The Maryland House of Delegates acted today to prevent developers from using a loophole to escape tenant-protection provisions of the state's recently enacted condominium conversion act.

Sponsors of today's legislation said it was aimed at developers who notified hundreds of tenants that their buildings would be converted, even though they had no immediate intention of doing so.

John R. Griffin, who advises Gov. Harry Hughes on condominium problems, said some developers, especially in the Washington and Baltimore areas, sent out such bogus notices so that if they later decided to convert to condominium ownership, they would be exempt from many restrictions in the new law.

Sens. Margaret C. Schweinhaut (D-Montgomery) and John J. Garrity (D-Prince George's) denounced as "rascals" and "scoundrels" building owners who needlessly frightened many elderly tenants in attempts to skirt the new law.

The biggest problem for lawmakers was figuring out how to snare the offending landlords without penalizing those few who really intended to convert their buildings. The bill approved today gets around that by rescinding all conversion notices except where 35 percent of a building is converted by March 15. Some extensions will be granted where owners are trying to complete complicated financing packages.

As soon as the Senate corrects a misspelled word in its version of the bill, which passed the House 128-to-0 today, Hughes is expected to sign it, to be effective immediately.