Smooth Bore Tips, The Next Generation

Smooth Bore Tips,

The Next Generation


When it comes to water delivery on the fireground, I think it’s safe to say that the fire service has come a long way. My knowledge of history in regards to this topic goes back to the use of buckets in bucket brigades. I can’t imagine what was done before then. We have since seen the coming of fire hose and water delivery appliances called nozzles, producing major improvements in our capabilities. I am pretty sure that the smooth bore nozzle was the first nozzle design used and we are still using it successfully today.


Rules governing the use of smooth bore nozzles have been in place without change for at least the last 60 years, and possibly even longer. I think it’s time for a change.



The smooth bore nozzle is a fire stream producing device (nozzle) consisting of a nozzle valve and a pipe like extension that forms the fire stream used in conjunction with handline and master stream operations to deliver water in the form of an effective firefighting straight stream. The flow rating of the smooth bore tip is based on the diameter of the tip as well as the nozzle pressure.



The following chart shows the most commonly used handline smooth bore tips with their corresponding flow and pressure ratings

7/8″ tip 159 GPM 50 psi NP

15/16” tip 185 GPM 50 psi NP

1”tip 210 GPM 50 psi NP

1-1/8” tip 265 GPM 50 psi NP

1-1/4” tip 325 GPM 50 psi NP


The following five rules on smooth bore tip handline operations are from the current fire stream management book by IFSTA .

#1-The maximum handline flow is 300-350 GPM. They claim that flows higher than this will create an unmanageable handline.

#2-The nozzle pressure for a smooth bore tip on a handline is 50 psi. If need be the nozzle pressure can be increased to 65 psi. Pressures higher than this will create an unmanageable handline as well as a broken, non-productive stream.

#3-The diameter of the smooth bore tip shall be no larger than half the diameter of the hose.


Let’s talk about the first three rules. The following chart shows various nozzle combinations and their capabilities as they relate to handline operations. The chart is divided into sections of flows ranging from 250 GPM to 500 GPM. It shows the nozzle (smooth bore or combination), nozzle pressure (NP), and nozzle reaction (NR).



250 GPM

15/16” tip@90 NP = 124 NR

1″ tip @ 72 NP = 113 NR

1-1/8″ tip @ 50 NP = 99 NR

combination @ 100 NP = 126 NR

300 GPM

1” tip @100 NP = 157 NR

1-1/8” tip @ 64 NP = 127 NR

combination nozzle @ 100 NP = 152 NR

325 GPM

1” tip @ 120 NP = 188 NR

1-1/8” tip @ 75 NP = 149 NR

1-1/4” tip @ 50 NP = 123 NR

combination nozzle @ 100 NP = 164 NR

350 GPM

1-1/8″ tip @ 87 NP = 173 NR

1-1/4″ tip @ 57 NP = 140 NR

combination nozzle @ 100 NP = 177 NR 400 GPM

1-1/8″ tip @ 115 NP = 229 NR

1-1/4″ tip @ 80 NP = 196 NR

1-3/8″ tip @ 50 NP = 148 NR

combination nozzle @ 100 NP = 202 NR

433 GPM

1-3/8” tip @ 59.5 NP = 177 NR

500 GPM

1-3/8″ tip @ 80 NP = 237 NR

1-1/2″ tip @ 56 NP = 198 NR

combination nozzle @ 100 NP = 253 NR

Now let’s analyze the chart. All combination nozzles listed up to the flow of 350 GPM are recognized by IFSTA as mentioned earlier.


250 GPM – combination nozzle – 126 NR

300 GPM – combination nozzle – 152 NR

325 GPM – combination nozzle – 164 NR

350 GPM – combination nozzle – 177 NR


The next list shows smooth bore nozzle pressure and flow combinations that according to IFSTA are unmanageable due to the nozzle pressure being too high. Every single one of these tips has an equal or lower nozzle reaction than the highest mentioned combination nozzle reaction that is sanctioned by IFSTA and yet it is said that they are more difficult to handle and. and not recommended.


