The Retooling of the 1" Smooth-bore Tip


By Capt. Joe Bruni

&

Lt.Rob Edwards

The Research


In 1996, the City of St. Petersburg, Florida, Fire and Rescue Department began an in-depth research project. This research took a detailed look at nozzles, fire streams, and the gallons per minute that were being delivered during fireground operations. It was discovered that we were only delivering approximately 90 to 110 gallons per minute from our 1-3/4" handlines and approximately 200 gallons per minute from our 2-1/2" handlines. The research began with a basic flow meter which had been kept in the Safety and Training Division. All handlines that were 1-3/4" in the city had either an adjustable gallonage combination nozzle or a combination nozzle that could flow anywhere from 50 to 300 gallons per minute. The 2-1/2" handlines had either a 250 gallon per minute adjustable gallonage combination nozzle or a stacked-tip smooth-bore which were comprised of a 1", 1-1/8", and 1-1/4" tips.

This project started out as a basic look at gallons per minute delivered. It turned into a nine-month research project that not only took a hard look at gallons per minute delivered, but also which was the best type of fire stream and attack (direct, indirect, and combination) for interior structural firefighting. This research project showed St. Petersburg Fire and Rescue that we needed to take a good hard look at one of the most critical tools used for fire suppression, the nozzle.

 

Different Nozzles Tested


The first nozzles we tested were low-pressure combination nozzles that required 75 pounds of nozzle pressure to reach their required flow. These nozzles are available with different stems which are threaded into the head of the nozzle. The different stems can flow anywhere from 125 to 300 gallons per minute. The low-pressure nozzles proved to be very satisfactory; however, it was discovered flows greater than approximately 150 gallons per minute required at least two firefighters on the line to effectively deal with the back pressure generated. A problem was occurring with one firefighter on the nozzle using a straight stream. The reaction force generated from a 100 psi combination nozzle flowing more than 125 gallons per minute was too much for one firefighter which was requiring the officer to become more of a firefighter than a supervisor. After all, the officer must be able to observe conditions, direct the firefighters, and keep everyone's safety first and foremost. It was also discovered, a firefighter would either gate-down the bail of any nozzle where they could not handle the reaction force. Or, a firefighter will use the nozzle on the narrow-angle fog setting to help reduce the reaction force. We discovered most firefighters did not feel comfortable with reaction forces higher than 60 to 65 pounds. This gating down action resulted in flows of less than 125 gallons per minute, even with 1-3/4" hose. We were defeating the reason why 1-3/4" hose came into the fire service, to generate higher flows with reduced friction loss. It was time to try a different approach.

Shortly after the low-pressure tests the Safety and Training Division looked into our fire service casualty reports. It was discovered over a two-year time frame that St. Petersburg Fire and Rescue had nine firefighters with reported steam burn injuries that required medical attention. These injuries occurred during interior structural firefighting. This did not include the firefighters who had felt the effects of steam, but did not receive any blistering injuries where a casualty report had to be generated.

We learned in the fire academy that the narrow-angle fog stream would protect us during flashover or rollover should either occur. What we discovered is that the fog stream was not protecting us inside the structure. Granted, the steam burns may not have occurred if adequate ventilation had taken place on the opposite side of the fire but with the reduced manning of the 90's, the personnel who performed ventilation were no longer or seldom able to perform this critical task. Other factors today include: double and triple-pane energy efficient windows which do not fail quickly under fire conditions, energy efficient construction, and materials inside the structure that burn hotter than ever before. St. Petersburg Fire and Rescue discovered direct attack with a straight or solid stream inside the fire room, or just outside of it, proved to be the most effective and safest type of fire attack nine-five percent of the time. We were over-using the fog stream.

 

Testing of the Smooth-bore Tips

 

Many different firefighters and fire departments were contacted about their use of smooth-bore nozzles for interior fire attack and it was decided to give them a serious evaluation. We discovered that it is a rare occurrence for a firefighter to have the opportunity to be on a nozzle, even in the busiest fire departments. The experience level on the nozzle has diminished in the fire service of America. This is partly be due to a drop in the number of structure fires in this country. Statistics report structure fires down forty-six percent.

The first smooth-bore nozzle tip we tested on the 1-3/4" handline was the 15/16" tip. This nozzle proved to be a great tip for knockdown because of the gallons per minute it flowed at 50 psi nozzle pressure (180 gpm), but it was still very difficult for one firefighter to handle that much reaction force. This size tip also did not offer a very wide window of error for the driver/engineer if it was slightly under-pumped or over-pumped. Over-pump this tip and the firefighter was faced with a serious and unmanageable reaction force to contend with, under-pump this tip and the hoseline had a kinking problem. We decided that the 15/16" tip was a great tip for the firefighting crew which worked together every shift with the same crew and driver/engineer. This was not the case in St. Petersburg. We decided to try another size tip on our 1-3/4" handlines.

