The HydroVent™ Nozzle

By Raul A. Angulo

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1963, Downtown Chicago, Illiniois-Firefighter Jim “Jaws” O’Donnell, of Truck 3, is responding to another midrise apartment fire with reported smoke and flames visible.

After searching for victims, O’Donnell finds himself face down on the ground trying to find one breath of good air. Back in 1963, there were no self-contained breathing apparatus, so you really did have to eat smoke. He found the end of an unmanned hoseline and immediately opened it up to breathe air from the nozzle. After getting a few good breaths, he decided he should start ventilating. He aimed the nozzle out the small window and opened it up. He could see and feel the smoke rushing out the window. He could also hear the guys from Engine 42 yelling, “We got it licked!”

As the smoke was clearing, O’Donnell could see there was a bigger window in the room. He knew if he took out that window, he’d have a better vent hole to clear the smoke faster-anything to end the beating they were taking. So, he shut down the nozzle and was immediately enveloped in smoke again. In the amount of time it took him to crawl over to the second window, conditions in the fire room went from good to bad. The steam was banking down and burning the guys from Engine 42. “We’re losing it!” O’Donnell took the big window out with the nozzle and opened it up. The smoke and heat immediately started to vent, and he could hear the engine officer yelling to his crew, “Wait! Hang in there, boys! We’re making it!” As O’Donnell held his position at the window, he kept thinking, “There’s got to be a better way to do this.” He put his mouth back to the nozzle to suck some more good air.

Like many firefighters, O’Donnell had a lot of ideas on tools and techniques but never acted on them. Fast forward 25 years. His son, Kevin, was now a third-generation firefighter. Although Kevin followed his dad’s footsteps on to the job, it wasn’t with Chicago; he joined the Franklin Park (IL) Fire Department in 1988.

After a house fire-which he thought went pretty well-Kevin mentioned to his dad, “I got yelled at yesterday by the battalion chief for spraying water through a window and attacking the fire from the outside. He said, ‘Franklin Park is an aggressive fire department. We attack fires from the inside,’ and warned me not to do that again. Dad, did I do something wrong?” O’Donnell answered, “No, son. You did it right. That’s the smart way to fight a fire. That chief just hasn’t figured it out yet.” He went on to tell him how attacking a fire from a window knocks the fire down and prevents a flashover, making the environment better for victims and safer for firefighters. Feeling protective of his son was just the spark he needed. He didn’t want his son to take the same beatings he took in fires and started sharing his ideas for hydraulic ventilation with Kevin.

Lt. Kevin O’Donnell, son of Jim “Jaws” O’Donnell and coinventor of the HydroVent,
prepares to put first water on the fire. The HydroVent is 7½ feet long and weighs 20
pounds with the pistol grip shutoff. The 95-gpm fog nozzle is at the tip. There is also
a 95-gpm straight-stream nozzle, spike to break windows, and windowsill holder.
This appliance can attach to any 1¾-inch hoseline with standard 1½-inch treads.
(Photos by author unless otherwise noted.)

Early Prototypes

Together, they came up with a prototype fog nozzle that was mounted on a tripod to spray water from the interior of the fire room to hydraulically ventilate it quickly and effectively. O’Donnell knew he wanted a hands-free unit, but this version took too long to set up, position, and stabilize. Plus, it still required a firefighter to be inside the unventilated fire room.

They decided to try the fog nozzle at the end of a pipe that they could insert into the fire room from the outside. The local muffler shop was the only facility that could bend aluminum pipe into a tight 90-degree angle, but the aluminum kept collapsing; so they had to fill the pipe with sand before bending the aluminum tube. The first attempts were a series of 90-degree wands-similar to a Navy fog applicator except the fog stream was directed out of the fire room. The results were not optimal and rather disappointing.

Switching to steel made the pipe too heavy, so they went back to heavy-duty aluminum. However, this time they had the pipe bent into an “S” shape. Having the fog nozzle positioned farther in through the window but still aiming out confirmed that the “S” design was the right way to go. They were ready to test the nozzle in live burns all over Illinois. In the first substantial live burn, Kevin filmed the nozzle’s performance from inside the fire room with an 8-mm camera.

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“I remember getting lower and lower. It got so hot, the camera shut off! We never did get any interior footage,” says Kevin. “If my dad didn’t open up the nozzle soon, I was going to bail. Finally, he put the fog nozzle in the window and immediately interior conditions dramatically improved. That’s when I really became a believer in the nozzle and realized that after 40 years with the Chicago (IL) Fire Department, perhaps my dad did know what he was talking about.”

They manufactured 45 (ventilation-only) nozzles. Before they could market them all, O’Donnell became ill with respiratory complications and their project stalled. All those years of fighting fires and eating smoke in the streets of Chicago finally took its toll, and O’Donnell died of lung cancer on June 12, 2002. His idea and nozzles hung in the garage for 20 years.

