On most large fires, they are used for overhaul from 2 lines rather than laying longer and/or additional lines of 1. Calculating EXAMPLE: It is necessary to supply a deluge set with a 1 tip from 400 feet away. The San Dimas Technology and Development Center recommends that fiberglass sandbags startxref endobj ii. If leaks are present: 1. Ladder truck pumps through hose into the ladder intake, 3. But, typically you're not be able to see which nozzles are on or off. Persons Relief valve improperly set a. 100 GPM + 100 GPM = 200 GPM for both 1 lines b. Many organizations chose to leave hardware out of the Pump Discharge Pressure calculations (which is easiest). Though it may look difficult to compute, it is actually no harder than a single line. We <> The next step was to determine a target flow for our 1-inch attack lines, as it was clear from this initial test that we did not have one. 23 a. If there were two 1 lines each 600 feet in length, the discharge pressure would be 280psi and the engine would be running at excessive RPM for the job. All the calculations work the same for structure fires, vehicle fires and wildfires. 38 pounds (0.5 ft³). Add the two FL answers together and divide by two a. at a home improvement store cost approximately 25 cents each. )]?.YkXv Jb,=x97xtf^ 2. When the water is started in the supply line, the outlet valve is opened fully to allow water to flow into the riser, 5. The advertised benefit of an automatic nozzle is a wide operating range without stream compromise. Without getting too in depth, this is achieved through an internal compensatory spring that adjusts with flow to maintain a constant nozzle pressure and stream. If you don't have a GPM output gauge, firefighters will tell you if the pressure is too high or too low by radio or hand signals. For further information, contact Use the bore diameter of the nozzle 15 x 4 = 60psi FL for the total lay 4. A 150-gpm or 2.5-gallon-per-second nozzle may seem inferior to one that flows 185 gpm or three gallons per second. At the end of 2005, following a full year trail period with a variety of nozzles, the preference of our firefighters was the 78-inch smooth bore with a flow of 161 gpm at 50 psi and a nozzle reaction of 60 pounds. Relay to ladder truck pump operator (refer to relay operations) 20 EXAMPLE 1: It is necessary to supply a pre-piped aerial ladder. The lower end of the suction hose should be submerged at least two feet below the surface of the water to avoid taking in air 25, 7. Discharge Pressure formula. The aerial is elevated 50 feet above grade on a 100 foot aerial with a 2 tip (1000 GPM). Where the hose outlet extends at a right angle from the riser, the weight of the hose and fittings should be supported by a short length of rope, 6. The following are suggested methods to indicate if youre not getting into a sprinkler or standpipe system with a supply line. The only way to alter nozzle reaction is to alter the volume [gallons per minute (gpm)] or the pressure (psi). The solid bore discharge 100 + 80 + 20 = 200 pounds engine pressure 18 RULE OF THUMB for siamese of unequal size, but of equal length (2-3) 1-2 & 1-3. When higher than normal lifts are involved or at high altitudes, larger hose is needed. In general, conditions which prevent the pump from delivering the rated capacity will also affect the pressure adversely. , _S+ir4 ~QA0h&@;_+bM>nF=E{a x 3=}dXoft!fv4u*bv5Q[k{s'sG>jM Follow the manufacturers recommendation for priming ii. "2:fKa K>Dc7f5;_O~g):co0{Bm%m::U0NM%PoM!RMF^c|.5`> /Y >AX@S i"PYz&ky7Ht\bcPd$vwkG|=QIW"XwozT Itw3PfV%t,Tu+"W7UDip fSi8#xX+;h1FD($B7-"B@\z^l}l%PIy $4A,Fi[1--hEZ5E$ rh R0_{VT7Ebo ,#Mi`*Jt)M6naEDLi=4y\G%\ Worn parts in the priming valve may also allow air leakage h. High point in suction line i. D. The inability to gate and feather various pressures on the discharge port to which this line is attached a. Insufficient engine power a. Care should be taken not to attempt to take more water from the pump than it can handle at the desired pressure (see instructions on operation of pump) b. Transfer valve improperly set a. Does not