250 GPM – 15/16” tip @ 90 NP – 124 NR


250 GPM – 1” tip @ 72 NP – 113 NR

300 GPM – 1” tip @ 100 NP – 157 NR


325 GPM – 1-1/8” tip @ 75 NP – 149 NR

433 GPM – 1-3/8” tip @ 59.5 NP – 177 NR


Nozzle reaction is nozzle reaction. It is the force measured in pounds opposite of the stream direction. As long as the combination nozzle is in the straight stream mode, there is no difference.



According to the books, an over-pressurized stream will lose its pipe like appearance and begin feathering on the edges causing a loss in reach and water volume.

The first question that comes to mind about nozzle pressures in smooth bore tips is why, again according to the books, does a handline stream begin breaking up at nozzle pressures higher than the 50 to 65 psi range while a master stream can be pumped up to 80 psi? There should not be any difference. Example, a 400 GPM flow is an accepted stream from a master stream appliance. It is produced from a 1-1/4″ tip at an 80 psi nozzle pressure. The stream quality is good and the reach is sufficient. Why then, can’t the same tip and nozzle pressure produce a sufficient stream on a handline? Does that make sense to you?

Flow tests have proven that 80 psi handline nozzle pressures do work just as good as they do on master streams. In fact, nozzle pressures reaching 120 psi and higher have proven to be very effective on handlines with the proper nozzle handling techniques. These higher pressure streams not only give a higher flow, they also increase the velocity and the reach of the stream significantly.


High flow handline stream resembling the quality of a master stream.

Now don’t get me wrong, I feel that there is a place for the 40 to 65 psi nozzle pressures. If penetration and reach are not a factor in the stream application a low pressure might be all that is needed. This can allow for higher flows for interior attack lines.


              TFT AUTO 100 PSI NBP      150 GPM    90′ REACH

              15/16″ TIP 50 PSI NP        185 GPM    84′ REACH

              1-1/8″ TIP 40 PSI NP        240 GPM    84′ REACH

              VIND. H.   30 PSI NBP       250 GPM    90′ REACH



One common issue about low nozzle pressures with smooth bore tips is the fact that the hose kinks more easily.  This has been common knowledge in the fire industry for years, especially in high-rise fires.  Kirk Allen, President of First Strike Technologies, has done a series of flow tests that disproves the low nozzle pressure / hose kinking theory in certain cases.  Following series of flow tests are designed to prove this concept.


       TFT AUTO 100 PSI NBP      150 GPM    KINKED 105 GPM

       1″ TIP      45 PSI NP        200 GPM    KINKED 170 GPM

       1-1/8″ TIP 40 PSI NP        240 GPM    KINKED 220 GPM

       VIND. H.   30 PSI NBP       250 GPM    KINKED 225 GPM



I think it’s safe to say that the nozzle handling techniques used for interior attack low flow handlines is working well. There are two nozzle handling techniques for high flow 1-3/4″ and 2-1/2″ handlines. The first one requires the firefighter at the nozzle to sit directly on the hose about 2-1/2 to 3 feet from the nozzle. The entire handline stays on the ground. The hose on the ground is important with this concept because the ground actually absorbs most of the nozzle reaction. I have found that looping the hose at this point makes no difference on how well the nozzle reaction is absorbed. Furthermore, in a quick attack/minimum manpower situation with the line already charged, setting the loop up takes time away from the initial quick hit.


For the higher nozzle reaction lines two firefighters should be used. The firefighter at the nozzle uses the same techniques as mentioned above. The second, or backup, firefighter sits directly on the hose behind the firefighter on the nozzle. The backup firefighter can use a hose strap secured to the hose for assurance, but in all honesty this will be more of a mental assurance than anything else. It is extremely important that both firefighters keep all their weight on the hose while flowing water to keep the nozzle reaction at a minimum. It is also equally important for the firefighter at the nozzle to keep one hand on the bale of the nozzle at all times in case it needs to be gated down to be manageable or shut down completely.


