IN THE BUSINESS . . . The Washington office of Arthur Rubloff & Co. has been signed by the Equitable Life Assurance Society of the United States to handle Equitable's 1.9-million-square-foot commercial real estate portfolio here. Rubloff will both lease and manage the property, which includes office and industrial buildings, as well as shopping centers clustered in Gaithersburg and Rockville. Rubloff says the deal is one of the largest single contract assignments ever made . . . Affiliates of Charles E. Smith Cos. have received a $2 million commitment from Rouse Real Estate Finance for mortgage funds for the Crystal Gateway and Skyline Square condominiums. The money will allow buyers to obtain 12 1/2 percent conventional loans up to $350,000, according to Rouse . . . Kettler Brothers Inc. is acquiring the Hidden Valley resort community and conference center in Somerset, Pa., and is planning a new 300-unit ski village there . . . Long & Foster Realtors has acquired the Warrenton real estate firm of Harding Realtors, which will become Long & Foster's 47th office . . . B. F. Saul is planning a groundbreaking in June for Phase II of its Avenel Business Park on I-270 in Gaithersburg. Phase I of the 40-acre park consists of three buildings totaling 111,000 square feet . . . The Virginia Association of Realtors has received a commendation from the U.S. Department of Housing and Urban Development for fair housing initiatives by its members and for voluntary compliance with federal fair housing statutes.

PERSONNEL FILE . . . The Maryland Chapter (Montgomery County) of the National Society of Professional Resident Managers will install its new officers Tuesday. They are: Margaret Back, president; Evelyn L. Lipford, first vice president; Margot Rolland, second vice presdient; Grace B. Alspaugh, recording secretary; Jean B. Ellis, corresponding secretary;a nd Elizabeth H. Fisher, treasurer . . . Bill Geghardt of the Woodbridge office of Coldwell Banker Routh Robbins-Realtors Inc. has been recognized as the company's number one sales associate for the firm's residential sales force in the District, Maryland and Virginia . . . Kathleen Hawkins Berkowe has been appointed a corporate counsel of Rockefeller Center Inc. Berkowe, originally of Silver Spring, has worked as assistant corporate counsel for Garfinckel's, Brooks Brothers, Miller & Rhoads Inc. and as an attorney at the Civil Aeronautics Board . . . Barnes, Morris & Pardoe Inc. has promoted Donald E. Dworkin to vice president of sales in its Northern Virginia office . . . Bruce Landerman has joined Carey Winston Co., specializing in financing for builder/developers . . . Eleanor Armstrong of Peck Properties' Silver Spring office received the Hugh T. Peck Memorial Award at the company's awards ceremony recently . . . Kent Butler, who has been with Merrill Lynch Realty/Chris Coile Inc. for the past 10 years, has been named general manager and executive vice president of Merrill Lynch/Boomhower Inc. in Sarasota, Fla. Joseph Minieri becomes region manager of Merrill Lynch/Chris Coile.

MOVING ON . . . Aetna Casualty & Surety Co. has leased 76,161 square feet in a building owned by the Prudential Insurance Co. of America at 7926 Jones Branch Drive in McLean. Smithy Braedon represented both tenant and landlord . . . And in another Smithy Braedon deal, Colonial Mortgage Corp. of D.C. has leased 8,393 square feet at Metro-Plex II in Landover . . . Manekin Corp. announces some tenant expansions in its buildings at Oakland Ridge Industrial Park in Columbia. United Technologies Communications and Toshiba Medical Systems both doubled their space, the former to 8,000 square feet, the latter to 5,026.