FREQUENTLY ASKED QUESTIONS
|This FAQ section contains some of the most frequently
asked questions regarding our products and other related information. The FAQ's
have been split into categories. Just click on the FAQ category to see the
If you have a Question(s) you would like us to consider...SUBMIT IT HERE!
Please Note, all questions are worded exactly as received by the person making the request.
|Deicing||Foam||Industrial||Large Diameter Hose Hardware||Miscellaneous||Monitors||Nozzles||Remote Controlled Monitors||Repair||Suction Hose||Tactics||TFT Company Questions|
|1||What is the correct pressure to pump an inch and three quarter handline?|
|Answer: The best answer would be....it depends. The pump pressure required is going to be ENTIRELY dependent on the flow YOU want to deliver. A common error some departments make is they assume just because they change to TFT automatics and 1 3/4" hose line, that they automatically are now delivering 200 GPM. Not so... UNLESS they are pumping the pressure (at the pump) necessary to deliver that flow. An automatic constant pressure nozzle uses the same flow hydraulics and calculations as any other type of nozzle. The main difference is that we KNOW what the nozzle pressure is going to be. Therefore, we eliminate the one variable in the equation that we did not know before. Using the standard formula of pump pressure (PP) is equal to the nozzle pressure (which we know is going to be approximately 100) plus the total amount of pressure losses due to hose size, length, elevation, device losses etc. Because we are working with basic "fireground 2 o'clock in the morning" type hydraulics, we can simplify the equation to be:
PP=NP+FL (FL=Hose Friction Losses) (the other losses are of less consequesnce)
Now it becomes a much more simpler question. Let's say we want to deliver 150 GPM through the 1 3/4" hose line. Using a slide chart, table, hose manufacturers data, or other source for hose losses, we find that a flow of 150 GPM corresponds to a hose loss of about 35 psi PER 100 feet of hose. If the hoseline is 150 ft. long, then we would take 1.5 times 35, or 52.5 psi. If it is 200 ft. long, then it is TIMES 2, or 70 psi hose loss.
What's the nozzle pressure? Of course, we know it is going to be about 100 psi, so we add that to the hose loss to get our required pump pressure.... for 150 GPM....
150 ft. = 150 psi pump pressure
200 ft. = 170 psi pump pressure
(note: I typically round all calculated numbers to the nearest 10 PSI. There are so many variations in hose types, and interior finishes that to "split hairs" any further is simply not practical on the fire ground. In a classroom maybe, but when pressure gauges typically flutter and bounce 5-10 psi, what is the point of trying to obtain 152.50 psi?
Finally, what happens when we have the same 150 ft. preconect and we increase the pump pressure to 200 PSI? Since, the nozzle pressure remains constant, we now have 100 psi for hose losses. Divide by 1.5 and we get the loss per 100 feet, or 66 psi. Again referring to your hose friction loss chart, this equals a flow rate of 200 GPM.
If you are using a Mid Force Dual pressure nozzle, rather than a single pressure nozzle, the nozzle operating pressure should be substituted. This is the reason that with the same hose length and pump pressure, the Mid Force will deliver more actual GPM, because there is about 30 psi (100-70) additional pressure which is used to overcome additional hose losses.
For additional information on calculating flows and pressures with automatic nozzles, refer to TFT publication LTT-010, "A Guide to Automatic Nozzles" available here on the TFT website, or available free of charge by calling 1-800-348-2686 email@example.com
|2||Who invented the automatic constant pressure nozzle?|
|Answer: The original automatic nozzle was designed on a paper table napkin by Chief Clyde H. McMillan on May 10th, 1968. The original hangs to this day in the conference room at Task Force Tips. (take the virtual TFT tour, Conference Room to view)|
|3||Can the Master Foam nozzle with a foam pickup tube that is LONGER than 8 feet?|
|Answer: Normally NO! The concern is that someone will attempt to use the nozzle to lift foam higher than just a few feet. If what is required is to move foam horizontally from a slightly greater distance it is likely possible. Please consult the TFT engineering department before attempting to do this in actual practice.
The 8 foot limitation on the TFT Master Foam is the same as the limitation on any self inducting foam nozzle. (Williams,or Elkhart)
This is a question of logistics: How does one get enough foam to feed one of these nozzles when it is flowing? The unfortunate truth is that many fire departments simply have not worked out an adequate system to deliver foam to supply this type of foam nozzle, and are under the impression that by means of a "bucket brigade" they have a workable foam device. In some cases the entire supply might consist of less than fifty gallons of concentrate total. Please refer to our MANUAL on the MASTER FOAM, part # LIZ-030 for foam requirement information.
Each department must work out the logistics ahead of time on a case by case basis, using one of these methods: (1)Draw from a reasonable-size reservoir built into the truck, and re-fill the reservoir using a pump, or some other means. (2)Draw from a mobile of fixed reservoir. (3)Pump concentrate to the nozzle using a metering/transfer pump. or (4)A bucket brigade to the truck could be made to work with planning and training, and an adequate supply of foam. In some cases, none of the above may be adequate. In this instance, we DO NOT want to encourage anyone to attempt to use a nozzle of this type. Liquid hydrocarbon fires are very hazardous, and unless you are prepared to make a serious attack, it is best to evacuate, and simply leave it until it burns out or other resources can be arranged. An extension to the ground off a truck will result in weak concentrate on all nozzles of this type. This should not be done as it produces significantly less effective foam production.
|4||What is the 'standard' nozzle pressure, and what is considered to be a "low pressure" nozzle? I know that the lower pressure nozzle has lower reaction (for the same flow), but do you loose anything with a low pressure nozzle?|
|Answer: Standard nozzle pressure is considered by NFPA and most training manuals as 100 Pounds Per Square Inch. There is nothing magic about this number and no one seems to know where it comes from. Low Pressure nozzles are any nozzle that is designed or used at a pressure below 100 PSI. As nozzle pressures go down the stream VELOCITY or SPEED goes down. The slower the speed the less impact that the stream will have and the shorter the distance it will travel. Just as higher muzzle velocities out of a rifle allow the bullet to go farther accurately, higher nozzle pressures allow the stream to go farther as well.|
|5||The 2.5 inch in line ball valve from KK Products has only a 1.375 inch hole thru the valve. Some manufacturers make a 2.5 inch inline valve that have a 2 inch hole. Isn't the 2 inch hole better??|
|Answer: Yes the 2 inch hole is better but how much is enough is the question. A 2.5 inch valve with a 1 3/8 ball only has 3 PSI of loss at 250 GPM, the lighter weight and smaller size make this an excellent trade off.|
|6||A sales person from another company said that a spinning tooth pattern did not have any fingers, and all fixed tooth nozzles would. Is this true for a TFT nozzle fog pattern?|
|Answer: This is more a testament to the long term marketing of the spinning tooth nozzle, developed in the early 1960's. First and foremost, the spinning tooth nozzle DOES HAVE A DEFINITE TOOTH (GAP) in the pattern. However it is curved, not straight. Here is the problem. Just looking at it, you can't see it with your own eyes.
In a movie, the film is made up of many individual pictures, or frames. By playing them rapidly at 15-30 frames per second, the human eye (and brain) blends the images together to look like one continuous motion. Likewise, the eye also blends the curved and spinning tooth gaps together to make the pattern APPEAR to be a solid cone, when in fact it has more gap to it than some fixed tooth designs and especially the TFT. This can easily be proven by looking at the pattern not as WE see it, but rather as the FIRE 'sees' it. Fire is a radiant heat energy wave moving at the speed of light. If it is not hitting an actual drop of water, it will pass easily through the spinning pattern to the firefighters behind the pattern. The closest we can get to simulating this, is through high speed photography. If a high speed photo is taken of the spinning tooth pattern, the gaps in the pattern become easily apparent. The result is the hollow cone of the spinning tooth pattern is easily penetrated by the radiant heat. Therefore, the sheet of water coming out of the nozzle has significant, (though not visably seen) spaces in the cone.
|7||I noticed that the teeth on the TFT have a small curve to them, where all other nozzles do not. Why is this?|
|Answer: The TFT Fog Teeth are covered under claims allowed under US Patent 4,653,693. Although it is fairly obvious how we beat the water back on itself, to fill the pattern, it is not as obvious how we fill the tooth gaps.
Imagine... You are sitting out on a hot summer day with a tall glass and a pitcher of ice cold lemonade. As you go to pour the lemonade out of the pitcher into the glass you do it quite slowly. What often happens is the liquid, rather than falling straight down will follow the curved lip of the pitcher backwards, causing the lemonade to run down the side of the pitcher and land, ice cold on your leg. This is called the Coanda Effect named after of course, a Dr. Coanda who studied the affects of surface tension of water. Pouring the liquid faster, usually results in the water landing in the glass, rather than running down the side. here's why...
For water moving at a given speed (velocity) there is a curve which the water will follow rather than separating. Here is a key element. the automatic nozzle is constant pressure right? Therefore, the water, although it varies in volume, is almost always exiting the nozzle at a constant velocity Because the velocity varies little, TFT Engineers were able to match a CURVE to the tooth which matches the velocity and therefore the water leaving the nozzle FOLLOWS THE CURVE OF THE TOOTH!!
