By JERRY KNAPP

Images Courtesy SmartCoat System

Several rooms of the house are fully involved. As your rig pulls up in front, you see dense smoke and fire through the windows. Dispatch notifies you of reported people trapped. You force the front door and make the landing just inside. Smoke is banking d own, but you and your partner press on aggressively with the search.

Our turnout gear or personal protective ensemble (PPE) has improved to the point that you cannot feel the intense heat of the flammable gases in the smoke burning over your head. Hoods cover the few bits of exposed skin we relied on for a general sensing of conditions. You can't detect the flames and radiant heat until your gear is saturated with heat. After thermal saturation, like water saturation, you just keep getting wetter or in this case hotter and then burned.

Radio reports confirm persons are trapped, so you press on. You may press in so far that when the fire takes its next step in its real life cycle-flashover – you are past the point of no return. You may get disoriented and trapped or killed. It is an all-too-familiar fatal scenario.

Until recently, we depended on our PPE to provide only limited protection from life-threatening situations. The fire service, however, is seeing a lot of technological changes – virtual conferences, interactive training, computer flashover simulation s, etc. Now with the invention, development and availability of the SmartCoat

System (SCS), firefighters can take an important first step toward integrating electronics to increase their personal safety. This article will describe the SCS, how it works and what first experience with production models have shown.

The Way We Were
Twenty-five years ago, my turnout coat kept me from getting wet, at least for a while. A few years later, we learned to keep our "winter liners" in for some thermal protection, but the cotton duck outer shell provided little fire resistance. In fact, it b urned faster than my infant son's fire-retardant pajamas!

The next giant leap was Nomex, a great fabric that was self-extinguishing. In training classes I would burn a swatch of duck and then a swatch of Nomex to show how it would self-extinguish. Great stuff. We also learned about how our turnout gear functione d as a system: shell, moisture barrier and thermal liner. Soon, two other important fabrics entered the fire service: Goretex and PBI. Goretex allowed the firefighter to release moisture from inside the gear, making his micro-environment inside the turnout gear much more comfortable. The PBI outer shell material raised the fire resistance to about 1,200 degrees Fahrenheit before it began to break down.

Despite these advancements, even today three important things still happen to firefighters. First, we are still getting burned through our space age materials. Despite our PPE not being damaged by events like flashover and rapid fire development, we are s till getting burned. Second, because the thermal protective performance of our turnout gear is so good, we can't detect dangerous heat levels inside the area of the fire building where we are working. Third, our gear is providing only limited protection a nd therefore limited time to escape in life-threatening conditions like flashover. In the numerous case histories of firefighters caught in flashovers they all said the same thing: when pain sets in, rational thought goes out.

The Next Generation
The SCS is the next generation in our PPE and it is available today. It consists of six heat sensors located at the shoulder, back and chest of the turnout coat, just under the outer shell. These read the temperature every five seconds and send that readi ng to a small computer and alarm device located in a special pocket of the coat. The computer works like a rate-of-rise detector.

According to John Cole, designer and manufacturer of the SCS, "The computer or microprocessor recognizes the effects of the ambient and radiant heat condition the firefighter is in as well as the effects of airflow. It calculates how quickly the protectiv e garment is heating up and projects when the interior of the PPE coat will reach levels that will cause injury to the firefighter. It is the heat that will or is penetrating the firefighter's PPE that is the most important because it is this heat that wi ll obviously burn him."

The computer will sound the alarm when the sensors pick up enough heat over time that will result in temperatures inside the coat reaching 150F. The sensing, calculating and alarm function of the system are based on:

1. The sensor's reading of exterior temperatures that the firefighter is subjected to.
2. The computer calculating how much heat is being absorbed by the PPE relative to how intense the heat is and how long the firefighter is exposed.
3. The actual computer calculation and sounding of the alarm that gives the firefighter one minute or less to leave the heated area.

To better understand the SCS consider that thermal saturation of your turnout gear is similar to water saturation. If we wear our PPE out in a heavy rain (or a hoseline water fight), at first we don't get wet. Then, as the water begins to soak our gear, i t eventually makes it through to our skin. It's the same with heat. The thermal protective performance of the gear protects us from feeling the heat until we are thermally saturated. After saturation is when we feel the heat. Unfortunately, it is usually too late and we get burned.

In a training situation we can quickly get out of the heated area. In a real situation we may not be able to escape in time to prevent being burned. This is what the SCS buys you – a short time to get out, before you get burned.

The SCS is not designed to replace your brain and make you a "robot firefighter." You still depend on your experience and your size-up of the fire conditions. What it is designed to do is to sense conditions that you may not be able to, or are too pre-occ upied to sense, and warn you that dangerous heat levels are being reached. You then decide what you want to do. It is a tool that provides information for you to use.

Think about your last search mission inside a fire building. Concentrating on the search and rescue effort you may not have paid enough attention to the fire conditions because you were concentrating on your job. That is natural. The SCS is a reminder tha t dangerous heat levels are present and unless something changes you will probably get burned right through your gear.

Alarm Temperatures
Critical temperatures were established based on data collected and feedback from firefighters in live-burn situations. It is well documented that when human skin reaches 119F, a first-degree burn will result; 131F will produce a second-degree burn; and 15 0F will give a third-degree burn.

"We learned the hard way that our first temperature setting for alarm of 130F inside the coat was too low," Cole said. "Burn building tests on New York City firefighters revealed the alarm was sounding long before the firefighter was even uncomfortable."