Lieutenant Kevin O’Donnell, now with the Hoffman Estates (IL) Fire Department, responded to a house fire with flames blowing out the front window. His nozzleman shouted, “Lieutenant! Shall I hit it through the window?” Kevin remembered the words of his dad and yelled back, “Do it!” The next shift, he brought in his dad’s nozzle and laid it on the kitchen table. He knew his firefighters would break it, fix it, or make it better. After a couple of years of peer input and studying the results from recent Underwriters Laboratories and National Institute of Standards and Technology tests on quick water application, Kevin reworked the tool, and the HydroVentTM Nozzle made its debut at the 2014 Fire Department Instructors Conference (FDIC).

The first-arriving fire company can place the HydroVent nozzle in
a window without entering an IDLH atmosphere. This can be a
tremendous transitional strategy for successful fire control for fire
departments with limited resources and personnel.


The concept is simple: HydroVent is a simultaneous hydraulic ventilation and fire suppression tool that is meant to be put directly into the fire room from the outside and left unmanned for the duration of the fire. The adjustable fog nozzle faces out from the window of the fire room for hydraulic ventilation and the interior nozzle, a series of straight streams, aims up and bounces off the ceiling to cool the interior temperatures of the fire room. Adding the interior straight-steam nozzle is the most significant change from O’Donnell’s original design. Both of these simultaneous water applications make the immediately dangerous to life or health (IDLH) atmosphere more tenable for firefighters and the victim by cooling the smoke and fire gases, preventing them from flashing over, and venting the interior heat and smoke to the outside atmosphere. There is no other nozzle on the market that does this.

The HydroVent nozzle is two sections of 46-inch pipe that connect together. It comes with a pistol-grip shutoff that connects to any 1¾-inch hoseline. Once connected, the 7½-foot pipe takes a 90-degree bend into the objective and horseshoes back out. The three- by six-inch windowsill holder is a mini iron rake that supports the weight of the tool and keeps it from sliding. In the middle of the horseshoe bend is a two-inch spike for breaking out windows. Next to the spike is the straight-stream nozzle tip with four smooth discharge holes. The horseshoe straightens out and ends with the adjustable fog tip.

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The nozzle reactions are directed back toward the horseshoe and down toward the windowsill. The length and the weight of the pipe rest against the exterior of the building. Simply placing the HydroVent and opening up the nozzle secures the tool in place for hands-free operation. All the connections are standard 1½-inch treads. With the shutoff, the unit weighs 20 pounds. It also comes with a piercing nozzle that can attach at midpipe for attic fires and enclosed spaces.

The length was designed to make it easy to place into any first- or second-floor window-our bread-and-butter fires. But, you can place it higher from any ground extension or aerial ladder. In fact, it could also be used at high-rise fires from the floor below if the window was already vented. There should be enough reach that you could attack a fire from an adjacent balcony of a high-rise unit.

The straight-stream and fog nozzles both flow 95 gpm at 60-pound-per-square-inch tip pressure, but increased pressures deliver more gpm and increases the efficiency and speed of smoke removal with better results. The fog nozzle horizontally ventilates thousands of cubic feet of smoke per minute while the straight-stream nozzle simultaneously applies water to the interior fire room, dramatically lowering the temperature, making it safer for firefighters, and increasing the survivability and rescue profile for victims.
The straight-stream and fog nozzles both flow 95 gpm at 60-pound-per-square-inch
tip pressure, but increased pressures deliver more gpm and increases the efficiency
and speed of smoke removal with better results. The fog nozzle horizontally
ventilates thousands of cubic feet of smoke per minute while the straight-stream
nozzle simultaneously applies water to the interior fire room, dramatically lowering
the temperature, making it safer for firefighters, and increasing the survivability and
rescue profile for victims.

Once in place, the fog stream hydraulically vents thousands of cubic feet of smoke and gases per minute. This helps control and redirect the flow path of the fire out through the window of the fire room, which is exactly where you want it to go-away from advancing firefighting teams. At the same time, water is being sprayed back into the fire room, “softening the target” or “hitting hard from the yard.” Again, no other nozzle does this.

The minimum nozzle pressure is 60 pounds per square inch, but higher pressures deliver more gallons per minute (gpm) and increase the efficiency and speed of smoke removal with better results. The interior suppression nozzle flows 95 gpm. Once the fire is knocked down, it can manually be twisted shut while keeping the 95-gpm fog nozzle open for continual ventilation. This prevents additional needless interior water damage. The HydroVent needs to be shut off at the pistol grip bail before you can close the suppression nozzle.