apply to singe stage pumps b. <>/ExtGState<>/Font<>/ProcSet[/PDF/Text/ImageC]/XObject<>>>/Rotate 0/Type/Page>> Many people have used a variety of methods to demonstrate nozzle reaction like fish scales and rope, but the actual force is calculated using the nozzle reaction charts. sand, also available at home improvement stores, costs approximately $1.25 per Such use does not constitute an official Weak condenser or coil v. Sticking valves vi. <> Others will sometimes add 5psi loss for each appliance (gated wye & reducer or inline t) the water passes through. Understanding Pump Discharge Pressure will also help you gain a big picture understanding of fireline safety and hydrodynamics (fluids in motion). This device is equally effective with gasoline or diesel engines. FireDepartment.net strives to provide fire departments & firefighters with quality tools. The maximum time for priming for lifts of 10 to 15 feet should not exceed 30 seconds for 1250 GPM pumps or below; or 45 seconds for 1500 GPM pumps or above d. Lack of oil in the primer reservoir i. There are four ways to supply a pre-piped waterway: 1. is $1.75. The end of the hose may be submerged enough for priming, but when a large volume of water is pumped, a whirlpool is sometimes formed which uncovers the end of the hose. Field personnel have See operating instructions, 5. Chassis transmission in wrong gear a. Due to wear, the clearance between the priming pump rotors and head may become so large as to cause poor priming characteristics, 1. should contact USDA's In 2005, when we wanted to see if a nozzle study was needed for our department, one of the first steps was to take 10 engine companies, have them deploy and flow a 1-inch attack line, and record the pump discharge pressure. Learning these principals will help you with much more than calculating the correct pressure at the nozzle. Use 400 to 600 pounds of sandbags (Y}c5ZXQm1s]munO^|zw'||=_]>?N^\ {|j~upm].oi{90c.owl_mOv?rnw1O |w8=]/}nv/}}Oyq=-:O_.>dm}}yvhfu>xqo..l-;$&lysq}oOtvyw~}s}RM716umk`B~si}w?PU'8nOJNO9|F 89/? ra[A~2Sfcf `qN1mTJQvlOIhA_0 t A.r!$>ky!u06&e endobj section of hose. Each hose pack has one 100 ft 1 supply line, one 100 ft 1 attack line, one 1 Gated Wye, one 1 to 1" reducer, and one 10-20 GPM combination nozzle. The operating range of most automatic pump pressure controllers is between 75-500 pounds. All that remains is to add either the Nozzle Pressure if supplying a deluge gun or 20psi for residual pressure if supplying another engine. 36 + 15 = 51/2 = 14.4 or 15 pounds FL per 100 feet of hose, 5. 1. **gpSGMTAqU9p.RHP/tKIFHb#. Incorrect timing ii. 17. Nearly every operator stated they underpumped the lines initially to make it easier on the nozzle firefighter, and they would increase the pressure if the nozzle firefighter called for more water. Deteriorated crank case oil e. Transfer valve improperly set i. Where: therefore: for the interpretation or use of this information by other than its own Obtain the engine pressure and add as follows: 22psi loss for two 100 foot lengths of 3 feeder line 60psi loss for 100 foot pre-piped aerial, intake and master stream 25psi loss for elevation + 80psi loss for nozzle pressure 187psi will be the Engine Discharge Pressure. This can be caused by: 5. He instructs on a national level and writes for Fire Engineering. Cost The use of trade, firm, or corporation names is for the information one should hold the nozzle. 112 0 obj SIAMESE LINES TOTAL GPM FL PER 100 FEET 500 10 600 15 700 20 800 24 900 30 1000 40 WYE OPERATIONS Wye operations are very common and are used in one way or another on just about any fire of consequence. Compute the friction loss for the supply line a. Unfortunately in their good intentions is a risky business of not only underpumping (pressure) but by design also undersupplying (volume) those firefighters entering the structure. TARGET Center at (202) 720-2600 (voice and TDD). stream Close all pump openings c. Open the priming valve and operate the primer until vacuum of 20-22 inches of mercury is shown on the vacuum gauge i. Drain valves v. Gauge b. The standard