The next tip tested was the 7/8" tip. This tip flowed 160 gallons per minute at 50 pounds nozzle pressure and had a reaction force of 60 to 65 pounds; therefore, we found this reaction force manageable by one firefighter and the window of error for the driver/engineer was larger than with the 15/16" tip. Over-pump this tip or under-pump it a little and it is no big deal. We were getting the same reaction force from the 7/8" tip that was generated from a 100 psi combination nozzle flowing 125 gallons per minute. This size tip proved very effective for quick fire knockdown because of the punch it delivered with its direct attack and added gallons per minute. This is when our firefighters and company officers discovered that the direct attack inside the fire room, or just outside of it, with a 7/8" smooth-bore nozzle proved to be the correct choice for almost every interior structural firefighting operation where the seat of the fire could be reached. Could the same thing be accomplished with a combination nozzle set on straight stream? It certainly could, but not with the reduced reaction force and additional gallons per minute available from the smooth-bore nozzle. Keep in mind, it is gallons per minute that extinguishes fire. Plain and simple, the higher Btu's of today's structure fires requires more water. Did the smooth-bore provide us with any protection inside the structure? If you keep the upper atmosphere from reaching the 1,200 degree mark (the point which flashover occurs). We found that not only did flashover not occur, but we were putting out interior fires with less water than if we were using a combination nozzle set on a narrow angle fog pattern that flowed the same gallons per minute. The theory taught about fog streams went right out the window. There was no protection offered from fog streams inside the structure. The fog stream inside an unventilated structure did not protect the firefighters, it burned them. Lloyd Layman discovered during his study of fog streams that if they are used inside an unventilated fire building, they will drive interior crews out of the structure. Fog streams can also burn any trapped victims inside the structure and push fire to uninvolved areas of the structure. This is due to the large volume of air they move. We have witnessed many fire victims with their skin hanging off. After nine months of research it was time to put the 7/8" smooth-bore on one 1-3/4" handline and a combination nozzle on the other 1-3/4" handline, (preferably a low-pressure combination nozzle that could flow 150 gallons per minute). We were now confronted with a problem, how to purchase the nozzles. This was a year that the department did not budget enough money under the nozzle category to accomplish this.


The 2-1/2" Stack-tip Nozzle


It was time to examine the 2-1/2" stack tip nozzles as well. The department had been using chrome-plated, heavy brass nozzles for years. While many of the firefighters in St. Petersburg had used and fought fire with these nozzles, it was discovered through a department survey that only one firefighter ever remembered removing the 1" tip from the stack to go with the next tip size to increase gallons per minute. This was amazing that firefighters went through the trouble of pulling a 2-1/2" line but were only flowing 200 gallons per minute with a 1" tip. Why were we going through the hassle of pulling a large line if we are not going to get the most gallons per minute out of it? The City of St. Petersburg has a more than adequate water system. So, it was at this time we decided to remove the 1" and the 1-1/8" tips from our 2-1/2" nozzles and start off with the 1-1/4" tip for initial fire attack. This proved to be very effective when we needed to flow big water on a big fire. The 330 gallons per minute at 50 pounds nozzle pressure delivered from the 1-1/4" tip was extremely effective when it came to quick knockdown of a large fire. The 1-1/4" tip also has the same reaction force as a combination fog tip flowing only 220 gallons per minute.

A Lieutenant from station 6, who was actively involved in the testing and evaluation of our nozzles, came up with a unique idea at this time. He asked, why put those 1" and 1-1/8" tips away on a shelf somewhere? Let me take them home and convert the 1" tips into 7/8" tips with my lathe. Our purchasing problem seemed to be solved.

The Retooling of the 1" Tips

 

The 1" tip was placed in the chuck of a lathe and the inside bore roughed up with some emery paper to help the epoxy bonding agent adhere the aluminum insert to the 1" tip. This also removed any dirt or corrosion. A 1" inch (outside diameter) piece of solid aluminum rod was cleaned up with emery paper, coated with a structural epoxy adhesive, and then pressed into the 1" tip and allowed to dry. Once the epoxy had dried, a 1/16" hole was drilled through the side of the 1" tip and into the 1" aluminum rod insert. A 1/16" aluminum pin was epoxied into this hole for added strength and to further secure the 1" aluminum insert. The tip was reset into the chuck of the lathe and a 3/4" drill bit was used to drill a hole through the 1" insert. A boring tool was then used to bring the hole out to 7/8". At the orifice opening, a recess was now cut into the end to prevent damage from use. At this point the tip was now turned around in the chuck to center the hole and to cut a taper inside of the thread side of the tip which provided a smooth tapered hole. The chrome was now machined off and some polishing done to complete the job. The tip was stamped 7/8", mated to the 1-1/8" tip, and added to a ball-valve-shut-off already carried inside a compartment on every engine. This shut-off was part of our air-aspirating foam nozzle assembly. To change to a foam operation, the smooth-bore tip is simply removed and the air aspirating foam tube is added to the ball-valve-shut-off. This has proved to be a very effective way of doing business and the City of St. Petersburg Fire/Rescue Department has not suffered any steam-burn injuries to the firefighters or any trapped victims since the implementation of the 7/8" smooth-bore nozzle. We now have two documented rescues of trapped victims from structure fires after use of a smooth-bore nozzle. Neither of these victims suffered steam burns that may have occurred from the use of a narrow-angle fog stream. Our firefighters have discovered that the direct attack offered from a solid-stream or a straight stream is the safest and most effective way to attack ninety-five percent of our structure fires, providing you can reach the seat of the fire to use a direct attack.

Bio:

Joe Bruni is the Captain of station 12C with the City of St. Petersburg Fire and Rescue Department. He has a total of 23 years in the fire service. He has an A.S. in Fire Administration He has served two years in the Safety and Training Division as a department Training Officer. He is an instructor with the Pinellas County Fire Academy and St. Petersburg Junior College. He is currently on track to complete a B.A.degree in Organizational Studies with a Public Leadership track. Questions and comments can be sent to him at uself@aol.com.

 

Rob Edwards is a Lieutenant at station 6B with the City of St. Petersburg Fire/Rescue Department. He has a total of 20 years in the fire service. He is an instructor with the Pinellas County Fire Academy and is a Florida State certified smoke diver.

 

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