This results in the 'finger' reconverging just an inch or so beyond the nozzle. At this point it truly is, a solid cone of water, which is fully saturated within the pattern as well.
|8||Can a Metro small body nozzle be configured as follows: 150 GPM @ 50 PSI? Or is 75 PSI required to flow 150 GPM?|
|Answer: Unfortunately no, that amount of flow at a low pressure is too much for the stream shaping ability of the small body. The stream would not be something that would be deemed acceptable by most.|
|9||I am in the process of specing out a new fire truck with a 1000 GPM pump and a CAF's system on it. "what kind of nozzles will I need.?"|
|Answer: We have primarily seen people using smooth bore nozzles on CAFS systems. The size would depend on your particular systems capabilities. We would suggest that you talk to your truck manufacturer for reccomendations.|
|10||I am looking for a nozzle for a "high rise pack" that can handle standard operating pressure and have an emergency setting for pressure loss. Or a good "break away" type nozzle.|
|Answer: No problem on that one! If you are looking for a high rise type nozzle with TWO pressure settings, there really is only one choice in the market, and that is the TFT Dual Force or Mid Force Nozzles. Though they are different in size and flow ranges, both series have the unique feature of being able to switch the nozzle operating pressure, from the standard 100 psi, to a reduced emergency pressure. This is also useful any time that pressure loss (for instance due to a pumper breakdown) occurs... For Break and extend, both series are available in the T-O Tip Only version, or STO Shutoff Tip Only models which can be combined with separate valve shutoffs. Here are some of the links for these items.|
|11||We do not use a standard USA coupling, but rather we use 2.5" British Instantaneous Connector. Does TFT make this nozzle coupling available?|
|Answer: Yes BIC connectors (the male side) are available for all TFT nozzles. In addition, many other types of couplings are available. Consult the table for couplings shown in the Product Specification or Price List sheet for more information. If you are unclear as to whether your coupling type is available, please contact the TFT Sales Department.|
|12||If the maximum length of the foam intake hose for the Master Foam nozzle is 8 feet, and the nozzle is fitted on a pumper deluge gun, how can it be adequately used when most pumpers are not set up to carry the volume of foam concentrate required when the nozzle is flowing at maximum with a 3% foam. In most cases, the foam supply would have to be at ground level, given the speed at which a 5 gallon pail is sucked dry. With the configuration of pumpers today, a lot of them would have the deluge gun at a height of 10' or more. thanks.|
|Answer: In a nutshell you are correct that it can be a real problem. The fire department MUST keep this limitation in mind when designing the truck. Two thoughts come to mind. First of all the department can consider the use of 1% foam. With a five gallon pail of 1% a 500 GPM booster tank can be applied before foam runs out. A second solution that works well with 3% or even better with 1% is to mount a foam tank on the top of the truck near the monitor. Some departments have a sub tank installed in their booster tank specifically for holding foam. Mother nature only provides 14.7 psi of "push" if the nozzle is making a perfect vacuum which it cannot. Therefore we have to live with a limitation of not only how high the nozzle can be above the foam supply but also how long the hose can be.|
|13||Does TFT sell a penetrating nozzle? I am an instructor and I have been asked about this type of nozzle.|
|Answer: Yes, in fact we make two different kinds. We make a "wand" style that attaches to our Pro Pak foam unit. This wand is about 3/4's of an inch in diameter and is used primarily for hay fires, it flows about 10 GPM. We also make a unit that attaches to a 1.5 inch line. It is about four feet long, has an angled point and delivers 95 GPM at 100 PSI.|
|14||Please relay the latest info on the debate concerning fog/automatic nozzles vs. smooth bore|
|Answer: There really is no current info on the status of the debate. There have been debates in the fire service over automatic transmissions, colors of trucks, leather helmets, rubber coats, siren types, nozzle types, wooden versus metal ladders, in each case there is eventually a winner some just take longer than others. The time factor is controlled by emotion, tradition, and availability of facts that people can see feel and understand. The reason that the smooth bore versus fog argument has gone on for so long is that in general a clear understanding of fire hydraulics is a thing of the past for most people. Our position which has never changed is that the water puts out the fire and we want to provide equipment that delivers that water with the most options for the fire fighter. When people compare a smooth bore against a fog nozzle they almost invariably maintain the same PUMP Pressure for the comparison. When a 50 PSi nozzle is compared against ANY nozzle even another smoothbore that is at 100 PSI it will flow more water for the same hose lay. For a given pump pressure the lower the nozzle pressure used the more pressure goes into friction loss and the higher the flow achieved. If the ONLY goal was flow then the ultimate nozzle would be a coupling itself as that flows the most water possible. The reason that does not work however is because we expect more out of a nozzle. We expect reach, pattern control, flow control, penetration, action out of a nozzle. What we see happening over and over is that a department lets its pump pressures gradually sink lower and lower as they encounter the "everyday" fire and even tho the flow has been reduced they "get by". Then they get a big one, the low flow doesn't cut it, and so they put on the new fangled low pressure smooth bore and get results. They conclude that the NOZZLE is what increased the penetration when in fact they doubled or tripled the flow and it is the increased FLOW that did the job. Had they simple brought the throttle up on that expensive fire truck that was bought to PUMP WATER they would have not only delivered that flow they would have also delivered it farther, with more impact, with more stream action, than a 50 PSI nozzle. Think baseball, which pitcher hits hardest, goes the farthest, has the least amount of drop to the ball, the slow pitch or the fast pitch?? Same principle applies to water which is nothing more than millions of tiny balls (droplets) being THROWN out of a nozzle. The faster they come out the farther and straighter they go before being pulled by gravity to earth. Thats the nozzle part, the tactics of when to use a straight stream and when to use a fog are yet another FAQ. I would highly suggest that if you have the opportunity of seeing the video called "FIRE" on the discovery channel please do so. It will change your mind about what the real seat of the fire is and WHERE it is.|
|15||What is the correct pressure to pump to a TFT handline|
|Answer: The pump pressure you choose is TOTALLY based on the size of the hose and what you want to flow. In the post that opened this thread there is a comment about 100 PSI at the nozzle versus 200 PSI at the nozzle. Not so!! An automatic nozzle BY DEFINITION maintains a CONSTANT pressure at the nozzle. Think of the nozzle as a screen door with a spring. If the wind is light the screen door does not blow open. As soon as there is enough wind to overcome the force of the spring on the door it starts to move and let some of the air go around the screen. The harder the wind blows the more the door opens but the FORCE against the door is constant as set by the spring. The automatic nozzle is the same thing. It has a spring and it maintains a constant pressure if the wind blows harder (higher pump pressure) more wind goes through the door opening (around the door. If the pump pressure is INCREASED the nozzle opens up so that the increased FLOW uses more FRICTION in the hose to eat up the increased pressure. If the pump is 150 the nozzle will set itself to a flow that allows just enough water to flow to equal 50 PSI of friction loss so that 100 is left over at the nozzle. If the pump is increased to 200 the nozzle will open more (the door swings) and it will let more water flow which increases the loss in the hose to where it equals 100 PSI. 100 at the nozzle plus 100 in loss equals 200 in that case. This is one of the neatest features of automatic nozzles, if the line needs more flow all you have to do is increase the pump pressure and you will get more flow and it happens without the operator having to set dials on the nozzle all he has to do is open the bail. There is a LOT of information on this topic at the TFT web site address www.tft.com. The short answer to your question would be "Determine what flow you want to start with, figure the friction loss for the hose length that you use either by using charts or by experiment, add the pressure that you come up with to 100 PSI and that is the pump pressure"|
|16||What is the current NFPA recommended flow for interior structural firefighting with a 1 3/4" line?|
|Answer: NFPA does not make recomendations on this that we are aware of. Iowa State, Oklahoma State, Texas A & M all have circulars and books that cover the wide range of conditions that must be examinned to determine this flow rate|
|17||Does TFT make nozzles that are suitable for use on high voltage. A use such as would be encountered in a power plant for example?|
|Answer: We have made this type of nozzle on special request on numerous occasions in the past. There are several critical characteristics of nozzles that make them safe or unsafe for use in electrical situations. They all involve the insulation of the firefighter from the electricity by means of space, in the water droplets such that the charge can not reach backward, and in physical distance of the firefighter from the electrically charged fire. Usually the testing is done on a very high voltage grid, where the amount transferred can be consistently measured. These four important elements are: 1. Limitation of pattern- all electrical type nozzles are limited in the travel of the stream shaper to eliminate the straight jet or stream position. In a straight stream the droplets are too close together and therefore the pattern is limited to about a 30-45 degree fog pattern as a minimum angle. 2. Water droplet size in the fog pattern- also a factor of nozzles pressure- when using a fog pattern in this application a higher pressure at the nozzle will produce a smaller droplet size, which likewise increases the amount of space between the individual droplets. An automatic nozzle in this application works quite well, since by maintaining a consistant nozzle pressure, it also maintains the droplet size in the fog pattern. With lower pressures, the droplets become much larger "globs" which allow more electrical energy to be transfered. 3. Stream Velocity - a factor of nozzle pressure - this has an effect on the electrical transfer. The higher pressure stream leaves the nozzle at a higher velocity. 4. Water purity: Dirty water; water which carries a significant amount of particulate matter will transfer electrical energy more readily than clean water free of this dirt and minerals etc. This has an effect on the insulation properties of the water, however this is not a factor which can be effected by the design of the nozzle. TFT nozzles have been made with the "Electrical" modifications, and have been used and specified by many agencies. however, due to the limited sales of this nozzle type, we have not obtained an official "Listing" such as with UL. However, several power organizations in the US as well as national electrical companies in France and Germany, have tested the nozzle modifications with excellent results and in following to the tests specified the TFT nozzles with these modifications. This testing is available on request...|
|18||At what point on an automatic nozzle is the 100 psi to be maintained? Is it at the base of the nozzle at the inlet screen, so that an in-line gauge would indicate 100 psi, or inside the nozzle where the water strikes the deflector. Also, what are the actual inlet pressures going to be? Will they stay close to the same for any given flow within the nozzle's range or will they increase and decrease as they do on a fixed gpm or adjustable gpm nozzle?|
|Answer: The goal is to maintain accurate EXIT velocity which means maintaining the nozzle pressure at 100 PSI at the exit. We do this at the factory during the nozzle design phase by small pitot tubes made with hypodermic needles that protrude thru the front baffle into the stream. Clearly that is not practical for the fireground. You are right that there will be variation if measured behind the nozzle. As the flow goes up the losses acrosss the "gasket grabber" screen also go up as well as the losses in the valve. Frequently people try and get far too accurate with nozzle pressures. Consider this fact (which adresses your second question). Lets say that an automatic maintains nozzle pressure plus or minus 20 psi over a flow range from 50 to 200 PSI, some would say that would be terrible accuracy and unacceptable. Lets compare that to a fixed gallonage 200 GPM nozzle. That 200 GPM fixed gallonage nozzle delivers that GPM at 100 PSI. If the flow is only 100 GPM the nozzle pressure falls to 25 PSI!! and if you went on down to 50 GPM it would be only about 12 PSI. Now which nozzle is "Accurate"???|
|19||Why do sidewall pressure gages not read accurately at high flows?|
|Answer: Any pressure measurement that involves flow in a pipe is a summation or total of two components. One component is called the Velocity Component and one is call the Static Component. When a gage taps into the sidewall of a pipe it is unable to measure the velocity component. When the pipe is capped off and not flowing then the pressure is all static component and so the gage reads accurately. As the flow goes up more and more of the pressure is in the velocity component, this ratio just like friction loss varies as the square of the flow which means that as the flow doubles the affect of the velocity component multiples 4 times. When measuring 95 GPM flows on a 1.5 inch coupling the velocity component is only a few PSI but as that flow goes up to 200 GPM with a 1.5 inch coupling on a 1 3/4 inch hose now that velocity component becomes in excess of 12 PSI enough that someone trying to make accurate measurements will be confused by. The solution to this problem is to use an in line pressure gage that has a small pipe that protrudes into the waterway so that it measures the total pressure not just the static pressure. All TFT in line gage adapters have this feature.|
|20||Why is it reccomended that all the nozzles on a particular apparatus be of the same type. For example all automatic or all manual.|