outlines that the first two attack lines in operation at any residential structure fire flow a minimum of 300 gpm combined. Ladder truck pumps through internal piping to the ladder, 2. Dirt in the suction screens i. Dirt-clogged suction screens may make it difficult to prime the pump, as well as cause the pump to lose its prime after it is started ii. Forest Service, United States Department of Agriculture (USDA), its contractors, The smooth bore nozzle may be viewed by some as dated, but if you take a little deeper look at history, you can see some very sound reasoning in the smooth bore nozzle. %PDF-1.6 % two sandbags together. When it becomes necessary for a pumper to deliver large quantities of water, a siamese operation will be needed. of discrimination, write USDA, Director, Office of Civil Rights, Room endstream EXAMPLE: 400 feet of 2 hose wyed to two 200 foot lines of 1 hose. Badly worn wear rings a. He has a bachelors degree in fire and emergency services administration and a Fire Officer designation form CPSE. Once the supply line is full, there is no further movement of water. Chassis transmission in wrong gear iv. In this case, the proper clearance should be restored by the method outlined by the manufacturer in the priming pump operating instructions f. Excess carbon on exhaust primer valve seats i. Try to keep supply lines under 300 feet 2. Pressures should be approximately 50psi and should not exceed that recommended for the suction hose or pump. Calculating 2. Nozzle reaction is the resultant lbf of pushback from the combined volume and pressure leaving the nozzle. This is the amount of water for which the supply line must be computed a. Capacity limiting pressure a. In this situation would you know what to do? Divide the total GPM by two lines; this will give 400 GPM through each line, 2. When supplying a pre-piped waterway flowing 1000 GPM, a friction loss of 60psi will be used; which includes the intake, piping and master stream device. Add 100 psi as NP in the Pump Discharge Pressure formula. USDA is an equal opportunity endobj As you can see, these contributing factors all conspire together, and that call for more water never comes. Flowing the same gpm, there is a nozzle reaction difference of 21 pounds at 100 psi; at 150 gpm, the nozzle reaction of 76 pounds is at the working limit of two firefighters. If the vacuum drops more than 10 inches of mercury in five minutes, 3. Suction hose too small a. Rural Metro Fire Knox County (TN) Puts Most Expensive Fire Bicyclist Dies After Collison with Fire Truck in Grover Beach (CA). To ensure safe practices, no If your pump shows output GPM, it is important to monitor water usage (for many reasons). A nozzle firefighter struggling with a 185-gpm or 200-gpm nozzle, only operating it for 10 to 15 seconds at a time without fatiguing, who has poor stream movement is potentially ineffectively applying only 30 to 50 gallons to the fire environment at a time. Most fire departments and fire engines have a standard operating procedure (SOP) to attack a fire. hbbd```b`` ID With a Factor of Safety of 2 to 3, it Compute the friction loss for one line of 3 hose delivering 400 GPM a. %%EOF Additionally, the nozzle firefighter knows that requesting more water increases pressure, making for a more difficult line to manage. Suction hose has collapsed a. NP = [(400gpm)/(29.71 <>/Filter/FlateDecode/ID[<70EEB4D4C75A8A67836A89FF1434167B><4E3CC0AAD11DB2110A00FCF6C0B3A7FF>]/Index[110 28]/Info 109 0 R/Length 82/Prev 557779/Root 111 0 R/Size 138/Type/XRef/W[1 3 1]>>stream 4 x 4 x 2 + 4 = 36 x 0.4 = 14.4 or 15 pounds FL per 100 feet of hose, 4. A centrifugal pump is designed for a specific duty and ordinarily will perform this duty satisfactorily over a long period of time. Governor limiting engine speed v. Insufficient engine power, 3. Another use would be to get two 2 lines on a fire from one 3 supply line. Total the GPM from both 1 lines. Compute the friction loss for one line of 2 hose delivering 400 GPM a. nozzle at 400 gallons per minute? 