by Alan S. Brown
The call awoke Lt. Jay Moltenbrey at the Windham, N.H. Fire Department at about 2 a.m. on Friday, March 17, 2000. Workers at an all-night Dunkin' Donuts just off Interstate 93 reported smoke coming up from the floor.
The Dunkin' Donuts was located in a two-story strip mall built on a hill. The Dunkin' Donuts and a Subway shared the top floor in front. Down the hill and around back were four other units. A police officer that arrived first drove around back and reported flames.
Moltenbrey's crew drove around back. "We saw a small amount of flame showing through exterior wall," he recalls. "We forced entry into the dance studio and found light to moderate smoke." His crew walked about 5 feet into the room and looked around the corner with their Bullard thermal imager, a device that can see heat emitted from objects through smoke or total darkness.
No hot spots showed up on the imager. Assuming that he had the wrong unit, Moltenbrey entered an adjoining store. It had even less smoke, so the crew, now joined by a fire crew from nearby Salem, N.H., began running hose into the first unit.
The room had grown smokier. From further in the room, the wall he had previously checked with the imager now revealed a door to a utility room. When he grabbed the handle to open it, it pulled off in his hands. The flame had burned it away. It was the first evidence of intense heat, but the fire itself was still hiding.
"At that point, it didn't seem like we were at the scene of the fire," he recounts. "There was not enough flame to account for all the smoke. So I used the imager to inspect the walls. Nothing. Then I looked at the ceiling. It was a dropped ceiling. There were no visible flames, but the whole ceiling over the dance studio was lit up white."
On thermal imagers, white represents the hottest part of the picture. The imager was telling him that hidden behind the dropped ceiling, the fire was burning up the trusses. It took Moltenbrey and Salem Capt. Joseph Kamel only seconds to decide to evacuate.
"We started pulling both crews. Joe Kamel was the last person out. The entire drop ceiling collapsed as one piece and caught in the wires and framework. Fortunately, he had a pair of cutters that he carries with him so he could cut himself out. If we had waited any longer, we would have all had to cut ourselves out," says Moltenbrey.
Did the thermal imager save their lives? Moltenbrey will never know. But had the responders been caught unawares 10 or 15 feet into the building, they almost certainly would have suffered serious injuries and burns. They might have been extricating themselves when the trussed ceiling began to fall.
They were fortunate to even have the thermal imager. One year earlier, Windham's selectmen had rejected the department's request for an imager. Moltenbrey, then head of the firefighter's union, petitioned to put it on the ballot where voters approved it overwhelmingly. While the department trained extensively with it and once even used it to find an Alzheimer's patient lost in the woods, they had never used it at a structural fire until the Dunkin' Donuts call.
Promises and Questions
Moltenbrey's experience encapsulates many truths about thermal sensors today. They have powerful capabilities to detect danger early. They are increasingly small, easy to use and durable. They can and do save lives and prevent injuries.
But thermal imagers are far from perfect. Moltenbrey, for example, missed seeing the utility room door the first time he entered the dance studio because the thermal imager flattened his view of the wall, hiding important details. While prices have come down in recent years, they are still expensive. Small departments may find them beyond their reach. Larger departments may find they cannot provide units to every firehouse.
Nor do standards exist for thermal image capabilities and use. While large departments have the resources and knowledgeable experts to test equipment, many smaller departments are unsure where to start.
Thermal imagers are one of the most widely used detector technologies available. Uses range far beyond structural firefighting. Battalion Chief Gary Linney of the Lawrence Livermore National Laboratory Fire Department uses his imager to direct the initial attack. He recalls walking into a large burning warehouse. "It was filled with smoke," he recalls. "But we were able to see just where the fire was and get the lines on it right away." Linney also uses it to visualize what's in a room and to detect hot spots after suppressing wildland fires.
Thermal imagers make it easier to find people who have hid from a fire. "People, especially kids, hide under the bed or in a closet," explains Lt. Larry Horn of Portland Fire & Rescue. "Without that thermal imager, firefighters might crawl over that pile of clothes or pass a couch with a cushion pulled over someone. The imager would show us the image of those people because of their body heat."
In August 2003, a barge struck a rock pile on the Mississippi River near Cordova, Ill., and began leaking fuel. Local responders used a thermal imager to locate the leak and track the movement of fuel on the water to ensure they had contained it with absorbent buoys. The same technique can be used to detect a leak on an overturned tanker or railcar, or even determine how much chemical is left in the container.
Responders have used imagers to find people who have walked away from nursing homes. At accident scenes, they have located people ejected from cars. One Indiana rescue squad was able to locate fingers amputated in a collision so fast, doctors were able to reattach them in the hospital.
Some uses are pretty sophisticated. Deputy Chief Ronald Carter of the Oakland Fire Department recently purchased a laptop communications system that lets him view thermal imaging pictures taken by a police helicopter. "It helps us look for hot spots in large-scale incidents and direct people to the right spots in wildland fires," he says.
Oakland's police use their imager to find people and get a better handle on hostage situations. Law enforcement use, however, has been limited by court rulings in Washington, Montana, California and Pennsylvania that define thermal imaging as invasive and a violation of personal rights.
The Law Enforcement Thermographers Association (LETA) notes that many more decisions have favored police use of the technology. It recognizes 11 law enforcement applications for thermography. These include uses in general surveillance (search and rescue, fugitive searches, vehicle pursuits, flight safety, marine and ground surveillance, perimeter surveillance and officer safety) and specialized surveillance (structure profiles, disturbed surface scenarios, environmental law enforcement and hidden compartments in vehicles). Still, many law enforcement agencies have backed off because of legal challenges.
