Ultra High Pressure
Fire Supression

Structure and Wildland Testing by Veteren Hot Shot Crew · Vandenberg Fire Department

Structure and Wildland Testing by Veteren Hot Shot Crew

OBSERVATIONS OF ULTRA HIGH PRESSURE IN THE STRUCTURAL & WILDLAND FIREFIGHTING ENVIRONMENT

By Devin Misiewicz Captain, Vandenberg FD, Santa Barbara County, California

The following are observations made by Devin Misiewicz and do not express endorsement or approval of any products or services by the United States Government, the United States Air Force, Vandenberg Air Force Base, Vandenberg Fire Department (VFD) or any other agency not specifically listed.

Devin Misiewicz is a Fire Officer of twenty years with proven success in training, operations and acquisition, with a superb nine-year history in the United States Air Force, five years fire alarm contracting and design, and five years as a decorated federal firefighter specializing in administration, training and operations.

Background

It is in the capacity as Training and Operations Officer that I came to use Ultra High Pressure (UHP). Vandenberg AFB has the unique (and honored) distinction to have the only Hot Shot Crew in the Department of Defense. As such, VFD is frequently requested within the Department of Defense (DOD) to provide training and expertise to our sister services, components, bases and departments. One of these agencies, Air Force Research Laboratories, Fire Research Directorate (AFRL), was conducting tests on various products and equipment through controlled burns. One of the technologies being tested was an Ultra High Pressure System provided by HMA Fire (HMA). VFD personnel were acting as both trainers and Incident Command. It was through these training and testing efforts that the capabilities of Ultra High Pressure were observed.

Further testing was set up at Vandenberg AFB to test UHP in a controlled manner with as realistic conditions as possible. Due to extreme fire conditions we were unable to conduct any controlled vegetation burns. However, we had the ability to conduct live fire training in a propane fired structural trainer and on condemned family housing units. These residential units are typical one story, wood structure, single-family units. For the ease of this narrative, I will defer the technical and analytical detail to AFRL/HMA, as they are the experts in this area. They were responsible for obtaining a vast wealth of data from these burns. I will simply try to express my observations of events as I personally witnessed them with respects of the employment of Ultra High Pressure firefighting technology in a practical manner. Following this testing I had the opportunity to use the UHP in a wildland environment during an actual fire on 30 Sept 2009 known as the "Highway Fire."

STRUCTURAL TESTING

Testing of UHP during structural firefighting was under the strictest control. VFD adheres to NFPA 1403 and all other pertinent codes, regulations and standards to the highest degree.  For the structural testing of UHP we set up conditions to resemble a realistic fire load in a residential structure. This was done using Class "A" materials such as wood, bean straw and paper. The houses were "wired" by AFRL's team of engineers and scientists using thermocouple trees, infrared cameras, video and timing technology. Again, I am not the expert in the area of the technical data so any inferences I make are based solely on my observations ...do not assume I am talking from "hard data", just the hard data of 20 years' experience in the fire service.

One of the most astounding aspects of UHP is the inherent flexibility to use current foams (agents) in amounts that are a fraction of what we're used to. Think of it as Compressed Air Foam Systems on steroids. I've only "played" with CAFS a few times in the past. My opinion of CAFS is that they are cumbersome, maintenance heavy and not really practical for the applications firefighters normally encounter. I must give you our set-up and training scenario to paint a better picture but trust me, UHP was a shocker.

