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

By James Chinni, Marius Magdun, and Marissa Cotten

Saving the lives of others can be a very dangerous business, especially for firefighters whose job it is to protect our communities.

In 2012, 81 firefighters died while on duty-18, or one fifth, died while responding to or returning from the scene.1 To address and reduce deaths in vehicular accidents, many fire chiefs across the nation stress the importance of buckling up. However, many take their firefighters' safety a step further by specifying supplemental restraint systems (air bags) on their apparatus.

History of Air Bags in Passenger Vehicles

The first commercial air bag systems were offered on some GM cars in the early and mid 1970s. These systems were much larger, heavier, and slower than today's air bag systems. They were strictly a supplement to seat belts and were marketed by GM as the Air Cushion Restraint System.

In the late 1980s and early 1990s, frontal air bags were reintroduced and federally legislated in passenger vehicles as supplemental restraint systems (SRS). Mercedes-Benz and Chrysler were among the first manufacturers to introduce a driver-side, steering-wheel air bag as standard equipment. Within a few years, driver- and passenger-side frontal air bags were standard in most vehicles sold in North America and Europe. By the mid 1990s, side-impact air bags started showing up, either integrated in a door panel or within the side bolster of the front seats. The 1995 Volvo 850 was the first vehicle to offer side air bags. The pyrotechnic air bag inflator was mechanically triggered by intrusion of the front door into a pyrotechnic primer charge. Today, all air bag systems are monitored and triggered by electronic sensors. It was the same company, Volvo, that introduced the first rollover air bag in 2003.

Rollover Air Bags

Although most people are familiar with air bags in their personal vehicles, their application in fire apparatus is specially designed for the unique seating environment, duty cycles, and crash characteristics of their installation. Air bags in fire apparatus originated with the discovery that rollover crashes accounted for roughly five percent of all heavy truck crashes, but were the cause of more than 60 percent of fatalities and 45 percent of incapacitating injuries to heavy truck occupants involved in a crash.2 To improve the outcome for firefighters and truck drivers in crashes, the industry researched rollovers to develop effective countermeasures. The first step in addressing this issue was to understand what happened to people inside a vehicle cabin during a rollover. That need drove the construction of a one-of-a-kind 90-degree dynamic rollover impact machine.

Engineers discovered that rollovers in heavy trucks are dramatically different than those in a passenger car or SUV. The air bag systems needed to protect the occupants would have to be different as well. After years of extensive testing and validation, including the rollover test of an entire vehicle, the first roll-protection-equipped fire apparatus was introduced in the spring of 2003. About the same time, Volvo introduced the XC90 SUV with roll stability control (RSC). The RSC contained an algorithm that deployed rollover curtain air bags and was touted as the first of its kind in the world. Today all makes of custom fire apparatus offer roll-protection systems as an option to better protect firefighters in a rollover. In addition to fire trucks, rollover air bags can also be found on commercial trucks and ambulances.

Rollover System

The brain of the system in a fire apparatus is a roll sensor that is mounted centrally within the cab. As soon as the driver turns the vehicle ignition on, the sensor goes through a self-diagnosis that typically lasts five to 10 seconds, then begins to sample vehicle status and conditions every 12 milliseconds, or about

By Paul Shapiro

The concept behind having a preconnected handline is to facilitate quick deployment for a quick attack.

Most pumpers are set up with two types of preconnects: one for what I like to call medium flows of 100 to 185 gallons per minute (gpm) and the other for large flows ranging from 250 to 500 gpm. The high end of the large-flow handline is normally 325 gpm. However, there are a few exceptions. Flows will sometimes reach 500 gpm, but that is more the exception than the rule. The main reason for having a large-flow preconnect is to make a quick large-flow attack on a significant fire to achieve a quick knockdown. This is usually done by the first-in unit. When it comes to large-flow handlines, the 2½-inch hose has always been the weapon of choice, because its lower friction loss capabilities allow for more flow. The drawback to using 2½-inch line is that it is heavy, making it tough to deploy, especially in a quick-attack mode. It is also pretty difficult to move around after it is charged. Because of these negative traits, firefighters will tend to not choose the 2½-inch line. The end result is that firefighters will pull smaller lines, delivering lower than required flows.

This article focuses on the large-flow preconnected handline with a different twist to it: using two-inch hose for the preconnected high-flow handline to make this big-hit line easier to deploy.

Why Two-Inch?

Two-inch hose has been around for several years. The advantages have been for slightly elevated flow and reduced pump discharge pressure (PDP), which reduces engine rpm, reducing wear and tear on the equipment.

The question that comes to mind is whether a two-inch attack line will provide the flows that a 2½-inch line can produce. In the majority of the cases, I would say yes. Take a look at the 2½-inch nozzles in use today. You will find that the majority have flows that top out at 300 to 325 gpm.

The reason for going to two-inch hose is to make hose deployment easier-especially for one firefighter. Whether the staffing on your engine company is four firefighters, three firefighters, or even two firefighters, when a first-in engine company is faced with enough fire to warrant the initial line being a 2½-inch, let's face it-you don't have enough people. This is where the two-inch line comes into play.

The flow tests comparing two-inch and 2½-inch hoselines used smooth bore nozzles. Because the two-inch will have a higher friction loss at high flows, a nozzle with a low nozzle pressure keeps the overall discharge pressure as low as possible. (Photos by author.)

Flow Study

Charts 1 and 2 show 2½-inch and two-inch lines at 200 feet with corresponding flows and PDPs. The two-inch hose is manufactured by Key Fire Hose and is the ECO-10 line. We tested the standard two-inch with 1½-inch couplings weighing 20 pounds per 50-foot section as well as two-inch hose with 2½-inch couplings, which is a new concept. The reason for the 2½-inch couplings is to reduce the friction loss. The tradeoff is two more pounds for the larger couplings (22 pounds total).

The nozzles used for this test are smooth bore tips for a 50-psi nozzle pressure. Because the two-inch will have a higher friction loss at the high flows we tried to achieve, a nozzle with a low nozzle pressure kept the overall discharge pressure as low as possible. The flows for the 2½-inch star