Sprinklers saved a Nunhead flat from being “severely damaged” after a fire broke out on Tuesday morning.
The fire started on the ground floor sheltered housing flat.
But by the time firefighters arrived, the blaze had already been put out by a sprinkler system.
The brigade had been called at 10.36am after a member of staff heard the fire alarm sound.
Two engines from New Cross and Old Kent Road had been deployed, but were able to stand down by 11.15.
“Sprinklers are the only fire safety system that detects a fire, suppresses a fire and raises the alarm,” said a brigade spokesperson.
“They save lives and protect property and they are especially important where there are vulnerable residents who would find it difficult to escape, like those with mobility problems.”
It is believed the fire was caused accidentally.
There were no reported injuries.