The second technique for handling a high flow handline utilizes a kneeling technique. The firefighter drops to both knees straddling the line perpendicular (facing it) with the hose going under the rear leg and over the front leg. This technique works the best for an advancing line because it is a position the firefighter can get into and out of quickly during the advancing. Again for the higher nozzle reaction lines two firefighters should be used.


Standing up creates a lot of work, just have a seat.

The back-up person on a high flow handline can either stand or sit on the hose to help support the nozzle man.

The straddle method hose handling technique.

No matter which technique is used, there could be a slight tendency for the hose to kink right behind the nozzle due to the nozzle reaction, especially in the

1-3/4” and 2”hose. Again I say this is a slight tendency. Being aware of this, countering the kink with proper technique is all that is needed to rectify the problem.


High flows using 1-3/4” and 2” hose can cause kinking at the nozzle due to the nozzle reaction. The firefighter can easily correct the kink by pushing against it.


Another method for dealing with the nozzle reaction problem is to use a short section of 2-1/2″ hose(five feet) at the end of the line just behind the nozzle.  the size of the 2-1/2″ will absorb the reaction better thus doing away with the kink.



The 2-1/2” playpipe with smooth bore stacked tips has been and continues to be a popular high flow handle nozzle. As previously mentioned, the tip sizes and their respective flows according to the traditional books are 1” @ 50 psi NP flowing 210 GPM, 1-1/8” @ 50 psi NP flowing 265 GPM and 1-1/4” @ 50 psi NP flowing 325 GPM. Now let’s see what we can get from these tips at higher nozzle pressures.


1” tip @72 psi NP = 250 GPM

@100 psi NP = 300 GPM

@120 psi NP = 325 GPM


1-1/8” tip @ 64 psi NP = 300 GPM

@ 75 psi NP = 325 GPM

@ 87 psi NP = 350 GPM

@ 115 psi NP = 400 GPM


1-1/4” tip @ 57 psi NP = 350 GPM

@ 80 psi NP = 400 GPM


To simplify the calculation for the PDP for a 2-1/2” handline nozzle utilizing the commonly used triple stacked smooth bore tips (1”, 1-1/8”, and 1-1/4”tips), here is an example of what can be done. Determine the maximum flow for the 2-1/2” handline evolution based on the largest tip, which is the 1-1/4” tip. The PDP should reflect that flow. This same PDP should be used for the 1-1/8” and 1” tips as well. It’s that simple. One PDP is good for all three tips. Below is an example of the flows that can be delivered from the three tips in the triple stack tips. The PDP used for these flows is based on the 1-1/4” tip flowing 325 GPM.

Tip Size    Flow

1-1/4”      325 GPM

1-1/8”      295 GPM

1”           260GPM


The triple stacked tips (1”, 1-1/8”, and 1-1/4”) on a 2-1/2” or 3” handline can provide a variety of flows using nozzle pressures higher than 50 psi.  The only thing that is required is to think out of the box.

In regards to rule #3, I am not sure why the tip diameter can be no larger than half the size of the diameter of the hose. The IFSTA offers no explanation for this. Many departments have been successful with nozzle/hose combinations that break this rule. In fact the FDNY is well known for their highly successful interior attack handline which is the 15/16” tip using 1-3/4” hose. I have had success with 1”, 1-1/8”, and 1-1/4” tips using 1-3/4” hose as well.


Now let’s go back to the old rules #4 and 5 for smooth bore tips used with handlines


#4-The books say when operating a smooth bore handline the ball valve must be fully open to produce the best quality stream. A partially opened valve will create turbulence in the waterway totally breaking up the stream. It’s fully opened or don’t open it at all. This rule is correct in regards to getting maximum flow and it should always try to be practiced.  However if the nozzle needs to be gated down for safety, I have found that most smooth bore tip nozzle combinations can be gated down to almost half way reducing the nozzle reaction enough to maintain safe control of the nozzle while still providing a working stream. Will the stream be pretty? Probably not. The key is getting the wet stuff on the red stuff. Does the stream have the reach and is it hitting the target? This is what we should be looking for. You need to evaluate the stream based on performance, not appearance. Firefighters tend to do the opposite.