|Answer: Automatic nozzles provide a variable orifice and the purpose of that is so that you get your pressure FIRST such that a working stream is obtained with the lowest flow possible. As the pump pressure is then increased above the nozzles operating set pressure the additional pressure goes into friction loss such that the flow increases. In this manner you always have a properly pressured stream. Now lets contrast that to how a fixed orifice or manual nozzle works. It has a fixed HOLE or orifice as the flow is increased to that orifice the pressure starts to go up. One fact that comes as a surprise to most people is the relationship between flow and pressure on a manual nozzle (same applies to a smooth bore as it is fixed also). If a manual nozzle is rated 200 GPM at 100 PSI and it is flowing one half that amount or 100 GPM the nozzle pressure falls to 25 PSI. Most would guess that the nozzle pressure would be half as the flow is half, not so, if the flow falls by half the nozzle pressure falls by the square or to 1/4 in this example 25PSI. The reverse is also true if you have a nozzle that is rated 95 GPM at 100 PSI it would take 400 PSI NOZZLE PRESSURE! to achieve 200 GPM out of it. This background information is required to answer your question as it is the fundamental reason that mixing nozzles can cause a problem. To illustrate lets use an example of where there is a 200 GPM automatic and a 200 GPM manual off the same pumper and the total flow available to the pump is 200 GPM (Imagine for example we are off the tank and it has a 2.5 inch tank suction). The manual nozzle will start taking water immediately and the automatic will choke off and try and make the pressure build. As the pump pressure is increased all of the flow will go to the manual nozzle until the pump pressure exceeds the automatic nozzles operating pressure at which point it will start to open. The problem is that the manual nozzle will be at full flow before the automatic starts to open up and so that stream out of the manual will look correct and the automatic will be short of flow. This condition frequently leads people to the WRONG conclusion that the manual nozzle is more efficient or works better. NOT TRUE. Had it been two MANUAL nozzles they would have only gotten to 25 psi nozzle pressure (100 GPM each) which would barely squirt past your boots. Had they been two automatic nozzles they would have each opened at the same time and shared the water leaving each at 100 GPM at 100 PSI. As an added benefit as one nozzle is shut down the water will move to the opposite line as that nozzle opens to accept the flow. Having automatics on all lines allows the water to be shared and balanced always maintaining proper nozzle pressures. Another way to think of it is like MAST pants. Why do we put MAST pants on an accident victim? The purpose is to move the blood out of the areas that don't have an urgent need and make it go to the areas that do have an urgent need. The pants help to increase the system pressure. Automatic nozzles do the same thing.|
|21||I need some specifics on 2 (two) inch attack line using your 50-350 gpm nozzle. That is, using a 200 ft. section of 2 in. what gpm is generated at engine pressures of 150 psi, 160 psi, 180 psi, and 200 psi using that particular nozzle. Also, what would the nozzle pressure be at these pressures? We are currently using 1.75" and want to move to a little bit larger diameter attack line and need some info.-Thanks!|
|Answer: By using the basic friction loss formulas published in the NFPA Handbook the following numbers will give you some idea about the increase in flow you can expect with 2" over 1 3/4" lines. This is based on a 200' section. (PDP 150psi 1 3/4" - 125 gpm 2" - 180gpm)(PDP 175psi 1 3/4" - 160gpm 2" - 205gpm)(PDP 200psi 1 3/4" - 180gpm 2" - 235gpm) You can see by the comparison that 2" line though somewhat heavier than most 1 3/4" lines does offer quite a bit more flow at the same engine pressure. Certainly, individual hoses offer different flow characteristics, so you should do your own field evaluations before you make your decisions. Secondly, your question about nozzle pressure is simply answered. As an automatic nozzle, the Handline throughout it rated flow of 50-350gpm operates at 100psi + - 15%. This is directly corresponding to the flow and pressure specifications called out in the NFPA 1964 Standard (1998 edition)on hand held nozzles.|
|22||Do you sell a retro kit to install a pistol grip on a TFTH series that is a break apart (50 - 350)?|
|Answer: The short answer is no but there is a reason. The main feature of most TFT nozzles is the slide valve. The slide valve design cannot be used in a breakapart nozzle. When we make a breakapart nozzle we utilize a ball valve. It would take an entirely different set of parts to make a normal TFT into a breakapart style.|
|23||Our Dept is considering switching to 75psi nozzles with 1 3/4" hose. I would like to know if there are any other depts. running this combo. Also i would like to know if they encountered any problems with kinking while doing fire suppresion.|
|Answer: There are many many departments that have gone to 75PSI nozzles. It does lower the reaction force some and allows slightly higher flows for a given hose layout and pump pressure. Clearly the lower the pressure the more a hose will kink. The interesting thing about kinks however is the dynamic that takes place when the hose kinks. When the hose kinks the flow is occluded and when that happens the prsssure starts to rise to the level of the source (pump). If the pump pressure is low then there will be no assistance to getting the kink out. But if on the other hand the department is keeping the pump pressure up in the range of 150 or above and using the lower nozzle pressure to deliver high flow rates thru increased friction loss then when the kink occurs the pressure increase will work to reopen the line. The best advice that I have is to make sure that fire departments understand that not all hose has the same kink characteristics. Yes it is true that there is a wide range in hose prices but people should not be quick to assume that the price is high without cause. The higher priced hose is woven on special equipment at a slower rate which dramaticly improves the kink resistance but unfortunately makes it more expensive as the production rate is less. Work with the hose manufacturers, they are the experts.|
|24||I reviewed the Technical Bulletin of 9/7/94 for the subject "Reach and Trajectory Data of Hand Held Nozzles". When noting the 'nozzle reaction' in lbs. on the graphs; what is the definition of this term? I found no reference to the spray patterns the nozzles were adjusted to. What is the typical spray patterns (straight stream to fog) that is being represented in the tests?|
|Answer: The highest reaction is when the nozzle is in straight stream and all of these forces are in reference to a flow and pressure in a straight stream.|
|25||This question is in regards to two other posts. Is the nozzle pressure of 100 psi at the nozzle inlet or the exit? If it is measured at the exit with pitot gauge devices then wouldn't this be a measure of total energy, different from the potential energy reading given by an inline gauge at the nozzle inlet. If the nozzle inlet pressure is going to vary, how can using 100 psi for flows within range accurately determine the needed engine discharge pressure?|
|Answer: Nozzle pressures for fog nozzles have always been referenced to the base pressure. You are correct that there is loss thru the nozzle and the the actual pressure at the exit is different than the inlet. We have used small syringe needles to measure the outlet pressure in pito form but it is clearly more difficult on the wall of water. The goal of an automatic nozzle is to maintain the base pressure to +- 15 PSI of 100 over the nozzles flow range.|
|26||At what pressures do you get the different flows from a deck gun nozzle i.e. 150-1000gpm|
|Answer: In the library under technical bulletins there is a document titled Determining Flow w/ Automatic Nozzles on Pre-Piped Monitors" This document has the answers to this question.|
|27||Do you sell solid bore tips for the Handline series (50-350), specifically the break apart nozzle?|
|Answer: The answer is a qualifed "Yes". We do sell smooth bore nozzles and we do have a breakapart handline nozzle. We call it an H-TO for handline "Tip Only". The problem is that when you go to a breakapart nozzle the valve can no longer be a turbulence controlling slide valve. Rather it must be a ball valve.|
|28||What is the friction loss in each 50ft section of 1 3/4" hose used for calculating TFT handline series nozzles in your flow tests. We would like to know so we can make adjustments when checking flow rates while using our hose.|
|Answer: We have found that there is a tremendous variation is the actual diameter of "1 3/4" hose. Each manufacturer wants to claim that theirs has a little less loss and that it most easily accomplished by running to the high side of the tolerance. We recomend that each fire department establish SOP's for their hose and their pumpers by using a flow meter. We have found that there can be a tremendous amount of loss in the pre-connect piping so it is important to get total pump pressure to achieve a given flow, not just the friction loss of the hose.|
|29||What certifications are carried on the TFT Nozzels & appliances. Do they include IMO (International Maritime Organisation), SOLAS (Safety Of Life At Sea) or USCG (U.S. Coast Guard)certifications? If not, when can we expect this to happen. Honestly, the only certified stuff available now is HEAVY Brass Crap.|
|Answer: Many of the nozzles that TFT offers (Not all) have been tested to NFPA 1901. There is a special section of the 1964 standard that was added by USCG representatives to the committee that covers corrosion resistance in salt and fresh water circumstances. Our products were tested to meet that minimum as well. We have not had it specificly confirmed by the Coast Guard that they followed thru with the paperwork on their end to make the changes that would allow these nozzles to be used. All we know is that this was their intent. We have done nothing with IMO or SOLAS.|
|30||Can we get NST threads on any of your nozzles and appliances?|
|Answer: Absolutely, NST we do every day as well as IPT (Iron Pipe thread, straight). We can do other special threads as well and have most special threads in stock.|
|31||Does TFT offer replacement handles in different colors. We are trying to color code our hoses to avoid confusion when 2-3 lines are in operation through the same doorway.|
|Answer: The answer to this question is "It depends". It depends on what nozzle series you have. If you have the 50-350 model then the answer is no we do not offer color coded handles but we have seen many people obtain colored shrink tubing from an electrical supply store and put that over the handle and shrink it with a heat gun. If you have the Mid-Matic series 70-200 GPM then the answer is YES we do have color coded cover kits that can be obtained at nominal charge. Recently we introduced a complete line of color coded pistol grips but those only fit nozzles that have been manufactured since January of 2000. See document Colored Pistol Grips|
|32||On page 60 of the November 1999 Fire Rescue magazine, a picture of a TFT handline nozzle was shown, which had a smooth-bore stack as the pistol grip. What type of nozzle was this, are they special orders, and what would be the price for 1 3-4" and 2 1/2" nozzles (preconnects).|
|Answer: That is a special nozzle that was made for Fallon Nevada. We did carry it in our catalog for a while but did not have enough activity on it to be worth the space in the book. It is available by special order.|
|33||If we are told time and time again volume extinguishes the fire then why do I care about velocity in a typical room and contents fire (10'x12')? Are the typical smooth bore nozzles not providing enough reach or something? Has anyone heard of nozzle reaction?|
|Answer: In the case that you refer to you are quite accurate in that either one will put out the fire with suficient volume. Too bad more folks don't look at it rather than standing out in a parking lot and evaluating nozzles. In answer to the second part that being nozzle reaction you can bet that we have heard of it. That is PRECISELY why we have the only nozzle in the world that allows the nozzle person to CONTROL THE FLOW and the REACTION. In the fire that your talking about the "fight" time is a matter of a few seconds. Most firefighters can hold huge flow rates for short periods of time especially in interior combat where they are on the floor, braced against a doorway etc. WIth an automatic nozzle you can go in and OPEN UP on it with huge flows, achieve extremely quick knockdown and then quickly throttle back to a smaller flow for overhaul/mop up. Unlike the smoothbore when the automatic nozzle is throttled back it will immediately resize itself to take the new flow at correct pressure so that its reach and action are not changed significantly. The ONLY reason that anybody is talking about smoothbores these days is that when automatics came on the scene they made it too easy and people got lazy with their pump pressures and over time the flows started to suffer. Firefigthers found themself getting backed out, to "fix" the problem they tried smooth bores. Since the smooth bores operate at a lower nozzle pressure all of a sudden the flows went back up because there was pressure left over for friction loss again. Unfortunately too many people assumed that the nozzle made the difference. It wasn't the nozzle that put the fire out it was the increased FLOW. Had they simply cranked the pump pressure back to what it was when they first got the nozzles they would have had all the fire killing capability back plus all the flexibility of a combination nozzle. We wonder every day why people strive to make pumpers that can go to higher flows and pressures, why the hose manufacturers work to get higher flows and pressures, when the fire departments keep lowering the pump pressure. Does not make sense to me. Stewart McMillan President|
|34||How can you flow the same GPM, at the same nozzle pressure, from both an automatic and a solid tip? In other words, if I were pumping water through an 1 3/8" solid tip, at a NP of 80 psi, flowing approximately 500 gpm, that an automatic tip would perform the same?|
|Answer: You have to start with the basic premise that any NOZZLE is just a hole that something flows thru, if it is fixed in nature as a smooth bore is, then the more you shove into it the higher the pressure goes. If it was a "straight line" relationship the the automatic nozzle would have never been invented. By straight line I mean that if you doubled the flow it would double the pressure, unfortunately that is not the case. Just like wind resistance and many other fluid equations a nozzle follows the squared law. To get double the flow out of a nozzle (fixed) it takes four times the pressure.
