By Alan M. Petrillo

Almost every first-due apparatus carries a ventilation fan of some sort on the rig, and often fire departments have special compartments designed on their pumpers, aerials, and rescues to accommodate an assortment of ventilation equipment.

The types of ventilation fans available today range from gasoline- and electric-powered units to hydraulically powered blowers that use the water flow from a hoseline to move volumes of air.

From Ejector to Positive Pressure

Roger Weinmeister, president of Super Vac, says since the mid 1990s there has been a strong push among fire departments toward using positive-pressure ventilation (PPV) equipment and away from traditional smoke ejectors. "That trend reached a high point about 10 years ago and now is moving more toward electric-powered fans with big motors," he says. "Gasoline-powered fans require a lot of maintenance," he notes, which is one of the chief reasons for the swing toward electric motors on positive-pressure fans, along with a movement toward variable speed motors. "The nice thing about a variable speed fan is that it can fake out normal 60-cycle electricity and make the fan run faster on its variable speed, which gives the fan a little bit more push and makes for a higher-capacity fan," Weinmeister points out. He maintains that variable speed fans make up the bulk of the electrical positive-pressure fan market today.

A firefighter sets up a Super Vac electric PPV fan at the entrance to a building. (Photo courtesy of Super Vac.)

Weinmeister estimates that a variable speed fan can increase the fan's capacity by 30 to 40 percent. "A typical motor runs at 1,700 revolutions per minute (rpm), but with a variable-speed motor, you can get up to 2,400 rpm for the same size motor," he notes. "The higher speed gets you better performance."

Super Vac's most popular electric positive-pressure ventilation fan is its VR3. Its biggest seller has a 6½-horsepower (hp) Honda motor with an 18-inch fan that displaces 15,500 cubic feet per meter (cfm) of air. Its next most popular fan is a 20-inch-blade model with the same horsepower motor but a larger shroud that can push up to 18,500 cfm.

Smoke ejectors are still used by a lot of fire departments, Weinmeister says, and are the right way to go in a lot of situations, especially where there is limited egress. "A smoke ejector used the right way to vent can pull fresh air from all over a building and exhaust it where the seat of the fire was located," he observes.

Weinmeister recommends that fire departments choose the largest fan that will fit easily into a compartment. "You want to move the most air possible," he notes.

He says that his company has battery-powered ventilation fans that it is excited about. "They give firefighters the ability set up a vent without a generator or power cords and will push almost as much air as a gasoline-driven fan," he says. "They'll run about 20 minutes, then can be supplied off a cord from the fire vehicle."

Allowing for Entry

James Neils, chief executive officer of Ventry Solutions Inc., notes his company makes both gasoline and electric PPV fans that can be used for aggressive attack to remove smoke from a structure to allow fire crews to make entry. "Our fans allow firefighters to set up about 10 feet outside of a building and shoot air into the structure to clear the air," Neils says. "We make eight gas-powered models a

By Robert Tutterow

This year's "Kill the Flashover" (KTF) project was once again held at the South Carolina Fire Training Academy.

Regrettably, the February 10-14 dates coincided directly with the worst winter storm in more than 10 years for the region. Three inches of sleet followed by a quarter inch of freezing rain prohibited completing all the scheduled burns. However, there was valid information from the completed burns, as well as from the classroom presentations and intense networking.

KTF is a research project for gaining a better understanding of fire behavior. Under the leadership of Joe Starnes and Shawn Oke, it is based on the premise that much of the conventional wisdom on fire extinguishment is flawed. The objective is to learn to control extreme fire behavior through:

1. Air management.
2. Enhanced water streams.
3. Thermal data.

This year's event brought leading edge fire behavior experts from across the nation as well as Canada, Germany, and Sweden.

This was the fourth consecutive year of live test fires for KTF. During the opening session, there was a panel discussion with one pertinent question: "What have we learned from the past three years?" The immediate response from all the panelists was simple: "Don't ever delay the application of water!" Or, as one panelist emphasized, don't delay the application of "enhanced" water-i.e., water with an agent that breaks down the surface tension of water.

A key part of the KTF test fires is the captured data. There are multiple thermal couplers, thermal imagers, and video cameras documenting every second of the tests. So far, all the tests indicate that the best chance for occupant survival is to apply water as soon as possible, even if that means an exterior attack.

Air Track Managment

Air track management is one of three components of understanding fire behavior at KTF. A key tool in managing air movement is using a portable door or portable air curtain. The concept is to install a fabric cloth in openings to manage the movement of air. This is not necessarily limited to exterior door openings but also to openings within the structure. This includes openings such as hallways and other openings within a structure that do not have doors installed. At least two United States manufacturers have added air curtains to their product lines. A benefit of using fabric is that it indicates if the air flow is moving in or out of the structure or confined room. Dr. Michael Reick, a firefighter and fire researcher from Germany, reports that several German fire departments are users of fire curtains at all openings.