The following flow tests are designed to show 1-3/4” handline nozzle capabilities. The first series of tests will show how far an interior attack nozzle can be gated down and still provide a working stream. The streams were analyzed at a point when either it reached a minimum of 25’, had a flow of 100 GPM or broke up becoming inefficient, whichever came first.




15/16” S.B.                     185 GPM                               145 GPM


1” SB                            210 GPM                               170 GPM


The next series of flow tests shows high flow handlines first in a maximum flow operation with the bale of the nozzle fully opened and then gated down to a point where the stream had a minimum reach of 50’, reached a flow of 250 GPM or start breaking up becoming inefficient, whichever came first.



1” SB                     300 GPM                               265 GPM


1-1/8” SB                350 GPM                               280 GPM

                            400 GPM                               322 GPM


1-1/4” SB                400 GPM                               305 GPM

                           500 GPM                               365 GPM


It should be noted that a 1-1/2” stream shaper can be used with the handline/smooth bore tip combination to clean up the stream much as master stream shaper is used. It should be placed between the nozzle valve and the tip.. The small shaper has also provided improvement to nozzles using the slug tip which is built into the nozzle valve. For this application placing the shaper between the hose and the nozzle works best.


#5-The size of the waterway in the ball valve should be larger than the tip size. If the waterway is smaller than the tip size it will act as the tip itself thus creating turbulence as it enters into the larger tip size. This will produce a broken stream. This rule is accurate.



Here is a basic definition of a master stream. A master stream is a heavy caliber stream delivered through a master stream water delivery appliance. A master stream is used when flows surpass 350 GPM becoming too difficult to be delivered from a handline operation due to nozzle reaction. The stream that a master stream operation produces is high in flow and usually in the form of a straight stream using a smooth bore tip or some type of combination nozzle.


There are three types of master stream operations, the fixed master stream, the portable master stream and the elevated master stream. The following information about master stream smooth bore tips can be found in most fire stream management books in circulation today. It’s information that needs to be understood to establish a base to operate from.


The most common set of smooth bore tips that come with a master stream is what is known as the stacked tips. The stacked tips gets its name because it consists of four tips connected into one stack, which is then attached to the master stream appliance. The tip sizes and the corresponding flows are based on an 80 PSI NP.


1-3/8” – 502 GPM

1-1/2” – 598 GPM

1-3/4” – 814 GPM

2” –     1063 GPM


For master stream appliances capable of flows higher than 1000 GPM the following tip sizes with 80 PSI nozzle pressures will apply. Again these are the most common.


2-1/4” 1345 GPM

2-1/2” 1661 GPM

2-3/4” 2010 GPM


It should be noted that the standard rule on smooth bore tip nozzle pressures used with master stream operations is to use a nozzle pressure of

80 PSI. Nozzle pressures higher than this will create a broken and insufficient stream, as well as an unstable operation in the elevated and portable modes according to most fire stream books. Nozzle pressures up to 100 psi can only be used with fixed master stream operations. We will show how smooth bore tips can be taken to a much higher level producing high pressure streams that were never thought possible while remaining safe and efficient in all modes of operation.





The purpose of high pressure smooth bore tip operations used in conjunction with a master stream is to provide the required GPM to extinguish the fire problem with a high velocity stream that improves the reach and penetration capabilities of the fire fighting stream itself while still maintaining efficient stream performance.

The maximum allowed nozzle pressure for this type of operation is based on the following rules

1. Maximum allowed inlet pressure to the master stream appliance. The three most common manufacturers of the master stream appliance for the municipal fire service are; Task Force Tips, Akron Brass and Elkhart Brass. Listed below are the specs for each of the three brands of these appliances in the fixed mode.


Task Force Tips 200 PSI inlet pressure 1250 GPM 631 NR 2000 GPM 1010 NR

Akron Brass 200 PSI inlet pressure 1250 GPM 631 NR 2000GPM 1010 NR

Elkhart Brass 200 PSI inlet pressure 1250 GPM 631 NR 2000GPM 1010 NR


I think you will find that most of the other master stream manufactures require the same 200 psi inlet pressure as well. Always make sure the inlet pressure is never exceeded when performing high pressure operations.

