UPMC Passavant is preparing to spend an estimated $100 million for a new hospital tower that will increase by about one-third the size of the McCandless medical center.

The project, which is part of a broader 10-year plan to also expand services at UPMC Passavant Cranberry in Butler County, is meant to tap population growth in the northern suburbs of Pittsburgh, said Robert E. Henderson, a spokesman for the hospital.

"This area that we live in is one of the few growing areas of all Western Pennsylvania," he said.

UPMC's plans for the North Hills hospitals are the latest in a series of hospital building projects in the region. Last month, the West Penn Allegheny Health System announced a large construction project at its Forbes Hospital in Monroeville, and construction is either planned for or in progress everywhere from Ohio Valley General Hospital in Kennedy to UPMC Shadyside.

The local activity matches a national trend of hospitals expanding, remodeling or replacing their existing facilities.

Growing patient demand for services at UPMC Passavant is shown by the 5 percent increase in visits to the hospital emergency room last year, said Mr. Henderson. The new hospital tower, which will add between 120,000 and 150,000 square feet to the medical center, will double the size of the emergency room and include space for trauma patients should the hospital decide to create a trauma center in the future, Mr. Henderson said.

Other changes include: more space for cancer and heart patients; six new operating rooms; between 16 and 18 new intensive care unit beds; and 20 new beds for surgery patients.

Ground could be broken on the project within 10 months, with construction scheduled for completion about two years later.

Population growth in northern Allegheny and southern Butler counties also explains why UPMC Passavant Cranberry will break ground on an expansion project for its emergency room in the next two months, Mr. Henderson said. Located just over the Allegheny County line in Butler, the hospital has plans for an additional 50 or 60 beds, although Mr. Henderson said the project is further down the road.

More details in tomorrow's Pittsburgh Post-Gazette.