To get directly to the answer to your question now.
An automatic nozzle when it is built gets set to its operating pressure. They are typicly set to 100 PSI as that is the generally accepted operating pressure that has been used for years. If however the sping or mechanism was set to operate at 80 PSI then for a given layout, and device and pump pressure the automatic would flow the exact same flow as the smooth bore. NOTICE THAT I SAID SAME PUMP PRESSURE, THIS IS CRUCIAL and where most folk get off track. The reason that they get off track is that the automatic closes off so that its set pressure is achieved immediately and so if you look at nozzle pressure only then what will happen is that it will take X flow to develop 80psi on the smooth bore (see paragraph one) and then when the automatic is put on it will get up to 80 right away as its orfice closes down and it is easy for someone to incorrectly see that the automatic is flowing less and therefore say that it is not working.
When the smooth bore is flowing at 80 PSI there are losses in the device, the hose, the pump, what have you. Record the pump pressure and then put the auto on that is set to 80 and when the pump is brought up to the same discharge pressure and the nozzle is at 80 THEN you will have apples 2 apples and they will flow the same.
When you have an automatic tranmission it still requires you to put your foot on the gas to go somewhere and the power required to go 55mph is about the same with a stick and an automatic. Same goes for nozzles, it requires energy to move flow, you have to bring the pump up to the same energy level with both nozzles to get equal flow.
If you do not have an automatic nozzle that is set for 80 but you do have a normal 100 PSI one then you can do the same thing only do it all at 100. Go up to 100 on the smooth bore and measure the flow. (There is nothing magical about 80 on a smooth bore just like there is nothing magical about 100 on a fog nozzle) It works at any pressure as long as equal energy is being put in on the front end.
I hope that this moves you on down a little farther on understanding automatic nozzles.
|35||What is the best way to covert a 2 inch NPT discharge port to something compatable with a 1.5 nozzle and for greater adaptation from 2inch NPT to say a 2 port 1 inch wye?|
|Answer: The first step is to get the 2 inch down to 1.5 NST, once you have it there it is a simple matter to obtain a 1.5 by dual 1.5 wye or a 1.5 by dual 1 inch wye. There are fittings that have a two inch pipe inlet to 1.5 inch fire hose threads. I would think that any spinkler contractor would have these in stock. A look in the yellow pages might find a contractor near you that can help.|
|36||Question: People who use your nozzles are buying into the lie..Bail half open.. same flow??If Velocity is what reaches the seat of the fire why would I want to close the bail halfway?? Same volume with half the velocity right? I thought I needed your pressure.|
|Answer: No they are not buying into a lie, you are mixing and matching terms and that will not work. We have NEVER said that bail half open equals the same flow as you stated above. What we say is that at half open the pressure stays the same and the pressure is what causes the velocity. Think about an extreme case, a 2 inch master stream flowing 1200 gallons per minute at 80 PSI versus a 1/2 inch smooth bore flowing maybe 80 gallons per minute at 80 PSI. The VELOCITY out of both nozzles is identical, that means that the SPEED that the water leaves the nozzle is identical. What is different is the flow. How does a river at flood carry more water? It MOVES FASTER as in that case the size of the tip, the river bed, is fixed. The pressure of a nozzle is the only thing that determines the speed of the water out of the tip, the flow has nothing to do with it. Therefore on an automatic nozzle where the pressure is maintained constant the SPEED/VELOCITY is also constant and that is what we say and that is not a lie.|
|37||Our nozzles need to be lubricated. Yes we have hard water. We have disassembled and clean up but need ot lube it prior to assembly. What type of lube do you recommend? Hopefully it is available in spray form?|
|Answer: The procedure for lubricating TFT nozzles is available in the library on this web site Field Lubrication Procedures. We recomend a product called Break-Free and it is commonly available at Wall Mart, auto parts stores, and gun stores.|
|38||Has TFT considered making, or does TFT have a shut-off, either standard or pistol grip with the slide valve that the tips can be interchanged between an automatic and smoothbore or is this option only available with a ball valve?|
|Answer: This product was introduced at the FDIC 2001, it is called an H-VIT which means Valve Integral Tip. It does not have the slide valve and that is unfortunate, we have been asked for that many times but it is physically impossible as the slide valve requires a plug in the stream to close against. When you make the valve break apart this plug no longer has a support pier. With this nozzle however we have made the only unit that has a user selectable bore size which is easily changeable in the field. For description of the VIT nozzles see a href="http://www.tft.com/literature/library/files/vitnozzle1.pdf">VIT Nozzles|
|39||We are a relatively small fire department, having only 4 stations with a minimum manning of 10 personnel. On a structure fire we can expect 6 - 8 personnel initially on scene. Each engine is equiped with 2 preconnects that are 200' of 1 1/2 line with Task Force Tips. Initial attack consists of one officer and a fire fighter on the attack line. I can understand the point of view that more water means a quicker knock down, but my concern is that when you advocate increasing the pressure to deliver these high flow GPM's, two people dragging 200' of 1 1/2 line make's it almost impossible to reach the fire in a timely manner. If manpower where not an issue we could put 3 or more firefighters on a attack line, but for our department and many other residential departments this is not possible. To make matters worse our training officer has came to the same conclusion as you, that having more GPM's means a more successful fire attack. Right now he has all the TFT's set on emergency (For the higher flow) and wants the pressure to be set at 200 psi. Once again if we had the manpower this would not be a problem, but two people pulling that line, trying to bend it around corners, carrying radios, tools and advancing to the fire is very exauhsting and not practicle. Also for our department and many like ours, one of the 2 FF's is the interior command, trying to be conscious of the surroundings and exsisting fire conditions. It is a little overwhelming to say the least. I guess my question is, does TFT recommend always having the nozzles set on emergency and recommend pressures of 200 psi. It makes sense to me that with minimum manpower to do the job we are going to have to sacrifice some GPM's and use lower pressures to make the situations a little more managable and safe. I beleive that with advances in technology companies such as yours should be designing equipment that uses lower water pressure while still allowing sufficient gpms to successfully extinguish fires. I look forward to your response, Thank you.|
|Answer: You bring up many points. Let me try and address each of them.
First the issue of flow and high pump pressures and what we are advocating. Let me make a comparison, how much horsepower does your car have? A lot more than you need on average right? But when you need it to pass or to pull away from a stop you want it and you want it right now. You do NOT want to have to call somebody up and say, Heh can I have an extra 50 horsepower, I need it for a few seconds. And because of that cars have throttles such that you the driver control the horsepower applied. That is EXACTLY what is going on when you pump at a high pump pressure and allow the NOZZLEMAN to control the flow. Pressure is only potential energy, it does not turn into flow until you open the bail of the nozzle and let the water flow. Letting the water flow causes friction loss which eats up the extra pressure leaving 100 PSI (or 50) at the nozzle. There is no reason to open the nozzle up all the way all the time, us it like a throttle.
Your next question regards hose handling and dragging line.
The line is not flowing when you are pulling line and the higher the pressure the easier the line pulls across the ground. It is a common belief that high pressure causes hose to be hard to bend but it is NOT true with modern hose. Take a piece of hose made in the last 10 years and pump it up to 200 and compare it to one pumped at 100, the difference is very very small and with High Combat from Angus there is no difference.
If I have a camp fire to put out and I have a bucket and a hand pump. Which is more fatiguing, to lift the bucket once and pour it on the fire and be done in seconds? Or to pump the hand pump for several minutes while the same water is applied. Clearly it less fatiguing to hit it hard and then go rest. Automatic nozzles with flow control allow you to do that safely.
