativeTests conducted at 3 different test sites from Oct 2010 thru Sep 2011, final report was issued in Apr 2012Six hose manufacturers participated in tests: Key, Angus-UTC, All American/Snap-tite, Mercedes, and North AmericanTest results indicated that the majority of the FL coefs for today’s fire hose fall significantly below current valuesConclusion: A fairly large degree of variability was observed in the test data. A more thorough statistical analysis is necessary for identifying statistically significant trends. Additional testing may be required to support the analysis.
4 Friction Loss Coefficients Friction Loss Formula: FL = C(Q/100)2(L/100)FL Coefficients (C) Currently Used by the BAVFC:For 3” hose, we normally use C = 1.0 for FL calculations in the fieldFor 4” LDH, we take 1/5 of the FL for 3”; C = 1/5 = 0.2For 5” LDH, we take 1/15 of the FL for 3”; C = 1/15 = 0.07We don’t calculate FL for the 1-3/4” handlines, EP = 150 psiCurrent Standard FL Coefficients:1-3/4” hose: C = 15.53” hose: C = 0.84” LDH: C = 0.25” LDH: C = 0.08FL Coefficients for New Hose Based on Mfgs Estimates:1-3/4” hose: C = 8.0 (Ponn Conquest Hose)3” hose: C = 0.44” LDH: C = (1/11)5” LDH: C = (1/30) (Key Fire Hose)
5 Example of Reduced Friction Loss in Modern Fire Hose Recent rural water supply test conducted in Rincon, GA to support ISODetermined how much water flow can be provided through a very long 5” LDH supply lineSeveral engines laid a 6,000 ft. 5” supply lineWhat is the maximum water flow (GPM) that can realistically be supplied through this supply line?
6 Hydrant Static Pressure Hydrant Residual Pressure Booster Tank Fill Rate TestHydrant LocationHydrant Static PressureHydrant Residual PressurePump Intake Valve UsedPump In GearTank Fill RateEnterprise Ct.(Box 313)45 psi35 psi2-1/2” AuxNO215 GPM20 psiYES375 GPM2-1/2” DTF-Selvin Dr. (Box 321)90 psi70 psi300 GPM575 GPMKEY COMPARISON:Filling the tank with 3” line into the Direct Tank Fill intake at 100 psi intake pressure takes about 1 min 15 sec for a fill rate of 600 GPMFilling the tank using the regular Tank Fill valve with pump discharge pressure at 100 psi takes about 2 min for a fill rate of 375 GPM
10 Q smooth = F x D2 C = Q2smooth Pinline - Ppitot Q auto = DETERMINING FLOW WITH PRE-PIPED MONITORSThe simplest procedure to determine flow with automatic nozzles is with a flow meter. If a flow meter is unavailable, then the flow may be estimated using pressure loss data between the nozzle and an in-line pressure gauge at the pump or considerably upstream from the nozzle. Data is taken with a smooth bore nozzle and handheld pitot gauge. Note: Equations assume no substantial change in elevation between in-line pressure gauge and nozzle.Step1: Determine flow of smooth bore nozzle.Flow water with a smooth bore nozzle and record the nozzle’s size, pitot pressure and in-line pressure gauge reading. The smooth bore nozzle’s flow is calculated from the Freeman formula:Where:F = for English units (GPM, INCHES, PSI)Q smooth = F x D2 Q smooth = flow in GPMD = exit diameter in INCHESStep 2: Find pressure loss constant.Using the results from step 1, use the following equation to calculate the pressure loss constant between the in-line pressure gauge and the nozzle:C = piping pressure loss constant in GPM2/PSIPinline = in-line pressure gauge reading in PSIPpitot = pitot pressure in PSIStep 3: Calculate flow with automatic nozzle.Using the pressure loss constant from step 2 and the following equation, the flow with an automatic nozzle can be calculated for your particular installation.Qauto = automatic nozzle flow in GPMPauto = nominal nozzle operating pressure in PSIQ smooth = F x D2C =Q2smoothPinline - PpitotQ auto =
17 New Special Tool on Rescue 351 Modified hydraulic fitting designed to relieve the hydraulic pressure on an Amkus HRT line that had become pressure locked in the field.This condition is caused by the charging of a hydraulic line without an HRT being hooked to the line.Without the use of the new special tool, the pressure in the locked line could only be relieved (bled off) back at the station and not in the field.
18 New Special Tool on Rescue 351 New Special Tool CouplingTool Stowed in LR Compartment
19 Pressure Relieved on E314 Line Pressure Relieved on R351 Line
22 Other Stuff in General What’s unique about the Siren Brake on TW331? What’s different about the Transmission Mode control on TW331 and R351 compared to all of the other apparatus?If you turn OFF the Auxiliary Braking Device (Jake Brake or Trans Retarder) in rainy weather, what should you also do regarding your driving?What should a good EVD always do immediately following each run?