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The NIPSTA Tests

Seeing this giant nozzle being lifted up and down at FDIC 2014 caught my attention. After listening to Kevin’s claims, I was intrigued but not convinced. He invited me out for upcoming live fire test burns, and I decided to take him up on his offer. If these claims were true, I wanted to see it for myself.

The burns took place at the Northeastern Illinois Public Safety Training Academy (NIPSTA). We used two large “L” shaped shipping containers. The smaller container was the burn room with a window for ventilation and two man doors. There was another door at the end of the 40-foot container. Firefighters could make entry to the fire room straight through the “front door” or “down the long hallway.” The fire load was four sheets of 7⁄16-inch oriented strand board, four wood pallets, and a full-size sofa. Thermocouples, set in the fire room at three feet and six feet, recorded interior temperatures. Thermal imaging cameras (TICs) and GoPro cameras recorded interior and exterior smoke and fire conditions.

We allowed the fires to really get going before closing all the doors. Smoke filled both containers before crews opened the ventilation window. Fire lapped out and up the container. This is what first-in units often see on arrival. Firefighters opened the first two man doors until a bidirectional flow path developed. This happens when the fire and the entry door are on the same floor and that door is the only source for fresh air or when smoke production can overwhelm the vent window and look for another path of least resistance on the same level. A bidirectional flow path exists when fresh air rushes in at the bottom of the door and thick black smoke vents out at the top of the same door. It creates a small tunnel that firefighters typically crawl through to search for victims and the seat of the fire. Visibility is usually good and temperatures are around 100°F. A dangerous situation occurs when a bidirectional flow path converts to a unidirectional flow path. This is caused by a wind-driven fire or a below-grade fire, like a basement. The entry door is charged with pressurized smoke from top to bottom and the tunnel becomes a chimney. This is where firefighters get trapped, injured, and killed. When the smoke flashes and gases ignite, that hallway becomes a blowtorch. Firefighters cannot outrun a unidirectional flow path once it lights off. Previous tests show that the HydroVent venturi effect can reverse wind speeds between 10 and 15 miles per hour, preventing unidirectional flow paths from occurring within this range.

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The fire room temperature at six feet was 1,303°F. The eight-foot ceiling was probably around 1,500°F-well within flashover range. Using the TIC, you could see significant rollover occurring into the 40-foot container hallway. The temperature in the hallway was about 80°F at the floor and 500°F at the ceiling. After we placed the HydroVent nozzle into the vent window of the fire room, temperatures immediately started to drop, and the rollover and smoke issuing out of the man door started to reverse itself. At 15 seconds, the fire room temperature dropped to 1,061°F. At 20 seconds, the smoke venting from the window turned to white steam. At 30 seconds, the temperature was 845°F, and at 45 seconds it was 719°F. At one minute, the fire room temperature dropped to 647°F, and smoke conditions had dramatically cleared. At 72 seconds, the temperature dropped to 590°F. Additional tests yielded similar results.

What impressed me at the NIPSTA fires was that the HydroVent hoseline was the only line laid. There were no backup lines. At the house fires, backup lines were in place but never operated because the HydroVent controlled all the room fires. This nozzle is a transitional attack appliance-from defensive to offensive. HydroVent doesn’t completely extinguish the fire. Attack crews still need to go in and finish the job, but think what this tool can do for volunteer fire departments or any department with limited resources. One firefighter can arrive with an engine, lay out the line, charge it, and insert the HydroVent™ into a window without even entering an IDLH environment.

I was also amazed at how quickly smoke in the 40-foot container cleared. The negative pressure created by the HydroVent in the fire room prevented the smoke from reentering the hallway. It was like a curtain was placed at the man door. There’s no way my crew could have ventilated this structure as fast as HydroVent did. How many times have you seen crews having trouble starting a positive-pressure ventilation fan? This appliance starts to horizontally ventilate as soon as the nozzle opens.

It is the simultaneous water application and ventilation that makes it different from simply putting water quickly on the fire from the outside. This nozzle is truly revolutionary and can change the way we do fire attack in the future. It’s still fast water and first water. It directs the flow path away from firefighters and kills the flashover, making the interior safer and increasing victims’ survivability/rescue profiles. I believe this nozzle will save firefighter and civilian lives. Anyone who scoffs at this new technology isn’t serious about firefighter safety. I’ve seen it for myself, and I strongly encourage you to check it out. I’m sure O’Donnell is pretty proud of his boy.

RAUL A. ANGULO, a veteran of the Seattle (WA) Fire Department and captain of Ladder Company 6, has more than 35 years in the fire service. He is a member of the Fire Apparatus & Emergency Equipment editorial advisory board. He lectures on fire service leadership, company officer development, and fireground strategy and accountability throughout the United States, Canada, and Mexico.

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