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Two key members of Congress have requested an official study of the limits on building heights in the District, another small step toward a possible change in the law.

The limit on building heights has given the District skyline a unique look. (Ron Edmonds — Associated Press)

House Government Reform and Oversight Committee Chairman Darrell Issa (R-Calif.) wrote to Mayor Vincent Gray and the National Capital Planning Commission last month to ask the city and the NCPC commence a study of the Height of Buildings Act of 1910, which dictates that that the height of buildings on commercial streets in the District cannot exceed the width of the street by more than 20 feet and cannot exceed 130 feet overall. (Buildings can be higher in just one area: on Pennsylvania Avenue between First and 15th streets NW.)

On residential streets, building heights generally can’t surpass street widths by more than 10 feet, up to a maximum of 90 feet.

Both Issa and Del. Eleanor Holmes Norton (D-D.C.) first said in July that they wanted the study done. The NCPC wrote back last week, agreeing to the request. The study will begin in December and will be concluded by September 2013.

“As time has elapsed and opportunities for economic growth in our nation’s capital continue to present themselves, this study will help Congress and local leaders evaluate the case for expanding existing boundaries for vertical growth,” Issa said in a news release Thursday.

Norton said the “study is just the beginning of what will be a complete public process examining the economic and aesthetic consequences of changing a law that has stood for more than 100 years.”

The Height Act has long spurred debate in the District. The lack of skyscrapers in the city has helped give it a much-praised skyline, with unobstructed views of monuments and other significant landmarks. But it has also limited the city’s tax base and potential growth in areas like downtown, which is attracting more workers and residents with little room to expand.

The Oversight panel held a hearing on the Height Act in July, where District Chief Financial Officer Natwar M. Gandhi testified that the city’s “potential for growth is nowhere near exhausted” and noted that office vacancy rates are extremely low.

Other witnesses testified that Congress and the city should think carefully before they consider lifting the limits.

Gray said Thursday that the study would “evaluate whether reconsidered and possibly different limits to building heights might affect federal and other interests, preserve the District’s characteristic skyline, and continue to give prominence to the views of stately landmarks and monuments that grace the District of Columbia.”