Another outcome from fire tests during the past three years is discovering that vertical ventilation is not nearly as effective as conventional wisdom suggests. For occupant survivability and firefighter safety, quickly applying enhanced water and isolating the fire room by closing doors and using air curtains are far better than the time spent performing vertical ventilation.

Thermal Imager Use

The success of the KTF fire tests is directly dependent on the data captured. In addition to thermal couplers and video cameras, using thermal imagers is mission critical. KTF staff members are adamant about using a thermal imager while performing a 360-degree size-up. In addition, the fire attack crew must use a thermal imager.

There has been a lot written about leadership and change that states we should make every attempt to make the "unknown known." Thermal imagers help us know what would otherwise be unknown.

Buyers, beware when purchasing a thermal imager. There are companies aggressively touting units that are inexpensive-and they are. But, they will not perform as needed in the fire environment. Always purchase National Fire Protection Association (

By Alan M. Petrillo

Fire departments tend to be traditional in many ways yet often take time to embrace new technologies.

But when it comes to sirens-audible warning devices for fire apparatus-a mix of old and new technology can be found on many fire vehicles. It's not unusual, for instance, to see a new first-due pumper outfitted with both electromechanical and electronic siren systems.

Electromechanical Sirens

Vic Hilbert, owner of Eagle Sirens Inc., makes traditional electromechanical sirens that he says use a forward projection of sound instead of a wall of noise. "We focused the sound from our sirens to send it forward," Hilbert says, "and also off on a 55-degree angle to each side to get great penetration at intersections. A lot of other sirens put up that wall of sound, which puts the noise out front but also has a backwash that penetrates backward into the cab of the fire truck."

Eagle Sirens Inc. makes the Screaming Eagle electromechanical siren, shown here pedestal-mounted on an extended bumper. The siren also can be flange-mounted and nested in a hidden mount. (Photo courtesy of Eagle Sirens Inc.)

Hilbert's company makes the Screaming Eagle siren in one model available in three mountings: a pedestal mount (for apparatus with extended bumpers), a flange mount, and a hidden mount where the siren is nested behind a vehicle's bumper.

Hilbert points out that Eagle Sirens uses a pure silicone formula for all of the noncontact sealed bearings in its sirens. "The silicone makes the siren run much quieter and longer, and it has an anti-vibration effect," he says.

Kevin O'Connell, owner of B&M Siren Manufacturing Co., says B&M has five models of electromechanical sirens in its line: two direct-driven Super Chief versions and three Siro-Drift models. O'Connell maintains that electromechanical sirens move traffic better than electronic sirens. The electromechanical signal sent by a siren depends on the number of ports it has and how fast the air is moving through the ports, he notes. "The faster you run the siren, the more it sounds like you're stepping on a cat's tail," he says.

O'Connell says a siren's spinning rotor is very similar to that of a centrifugal pump. It draws air in at the front of the siren; compresses it slightly; and, as the air escapes out of the ports, the siren pops with sound.

One of the advantages of a mechanical siren over an electronic one, he points out, is that the mechanical siren emits a lower-frequency signal, which travels much farther. "The lower the frequency, the farther the sound travels, which is why air raid sirens operate at a low frequency," he says. "There's no beating a mechanical siren for attracting attention down the road," O'Connell says.

Code 3 has developed the Banshee, an electronic device that can be attached to any siren in the industry to produce attention- getting low-frequency tones among its 25 tone combinations. (Photo courtesy of Code 3.)

Timberwolf Siren Technology also builds an electromechanical siren-the Timberwolf 45, which develops a 123-decibel sound level from a 12-volt, 28-amp power source. The Timberwolf 45 uses an angle-designed rotor that the company says won't lose acoustic energy because the sound is d

By Christian P. Koop

Cooling system maintenance for emergency response vehicles (ERVs), in my book, has become more important than ever.

It seems to me that it often takes a back seat to other major areas such as lubrication, air filtration, and oil filtration in the overall preventive maintenance scheme. However, it is an area where failure can lead to considerable downtime and can be extremely costly to repair. I am sure most in this business will agree that this makes it even more important to ensure the cooling system is properly inspected and maintained. Additionally, the coolant itself has become more important than ever in providing the necessary protection for the highly sophisticated modern engines in use today. This article will cover a brief history, basic required cooling system maintenance and some characteristics of the diesel engine cooling system, and tips on coolant chemistry and how to ensure it is protecting the cooling system adequately.

