By Sam Massa

In recent years, the types of components plugged into fire apparatus electrical systems have changed significantly. Modern electronics have enhanced first responders’ ability to accomplish the tasks at hand quickly and effectively.

Some Fire Apparatus Manufacturers’ Association (FAMA) member companies build apparatus, while others make the generators that produce the power, and still others make the lighting and equipment that consume that power. As technology becomes more sophisticated, it is important that all those who manufacture the components work together to ensure coordination and that the firefighters who use the equipment recognize potential conflicts in equipment loads.

Equipment and tools have gotten lighter, more powerful, and more capable. With these advancements, equipment also has become more electronically sophisticated. In today’s technologically and electrically driven world, it is important to understand that when we plug individual components and equipment into a common power system, all of the individual components then work together to become just that: an entire system. Each part has an effect on the overall system. Subsequently, adding and subtracting components can have an effect on the other equipment sharing that common electrical bond.

Types of Power

Most fire apparatus have at least two types of electrical power on board. The 12- or 24-volt power is direct current (DC) and is supplied by the chassis’s alternator. This power runs much of the apparatus lighting and controls and is referred to as “low voltage.” If the apparatus includes a generator or inverter, it will provide 110- or 220-volt alternating current (AC)-just like a wall outlet. This power may be available in either single-phase or three-phase and is referred to as “line voltage.”

The reason it is called “alternating” is because the voltage alternates between positive and negative charges multiple times per second. This can be illustrated on a graph in a shape like a wave. The number of times per second the power alternates between negative and positive (and back) is considered its frequency. In the United States, the standard power frequency is 60 cycles per second, or 60 hertz.

Types of Loads

When working with a small electrical system, like that of a mobile generator, the load that is plugged into the system can impact the electrical waveform. There are two types of loads: a linear load and a nonlinear load. Linear loads are often the types of technologies used in legacy fire service equipment like 1,000-watt quartz halogen scene lights, single-speed AC box fans, or traditional hydraulic power units. Electrically speaking, these types of loads are very simple and consume power consistently and uniformly. Imagine a traditional 100-watt lightbulb attached to a switch. When you throw the switch, the lightbulb turns on and draws a constant amount of power until the switch is shut off. The lamp is essentially just a piece of coiled wire that gets hot and emits light. These types of loads do not typically cause problems with the electrical systems on fire apparatus.

When modern technology gets involved, things get more complex. Many of the computer circuits that control today’s technology require a more fine-tuned DC power source. In DC power systems, the voltage does not alternate; it remains constantly positive. To turn AC line voltage into DC voltage, a piece of circuitry called a switch mode power supply (SMPS) is often used. Unlike the example of the 100-watt light bulb above, the circuitry inside an SMPS module has a tendency to act more like someone flashing the light switch off and on multiple times per second while it converts the AC input into a DC output. This rapidly c

By Sam Massa

In recent years, the types of components plugged into fire apparatus electrical systems have changed significantly. Modern electronics have enhanced first responders’ ability to accomplish the tasks at hand quickly and effectively.

Some Fire Apparatus Manufacturers’ Association (FAMA) member companies build apparatus, while others make the generators that produce the power, and still others make the lighting and equipment that consume that power. As technology becomes more sophisticated, it is important that all those who manufacture the components work together to ensure coordination and that the firefighters who use the equipment recognize potential conflicts in equipment loads.

Equipment and tools have gotten lighter, more powerful, and more capable. With these advancements, equipment also has become more electronically sophisticated. In today’s technologically and electrically driven world, it is important to understand that when we plug individual components and equipment into a common power system, all of the individual components then work together to become just that: an entire system. Each part has an effect on the overall system. Subsequently, adding and subtracting components can have an effect on the other equipment sharing that common electrical bond.

Types of Power

Most fire apparatus have at least two types of electrical power on board. The 12- or 24-volt power is direct current (DC) and is supplied by the chassis’s alternator. This power runs much of the apparatus lighting and controls and is referred to as “low voltage.” If the apparatus includes a generator or inverter, it will provide 110- or 220-volt alternating current (AC)-just like a wall outlet. This power may be available in either single-phase or three-phase and is referred to as “line voltage.”

