Towering inferno: from a 40-story apartment building in Houston to the World Trade Center in New York City, firefighters wield high-tech tools to battle monster flames. (Physical/Tech Science: Firefighting * Pressure Laws).

At 4:15 a.m. on October 13, giant flames burst through a fourth-floor window in Four Leaf Towers, a 40-story residential high-rise in Houston, Texas. Within minutes, the blaze spread uncontrollably, devouring furniture, ceilings, and walls. Clouds of suffocating black smoke filled stairwells and hallways. Visibility was zero, and the high-rise became a 427 [degrees] C (800 [degrees] F) inferno.

"There was glass and fire just pouring out," says resident Georgann Sievert, who escaped down 19 flights of stairs. It took more than 175 firefighters to extinguish the blaze, and Captain Jay Jhanke of the Houston Fire Department lost his life while helping the building's occupants. The cause of the fire is still under investigation.

Fire kills one American every 40 minutes. Last year, structural or building fires claimed 4,125 lives, including 64 volunteer and 38 career firefighters. Over 30,000 people were injured. More than 400 firefighter fatalities will be reported in 2001 due in large part to the World Trade Center tragedy, which killed 343 firefighters in a single day. Still, thanks to an armory of new high-tech tools, firefighting has become significantly safer and more successful than ever.

RED-HOT CITY

Jack Williams, district fire chief of the Houston Fire Department, has battled fires for 27 years. "Some people want to be doctors or lawyers," says Williams. "Not me--I've always wanted to fight fires."

Firefighters like Williams work in 24-hour shifts, ready at a moment's notice to respond to an emergency fire call--even a 4:15 a.m. call, like the one from Four Leaf Towers. A fire call automatically kicks on the lights in the firehouse and sounds an alarm. "As soon as I hear that `boop' noise, my heart jumps," says Williams. He has less than two minutes to suit up into "bunker gear": protective trousers and a jacket coated with Kevlar, a lightweight, fire-resistant fiber made of plastic. It's 60 times stronger than steel and is also used in bulletproof vests and spacesuits.

On the way to the fire, Williams straps on an air tank, otherwise known as an SCBA, or self-contained breathing apparatus (see diagram, right). In a smoke-filled building, the SCBA supplies a lifesaving 30 or 60 minutes of air pumped through a "positive pressure" mask. That means that the pressure--the force exerted on a unit of surface area--inside the mask is higher than it is outside the mask. According to Pascal's law of fluid pressure, air molecules travel from areas of high pressure, where they are tightly packed, to areas of lower pressure, where they can flow more freely. So if the mask springs a leak, high-pressure air rushes out and blocks incoming smoke.

SCBAs also come equipped with an alarm that blares when less than five minutes of air is left in the tank, as well as a two-way radio tucked inside the mask. "It's similar to those found in a pro quarterback's helmet," says SCBA specialist Gary Henkel at SCBA Safety Check, Inc. "All you have to do is start talking and you reach the command post."

Once on the scene, Williams and his crew always try to combat a blaze from the inside out: "Anytime you stick a hose in a window, you're pushing fire and smoke back into the building--where people may be trapped." Williams's top priority: to get inside and search for victims, and then keep fire from spreading to unburned areas. "Time is of the essence because of the possibility of losing lives," he says. If the "seat" or heart of the fire blazes on the 20th floor, for example, a firefighter has to be fit enough to sprint up the stairwell. And that grueling task doesn't get easier with a hose in tow, which "adds another 100 pounds," Williams says.

THE PRESSURE IS ON

Once a firefighter reaches the fire floor, the next challenge is to pump up water. The dilemma is that elevation decreases water pressure. For every 0.3 meters (1 foot) in elevation, the pressure pushing water through a hose decreases by 0.434 pounds per square inch (psi). Pumping water to a building's second floor, for example, results in a pressure loss of 4.3 psi; to the 51st floor the pressure loss is 271 psi; and on the 101st floor you lose 434 psi!

To offset pressure loss, firefighters use "standpipes," or a system of water pipes usually tucked behind the stairwells--they are designed to provide a three-hour refuge area from the flames. To access the pipes' water, a firefighter totes up a "high-rise pack"--a shoulder bag filled with 30 m (100 ft) of hose, an adapter to attach to other hoses, and a hose nozzle--then plugs the apparatus into a standpipe valve to crank out water.

But too much water pressure also creates problems. A typical hose nozzle can spray up to 1,893 liters (500 gallons) of water per minute. But at that rate, the gushing water would create enough reaction force, or backward pushing force, on the hose to lift a 113 kg (250 lb)-man clear off the ground! Newer nozzles, like the Blitzfire, come equipped with an acceleratometer, a device that detects sudden hose movement and shuts off water supply within 0.3 seconds.

