RALEIGH - Wake school Superintendent Del Burns today rebutted arguments that the system could absorb a growing student population without converting schools to a year-round schedule.

Burns, guest speaker at a meeting of department heads and other employees of The News & Observer, said alternatives suggested by opponents could hurt student learning. He defended as "fiscally responsible" the school board's decision to add seats for 3,000 students by converting 22 schools to a year-round calendar.

Parents who have filed suit to stop the conversion say that the schools could instead add mobile classrooms or increase the number of students in classes across the county.

But Burns said the schools would need 200 to 300 new mobile units to handle the overflow. The system, he said, lacks money to acquire the units and the time to install them. It takes five to nine months to acquire and set up a mobile classroom, he said.

Further, he said, adding mobile units would strain the capacity of a school's media center, cafeteria, restrooms and other such facilities. And that, he said, would have a negative impact on teaching and learning.

Adding students to classrooms across the county, he said, would be only a temporary solution and would not be practical because growth is not spread evenly in Wake. It also would put an extra strain on teachers, who are increasingly accountable for the performance of their students and face rising expectations for performance, Burns said.

Burns focused on growth in his speech, pointing out that Wake's enrollment of 128,070 students is projected to rise to 160,000 by the year 2011. Wake is likely to overtake Mecklenburg next year to have the state's largest school system, he said.

"I believe the greatest challenge we have in the Wake County Public School System ... is making sure growth does not distract us from our core mission of teaching and learning," he said.

As superintendent, he said, a chief goal is to make sure that every student graduates on time, prepared for a future of higher education and employment. Currently, 82 percent of Wake's students graduate on schedule, he said.

Burns, a long-time school employee who became superintendent in July 2006, also touted a "curriculum management audit" to take place in the next few weeks. About 25 auditors will visit schools and classrooms and make recommendations this summer in a range of areas, including governance, programs, structure and use of resources.

"What I'm looking for are not commendations," he said. "What I am looking for are those recommendations that will help us move Wake County schools and our kids to the next level."

Since taking over the job, he said, he has moved to flatten the system's organization, eliminating the job of deputy superintent and adding a chief academic officer and a chief business officer. The business officer, he said, is assigned to improve the system's business practices.

Burns cited a number of other recent initiatives, including:

- A pilot project at East Wake High School to effectively break the school into four smaller units to develop "a small school feel" for students there.

- Wake Early College, which allows students to graduate with an associate's degree in health sciences.

- A 9th grade academy to help students make the transition from middle to high school.

- Team-based collaboration among teachers.

- A focus on leadership development at every level of the system.