At 3 a.m. yesterday, Frances Bozzelli, a 51-year-old diabetic invalid heard a noise she said sounded like "a drunk setting off an air horn."

The sound was a small smoke detector she and her husband had installed in their Annandale apartment.

Awakened by his wife, Joseph Bozzelli followed the noise and found the couple's kitchen in flames.

"I tried putting [the blaze] out myself," said Bozzelli 56, an Annandale postal service employe. "But the fire was spreading so that it was beginning to block the doorway out."

Bozzelli then rushed back to the bedroom to dress his wife, who is unable to walk by herself.

"I've never been through anything like it in my life," he recalled later. "We get plenty of luck, but it's all bad."

Yesterday the Bozzellis were in luck. The fire department lived in the same building.

As the couple was struggling to leave the apartment, Craig DeAtley, a 30-year-old Fairfax County paramedic and volunteer fireman, was two floors above them struggling to get into his firefighting gear. DeAtley had been awakened moments before by the Annandale Fire Department, which had been alerted by a neighbor.

"[Craig] got there quickly enough to help him carry her down the stairs and away from the smoke and flames," said DeAtley's wife Betty, who works as a volunteer firefighter in McLean.

Both Bozzellis covered with soot and suffering from smoke inhalation, were treated and released from Fairfax Hospital. Frances was back at Fairfax Hospital yesterday, complaining of chest pains. Damage to the Bozzellis' apartment at 7401 Eastmoreland Rd., was estimated to be $20,000.

"They [the DeAtleys] said they would put us up in their apartment until we could find another place," Joseph Bozzelli said. "They're really unbelievable. They're just fantastic."

The Bozzellis and the DeAtleys -- like many apartment dwellers -- had never met before.

Firs investigators were unable to determine the cause of the blaze yesterday, but arson was ruled out.

"I just can't figure it," Joseph said. "Neither of us smoke. I cooked some spaghetti earlier and made sure I turned off the stove. I have no idea how it got started."

By late afternoon yesterday Red Cross officials had told Bozzelli that they would supply temporary housing in a local hotel. But Bozzelli said he had already located another Northern Virginia apartment.

"It's going to be like starting over again" Bozzelli said from Fairfax Hospital yesterday. "But I guess it might have been worse."