The first test was the UHP in the structural training tower in a propane fuelled, interior fire setting. We operate a Kidde Live Fire Facility with two burn rooms. The fires we conducted were on the larger ground floor room (12'X25' approx) lined with a fire resistant material similar to firebrick. The live fire prop simulates a double bed in size and height. Propane gas bubbles up through water in the prop to diffuse and enlarge the fire area within the room. Typical scenarios in our burn room get a fairly large amount of "roll over" type fire behavior, where the fire can start reaching down the wall opposite of the prop. On these particular fires we brought in both a standard 1 ½ “ attack line supplies with 100 gpm. At 100 psi and the ¾” UHP line working at 1200 psi @ 20 gpm. The attack crews were arranged side-by­ side in the room with two firefighters per line. Our first evolution was with the "traditional" attack line using roughly a 30% semi pattern working in either a "Z" or circular pattern. The effects were typical for the prop and the heat inversion was evident after about 20 seconds of discharge. Steam generation was average and the effect on the prop was typical.

Staying inside the room, the next evolution was started by igniting the prop and letting it build up as we had in the first. Once roll over was about the same as the prior fire, the firefighter using UHP was instructed to attack the fire like the evolution before. The effect was noticeable and immediate. The UHP line nearly blew out the propane fire and you could feel the reverberations in the walls behind us, there was no inversion evident and I had to instruct the firefighter on the nozzle to shut down to let the fire build up again. At this point, I noticed the heat soak was next to nothing and the pattern was consuming and absorbing the heat at the same time. In a propane-fired trainer the water passes right through the flames, bounces off the ceiling and walls then the steam is generated and slams down to the ground. Our instructors refer to water vapor/heat eventually being felt through our turnouts as heat soak.

Typically, after the first evolution tolerance gets shorter and shorter due to the high heat and steam generation. However using UHP we were able to continue these comparative evolutions for another 3 cycles and then exited the burn room. One attack with traditional then one with UHP, on the last evolution the firefighter had actually extinguished the propane fire but the protected burner/igniter facilitated a re-ignition. Worth noting was that each time we discharged using the 1 ½ " line we felt heat comes down and it drove most of us closer to the floor. When we used the UHP there was no discernible inversion or steam generation - actually, the room temperature seemed to decrease and ventilation under the doors was noticeable.

I've done hundreds of evolutions in the "burn house" and watched every rookie and vet alike enter the burn room. With varying degrees of "success," based on our training scenario and the intent of the training, the effect of the hand line on the fire was pretty much the same; the line would blow through the fire and we (instructors) would get pounded with the steam inversion. To the point instructors started checking hand lines before they entered to make sure they weren't on a full fog pattern.

What was amazing about UHP was that the hose stream seemed to actually consume the fire. I can't find a better way to put it than that. When you pointed a UHP semi-pattern at the fire it just went away. We felt the air rushing around us and the doors and windows puffed with each discharge. ***Now this bears note*** This effect of the air and the walls vibrating with the UHP made us wonder what it would do in an actual environment, most notably a flashover or back draft scenario.

Crew comments were made such as, "I never thought such a little line could do that" and "easy to handle." The UHP hand line is a hydraulic hose and has a modified Elkhart Brass 1 ½” nozzle (for UHP) and a typical pull to open bale. The pattern adjustment is the same as any other nozzle as well. The only noticeable point about the nozzle was that it took more effort to open than a regular nozzle to open. Closing it was not an issue and I never noticed any type of water hammer from slamming it open or closed on the UHP. I actually think that UHP likes to slam open and closed because the reaction of the pump was faster. Reaction force was similar to a standard hand line, but the hose diameter was so much smaller and flexible it almost made it fun to play with. In firefighter parlance, we'd call it a glorified pressure washer, right up until you go into a burning structure with it. It's lighter (exponentially) and easier to maneuver, sucks the life out of the fire, does amazing hydraulic ventilation and uses about a 10th of the water to the same affect. Here's what it didn't do - soak the burn room. The energy of the UHP stream appeared to be used up in consuming the thermal energy while cooling at the same time. AFRL has the hard data to either confirm or debunk this...so bug them for the data. I'm telling you UHP sucked the life out of the fire and did it faster than anything I've ever seen before.

