Residents on upper 16th Street NW, saying they want to preserve the residential nature of their neighborhood, have successfully blocked efforts by a 4-year-old college prep school for District youth to locate in a $130,000 house at 16th and Longfellow.

The action by the board of zoning adjustment drew criticism from Ruby G. Woodson, proprietor of the Cromwell Academy, who said her school would have been less of an intrusion than the "embassies, churches, day care centers, rooming houses and old folks homes" that now line the street.

Woodson, a former District teacher, formed the academy as a means of providing a rigorous pre-college curriculum for students of high ability from both poor and affluent families, most of them in the District. The school has sent its graduates on to Ivy League and Seven Sisters colleges.

The school has been in the 16th Street neighborhood for two years, operating out of the basement of the Sixth Presbyterian Church at 16th and Kennedy. Woodson bought a 15-room house on Longfellow Street, a block north, feeling that the school's reputation would enable it to get the special zoning exception.

To most 16th Street residents, however, the academic standing of the school was irrelevant when Woodson requested the exception. Before both Advisory Neighborhood Commission 4A and the zoning board, residents urged that the sanctity of the residential zoning be maintained. They said they feared the precedent even one exception would set.

"If she gets in, who says that two or three years from now Standard Oil can't put up something on 16th Street? They'll say, 'Well, you gave it to Cromwell Academy,'" said Lawrence Chatman, president of Citizens for Preservation of Neighborhoods. Chatman's group includes residents in the triangle-shaped area defined by Rock Creek Park, Military Road and Colorado Drive.

Lapolic Ashford, the ANC commissioner for the area, said he knew about the academy "and I know it's good." He said residents wanted to be vigilant in limiting exceptions to the residential zoning, but that Woodson could have gotten the community's support if she had handled her case better.

"She said right off that she had not tried to communicate with her neighbors because she didn't consider it important . . . Mrs. Woodson had no understanding of what type of neighborhood we are. There was no sensitivity to those neighbors. She in effect told them, 'Y'all go to hell,'" Ashford said.

Woodson said she felt both the ANC and the neighborhood association had made up their minds before they heard her case. She said residents at the ANC hearing in June were "irrational" and "abusive," and she said she heard that members of Chatman's organization solicited petitions against her, telling residents that the school was for "delinquent" youth. She said none of the students are deliquents.

Chatman said he understood the school to be for delinquent youth, but that he did not tell anyone that. But he said two residents have complained about racial slurs from the academy students and he said there have been problems with trash left by the students and congestion in neighborhood because of the school.

Both Ashford and Chatman disputed Woodson's contention that 16th Street was already filled with establishments that didn't conform to the residential zoning. They acknowledged the many churches and embassies, which are allowed as exceptions under the zoning code, but said they were fighting other nonconforming uses.

The Advisory Neighborhood Commission voted unanimously against the zoning exception in late June. The board of zoning adjustment had a full hearing on June 28 and voted 5-0 against the exception on July 12. The zoning board's action was to become effective this week, with the release of a full report, according to Steven Scher, the board's staff director.

For the Cromwell Academy and its 50 students and six teachers, however, the matter has been decided for the coming year. Woodson leased the Longfellow Street house last week, and found space for the school at Temple Sinai, 3100 Military Rd. She said the rent, higher than at Sixth Presbyterian Church, will be a hardship.

Meanwhile, Woodson has found that running a school can be an educational experience even for the school's proprietor. She said plans to challenge the decision against her, partly because of her recent conclusions that zoning is a matter of "politics - political pressure," and that "the whole (16th Stree) area ought to be rezoned."