But as the single-story home from the early 1900s burned, residents walked calmly by and chatted with the fire crews on duty.

The fire--or fires--that gutted the house at 928 S. Wolfe Road were part of a "live burn" exercise put on by the Sunnyvale Department of Public Safety.

According to Lt. Marty Dale, the owners had applied for a permit to demolish the house. The department then requested the owners allow the city to use the empty house as a training facility for its firefighting crews as well as crews from Mountain View and the NASA Ames complex.

Unlike the cement training towers that use clean-burning fires to simulate structure fires, having a fire in a real house gives public safety officers a chance to encounter real problems, such as the excess smoke, weak structures and intense heat they'd find in real fire situations.

"These 'live burns' are rare events, because it's tough to get clearance for these, and there just aren't a lot of structures that we can burn anymore," Dale said.

In addition to getting permits from the city to do a controlled burn, Dale said the department had local Boy Scout troops blanket the neighborhood with more than 200 fliers telling residents what was planned.

The entire exercise lasted for three days, Feb. 14 through 16. This gave each of Sunnyvale's six fire stations a chance to rotate through the training program and still have crews on call in case of real emergencies.

To prepare the house, DPS turned off all gas and electrical lines, cleared any asbestos from the structure and removed the windows and doors. In their place, wood panels were lightly attached.

"This way, if any firefighter gets in any trouble inside, they can just shoulder the window, and its wood will pop right off," Dale said.

As an additional precaution, a paramedic team was at the scene.

"We want to make sure things are good and safe, and this is a very secure site, but things can happen," said John Pilger, Sunnyvale communications officer.

Inside the burned-out house, a dummy served as a fire victim lying on a floor, and when the fire was set, response teams had to enter the home through one of several entrances, find the "victim," remove it and put the fire out.

There were also crews outside using firehoses to put out the fire and prevent it from spreading.

The outside crews also watched to make sure that high winds did not cause the controlled fire to spread to neighboring homes.

One neighbor, 42-year resident Lee Colby, stopped by with his dog to watch the drill. He said he didn't mind the fire being in his area.

"It has to be in somebody's neighborhood, and since they have this old building here, I think it's a good thing," he said. "I'm really glad that they had the opportunity to practice on this building."