Despite their many uses, a joint survey by the Federal Emergency Management Agency (FEMA) and National Fire Protection Association (NFPA) found that only one in four fire departments own thermal imagers. This may underestimate coverage, since many larger departments have only one or two units to share among many companies.
There are several reasons for this, says Jonathan Bastian, training manager for Bullard Co. of Cynthiana, Ky., a leading supplier of thermal imagers. Some departments, he says, flat out refuse to consider it. "They think the old-fashioned ways are good enough, but they're fading away."
Price is a more serious barrier. When the first thermal imagers reached the market in the mid-1980s, they cost around $50,000. As recently as three or four years ago, prices hovered above $20,000. Today, they run from $8,500 to $16,000. While more affordable, they are not cheap. For many volunteer organizations, which constitute three-quarters of all fire departments, this is equivalent to one or two years' budgets.
Another roadblock is the "tool vs. toy" argument. "There's still a widespread belief that thermal imaging is a nice toy but not an essential tool," says Bastian. "When the first ones came out, they had poor image quality and a propensity to break when exposed to high heat, which made them expensive to take into fire."
Portland's Horn agrees. The first imager Portland bought was a $50,000 helmet-mount imager. "It was heavy and awkward, and it kept dragging the helmet down over the face," he says.
Since then, there have been dramatic improvements in size, durability, simplicity and features. For one thing, the electronics have grown more sensitive. In the beginning, thermal imagers tended to do a poor job of distinguishing between temperature gradients. Pictures saturated or lost their crispness. Newer technologies have improved performance.
Cameras have gotten much smaller over the past three years. At Mine Safety Appliances Co. (MSA), the company halved the size of its viewscreen to 160 x 120 pixels. This enabled it to shrink the size of its batteries and packaging. The result? MSA's new Evolution 5000 &endash; one of many new lightweight units on the market – weighs half as much as its predecessor, says thermal imaging product line manager John Raimondi. Its smaller size allows such ergonomic improvements as pistol grips, batteries in the handle for balance (similar to a cordless drill), dual handles for hand-offs, and D-ring attachment to turnout gear.
Thermal imagers have also grown more durable. They stand up to drops, water immersion and dust and soot. "We know the fire service is a tough environment, and we build our package for that environment," says Raimondi.
With several companies marketing products (see sidebar), new features and improvements are everywhere. Cameras warm up in a couple of seconds, and many operate in sub-zero weather. Others give digital readouts of surface temperature. Many now provide full color as well as black and white images. The International Safety Instruments Inc. (ISI) Surveyor enables firefighters to superimpose video images over thermal images to improve depth perception. Total Fire Group has developed a very small helmet-mounted camera that lets firefighters use both hands, both eyes, and the camera at the same time.
In fact, today's thermal imagers are so good, it's easy to get complacent. "You go into a smoky fire and everyone's bumbling around. You've got the imager and you're zooming straight ahead," Horn continues. "We don't want to get into a situation where you're in the middle of a warehouse and the batteries die and now you don't know where the walls are. We make sure everyone uses a tag line and we still work the buddy system."
It takes training and exercises to fully get the hang of the equipment. "We spend our whole life trying to understand what our eyes are trying to tell us," says Bastian. "Even though the thermal images look like camcorders, they present completely different types of images."
Most exercises, for example, take place at ambient temperatures where people are often the hottest objects in the room. Thermal imagers automatically represent the hottest objects as white. In a fire, however, the walls are likely to show bright white while victims are light gray. "You have to practice looking for shapes, not colors," says Bastian.
About half of all imagers take temperature measurements. Many firefighters believe they can predict flashovers. That's not the case because imagers only measure surface temperatures, not critical air temperatures.
One problem that all but the largest departments face is lack of standards for thermal imaging performance. "When fire departments evaluate cameras for purchase, they need to verify every claim the manufacturer makes," says Bastian. "That way, they can make sure they're getting exactly what they think they're getting."
That's what Portland did, says Horn. "We checked out several brands at our training center," he says. "We would send recruits and different crews to work with them. They said some were too heavy, and others too hard to operate. We went through a field test."
For smaller departments with fewer resources than the city of Portland, help may be on the way from Nelson Bryner, a scientist at the National Institute of Standards and Technology (NIST). His research will characterize thermal imager effectiveness so that NFPA and/or other organizations can write standards for performance.
The program is impressive in its reach. Bryner plans to measure how thermal imagers see well-defined targets under a variety of conditions, such as brown and black smoke, heavy particulates, steam and dust. He'll look at whether such atmospheres affect performance, and compare the capabilities of different technologies on the market.
Standards, which guarantee a level of performance, promise to simplify the buying. So do lower costs, and they may be on the way. Over the past couple of years, thermal sensors based on amorphous silicon have made it to the market. While technical issues remain, the good news is that they are based on silicon rather than more exotic sensor materials. Thermal imager manufacturers are hoping that prices will fall rapidly as they have for such other silicon applications as computer chips.
Cheap, small, consistent and rugged – and capable of saving lives. It sounds like an unbeatable combination.
Sidebar: Thermal Imager Suppliers
Bullard Co.; www.thermalimager.com; (800) 227-0423
International Safety Instruments Inc. (ISI); www.intsafety.com; (888) 474-7233
ISG Thermal Systems USA Inc.; www.isgfire.com; (877) 733-3473
Mine Safety Appliances Co. (MSA); www.msafire.com; (800) 672-2222
Scott Health & Safety; www.scotthealthsafety.com,/a>; (800) 247-7257
Total Fire Group; www.totalfiregroup.com; (937) 264-2662