flame to the surface of the walls or the ceiling. The farther the flames move from the fuel package, the less heat they’ll have, and the less damage they’ll cause.”
Lien-hua’s eyes scanned the room like careful lasers. Beautifully dark, mysteriously inviting lasers. Then she pointed. “So, here, the wallpaper is scorched and peeling …” She stepped into the room beside us, looked over the walls again. “But here, the wallpaper at that same height is gone, and the fire ate into the drywall. So, this room is probably closer to the place the fire started.”
I love watching her work.
Actually, I don’t mind watching her, whatever she’s doing.
“Si,” Aina said. “Of course, other factors can affect heat flow—the building materials, room layout, airflow, and so on, but the extent of surface damage is one of the first things we look for.”
As we picked our way through the corpse of a home, it struck me how similar Aina’s job is to mine. Both of us evaluate the evidence, study the way something moves through space and time, and then use what we know about patterns to pinpoint the point of origin.
She studies the flow and movement of smoke and flames; I study the flow and movement of people. But the principle is still the same.
The secret to solving a case boils down to timing and location.
I heard a ring tone. Aina glanced down, tugged her phone off her belt. “Excuse me, I need to take this. You two look around. I’ll be back in a minute.”
Lien-hua and I stepped carefully past some blackened boards.Nearly all of the structural supports and door frames were still in place, but most of them were at least partially charred by the blaze.
I directed Lien-hua’s attention to the ceiling on both sides of a door frame. “See how only one side is covered with soot?”
She walked back and forth beneath the doorjamb, examining the ceiling on each side. “Yes.”
“Buoyant gases move though the air similar to the way water flows down a river,” I said. “When water meets a rock, it passes around the rock, and then some of the water curls back toward the rock.”
“You sound like an ex-raft guide.”
“Guilty as charged.”
“It’s called an eddy, right?”
I nodded. “Sometimes the eddies are so strong the water actually flows back upstream. That’s what happens when hot gases pass through a building. As the gas passes through a doorway, some of it curls back toward the ceiling, creating an eddy of air that doesn’t consume the wood but leaves a sooty residue. By identifying these eddies, we can work backward through a structure—”
“To find the source of the fire.”
“Right.”
We passed through several more rooms, Lien-hua carefully observing the eddies above the doorjambs, working with surprising acuity to lead us to a room at the back of the house. From the evidence I’d seen so far, I agreed that this room was probably the source of the blaze. “Not bad for a profiler,” I said.
“Yeah, well, this environmental stuff isn’t that complex. Maybe I should write a novel about it.”
“Touche.”
The electricity in the house was off, but enough sunlight cut through the window for us to see around the room. I noted that the glass in the window frames was still intact.With an exacting gaze, Lien-hua traced a line up the wall toward the ceiling. “These marks, here; what do they mean?”
“The fire plume made those. Usually, when you find them, they indicate proximity to the point of origin.”
I heard Aina’s footsteps by the doorway. “Very good, Dr. Bowers,”
she said. “When a fire is started against a wall, the wall does two things: it reflects heat and doesn’t allow the cooler air to escape the blaze. This creates a taller flame than a similar fire with the same heat release rate located in the middle of a room. In corners, the effect is increased, creating an even higher fire plume. And see how the floor directly beneath the plume is consumed? That’s
Lien-hua’s eyes scanned the room like careful lasers. Beautifully dark, mysteriously inviting lasers. Then she pointed. “So, here, the wallpaper is scorched and peeling …” She stepped into the room beside us, looked over the walls again. “But here, the wallpaper at that same height is gone, and the fire ate into the drywall. So, this room is probably closer to the place the fire started.”
I love watching her work.
Actually, I don’t mind watching her, whatever she’s doing.
“Si,” Aina said. “Of course, other factors can affect heat flow—the building materials, room layout, airflow, and so on, but the extent of surface damage is one of the first things we look for.”
As we picked our way through the corpse of a home, it struck me how similar Aina’s job is to mine. Both of us evaluate the evidence, study the way something moves through space and time, and then use what we know about patterns to pinpoint the point of origin.
She studies the flow and movement of smoke and flames; I study the flow and movement of people. But the principle is still the same.
The secret to solving a case boils down to timing and location.
I heard a ring tone. Aina glanced down, tugged her phone off her belt. “Excuse me, I need to take this. You two look around. I’ll be back in a minute.”
Lien-hua and I stepped carefully past some blackened boards.Nearly all of the structural supports and door frames were still in place, but most of them were at least partially charred by the blaze.
I directed Lien-hua’s attention to the ceiling on both sides of a door frame. “See how only one side is covered with soot?”
She walked back and forth beneath the doorjamb, examining the ceiling on each side. “Yes.”
“Buoyant gases move though the air similar to the way water flows down a river,” I said. “When water meets a rock, it passes around the rock, and then some of the water curls back toward the rock.”
“You sound like an ex-raft guide.”
“Guilty as charged.”
“It’s called an eddy, right?”
I nodded. “Sometimes the eddies are so strong the water actually flows back upstream. That’s what happens when hot gases pass through a building. As the gas passes through a doorway, some of it curls back toward the ceiling, creating an eddy of air that doesn’t consume the wood but leaves a sooty residue. By identifying these eddies, we can work backward through a structure—”
“To find the source of the fire.”
“Right.”
We passed through several more rooms, Lien-hua carefully observing the eddies above the doorjambs, working with surprising acuity to lead us to a room at the back of the house. From the evidence I’d seen so far, I agreed that this room was probably the source of the blaze. “Not bad for a profiler,” I said.
“Yeah, well, this environmental stuff isn’t that complex. Maybe I should write a novel about it.”
“Touche.”
The electricity in the house was off, but enough sunlight cut through the window for us to see around the room. I noted that the glass in the window frames was still intact.With an exacting gaze, Lien-hua traced a line up the wall toward the ceiling. “These marks, here; what do they mean?”
“The fire plume made those. Usually, when you find them, they indicate proximity to the point of origin.”
I heard Aina’s footsteps by the doorway. “Very good, Dr. Bowers,”
she said. “When a fire is started against a wall, the wall does two things: it reflects heat and doesn’t allow the cooler air to escape the blaze. This creates a taller flame than a similar fire with the same heat release rate located in the middle of a room. In corners, the effect is increased, creating an even higher fire plume. And see how the floor directly beneath the plume is consumed? That’s