Four fire engines and approximately 25 firefighters from Bromley, Lee Green and Lewisham stations were deployed to a house on Pontefract Road on June 6.
The fire destroyed the ground floor and extensively damaged the first floor.
A woman had fled the house prior to the brigade’s arrival.
The brigade was called around 12.25pm and controlled the situation by 1.48pm.
The cause of the fire remains under investigation.
Station Commander Daniel Capon, who was at the scene, said: “Crews did a great job in challenging conditions to tackle this house fire and then were able to focus on Sage, the 18-month old cat they had rescued.
“Having something specially designed made so much difference as the mask is properly sealed around the animal’s muzzle and all the oxygen is going into their lungs.
“The crews were quick to get to work with the equipment and ultimately saved the cat’s life.”
A spokesperson for the London Fire Brigade said: “Of course a firefighter’s priority is always to save any human life, but we know how precious people’s pets are to them and we also know owners will put their own lives at risk by trying to return to a burning building to rescue them.
“This equipment allows our crews to safely provide oxygen to any animals which need medical attention in the immediate aftermath of a fire. They also bring a bit of hope and positivity to families in a traumatic situation.
“The equipment for pets builds on the Brigade’s significant investment in its equipment in recent years, including fire escape hoods, which are carried on all fire engines and are used to help bring people out through smoke filled environments safely, and the roll out of three 64m ladders – the tallest in Europe – and eight 32m ladders.”
The fire is believed to have been accidental and caused by a lighter left too close to a combustible items.
A spokesperson for the London Fire Brigade said: “Four fire engines and around 25 firefighters tackled a fire at a house on Pontefract Road in Bromley.
“The ground floor was destroyed and most of the first floor was damaged by the fire. One woman left the building before the Brigade arrived.
“The Brigade was called at 1225 and the incident was over for firefighters at 1348. Crews from Bromley, Lee Green and Lewisham fire stations attended the scene.
“The cause of the fire is under investigation.”