Cole explained why alarm temperatures were increased. "A further review of information from medical research showed us that not only must the minimum temperature inside the coat be reached to cause a burn, the skin temperature itself must be raised to res ult in a burn. We increased the alarm temperature to 150F. This corresponds to the fact that human skin must be exposed to 160F for 60 seconds or 180F for 30 seconds or 212F for 15 seconds to produce a second-degree burn."

I tested the SCS in three situations. During these burns, Christian Delisio (an FDNY and West Haverstraw, NY, firefighter who is a New York State certified fire instructor) and I wore the SCS first in the Swede Survival Flashover Simulator at the Rockland County Fire Training Center in Pomona, NY. Flashover training is designed to teach and show the warning signs of flashover and to provide firefighters with an opportunity to witness the real-life cycle of fire. In the flashover simulator controlled flash overs subject firefighters to large amounts of radiant heat, slowly at first, then massive amounts after flashover.

During the early parts of the burn, firefighters take radiant heat slowly but steadily. The intermittent alarm sounded at what we judged to be the correct time. This alarm function tells the wearer that he or she is taking low doses of radiant heat over a long period of time and is becoming saturated with heat slowly. This condition may be unnoticed by preoccupied firefighters during an interior search mission.

After the rollover then flashover, flammable gases ignite directly over our heads. Huge amounts of radiant heat pour down. For test purposes we remained in position. We felt the heat starting to penetrate through our PPE, then the alarm sounded. Despite t he alarm sounding, we remained for approximately 30 seconds. Finally, we were forced to retreat, not willing to risk a burn. A few more seconds we would have been burned through our PPE.

As our PPE cooled, the alarms subsided and the SCS was immediately ready to monitor conditions again. The SCS performed as advertised and gave us the time we would have needed to escape. As with any tool, you need to understand the theory of how to use it , then practice with it in training before you feel comfortable with it on the fireground. From my experience with the SCS, I want it with me, all the time. It is lightweight and does not restrict movement or add any detectable physical stress.

Thermal Stratification
During an instrumented live burn to collect data on the performance of energy-efficient windows under a fire load, an interesting fact became apparent and is displayed on the accompanying graphs. This test burn was set up to replicate a room-and-contents fire.

Graph 1 shows the temperatures recorded at 20 inches off the floor, the height at which a firefighter would be crawling. Graph 2 shows recorded temperatures at the top sash of the energy efficient window at 60 inches off the floor. Temperature-sensing ins truments were located one over top of the other (same plane) of the test room.

The data shows that at the firefighter's level, temperatures remained at about 200F for nine minutes. Then there was an almost instantaneous increase in heat to 600F then on to 800F. Just three feet above the firefighter's working (crawling) level tempera tures topped 600F in only three minutes and hovered there until nine minutes into the burn, when temperatures shot to 800F then beyond 1,400F.

From this test data it is reasonable to conclude that the high temperatures over our heads are undetectable to us. Then, when the fire goes through a period of rapid fire development (part of the real-life cycle of every fire), conditions for the firefigh ter quickly become untenable and even life threatening. The SCS provides a means for us to sense the superheated smoke above us and the radiant heat that it is raining down on us.

The SCS can sense the heat, then sound the alarm before the design limits of thermal protective performance of our gear is exceeded and we are burned.

For another test of the SCS we were invited to Fort Indiantown Gap, PA, by Fire Chief Jerry Hitchcox and Chief Ken Hetrick, now of the West Point, NY, Fire Department, to experiment with Class A foam for interior structural firefighting applications. The federal firefighters there had an unusual opportunity: 322 wood barracks slated for demolition, unless the fire department could burn them first.

While training on the use of Class A foam for interior structural fire attacks, we were able to use the SCS on several realistic fire-suppression operations. During these burns, the coat performed as predicted.

System Availability
Many innovations that have a positive impact on firefighter safety are simply too expensive to field for many departments. Thermal cameras, computerized accountability systems and other high-tech improvements are simply out of financial reach for most of America's fire departments. The SCS is affordable and fieldable today. It sells for $300 and can be built into new turnout gear or retrofitted as a vest system into existing gear. That makes it transferable from one firefighter to another. The SCS was fiv e years in development and two years in field testing and product improvement, and now is available for use.

Summary
For years, we have used parts of our body – uncovered ears or ungloved hands – to sense the heat of the fire. For this, our sons and daughters will look back fondly on us, much as we look back on the brothers who used their big mustaches to filt er smoke. The availability of the SCS marks the first point at which a firefighter's safety is increased by the application of state-of-the-art electronics. This is the beginning of a new generation of PPE for us. The miniaturization of computer technolog y will make a wide variety of remote sensing and data displays available to firefighters in the next five years. We now have firefighters with a "computer on board."

Today, we see images from an American remote-control vehicle on Mars. Armed forces pilots use heads-up displays, night-vision goggles and infrared cameras to safely complete their missions. If firefighters embrace this type of technology, we can be safer and more efficient on our battleground, the fireground.

Thanks to Chief Jerry Hitchcox and the Fort Indiantown Gap, PA, Fire Department; Chief Ken Hetrick, West Point, NY, Fire Department; Lee Delarde, U.S. Military Academy, operations office; and Chief Walter Morris, supervisor of training, Rockland County Fi re Training Center. Further information about the SmartCoat System is available from the manufacturer at 860-868-7991; fax 860-868-1701.