STRUCTURAL LIVE FIRE TRAINING IN HOUSING UNITS

We then tested to the flashover state in our housing units and found some interesting results. We had four houses set up room by room with comparative tests like we did in our propane trainer. All had similar results with UHP coming out way on top with one exception; we sealed up a house, double the contents (class a material) and lit it off until it actually flashed-over. The ground level thermocouples reached something like 1100°. Then we open the front door, discharged the UHP into the upper layer and within (roughly) 14-20 seconds we lowered the temperature below 400° F. Again, bug AFRL to confirm or deny the data. I had firefighters that were suspect of the UHP but after using it had a very different attitude. Some even commenting that they'd like to have it on their engine.

One last note in the structural setting - Using UHP for hydraulic ventilation as compared to the 1-3/4" attack line was staggering. There was a significant and noticeable difference in the efficiency and speed at which UHP ejected the remaining smoke and heat from the structures. I'm sure there's a scientific way to prove this but it was obvious how efficient UHP was.

REAL WORLD WILDLAND FIRE - 600 ACRES 30 Sept 2009

Extreme Red Flag Conditions in Santa Barbara County - Winds 20-40 kts, RH below 20 percent. The high winds brought down a power line in heavy chaparral between Hwy 1 and a 1,400 unit housing unit and industrial/commercial area of VAFB. We purposely chose the trailing (cold) edge of the fire close to the point of origin to ensure we weren't going to get caught out. After working some spots and mop-up, the unit quickly made its purpose apparent. The dozers punched in a section of line in some really steep and thick terrain and there was a real threat of rekindle in those areas - generally chaparral of oak and Manzanita. That was not the active part of the fire (Div Z) but posed a huge threat. We used the UHP to hold the dozer line and ensure no slop over.

One of the corners between Div Z and A was a 120 percent turn in a drainage with heavy vegetation and only hand crew accessibility. Our unit was able to access this terrain and fight the fire effectively. Since we carried only 90 gallons of water/foam, we nursed off of progressive hose lays into the area and fought fire at will. Spot fires were dealt with ease as the punch from the UHP reached well into areas we would normally not try to with 1" lines. The mobility of the unit and the reaction speed, coupled with the firefighting ability, also drove home the point that we could easily over-extend our capabilities. 90 gallons with UHP is more like 500 using traditional methods means you could simply act like a type Ill when you're not. We chose to stick close to hose lays and other engines in the area and do a "hit and run" type of effort. During the mop-up phase of the fire another benefit we found was that the power of the stream from UHP was outstanding at dealing with burning roots and cat-piles (dozer rows). The power of the stream simply blew its way into the piles/roots and soaked into the area. I could really see this on a Type Ill engine as a useful way of extending the on-board agent while covering much larger areas. Since we've only used it for one actual wildland fire, there is much left to be discovered about UHP, but in its present form it is impressive, to say the least. The technology opens so many doors that the potential is limitless. It already has proven very effective in a holding line scenario; I could just imagine UHP working with a 500-gallon tank...it would be like bringing a 2,000-gallon tender with you!

CONCLUSIONS

With all of that out of the way, overall my opinion is that UHP can and will play a significant role in modern firefighting. I do not envision UHP replacing firefighters, saving our ozone layer or replacing traditional firefighting techniques. It will be effective as a RIC line, integrated into rescue rigs or rapid intervention vehicles, supplementing low pressure, high volume apparatus. UHP has proven it is highly capable to remove heat in a structure, efficient and effective in the wildland setting, and exceptional In the ARFF role. What remains to be seen is how it is integrated into the fire industry. There is the ever­ present need for firefighters to reduce loss due to fire. UHP is one possible answer, by seriously reducing the amount of water needed to efficiently extinguish a fire as fast, if not faster than current techniques. Using UHP there is inherently less damage: something  citizens,  insurance  companies and firefighters all would like to achieve.  Less water, more pressure, more flexibility, more mobility, less physical stress and increased efficiency is a great direction to be headed. UHP has all of those characteristics and likely more.

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