It happened around 6:30 Tuesday evening on the 2600 block of Welsh Road.
The fire is believed to have started in the boiler room and crews reported heavy smoke pouring from the three-story building upon arrival.
The victim, in his 50s, suffered what's described as 2nd and 3rd degree burns to his face and hands.
He was rushed to Aria-Hospital, Torresdale Division for treatment. He was then taken to Temple University Hospital Burn Division where he remains critical.
The fire was brought under control within a half hour, but authorities are still investigating the cause.