The reason it is called “alternating” is because the voltage alternates between positive and negative charges multiple times per second. This can be illustrated on a graph in a shape like a wave. The number of times per second the power alternates between negative and positive (and back) is considered its frequency. In the United States, the standard power frequency is 60 cycles per second, or 60 hertz.

Types of Loads

When working with a small electrical system, like that of a mobile generator, the load that is plugged into the system can impact the electrical waveform. There are two types of loads: a linear load and a nonlinear load. Linear loads are often the types of technologies used in legacy fire service equipment like 1,000-watt quartz halogen scene lights, single-speed AC box fans, or traditional hydraulic power units. Electrically speaking, these types of loads are very simple and consume power consistently and uniformly. Imagine a traditional 100-watt lightbulb attached to a switch. When you throw the switch, the lightbulb turns on and draws a constant amount of power until the switch is shut off. The lamp is essentially just a piece of coiled wire that gets hot and emits light. These types of loads do not typically cause problems with the electrical systems on fire apparatus.

When modern technology gets involved, things get more complex. Many of the computer circuits that control today’s technology require a more fine-tuned DC power source. In DC power systems, the voltage does not alternate; it remains constantly positive. To turn AC line voltage into DC voltage, a piece of circuitry called a switch mode power supply (SMPS) is often used. Unlike the example of the 100-watt light bulb above, the circuitry inside an SMPS module has a tendency to act more like someone flashing the light switch off and on multiple times per second while it converts the AC input into a DC output. This rapidly c

By USDD Staff

Imagine that you’re performing a routine daily task, such as completing an incident report. Then all of a sudden, an extremely loud noise startles you and catches you off guard.

As a result, your heart rate increases, a bit of panic may set in, and your blood pressure spikes.

This is the exact scenario that takes place every day—often more than once daily—in the life of a firefighter. This puts a firefighter’s health and wellness at risk.

In a firehouse, going from a relaxed state of mind and suddenly being thrust into an alarm response mode is definitely not healthy for one’s body and, while biological effects from incidents like these can’t be prevented, firefighters can take steps to better prepare their bodies for this type of shock.

Here are six ways to maintain firefighter health and wellness under extraordinary conditions:

1. Minimize Stress. Let’s face it. Being a firefighter is already stressful enough, so taking measures to minimize stress within the firehouse work environment is a good first step. A fire alarm going off full-volume at 140 decibels at four o’clock in the morning is not going to help minimize one’s stress level, so consider alternatives to the traditional siren—devices that are more advanced and feature alarms that gradually get louder and reduce the “startle response” effect. In addition to adding to stress, studies have shown that traditional fire alarms may have the effect of causing long-term damage to one’s hearing as well!
2. Stay Fit. Time and time again, research has revealed that a steady workout routine combining both aerobic exercises with weight training has tremendously positive benefits on one’s body. A firefighter must be in top shape to perform many of his/her search-and-rescue operations, so ensuring that a proper workout regimen is in place goes a long way in this regard. Many fire stations that aren’t already equipped with fitness facilities can improvise. Workouts could include using the fire trucks for step-ups, fire hose, for dragging/stretching, and creating an open space for pushups and squats.
3. Maintain your sanity. Taking care of your mental health is just as important as taking care of your physical health, and being startled several times a day by loud sirens going off doesn’t bode well for one’s mental health. In addition to implementing more modern fire station alerting systems such as those that minimize firefighter stress by slowly increasing the alarm tone’s volume (from “off” to “full volume”) over a longer amount of time, fire chiefs should also consider offering members an array of mental health programs if they aren’t currently in place. There are many nonprofit organizations that offer printed materials and online videos at very little cost. They often contain a wealth of information about how firefighters, specifically, can better deal with and manage their mental health.
4. Eat right. Depending on their location, firefighters might go days (or weeks) without responding to an emergency call. During this down time, they often spend their shifts sitting at a desk completing paperwork. It might be tempting to have a sausage pizza delivered or to take a drive to the fast-food restaurant down the street. Instead, pack a healthy lunch consisting of salad, fruits, proteins, and a moderate amount of carbohydrates and healthy fats. To optimize firefigther health and wellness, start slow and gradually try to make changes to your eating habits. Trying to do it overnight isn’t realistic or smart, and often leads to cheating or giving up entirely on the new diet.
5. Have fun on the jo