The new 42,950-square-foot, one-story building will be east of the main building in the hospital campus, which is bounded by Fifth Avenue, 14th Street, Ninth Avenue and Dr. M.L. King Jr. Street N.

When finished, the building actually may be significantly larger.

The hospital originally considered a three-story addition for emergency room facilities. That project would have required a zoning change and an amendment to the city's land use map.

City officials are now revising building codes to allow greater future expansions, not only at St. Anthony's, but at All Children's and Bayfront hospitals, as well.

Once the code is changed, St. Anthony's plans to submit a revised site plan that includes the original, larger expansion, according to Deputy Zoning Official Corey Malyszka.

As now planned, entry to the new emergency room will be from a drop-off area on the south side of the building; ambulances will drop off patients on the east side.

Parking will be redesigned, and additional sidewalks will connect medical buildings with the new emergency room.

Regardless of its eventual size, the emergency room's contemporary design will complement other buildings on the hospital campus.

Hospital officials say the current emergency room might be used for outpatient services.

"We are looking at ways to improve and move forward to meet the needs and continue to provide services to the community," said St. Anthony's president Bill Ulbricht.

Once completed, the emergency room's entrance will move from Fifth to 10th Street.

To accommodate the emergency room, the hospital will tear down several houses and a 1960s-era convent where seven Franciscan Sisters of Allegany now live.

A new one-story convent, expected to take about seven months to complete, will be on hospital grounds at Fourteenth Street and Seventh Avenue N.

The sisters' order first came to St. Petersburg in 1931 to establish St. Anthony's, the only Catholic hospital in Pinellas County.

Through the years, the hospital campus expanded from the original historic building on Fifth Avenue N. The hospital is licensed for 395 beds, employs more than 1,100 people and serves more than 11,000 patients annually.

The most recent expansion occurred in 2005 when the hospital opened its Heart and Vascular Institute in a new three-story, 45,000-square-foot medical office building.

"St. Anthony's is an excellent facility, and I am pleased that it is staying in St. Petersburg and is getting better," said DRC member Sharon Heal-Eichler.

Before approving the site plan, the DRC okayed vacating a number of alleys and part of Sixth Avenue and Jackson Street N, and also required that one-way 10th Street N be reconfigured for two-way traffic.

Many of the alleys are unused or were vacated years ago.

The hospital owns virtually all land surrounding vacated rights of way. A one-story medical office building at 509 Jackson St. N was not affected.

Construction of the new emergency room will take about 13 months and will start once the new convent is completed.