Leah Connolly had been kept under close supervision at the Kibble Education and Care Centre in Paisley when she was found by workers in the early hours of Thursday.
Shocked staff rushed to help the 15-year-old, who is from Livingston, and she was rushed to the Royal Alexandra Hospital but died later that day.
Staff had been checking on her twice an hour prior to her death. They performed CPR and used a defibrillator until she was taken to hospital.
The former pupil at Inveralmond High School in Ladywell, who had expressed an ambition to go into modelling, had been staying at the centre since September 2011 because of a “history of emotional and behavioural issues”.
Yesterday, scores of tributes were left on her Facebook page by shocked friends. Shannon Ann said: “I was hoping and praying you could wake up, but they say God only takes the best. I have so many memories with you ... you were the most caring person I knew, helped me through everything. I will miss you soo much.”
And Nicole McGregor said: “We are all gonna miss you so much, what a beautiful lassie u were. It wasn’t yur time Leah ... it was brilliant every minute I spent with you, you were a right laugh and everyones gonna miss you. Love you babygirl.”
Kibble chief executive, Graham Bell said: “Our thoughts and prayers are with Leah’s family and friends after this sad and tragic incident. Leah had been staying in Kibble since September 2011 and because of a history of emotional and behavioural issues, staff in the unit were checking on her twice every hour during the night as part of her care plan.
“At 00.20am on Thursday, during one of these routine checks, Leah was found unconscious.
“The care of young people here at Kibble is paramount. Our staff are trained to deal with medical emergencies such as this and they reacted quickly, following the correct procedures and doing their utmost to save Leah’s life.
“We will, of course, co-operate fully with any inquiries into Leah’s death.”
A spokesperson for Strathclyde police confirmed that the incident was not being treated as suspicious.
They added: “She was in a serious but stable condition when in the intensive care unit. Unfortunately she died later that day.
“Inquiries are ongoing to establish the circumstances surrounding the incident and will be reported to the procurator fiscal.”
The Care Inspectorate said they would not investigate at this time, but would keep a close eye on the situation.
Bosses at the Paisley home were criticised in 2011 after 13-year-old schoolboy Bryan Ross hanged himself in his bedroom. Following a fatal Accident Inquiry, Sheriff Neil Douglas expressed concerns about their “structure” after it emerged staff discovered the boy had hidden a cord in his room just two months before he took his own life.