Three new immunization clinics for school-aged children will be open through Aug. 31, according to D.C. Director of Public Health Dr. Raymond L. Standard.

All D.C. public school students must be immunized against diphtheria, tetanus, polio, measles, mumps and rubella by September or they will not be allowed to attend classes. Except for rubella, a history of having had these diseases is acceptable instead of immunization.

The free clinics, staffed by the Department of Human Resources, will be open Monday through Friday from 9 a.m. to 4 p.m. The new clinics are: Fletcher-Johnson Elementary School, Benning Road and C Street SE; Orr Elementary School, Minnesota Avenue and Naylor Road SE, and Raymond Elementary School, 10th Street and Spring Road NW.

Other health centers where children may received free immunizations during the same hours are: Hunt Place, 4130 Hunt Place NE, telephone 727-0533, and 15th Street, 702 15th St. NE, 727-0410.

Immunizations at the following clinics will be given Monday through Friday from 2 to 4 pm. or other hours by appointment only: Anacostia, 1328 W St. SE, 767-7880; Arthur Capper, 1011 7th St. SE, 727-3454; Congress Heights, 3855 8th St. SE, 767-7872; Potomac Gardens, 1227 G St. SE, 727-3451; Benning Heights, Benning Road and C Street SE, 767-7563; H Street Clinic, 635 H St. NE, 727-0370; Parkside, 701 Kenilworth Ter. NE, 727-0370; Southwest, 850 Delaware Ave. SW, 727-3611, and Northwest, 1325 Upshur St. NW, 576-7020.

Three clinics will give immunizations for presently registered patients by appointment only: Center 10, 1300 Rhode Island Ave. NE, 576-6654; Center 2, 1810 14th St. NW, 673-6649, and Walker-Jones, 1100 First St. NE, 724-4375.

In addition, Children's Hospital operates two neighborhood facilites that are open Monday through Friday from 8:30 a.m. to 5:30 p.m. - Adams-Morgan Clinic, 2200 Champlain St. NW, and Comprehensive Health Clinic, 13th and V streets NW.

Parents are advised to check with the health facility nearest them to determine the time and day that is most convenient.

Volunteers to assist the immunization teams are needed. Interested persons may call the Volunteer Clearinghouse of the District of Columbia at 333-0455. For more information about the immunization program, call 673-6700.