2. Maximum allowed flow for the master stream appliance.

3. Maximum allowed nozzle reaction for the master stream appliance. This is based on a 100 psi combination nozzle at the rated flow of the appliance. For example a 1250 GPM master stream appliance using a 100 psi combination nozzle flowing 1250 GPM has a nozzle reaction of 631 LBS.

4. Maximum allowed operating pressure for the discharge hose supplying the master stream appliance when applicable. This applies to elevated stream operations using a non-quint truck company and portable master stream operations.

5. Stream angle capabilities for the appliance/apparatus combination. In order to provide the required pressure for the high pressure operation the pump operator needs to understand the limitations mentioned above and throttle up accordingly. Flow tests will determine what the maximum pressure can be, again based on the above mentioned criteria. A pump chart should than be designed showing all possible pump operations that can be used. The pump operator should plan on throttling up to the maximum allowed pre determined pressure unless something stops him. Does this mean that every time a deck gun operation is placed into service the pump discharge pressure needs to be maxed out? No. The pre determined pump discharge pressure is the number that the pump operator will try to reach unless something stops him.


Some of the things that may stop the operation from going to maximum pressure are:

1-run out of water

2-run out of throttle

3-run out of RPMs

4-the stream accomplishes its goal

5-other rules set by the department

6-orders from the company officer


The following smooth bore tip sizes with their corresponding nozzle pressure and flows have successfully produced high velocity/high flow streams using a master stream. The maximum nozzle reaction for a 1250 GPM appliance is 631 LBS and for a 2000 GPM appliance, 1010 LBS.


1-3/8″ tip @ 175 psi NP = 743 GPM 519 NR

1-1/2” tip @ 150 PSI NP = 817 GPM 530 NR

1-3/4” tip @ 120 PSI NP = 996 GPM 577 NR

1-3/4” tip @ 150 PSI NP = 1114 GPM 721 NR


2” tip @ 100 PSI NP = 1189 GPM 628 NR

2” tip @ 110 PSI NP = 1250 GPM 691 NR

2” tip @ 120 PSI NP = 1303 GPM 754 NR

2” tip @ 140 PSI NP = 1407 GPM 879 NR

2” tip @ 150 PSI NP = 1455 GPM 942 NR

2” tip @ 160 PSI NP = 1500 GPM 1005 NR


It should be noted that the 2” tip at 160 PSI NP produced a stream with a footprint reaching 360 feet.



Picture a large fire that has totally consumed the structure ending up with a large pile of burning rubble left to be overhauled? This is where the digging power of a high velocity stream can really have a positive effect. The following smooth bore tip sizes and corresponding nozzle pressures and flows have been successfully used in this type of operation. One point to remember is that the goal in this type of operation is to produce velocity, not high flows.


1-1/8” tip up to 180 PSI NP = 504 GPM


1-1/4” tip up to 180 PSI NP = 623 GPM


1-3/8” tip up to 180 PSI NP = 754 GPM


This deck gun is using a 1-1/4” smooth bore tip flowing 623 GPM at 180 PSI NP.


Working a brush fire from a fixed master stream appliance is a heck of a lot easier than pulling hose. When possible, a fixed master stream can make very large sweeps in burn areas with the above mentioned high pressure stream operations. In fact, the

1-1/8” tip application will more than likely be the tip of choice for this operation.

These same three also apply to portable master streams and elevated master streams.  However, with elevated master streams you have to follow the guidelines for flowing water at specific angles.  This information is always found on a placard on the turntable console.