Your training officer is highly enlightened, I wish there were more like him
|40||Using a Mid-Matic Series nozzle, what would the gpm's be on 200' of 1 3/4 at a pump pressure of 150psi.|
|Answer: The quick answer is 125 GPM. The way that this is obtained is like this. The nozzle pressure is 100 (It's automatic) Therefore 150 minus 100 gives the friction loss of 50 psi. To get the friction loss for one hundred feet divide by 2 as you asked for the flow on 200 feet. So now we have 25 psi of friction loss per one hundred feet of hose. Go to the chart for 1 3/4 hose and that is approximately 125 gallons per minute. We must say approximately as the hose manufacturers all have a different idea of what 1 3/4 is and sometimes to gain competative advantage they size the hose oversize by 1/8 of an inch or so which makes a large difference.|
|41||We are using TFT 1.5" Handline series 50-350 nozzles now on our 2.5" lines. We wondered what the difference in GPM would be if we switched to a 2.5" Handline series nozzle pumping at 100 PSI NP. What model would I want if I wanted pistol grip and break apart still?|
|Answer: The only difference between a 1.5 50-350 handline and a 2.5 inch handline is that one has the 2.5 coupling built in rather than needing an adapter. The flow you would get would be the same. We feel that it is better to keep the 1.5 coupling and use the adapter as it increases the versatility of the nozzle.|
|42||What is an acceptable range of reaction force (lbs.) that a fire fighter could be expected to handle safely, either by himself or when teamed with another, when operating an 1-1/2 inch attack fire hose line and nozzle? Are there any guidelines published for recommended reaction forces that would permit a fire fighter to operate a fire hose line safely?|
|Answer: There are no "standards" that we are aware of. It varies widely but not so much on the size of the firefighter although of course that is a factor. What also is a large factor is 1) Standing up or kneeling or laying down 2) backup 3) footing 4)height above ground 5) grip or no grip 6) training. Those are in no particular order, they are all very important. Another factor that is important is control. With many nozzles in particular NON automatic nozzles the choices are either full on or full off for the nozzle. With an automatic nozzle and a slide valve it is possible to throttle the flow up and down depending on the mix of above conditions such that the firefighter can maximize the flow delivered for that particular situation. We have had people argue that what we recommend is for the firefighter to gate down and therefore not deliver all the water that they could. That is exactly what we are advocating. We would much rather have safe delivery of X amount of water rather than X + Y delivered un-safely and likely un-effectively. When nozzles are evaluated it is frequently done in a parking lot, standing up, for minutes on end and then the firefighters are asked what they can hold comfortably. That is a very poor test as it is not even close to real world. In the real world the fire is fought down on hands and knees in short bursts as the line is advanced which is very different. In addition a parking lot does not exactly inspire a person to do their best work. When the going is tough most people can do more than they would do in the parking lot. Sorry that we cannot give you a number, we just don't think that one really exists.|
|43||What is your most powerful nozzle?|
|Answer: The question has to be clarfied somewhat to be answered. What is powerfull? Our LARGEST nozzle that has the highest flow is the Typhoon at 4000 gallons per minutes or 16 tons of water per minute.|
|44||On the Mid-Matic nozzle which is set at 75 psi we noticed that if we over-pressured the nozzle to create flows in excess of 200 gpm that the nozzle appeared to open up and revert to almost a flush mode. Is this by design because when this happens the flow rate appears to increase dramatically.|
|Answer: The Mid-Matic nozzle has a flow range of 70-200 GPM, @ 75 psi, in the case of your particular model. When the nozzle reaches its maximum rated flow, the pressure control unit is opening the baffle as far as it can, which then causes the nozzle to act similar to a fixed gallonage nozzle, and the discharge opening cannot become any larger. When you over pressurize the nozzle the flow will increase, but the high nozzle pressure causes a great deal of turbulence in the stream, which may appear similar to the stream in the flush position. The same results would be relized in a fixed gallonage nozzle, if you attempt to flow more than its rated flow capacity, which will cause increased nozzle pressure and increased nozzle reaction force.|
|45||First Question: My department (a large east coast dept) currently uses 125 gpm constant flow nozzles as our standard attack line. The theory behind NOT using automatics, one I'm sure you've heard before, is that automatics hide low flows. Now I understand that Nozzle Reaction would be much lower, etc, but I was wondering if you made an automatic that had a limit to how much the baffle would close, say one that would only close to 125 gpm at 100 psi.
Question Two: Do you make a 50 psi NP version of the 50-350 handline tip?
Question Three: For the Thunderfog, are custom versions availiable with fewer and / or different baffle settings (within 95-250+)
Question Four (for the webmaster): what is the field next to the "availiable categories" pull down list on the faq submission form? I'm guessing email address and am going to try it now.
|Answer: First Question, yes we have HEARD that before but that does not mean that we agree with it. Automatics do not hide low flows, they make low flows usable. Certainly we could easily make an automatic that had a minimum orfice of 125 at 100 and then any flow below that would cause a drop in nozzle pressure. Any flow above that would be at correct pressure. I can see why you might want to do that and it is doable.
Second Question Yes we do make a low pressure version of the 50-350. It is called the Dual Force and it has a switch that allows you to choose 100 PSI or 50 PSI
Third Question We only make the Thunderfog with one set of flow ranges. To take settings out would server no purpose that we can see.
|46||RESEARCHING LOW PRESSURE NOZZLES FOR HIGH RISE APPLICATIONS. WHAT WOULD BE THE FLOW USING A DUAL PRESSURE NOZZLE ON 100 FT OF 1.75 INCH HOSE HOOKED ONTO A HOSE CABINET WITH 100 PSI AT THE OUTLET.|
|Answer: For your scenario, the flows would be as follows: With the nozzle in the standard (100 psi) setting the flow will be approximately 80 GPM with a nozzle pressure of about 87 psi (13 psi friction loss) With the nozzle in the low pressure setting the flow will be approx. 170 GPM, nozzle pressure of 55 psi, friction loss is 45 psi. These are approximate calculations, using the NFPA coefficients of friction loss. The hose you are using may have different friction loss characteristics, but these flows should be in the ball park. You can perform actual tests on your hose and calculate the numbers. If you need more information, please refer to the instruction manual for our dual pressure nozzles. Click on this link to view the manual. lin-035|
|47||We have TFT Mid forces nozzles with dual pressure of 70-200. Standard mode is maintained at 100 PSI and emergency mode is 30-70 PSI. What is the GPM for the nozzle when set on standard. but more importantly, What is the GPM when it is set in the emergency mode. What will the difference be when going from a flush-fog-straight stream.|
|Answer: The easy answer first. All TFT automatic nozzles are of a style called CONSTANT GALLONAGE one of the most confusing terms in history. It means CONSTANT GALLONAGE with change of pattern. Fog or straight stream the flow does not change. When put in flush the nozzle pressure falls to nearly zero and so the flow is what a line with no nozzle would flow. The nozzle pressure is nearly constant at 100 in standard mode so the flow is equal to the pump pressure minus 100 and then that flow is looked up on a friction loss chart for the size hose being used. (There are many faqs here about how to calculate flow) On low pressure the pressure is not quite as constant but it would be safe to say that it is on average 50 psi. The same calculation needs to be made, pump pressure minus 50 instead of 100. The reason there is more flow is that there is 50 psi more friction loss.|
|48||what style nozzle in the TFT line would you recommend to be used in CAFS?|
|Answer: TFT will introduce at FDIC a nozzle that has been specificly changed to perform with CAFS. The model number is CAFS-PAK21|
|49||Just saw for the first time your automatic pressure control handline nozzle, 50 - 350 gpm @ 100 psi, and have two questions. (1) does one manually set the gpm by adjusting the nozzle? What does the impact on the different settings on the handle (between on & off) have?|
|Answer: Answer to 1) The switch on the front changs the pressure. It has a high and a low mode. When set to high pressure the nozzle maintains 100 PSI and so any pump pressure above 100 goes into friction loss. Lets say the pump is at 150, in that case there is 50 PSI of friction loss. If the switch is moved to low pressure then the nozzle pressure is approximately 50 and now with the pump at 150 there is 100 PSI of friction loss. Twice the friction loss means more water delivered. Answer to 2) The detents are there to keep the handle in intermediate positions and to give the message to the firefighter that it is ok to now open the nozzle at full open|
|50||I am currently taking a detection and suppression course and the instructor asked us to define "k-factor". I have been unable to find an answer as of yet. Is it possible that you could assist with this task?|
|Answer: K factor is another way to express the flow and pressure capabilities of the nozzle. It can be determined in the following formulas. K = Q divided by the square root of P where Q is flow in gallons per minute where P is nozzle pressure in psi For example: a 250 GPM nozzle rated at 100 psi has a K factor of 25. K factors are used quite often in industrial fixed fire protection system design.|
|51||We are confused about the advantage of using Mid-Force nozzles with standard and low pressure settings. According to your flow and reaction chart, using a Mid-Force nozzle with 200' of 1 3/4" line, regardless of what discharge pressure you are at, you will always get more flow with the low pressure setting than with the standard setting. The differences in nozzle reaction between standard and low pressure settings seem to be pretty nominal or non-existant. What then is the advantage of using the standard setting at all? In other words, why not save money and just purchase a low pressure nozzle?|
|Answer: Your basic premise is correct. For a given pump pressure you will always get more flow out of the lower nozzle pressure. The question that you MUST ask that is not asked often enough is how low is too low. A fire fighting stream is a CHOICE between flow and pressure. Lots of pressure and no flow is not good and neither is LOTS of flow with no pressure. The pressure is what delivers the stream. When the pressure is cut from 100 to 50 psi the energy of the stream is cut in half, the reach is less, the bouncing action in the room is less, the fog has larger droplets. The whole reason that we buy expensive pumpers is to develop PRESSURE but everybody seems afraid to use it. The bottom line is that there is a place for high and for low pressure and that is why we developed a nozzle that has a choice. If you can't get pressure or you want to deliver lots of water with a lower reaction then switch to low pressure. If you want to reach a long distance, have great fog protection, ventilate a room, bore into debris for overhaul then switch to high pressure. The choice is yours!|
|52||Kendall Valley Fire just received a new Dual Gallonage Twister model FS2060 SN TFT-F5000259 via LN Curtiss. The manual that came with it is for the Thunderfog & Quadrafog. Where can I find a manual for the 2060. It is not clear to me how to select between 20 and 60 gpm capabilities.|
|Answer: There is not a specific manual to this nozzle as it is a very basic design. Put it on a line and screw the stream shaper all the way clockwise looking at it from the nozzlemans view. As you then turn left the nozzle will turn on and flow a straight stream in the 20 gpm setting, as you crank the shaper further to the left you will note a transition point where the stream jumps into a semi fog and then goes back to straight stream, that is the 60 gpm setting, turning it further will send it into fog pattern.|
|53||We are utilizing the triple layer hose load for our pre-connected attack lines. We have many KK nozzles. It is difficult to place the two layers of hose through the bale of these kk nozzles. Can we remove the center part of the nozzle bale without causing any structural problems to the nozzle bale?|
|Answer: Removing the center portion will substantially reduce the strength of the handle and is not reccomended. Get a bungee cord and tie the nozzle to it. We do NOT reccomend the practice of putting hose thru the handle. If the line is pressurized before the hose is fully removed it will become very difficult to remove quickly and it could break the handle.|
|54||Could you please explain the math (the origin of every term, especially the 0.505) in the equation of NR = 0.0505 Q ?ãNP ? Shouldn't there be the size (diameter, area) of the nozzle in the equation ? Thank you, P.Jean Bernier Shannon Fire dept.|
|Answer: This formula NR = 0.0505 times Q times square root of NP is used to determine the nozzle reaction from a fog nozzle. NR is Nozzle Reaction in pounds Q is Flow through the nozzle in gallons per minute NP is Nozzle Pressure in psi. 0.0505 is a constant, or multiplier that is always the same. The formula for a smooth bore nozzle is NR = 1.57 times d squared times NP. 1.57 is a constant d is the diameter in inches NP is Nozzle Pressure in psi. IFSTA and NFPA manuals have more information on this subject.|
|55||Do you have a chart that depicts the max elevation with the associated max range for various monitor and nozzle packages? Looking to use for monitor placement for both fixed and mobile.|