FIRE SCIENCE

A building fire usually begins as a small accidental flame, perhaps from an overturned candle or faulty electrical wire. But in minutes, a modest spark can engulf a building. Why does fire spread so quickly? Flames feed on oxygen, an element readily available in air. A hot spark kicks off a chemical reaction called oxidation, which burns oxygen and releases heat. The heat then spreads to flammable materials, like furniture, clothing, and carpet. When they get hot enough to reach their flash point, they combust or burn. The heat is so intense "one breath can singe your lungs," says Williams.

Flames may be scary, but 90 percent of fire victims die from heat and smoke inhalation. That's because smoke can contain hundreds of deadly chemical impurities--like carbon monoxide and cyanide, common byproducts of burning plastic, electrical wire, wool, silk, rubber, and paper products. Inhaled in large quantities, the toxins disrupt the body's ability to carry oxygen to the brain. The result: a coma, or state of deep unconsciousness.

Four Leaf Tower's resident Lida Blue suffered minor smoke-inhalation injuries while she escaped the building with her husband and dog. Paramedics gave her an oxygen mask to revitalize her lungs. "It just goes to show, you can't worry about terrorists," Blue told the Houston Chronicle. "Danger can be a lot closer."

HOT DRESS CODE

Some dress for success--others for survival. Find out how high-tech clothes and equipment help keep this firefighter safe on the job.

HELMET Shell crafted of Ultem, a fire-resistant plastic able to withstand temperatures up to 204 [degrees] C (400 [degrees] F).

FIRE-RESISTANT CLOTHES Made of self-extinguishing fabrics like Nomex and Indura.

SCBA (self-contained breathing apparatus) Delivers up to 60 minutes of pressurized, filtered air.

PIKE POLE Ax/backhoe used to pull down unstable ceilings and walls.

FACE MASK Protects against smoke, flying embers, and deadly gases.

PRESSURE GAGE Controls SCBA air flow.

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FIRE SAFETY TIPS

* Work with your family to develop and practice an escape plan from your home.

* Check smoke detectors' batteries once a month and change at least once a year.

* If caught in a burning building, remember: Smoke and heat rise, so "get low and go."

FOUR LEGGED FIREFIGHTERS California is no stranger to deadly fires especially in October when hilltops are tinder-dry and fires gorge on the land's dense flammable undergrowth. Last year, the state endured 6,728 blazes, which burned 355 sq. km (87,700 acres) of land.

One popular solution: hungry goats. The horned beasts have voracious appetites for thorny brush and vegetation, and their work ethic is impeccable--they eat 24 hours a day. Goats are especially effective at clearing hazardous underbrush from steep slopes, which pose problems for human-powered mowers. Their favorite meal: the highly volatile manzanita plant, which can spontaneously combust, or burst into flames, thanks to its low ignition point. "We need all the tools we can get to fight fires, including goats," says fire consultant Carol Rice, Goats R Us, a company specializing in fire-fighting goats, increased its goat fleet to 4,000 last year, up from 54 in 1995.

Cross-Curricular Connection

Drawing: Draw a floor plan of your home showing at least two exits for each room. If you live in a building with many floors, investigate which windows have a fire escape. Share and rehearse the plan with your family.

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Did You Know?

* According to the Federal Emergency Management Agency, working smoke detectors more than double the chance of surviving a fire.

* Asphyxiation--the prolonged interruption of breathing due to a lack of oxygen or an overload of carbon dioxide--is the number one cause of death in a fire.

* During a fire, temperatures at floor level can be about 500 degrees cooler than temperatures at eye-level!

* More than 80 percent of home fires occur while people are sleeping.

National Science Educational Standards Grade 5-8: abilities of technology design * chemical reactions

Grade 9-12: abilities of technological design * chemical reactions

Resources

Fire! by Joy Massoff, Scholastic Inc., 1998 The New York Fire Department Fire Zone web Site: www.fdnyfirezone.org

The Federal Emergency Management Agency Web site for kids www.fema.gov/kids

Directions: Match the word(s) in the left column with the correct
  phrase in the fight column.

-- 1. oxygen                   a. point at which an object combusts

-- 2. SCBA                     b. material made of fire-resistant
                                  plastic fibers

-- 3. law of fluid pressure    c. an element consumed by fire

-- 4. Kevlar                   d. provides fresh air supply

-- 5. oxidation                e. molecules flow from high pressure
                                  areas to lower pressure areas

-- 6. flash point              f. backward-pushing force

-- 7. reaction force           g. oxygen-consuming chemical reaction

ANSWERS

1.c 2. d 3. e 4. b 5. g 6. a 7. f