165 NP     1527 GPM         220′ REACH       1005 NR




NFPA requirements for tank to pump flow delivery capabilities state that a minimum of 500 GPM shall be delivered. Unless a department has specified their apparatus to deliver more, this is the flow rate capability they will have. A very high percentage of fire apparatus have the 500 GPM maximum flow capability. Two popular tip applications for a 500 GPM Blitz attack are the 1-1/4” tip @ 115 PSI NP which delivers a flow of 495 GPM and the 1-1/8” tip @ 180 PSI NP flowing just at 500 GPM. These high nozzle pressures produce hard-hitting streams capable of penetrating deep into the fire which could very well be needed in an offensive Blitz attack operation



The following information is based on any size discharge hose used as either a single line or Siamese lines.


Just as with the fixed master stream operation, the portable monitor can deliver several different flows with each potentially having a different pump discharge pressure. It is not practical to list all of them on the pump chart The only pressure that needs to be listed is the numbers for the maximum flow operation with the most common being 1250 GPM with a combination nozzle at 100 psi NP. Adhere to the specific manufacturer’s ratings on what the highest flow in the portable mode should be. The manufacturer should also be able to tell what the friction loss in the appliance is, at the high flow. Add the appliance friction loss and the nozzle pressure together and note it on the chart. The number for the nozzle pressure should be based on the highest nozzle pressure used in the department’s arsenal. Here is an example. If a department uses smooth bore tips rated at 80 PSI and a 100 PSI combination nozzle for their portable monitor operation, the pump chart should reflect the higher 100 PSI figure in the formula listing on the pump chart. The friction loss per 50 or 100 feet of the hose evolution being used (whichever works best) should also be noted. Remember the friction loss is based on the highest flow the departments operations allow for. Determine how much hose is being used in the evolution and add up the friction loss plus the numbers from the appliance and nozzle pressure and to develop the pump discharge pressure. Example, a portable monitor is flowing 1000 GPM through an automatic nozzle with a 300 foot 5” discharge line. Add 15 for the appliance friction loss, 100 for the nozzle pressure based on the fact that the highest nozzle pressure used is 100 PSI, and 5 PSI per 100 feet of 5” hose (15 PSI for the 300 feet) bringing the sum to 130 PSI.


When using smooth bore nozzles, the maximum flow pump discharge pressure listed on the pump chart will work with any size tip from 2” down to 1” and still provide for a safe and efficient operation. Yes the rated flow at the standard smooth bore nozzle pressure (80 PSI) will probably be surpassed. However it will do this while keeping within the required inlet pressure of the appliance (200 psi) and the maximum allowed flow and nozzle reaction. Here’s an example. The pump chart lists a pressure of 115 PSI plus 5 PSI per 100 feet of 5” for a portable master stream supplied by 5” LDH flowing 1000 GPM. The 115 PSI represents the appliance friction loss of 15 and the nozzle pressure for the automatic nozzle, which is 100 PSI. Now, for whatever reason, the automatic nozzle is being replaced with the with the 1-3/8” tip. The pump discharge pressure for the 1-3/8” tip at its rating of 500 GPM has a friction loss of

2 PSI for the 5” hose. But since the pump discharge pressure will remain at the high flow pressure, the excess pressure in the hose (3 PSI per 100 feet) will be added to the nozzle pressure creating a slightly elevated flow. A picture tells a thousand words so do the flow tests and take a nozzle pressure reading.



Pump to the largest tip

Based on a 2″ tip flowing 1060 GPM @ 80 psi NP.


                     1-38″ tip   589 GPM    110 psi NP

                     1-1/2″ tip  634 PGM    90 psi NP

                     1-3/4″ tip  814 GPM    80 psi NP

                     2″ tip       1060 GPM  80 psi NP        


The information presented in this text is based on being progressive, keeping an open mind, and continuous evaluation of equipment and techniques. Much of the information presented will not be found in IFSTA. Does that mean that this is not an acceptable way to use smooth bore nozzles on the fire ground? In my opinion, it does not. At no time do any of the above mentioned flows, nozzle combinations, nozzle pressures, hose evolutions, and techniques go against what the manufacturers say their equipment can do. If you like what you have read, don’t implement it today, instead practice, practice, practice. Feeling comfortable and confident is the key to success. Once that is accomplished implementation will be easy.