|Answer: yes, this information is all detailed in the back of the manual for the specific nozzle that you have. The manuals can be found in the library section of the website under manuals and technical bulletins. The Master Stream manuals already have reach at various flows and pressures for a fixed angle. We are adding a chart to suppliment this (as of 1/30/2008) which will allow the angle to be changed and the reach then calculated as a percentage of maximum reach. Email firstname.lastname@example.org to request this chart.|
|56||This is more of a comment than question but we are a fairly large combination dept. in NC. Our district is high value residential with homes from 4 to 25,000 square feet estates and some commercial properties...our layout on apparatus is typically 2 1.5" crosslays 200' with fog nozzles (adjustable gallonage) recently adjusted from 95gpm to 125gpm for obvious reasons, and 1.75" rear precon 250' long with fog nozzles recently adjusted from 95gpm to 125gpm (also for obvious reasons), our last precon is a 2.5" with fog nozzle @ 250gpm. I am a live burn instructor and have burned many structures and used 7/8" and/or 15/16" smooth bores on 1.5" and 1.75" nozzles respectively. I demod your 7/8" smooth for our dept on a burn in April and our officers loved it. I recommended and got approval to change out the fog from the 1.75" @ 125gpm to a 7/8" tft smoothy @ 160 gpm, I was looking for another "option" in our arsenal since some of our interior fires are in gigantic homes on 3rd floors and attics. We have yet to use the smooths but I feel confident that it will to what I envisioned, more water at a little less pump/back pressure. The change was only made to the 1.75"s on the 1st in pumper from our 3 stations, all other pumpers/tankers still have turbojet fogs on them. My next venture is to change out the 1.5" nozzles on our precons to your combo-nozzle which I also demod at a recent burn. Budget issues may hinder my effort for now but hopefully not. I respect your position on smooth vs. fogs, but I have also spent the night in a hospital because my nozzleman mistakenly fogged a room as we went in under a fire and charbroiled my shoulders and back. Was that the nozzles fault? Probably not. Do I wish he couldnt have made that mistake? Absolutely. I believe in tradition to a degree in the fire service, but my 19 years doesnt include "back in the days", but I do think there is a place for smooth bore applications especially in a compartment fire. I also believe there are absolutely no "nevers" or "always'" in our profession. Thanks for your reponses to faqs, some are very informative. Captain Roddy Hubbell|
|Answer: If someone kills somebody with a gun is it the guns fault or the persons fault. There are all kinds of tools on the fireground that used incorrectly will hurt people. It is far more than the smooth bore versus fog issues. The smooth bore is a single choice nozzle. It has one flow and pressure it is designed for. If the fire is bigger it is wrong, if the fire is smaller it is again wrong. The automatic nozzle allows the firefighter to on the fly choose whatever flow is needed and deliver it. My father was burned and off work for a year because of a smooth bore so you can find stories for both. The simple truth is that the smooth bore is the oldest technology that can be found on the fireground short of the axe.|
|57||We are getting ready to purchase a new engine with a CAFS ,can you recommend nozzles for 1 1/2" and 2 1/2" discharges like the VIT models|
|Answer: CAFS, Compressed Air Foam System, can deliver various types of finished foam, for different applications, and one determining factor is the type of nozzle used to manage the stream. The most versatile set up is a "break-apart" consisting of the VITG and a combination nozzle tip, such as the HM-TO (for 1.5") or H-TO (for 2.5"). The H-VITG (H-2VITG for 2.5") is a ball valve with integral smooth bore inserts of 4 different sizes. The smooth bore will give you the driest CAFS foam, typical for exposure protection needs. The combination fog/straight stream nozzle can be used when wetter, faster draining CAFS foam is desired, and for most of the day to day uses with water, foam or CAFS. If the drier foam is desired, just screw the combination tip off, and the smooth bore is exposed on the ball valve outet. I strongly urge the use of pistol grips, as CAFS has a much, much higher nozzle reaction than non-CAFS streams.|
|58||What specific characteristics must a nozzle have to be considered a playpipe?|
|Answer: Typically it just means that it has large D shaped handles so that more than one person can get a hold of the line.|
|59||It would appear that operating a variable pressure nozzle in the low pressure setting gives greater gpm regardless of PDP. What is the disadvantage to operating the dual pressure nozzle in the low pressure setting as a standard practice, not just low PDP situations or high rise applications?|
|Answer: This could certainly be done. You are right that if the nozzle pressure is lower it is going to flow more water at all pump pressures than will a nozzle that has a nozzle pressure. At the same time however you have lost one half of the velocity by going to 50 PSI versus 100 and so you have also cut your impact and stream reach down by 1/2. It is all about what is the best compromise for your situation and the switch gives the firefighter the ability to chose between higher pressure higher impact higher reaction and higher reach versus low pressure, low reaction, higher flow, lower reaction.|
|60||I was presented with a difficult question today.... how much air is pulled into a fog patteren when a fog pattern is being used? I assume no air is coming in from the hose line, but I do assume that that air must enter the fog patteren due to venturi effects... anyways I'm trying to do some research into the subject and and thought I'd ask the experts! It come up during a training sesion about the amount of air the can be potentially pushed at a fire, increasing/fanning the fire. Thanks for your time. BTW that hose hook looks awesome, I'm gonna have to get one. Josh Leonard|
|Answer: Josh: Thanks for your inquiry on air movement. You are correct to say there is a huge quantity of air moved by a nozzle set on full fog position. This can be used as a powerful tool in the proper situation, but it can be a serious problem when used by untrained people in an inappropriate manner. We know that when a nozzle is put in full fog position the water quickly slows down and falls to the ground as all the kinetic energy (mass times speed) of the water is transferred to the surrounding air. The formula for water horsepower = GPM X PSI / 1716. So a 200 GPM nozzle at 100 PSI nozzles is a 11.7 horsepower tool. The nozzle can be used as an 11.7 HP fan. As an idea of comparison a 3 horsepower fan will generally deliver about 33,000 CFM of air. So a quick estimation would be the nozzle moves about 130,000 CFM. (11.7/3 X 33,000) Examples of proper use of the full fog: Personal protection in a flashover or explosion To drive away, or control flammable vapors or sprayed fuels To clear smoke from an enclosed space To force fresh air to victims Radiant heat protection Exposure protection Examples of improper use of full fog: Disturbing the thermal balance Spraying in confined areas with superheated gases Creating clouds of class A dust or "fines" On the opposite side there are times when the use of a straight stream can be a serious problem. Again - I stress training. Examples of improper use of straight stream: Application of straight stream into high voltage electrical equipment Plunging water into ignited pools of liquids. (IE: Bilge of a boat, basements, pits, fuel tanks) Aiming at people Spraying into coal dust piles and the like which create a cloud of dust which can explode Dislodging materials which can fall onto people There have never been two identical fires. Neither straight stream nor fog can be used for every situation. We believe the best tool is versatile. It lets the firefighter match the tool to the situation provided adequate training has been performed. Kind regards; Bob Steingass|
|61||Our Department is considering a change to low pressure nozzles.I read in the other FAQ's that a "Bubble Cup Nozzel" is not NFPA approved but I am wondering if all of your other (regular and low pressure) nozzles are?|
|Answer: The reason that the Bubble Cup nozzle is not approved is that it does not pass the drop test of NFPA, it has nothing to do with the pressure. The Bubble Cup was designed for foresty fire fighting use and so the NFPA requirement that it withstand a drop on concrete when cooled to minus 30 degrees F did not seem like a reasonable test. There is not a lot of concrete in the forest and the temperature when fighting a forest fire is clearly not minus 30 degrees. The low and high pressure nozzles are all NFPA approved|
|62||Can an Automatic Nozzle be used with a Straight Bore Nozzle in a gated wye application on the same appliance ?|
|Answer: It can but it must be done with clear understanding of what will happen. The automatic nozzle will NEVER steal water, it will close down and try and make the pressure of the system stay up and in the process it will give the water to the smooth bore (or any fixed flow device) In addition there is a problem with pressure. Most people want 50 psi on the smooth bore and 100 on the fog nozzle. If the line is pumped correctly such that the smooth bore has 50 psi then there will never be enough pressure to "open up" the fog nozzle as it will not get the 100 psi that it needs. Even if a low pressure automatic is put on the line that is set for 50 psi it will close itself off until the smooth bore is at full flow. As a quick example lets say a 200 GPM smooth bore is on one side and a 200 PSI low pressure automatic is on the other and 300 GPM is all that is available. The smooth bore will deliver 200 and the automatic will size itself to 100. It will APPEAR that the smooth bore is the "better" nozzle but that is only because it is selfish and takes its water away from the automatic. In the end it is best to match nozzle types on wyed lines.|
|63||Does TFT have any nozzles rated for use on Class C (Energized Electrical Equipment) fires? If so, are there any limitations on their use or ratings?|
|Answer: No specificly. We have had several customers (power plants) do their own testing and they are currently using our products in this application. The market for this type of nozzle is so small and the conditions so widely varied that we have never found it worth while to do this testing and offer a product that is certified.|
|64||Do you recommend any OTHER lubricants in lieu of Break Free. We do not want to use something that will damage the Nozzles, but are having a hard time finding a local supplier for Break Free.|
|Answer: Break Free is available at Wallmart, Ace Hardware, and almost every gun shop. It is what we have tested the most and reccomend.|
|65||What is the warranty on the mid force TFT automatic nozzle?|
|Answer: 5 years|
|66||I would like to know the gpm for 1 3/4 hose "handline" serries for the following engine pressures: 50, 75, 100, 125, 150, 175, 200, 225, and 250|
|Answer: This information is all outlined in detail for various hose lays and sizes in the appendix of the instruction manual for the nozzle. This can be found under manuals and technical bulletins in the library section of the tft web site|
|67||In a recent fire training course, the instructor was advocating the use of smooth bore nozzles and was speaking about the negatives of combination nozzles. The major point the he was advocating was that Task Force Tips recommends that you send the nozzles back in for re-calibration every year. Is this true?|
|Answer: Absolutely NOT!!!! We reccomend that the fire department check all nozzles for proper function once a year. This calibration issue is a myth that is caused by people not understanding how to properly check the flow of an automatic nozzle. The nozzle uses a spring, a properly designed spring that is not overstressed will last FOREVER. The calibration of the nozzle does not change with time.|
|68||Our department (Leipzig FD, Saxony, Germany) purchased this year TFT-Midforce nozzles; our firefighters asked for them already since 2001. Now we are wondering, that these new nozzles have no longer the dirt grabber gasket in the nozzle entrance. The european / german TFT-dealer "Leader GmbH" says, that these nozzles aren't sold with the gaskets anymore. The informations, TFT gave until 2001 said, that the gaskets are an important part oft TFT-nozzle concept and we understood how useful they were. Is it true, that these gaskets are no longer built in, and if, why? Thank You for your answer! Mike Hartnick, FF at LeipzigFD, Germany|
|Answer: You will have to talk to your DIN standards committee members to get that answer. We absolutely believe that it is important and we still make all nozzles with it EXCEPT the ones that go to Germany. Any device that is in the flow path causes losses and the screen is no exception, we think that it is a loss that is acceptable but it interferes with the method that is called out in the standard for certifying nozzle pressure and so we were forced to take it out to meet the standard. This is in general the problem with standards. Standards are made by a group of people that represent many different manufacturers and users. New and innovative features are difficult to introduce when the standard was written years prior and does not take into account that new features might change how things are tested and measured.|
|69||Hi - I am working on the part of the book where problems are set up to determine the required pump discharge pressure for various layouts. The solution to these problems requires knowing the nozzle pressure and the flow. I have no problem setting up problems mentioning fixed gallonage nozzles or selectable gallonage nozzles but I guess I don't know enough about automatic nozzles. I know they maintain a constant pressure and the flow changes when insufficient pump pressure is supplied to provide full flow. How do I know what the flow is when the pump pressure is below that needed? I would like to refer to automatic nozzles on some of the problems.|
|Answer: Dear Mr. Mahoney
Let me try and take a cut at this. Please realize that trying to put into words what you are asking is much like trying to put into words how to tie a shoe. Once you have been shown and done it it is easy. Trying to describe it is darn near impossible. Fortunately this is not as tough as shoe tying.