Using a test strip is simple and quickly reveals glycol percentage, pH, and additive concentrations. Be sure to follow instructions printed on the bottle. (Photos by author.)

Cooling System History

In the early days of internal combustion liquid-cooled engines in the automotive and emerging heavy-duty truck industry, people experimented with different ingredients to keep the cooling system from boiling over in the summer and freezing in the winter. Many will be surprised to know that people added ingredients such as sugar, honey, and molasses to the water in the cooling system for this purpose. This was prior to 1927, when Prestone came out with its all-season antifreeze and coolant, which was formulated with ethylene glycol. Ethylene glycol is actually a weakly toxic, odorless, colorless, sweet, viscous fluid that, when mixed with water, will effectively lower water's freeze point and increase the boiling point. Prestone's all-in-one summer coolant and winter antifreeze, when mixed with the correct proportion of water, offered year-round protection. It did not need to be changed every season, making it a better choice over the ethyl-alcohol-based coolants available at the time. This was also around the introduction of the pressurized radiator cap. Prior to this, ethyl-alcohol-based coolant would slowly evaporate out of the nonpressurized systems that were the norm. This new antifreeze and coolant contained corrosion inhibitors and water pump seal lubricants.

Pressurizing the system greatly increased the boiling point of the fluid when combined with a 50:50 ratio of water to coolant. To this day, it still remains a basic guideline and an important factor. For example, a 15-pound radiator cap will provide freeze protection down to -34°F and will increase the boiling point up to +265°F. Greater concentrations of coolant to water give more protection in both directions. However, once you go beyond a 70:30 ratio of coolant to water you can actually start raising the engine's temperature because water transfers heat better than pure coolant can. On the back of every coolant container is a chart that provides the recommended ratios of coolant to water and the freeze and boil overprotection it can provide based on the radiator pressure cap rating.

Today's engines generate more heat than ever before, making it even more important to stay on top of the cooling system especially because there is no shutdown protection in fire apparatus if the engine overheats. If there is an overheat condition, the only thing allowed is a gradual derating

By Alan M. Petrillo

Pumpers, rescues, and aerials are the workhorses of a fire department's apparatus fleet and often spend considerable time idling at a scene yet not flowing water, raising a ladder, or using rescue tools.

Main engine idling is proving costly to fire departments, eating up pricey diesel fuel, putting additional particles into the diesel particulate filter (DPF) and generating engine wear and tear that requires more frequent maintenance.

Auxiliary power units (APUs) are designed to stand in for the main chassis engine when it is not needed, allowing the APU to provide power for warning and other lighting and electrical needs as well as heating and cooling of the apparatus cab. Despite these realities, manufacturers report that APU integration into fire department fleets has been a slow process.

KME installed APUs on each of the 20 pumpers it built for the United States Air Force. The units, located in the pumpers' dunnage areas, use 10-kW Westerbek generators. (Photo courtesy of KME.)

Growth, but Slow

Joel Konecky, regional sales director for Smeal Fire Apparatus, says that sales of APUs continue to grow, particularly in the southeastern United States and in Canada. "We've made some changes to our SG-09 units operationally," Konecky points out. Smeal offers two models of its APU-a parallel system that has completely independent chassis heating, ventilation and air conditioning (HVAC) and SG-09 HVAC systems-and an integrated system where the chassis evaporator, fan, and air conditioning controls are used with the air conditioning compressor of the SG-09.

"Charlotte (NC) Fire Department has been using our parallel system SG-09 and reports good experience with it, especially in fuel savings and reduction of maintenance frequency," Konecky says. He adds that Smeal is considering upsizing the SG-09 system to work with larger generators and that the company continues to improve the product for climates with weather extremes. "It's especially a concern in the Midwest and other areas where they have very cold temperatures," he notes.

Konecky maintains that Smeal's APU is the most sophisticated system on the market and the easiest to use because of the unit's electronics. "It's a part of the vehicle that an operator doesn't have to think about or do anything about," he says. Because the SG-09 will automatically shut down the chassis engine after a preset amount of idling time, Konecky says "there is no operator intervention to turn the system on."

The control panel displays made for the KME APUs on the Air Force pumpers are located inside the cab (shown here) and on the pump panel. (Photo courtesy of KME.)

Battery Innovations

Rosenbauer's vice president of sales Scott Oyen says that Rosenbauer offers its Green Star idle reduction technology as a dual system where the vehicle's systems can be run either off the diesel-driven APU or through Smart Batteries-lithium-ion or lithium-polymer batteries separate from the chassis battery. Depending on what emergency lighting and electronics systems are to be used, the vehicle can run those systems off of two to six batteries, O