Barbara Lima has few memories of her father, Charles A. Buchanan, a Boston firefighter who died just days after she turned 5 while battling an early morning blaze in Brighton 75 years ago. But in a moving surprise Saturday, she was able to celebrate her father’s life and honor his sacrifice during a reunion of firefighters and their families at a firehouse in Roxbury.

Lima helped unveil a plaque bearing her father’s name mounted outside the city’s new Columbus Avenue fire station during the reunion, along with a firetruck that bears his name.

“I feel like he was finally honored, and deservedly so after 75 years,’’ Lima said in a phone interview. “I think he’s a hero, definitely.’’

For decades, she didn’t know much about her father, beyond that he was a Boston firefighter. But a few weeks ago, she responded to a social media post from the department’s firefighters, who said they were trying to reach Buchanan’s family.

Buchanan died the morning of March 24, 1947, when he fell to his death battling a three-alarm blaze on Brighton Avenue. The 38-year-old firefighter was married with four young children, including Lima, who had celebrated her fifth birthday only days before his death.

He was among the firefighters dispatched around 3:30 a.m. to what was initially a one-alarm fire inside the single-story building at 116-120 Brighton Ave.

Buchanan was a Boston firefighter for about three years and a member of the department’s Rescue 2 company based in Roxbury. He was the son of Lawrence Buchanan, a retired 40-year veteran Boston firefighter.

Buchanan and a comrade, John Heise, were standing just a few feet apart inside the building, Heise later told a reporter. When a large section of floor collapsed into the basement below, Heise lost sight of Buchanan amid a “jolting air blast’’ that shook the building and shattered its windows.

“I yelled for him, but didn’t get any answer,’’ Heise said, according to Globe news stories at the time.

He remained missing for about two hours before Heise spotted his flashlight flickering in the flooded basement. Nearby, Heise later said, he discerned Buchanan’s motionless form. Firefighters used ropes to lift Buchanan out of the basement.

Buchanan left behind his wife, Helen, who was then 35, and their children — Charles Jr., 9; Robert, 7; and Lois, 2; along with Barbara. His death took a heavy toll on the family, as Lima’s mother had to work three jobs to support them, Lima said. Her siblings are all deceased.

Lima had responded to a social media message placed by firefighters, including Bobby “BK’’ Kilduff, a member of Rescue 2 who had been researching city firefighters who died in the line of duty.

Buchanan, who was remembered in histories published online, had not been recognized with his own plaque at the Columbus Avenue firehouse that served as Rescue 2’s home base.

Kilduff said firefighters had hoped to connect Buchanan’s family with the wider firefighting community.

“Our business as firefighters, in general, is unique. We show up on people’s really bad days, and try to make them a little bit better,’’ Kilduff said. “If we can make Barbara and her family feel a little bit more included and loved . . . then we’re definitely doing that job.’’

Boston Fire Commissioner John Dempsey, who was at the service, said the department will not allow Buchanan’s sacrifice to be forgotten.

“We are just very happy that he is now rightfully recognized, and from here on out, people can go by the firehouse, and see his name,’’ Dempsey said in a phone interview.

Lima, who with her husband splits her time between Clearwater, Fla., and Seabrook, N.H., was joined at the ceremony by more than 20 family members, including sons, grandchildren, and her 4-year-old great-grandson at the Roxbury home for Rescue 2.

Lima said seeing her father’s name on the truck, and knowing that he will be with firefighters on every call they respond to, gave her some closure.

The experience left her in awe, she said.

“It’s amazing for all of my sons, grandchildren, and great-grandchild to see all this, and understand how important he really was,’’ Lima said. “That was very important to me, that they were all here.’’

John Hilliard can be reached at john.hilliard@globe.com.