Lets start with the 50 to 350 nozzle.
There are three possible circumstances that this nozzle can be operated at.
1. A pressure that is so low as to be below 50 GPM (the one you are interested in)
2. A pressure that delivers a flow in the 50 to 350 range
3. A pressure that delivers a flow above 350.
Lets take number two first. An automatic nozzle by definition maintains a nearly constant 100 psi (or whatever pressure it is designed for, lets assume that this one is 100psi)
The normal formula for flow is EP = FL + NP. Engine Pressure equals friction loss plus the nozzle pressure. And normally you work this from right to left. You say you have a 200 gpm nozzle at 100 PSi and then for the hose length you find the loss, add them together and you get the pump pressure. People get confused with automatics because they don't know the flow. So what to do, PICK a flow, any flow that is in the 50-250 range and whatever friction loss you get add it to 100 and that will be the pump pressure. The will size itself to be just right so that it has 100 psi at its inlet. If you pick 123 gallons and get a friciton loss of 82 psi then 182 psi on the pump will deliver 123 gallons. (Of course nothing is this accurate in fire fighting but you get the idea)
Now lets look at number one. The flow is LESS than the rated flow of the nozzle meaning in this case less than 50 GPM. What to do? What is actually taking place in an automatic below its rated flow is that the baffle/spring mechanism runs out of travel and it can no longer control the flow. It becomes a 50 GPM at 100 PSI fixed gallonage nozzle. It will behave exactly the same as ANY fixed gallonage nozzle whether it be a smooth bore or a fog nozzle. It works out that 50 GPM at 100 PSI is the same as a .375 tip. A 3/8 inch nozzle. Most charts end at 1/2 inch and for what your doing here going with 1/2 inch would be more than accurate enough. This range will be entered when the pump pressure minus the friction loss is less than 100 PSI and in this case the calculation becomes traditional and difficult. What is commonly forgotten when applying all these calculations to actual fireground situations is that we do not have a pressure gage out there on the nozzle. If the calculations are right and the pump pressure is right and the nozzleman has it set to the right setting we get the flow we expect. If anything is wrong we get an under pressured or over pressured stream. That is where the automatic comes in, sock it to it at the pump, the nozzle will size to whatever the nozzle person decides to let thru and the pressure on the nozzle and hence the stream is always perfect. Automatics were one of the biggest steps forward ever made in the fire service. it is very unfortunate that in the process of trying to "learn to tie their shoes" that so many people got lost and made bad choices. Hopefully your book will help them make GOOD choices. I hope that this helps, if not please call me at 800-348-2686
|70||WHAT PUMP DISCHARGE PRESSURE SHOULD I OPERATE A RUBBER LINED 1 1/2" OF 150' AND 200' WITH A TFT 50-350GPM. WHAT IS MY GPM FLOW FOR BOTH (150'AND 200') SECTIONS OF RUBBER LINED 1 1/2" WITH A TFT|
|Answer: The pressure depends on what flow you desire. Choose a flow and then look up the pressure loss per hundred on a flow chart. Then if the length is 200 feet multiple the number from the chart. Add 100 (for the nozzle pressure) to the loss that you obtained and that is the pump pressure. If you need further information please go the library section of the web site and download the publication "Guide to Automatic Hydraulics"|
|71||Does the Bubble cup nozzle comply with NFPA standards|
|Answer: The short answer is NO but that is not a complete answer. The long answer is that it meets most of the criteria but not all. The primary problem is the cold weather abuse drop test. This nozzle was designed primarily to be used in wildland fire fighting where the temperatures are rarely below freezing. The PVC foam shaper on the Bubble Cup does become brittle at low temperatures and will not survive the drop test under NFPA.|
|72||My department recently tested all of our nozzles. The TFT Mid Force nozzles were tested at 150 lbs pump pressure using 200 feet of 1 3/4 hose. We were shocked to see most of the nozzles performed poorly when used in the standard 100 psi mode. Can you tell us why this happened and how we can correct the problem. Our flows varied from 63 gpm to 78 gpm.|
|Answer: The problem that you are experiancing more than likely has to do with the testing method not the nozzles at least that is what our experiance has shown. We will soon be posting a document in our library that explains how to field test automatic nozzles. Let me try to put a short version here. Likely the way that you tested is as follows. You ran each nozzle up to a given pressure and then measured the flow and saw huge differences. It is commonly done that way because pressure is easier to read and set and then when the flow settles down we write that number down. The correct way to test an automatic is to set a range of flow rates. 50, 100, 150, 200 and write down the pressures on the nozzle. If you were to retest these nozzles using flow first and then reading the pressure my bet is that you would find that they are all within plus or minus 15 psi of 100 which is within the NFPA standard.
The nozzles are designed to maintain 100 PSI over their entire flow range. If you simply go to 100 PSI you do not know if your at the high end or the low end of the nozzles flow range. In fact if the nozzles could be PERFECT and be exactly 100 PSI it would be impossible for you to determine the flow rate with pressure alone.
Think of a screen door and a breeze blowing thru. When the breeze blows to a given level the spring gives way and the door opens dumping more air out the door than can get thru the screen alone. This is what an automatic nozzle does. As the pressure comes up the baffle gives way and lets out more water. So lets say that the measure of the breeze that makes the first door give way is 100 PSI. What if the next door that you tested had a 105 PSI door spring and you only brought the breeze to 100. The spring would not give way, teh door would not open, and the flow would be very small. If however you could measure the flow of air thru the door and bring the flow of air to the same point each time the one door would open at 100 and the other would open at 105 flowing only slightly less air because of the slightly higher pressure.
Yes thinking about this can be painfull. The beauty of automatic nozzles is that they do all the thinking for us, if we let them.