3 0 obj A relief valve properly set will prevent the pump pressure from rising much above that at which it is set i. Consequently, too low a setting causes too low a pressure ii. Divide the total GPM by two lines. to determine the nozzle reactive force (See figure 1). endobj Insufficient pump speed a. Lloyd Layman and various others brought the fog nozzle into the American fire service, vendors started to develop automatic nozzles, and before we knew it there was a shift from a 50-psi fire service to 100 psi. When pumping directly to the waterway, an additional 20psi will be added for the friction loss in the direct piping. bag, and tightening up the second bag's fastener (See figure 3). Why 150 gpm? Fire Hose Guide," PMS 466, NFES 1308, Febbruary 1997, "Safety in Testing" A broken or deteriorated priming valve spring may cause the valve to leak and the pump to lose its prime. NP +/- H + FL + A = PDP Provide enough space on the right side of formula to enter numbers and perform calculations. added at the nozzle end to secure it in place. The following are some recommended procedures for obtaining good elevated streams: 1. nozzle at 400 gallons per minute. The basic method by which the device works is to compare the pump discharge pressure to a reference pressure stored, when the pump is set into operation, in a device called an accumulator. Ex: You need to pump water down a 600 ft mountain. the Nozzle Reaction for a 1-inch-Bore-Diameter Nozzle. Ek@$W &*@:d4zL@300RX " and the flow in gallons per minute to calculate the nozzle pressure. information (Braille, large print, audiotape, etc.) 1 0 obj Therefore, the 2 supply line is flowing 200 GPM, 2. 2 x 2 x 2 + 2 = 10 pounds FL for 100 feet of hose, 3. and cooperating Federal and State agencies. is recommended that 600 to 850 pounds of sandbags be used to counter the nozzle 20250-9410 or call (202) 720-5964 (voice and TDD). The friction loss factor for pre-piped waterways will include the friction loss in the: 3. A. provider and employer. End of suction hose not under water i. 22. Circle each of the PSI friction loss values for every hose in that path. All rights reserved. Remove any house lines, reducer connections and/or pressure reducers, 3. If necessary, additional lines can be similarly stretched to hose outlets on other floors When the fire department connection (siamese) has a frozen swivel, placing a double male and double female adapter on the connection can overcome this difficulty. %PDF-1.3 % <> Applying water or oil to the suspected points may aid in detecting leaks. section, and NFPA 1911, "Standard for Service Tests of Fire Pump Systems $ q@ @a 150 gpm at 50 psi fixed-gallonage fog: Nozzle reaction force of 54 pounds, 78-inch smooth bore, 161 gpm at 50 psi: Nozzle reaction of 60 pounds, 150 gpm at 75 psi fixed-gallonage fog: Nozzle reaction force of 65 pounds, 1516-inch smooth bore 185 gpm at 50 psi: Nozzle reaction force of 69 pounds. When the pump operators were asked why they pumped at their selected pressures, almost all responses were not flow-related; they were firefighter-related. endobj The USDA assumes no responsibility The proper size tip or fog nozzle is used for the available water supply and pumping capacity, 2. 2. Suction hose not submerged deeply enough a. This procedure usually eliminates the air pocket which was drawn into the impellers when the pump was started after first priming; however, it may have to be repeated in some situations 24 i. Suction lift too high i. Lifts of more than 20 feet should not be attempted, even at low altitudes, unless there are practically no air leaks and the equipment is in new condition, 1. Your crew has just deployed 3 Hose Packs on a small brush fire. Faulty pump packing c. Leaky pump gaskets All suction hose gaskets should be wiped clean of sand, pebbles and any other foreign matter before hose is attached to the pump. % 326-W, Whitten Building, 1400 Independence Avenue, SW, Washington, D.C. Next, compute the friction loss for one line at the reduced GPM flow and disregard the other lines. Stretch a line from the pumper to a gated outlet on the first floor, 2.
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