|73||Do you make a nozzle that shoots and straight stream and a fog pattern at the same time? if so could send me the info on that nozzle.|
|Answer: No we don't and for several reasons that we feel very strongly about. First of all despite Akrons current claims about their nozzle of this type being somehow "new" it is not. It is only new in that they make it and it is out of aluminum. Combination straight stream and solid stream nozzles have been made in Europe for over 100 years. We have yet to identify where you would actually want a fog and a straight stream at the same time. They are used for very different purposes. Secondly the hydraulics of a nozzle of this type are nothing less than nightmarish. If you are pumping correctly to get 50 psi on the smooth bore and then open the fog you are going from a 180 gpm nozzle to a 280 gpm nozzle. THe nozzle pressure falls to approximately 20 psi which is ineffective for not only the fog but the straight stream as well. Another problem is in the fact that this nozzle has two methods to be shut off. Fireman have been taught for generations that the bail forward is off and the bail back is on. This provides "deadman" control in that as the line gets away from too much reaction the natural tendency is to go towards shutoff. The Akron nozzle has a bail shut off for the smooth bore and a twist shutoff for the fog nozzle. When time is of the essence there is not enough time to handle both plus the fact that you cannot look at the nozzle and know whether it is on or off before charging it. The only reason that this nozzle has captured the fancy of some is that it combines a smooth bore with a fog nozzle, this is of interest to those that believe that a stream from a smooth bore is somehow superior to that of the straight stream from a fog nozzle. Our testing and years of experiance have shown that this belief is without any proof of any kind. It is if you will, folk lore of the fire service. In summary too give up automatic pressure control, and single point shutoff control for the new problems that the Akron "solution" provides is in our opinion a very poor trade off.|
|74||We currently use TFT Mid-matic nozzles on our pre-connected 1.75" lines (200'@140 psi). We are going to purchase several new nozzles and have been given a TFT Mid-Force Dual Pressure nozzle to test. There is some dispute as to when the nozzle should be used in the low pressure mode and when it should be in standard. Also, what would be the main advantages of the dual pressure vs. standard mid-matic. We are very satisfied with TFT and want to get the nozzles that would best serve our uses.|
|Answer: An excellent question. The primary advantage of the low pressure switch is to be able to gain a higher flow for special needs as in a very high fire load situation or in the case of pump failure or low pressures where normal flows cannot be achieved. By lowering the nozzle pressure by approximately 50PSI that amount of pressure becomes available for friction loss in the hose which means that for any pump pressure the low pressure setting will give a higher flow at a lower nozzle reaction. Of course the downside is that with lower pressure the stream will not reach as far nor hit as hard and the fog pattern is degraded from optimum. The switch also requires more training in that people need to know it is there and when to use it. If you want to have the ability to handle higer flows on small lines with reasonable pump pressures the dual pressure unit is the way to go. Many departments purchase them and leave them in low pressure all the time. It is simply giving the firefighter more options.|
|75||Do you offer conversion of 100 psi nozzles to 80 psi nozzles|
|Answer: Yes, not a problem|
|76||We recently purchased Dual-Force automatics for our pre-connected handlines (200'of 1 3/4"). We established a target flow from these nozzles of 175 gpm for structure fire attack. This means that we run pump pressures of 180 - 190 psi (it varies a little from one engine to another)to create this flow with the nozzle set in the standard pressure setting. We were orginally told by our TFT representative to use the nozzles this way, and have the low pressure setting as a "reserve" in case we needed more flow. Recently some of our personnel attended a TFT maintenance class at the factory and were told the Dual-Force should be used in the low pressure setting for interior firefighting, and the standard setting outdoors. We are now a little confused as to what to do, most of what we do is interior work, and we want a substantial flow. We could do that at a lower pump discharge pressure if we set the nozzles to low pressure. Also the reaction force may be better. What's the real story on the best use of these nozzles for our application?|
|Answer: Some departments go with low pressure inside and high pressure outside. High pressure gives greater reach which is needed outside and low pressure gives lower nozzle reaction (for the same flow) for interior where reach is far less of an issue. If your willing to run the higher pump pressure (applause applause) then by all means put it in 100 PSI and leave it there unless there is an emergency like a pump failure. This whole low pressure thing got started because of people wanting to lower pump pressure for some unknown reason thinking that it would make the line easier to handle. Modern hose has a different weave than days of old and bends just fine at higher pressure. It drags better at high pressure for the same reasons that a tire rolls better at high pressure and it kinks less. We strongly encourage the correct/higher pump pressures but I have to admit that times we get worn down by all the low pressure rhetoric.|
|77||With the flow control nozzle, what does each increment represent in GPM. We have both the 2.5 50-350GPM and the 1.5 10-125GPM Nozzles.|
|Answer: It is not possible to give a standard answer to your question as it depends on the pump pressure and hose layout. If the pump pressure is low and the line long then the first click will allow all the flow that is available to get out and additional opening of the valve will have no affect. Conversely if you have a large hose short lay and lots of pump pressure each click will allow more flow all the way to the last click. The intent of the detents was to indicate to the firefighter that its "OK" to open the valve part way. For many years firefighters were taught to open it all or nothing and that is not the case with automatics. If you have a standard preconnect however and a standard pump pressure you can test the nozzle with a flow meter and determine what each click gives you and then set that as part of your Standard operating procedures|
|78||I was checking out the Handline Flow and Nozzle Reaction Chart on your web site and it gives differnt figures than the one that we recived with the nozzles that we have been folowing for years. For example 150 PSI pump discharge pressure, through 200 ft of 1-1/3 in hose = 150 gpm on the old chart and 125 gpm on the new web site chart. What is the correct flow?|
|Answer: The "correct" flow is whatever that pump pressure delivers with your hose. In the interest of competition some hose manufactures have chosen to open up the diameter so that a 1 1/2 is now more like a 1 5/8 inch line and a 1 3/4 can be 1 7/8 or even 2 inch. The hose guys claim that the reduced friction loss in their hose is due to smoother linings and other such things when in fact many times it is simply bigger. Each department needs to test with their hose and see what flows they get. The reaction force is dependent on the flow and not what size hose it is attached too.|
|79||Are all TFT nozzles based on US GPM or Imperial???|
|Answer: TFT nozzles sold in the US and Canada are rated at US Gallons per Minute.|
|80||Could you explain the expression "nozzle reaction" and the unit "lbs" and should it be included in the equation PDP = NP + FL + DL + EL ?|
|Answer: Nozzle Reaction is Newtons law of motion applied to nozzles. For every action there is a reaction. A rocket achieves thrust to lift the rocket by accelerating hot gases out the exhaust pipe just as a ballon flies around the room when it is let go of. The equation that you have given above is used to calculate the pump pressure to achieve a flow and a given nozzle pressure. The reaction force is a result of a given flow being expelled at a given pressure. Reaction force can be obtained from the formula above but should not be a part of that formula. The unit lbs is POUNDS. The measure of reaction force is in pounds of force back on the person holding the nozzle|
|81||Our apparatus is equipped with pressure governor controls the automatic nozles and 1 3/4 hose do not seem to work together. What nozzle should we be using to have maximum impact with this setup?|
|Answer: Automatic nozzles work PERFECT with 1 3/4 hose and pressure governors. All you have to do is set the pressure to deliver the maximum flow that you want for the line and then leave it alone. At the nozzle the nozzleman can use the valve to then adjust to whatever flow is needed for the situation. A perfect combination.|
|82||What nozzles do you recommend for use in an manufacturing plant being supplied off of 1" sprinker connections. My company removed all of the fire hose stations in the plant because it was too expensive to maintain. I would like to have something available to me, just in case. Thanks.|
|Answer: You should be using something on the order of our D1024. It has flow settings of 10 and 24 GPM which should work quite well on a one inch hose. It is a not automatic nozzle that has a simple inexpensive twist shutoff mechanism.|
|83||Our department just purchased a TFT Blitzfire. The rated flow is 175-500 gpm @ 100 psi. If the Max Force nozzle on it will flow 500 gpm at full flow, at what psi are other flows (200,300,400,etc.)? Are there charts available that show the flow will be X gpm @ X number psi from flow tests done previously?|
|Answer: The rated flow is actually 500 at 100PSI. The numbers you have stated are the MAXIMUMS. The Maxmatic nozzle is an automatic nozzles. The nozzle pressure will be 100 at 200,300,400, or 500. The more you raise the pump pressure the more friction loss is available to deliver higher flows.|
|84||Is there any reason why TFT has not developed a slide valve for use with smoothbore nozzles? It seems to me that a slide valve would be more versitile because the nozzleman could back off from maximum flow at a given pump pressure without creating the turbulance generated by a ball valve, and thereby maintain a good column of water at a reduced flow without having to communicate with the pump operator. Tom Abbott, Asst. Chief, City of Oswego Fire Department.|
|Answer: This is an excellent question to be answered in these FAQ's as it has been asked many times. There are two reasons why we don't do this. The first is that the slide valve requires a central "pier" in the waterway to support the valve plug that the slide closes against. If this central pier was present with a smooth bore it would be very difficult to get a good stream. (difficult read impossible in our belief) The reason that the partial open condition of a slide valve works so well with an automatic nozzle is that the nozzle adjusts to the reduced amount of water that is allowed thru and the stream pressure stays correct. Most people do not realize the dramatic affects of reduced flow on nozzle pressure with a smooth bore. Lets take an example. A 15/16 at 50 PSI is 180 GPM. If that flow is cut in half to 90 GPM the nozzle pressure falls to 12.5 PSI which is not a very effective stream. An automatic nozzle would still deliver that 90 GPM at the 50 PSI if it was a low pressure automatic or at 100 if it was a high pressure automatic. The problem with smooth bores is that they are basicly single flow nozzles. Too much flow and the pressure at the tip makes them unmanageable and too little flow and they are in-effective.|
|85||For training my firefighters on the use of straight bore handline nozzles, where would you recomend the use over the conventional fog/ straight stream nozzles.|
|Answer: The simple answer is that we wouldn't. I am sure that you have heard the old saying "You can't fight city hall" Yes we make smooth bore nozzles because there are some people that no matter what believe that they are better. Our experiance has shown this to not be true. We have done dozens of comparisons of reach and have found consistantly that when they are compared at equal flow and pressure they go equal distances. We have thrown streams thru 2000 degree heat tunnels and measured the water drop out and found it to be identical. We have done impract tests at various distances and found them to be identical in all cases except short range where the fog nozzle has MORE impact. The simple fact is that the stream out of a fog nozzle is NOT hollow it is parallel and focused and it works. We would not reccomend a smooth bore over a fog nozzle for any application for at least two reasons. The fog pattern is too important to give up and the smooth bores flow size is not easily adjusted. But as always, people will believe what they want to believe and especially in the fire service the traditions live on.|
|86||Not a question, but a comment. In FAQ #54, the sender stated a factory representative told them that for Dual-Force nozzles the low pressure setting should be used for interior fires and the standard for exterior. In your response, you stated that you weren't sure who told them that, but the information was wrong. After reviewing your on-line library, I discovered that in the Power Point presentation on Dual Force nozzles, the way it is written would easily lead anyone to conclude that Red is for interior and Blue is for exterior. See slide #5. Better make that clearer in your literature before you yell at your rep.|
|Answer: Change made to response, the whole point is that we do not reccomend either. Lower pressure gives higher flow for a given pump pressure, how that gets used is the fire departments choice|
|87||Does TFT make a Foamjet Connection for the Max-Force nozzle?|
|Answer: Not yet, one is planned for the future|
|88||What is the optimum nozzle pressure for a dual-force or mid-force nozzle operating in low-pressure mode? Can you use this nozzle effectively on a hi-rise pack in conjunction with another crew operating a smooth-bore nozzle at 50 PSI off a standpipe feeding both handlines?|
|Answer: In low pressure the nozzle pressure is approximately 50 PSI at the low end of the flow and it starts rising to where at full capacity it will be at about 75 PSI. Can it be used with a smooth bore the answer is a qualifed yes. What it will do is stay shut off until the smooth bore is fully pressurized. If there is enough water both streams will look good. If there is NOT enough water the dual-force will sacrifice its flow to help the smooth bore. In that case the smooth bore will of course look like its doing the better job but ONLY because the automatic is preventing the system from "bleeding to death". If in that same low flow situation you put two smooth bores into play they would both be low on pressure and would both be drooping.|
|89||We have a piped in deck monitor (a monsoon). The piping can take a maximum of 200psi apparently. How much pressure should we be putting to the actual monitor? -Is a smoothbore nozzle just basically a pipe with a shutoff valve? -Our nozzles have flow settings on them, is that what you mean by the firefighter adjusting the flow, or do you mean they should vary the flow with the shutoff handle?|
|Answer: You should put the maximum pressure to the monitor that you can for a given situation. Typically you will run out of supply or power before you reach the 200 PSI. In any even the nozzle will constantly adjust to be the right size nozzle for whatever flow you can get to it. Yes a smoothbore is basicly a pipe with a shutoff valve, that is why the design is over 125 years old of not older. Your question about adjusting the flow on a selectable is a whole bok in itself. Please download out of the library the book on Automatic nozzles. The issue of flow control is addressed in this book in detail|