Construction is under way on a conference center at Henry A. Long Co.'s 1,100-acre Westfields Corporate Center, near Dulles International Airport.

The $65 million, 350,000-square-foot conference center is being developed by WestScot, a joint-venture partnership of Henry A. Long Co., Perpetual American Bank, MJ Property Co. and the principals of International Conference Resorts of America (ICRA).

"We made the determination that a conference center was a necessary element of making Westfields a top-notch corporate park," said Francis C. Steinbauer, senior vice president of the Henry A. Long Co. "This will be a dedicated conference center, which will provide a complete atmosphere for conducting corporate conferences."

The facility is being built on a 25-acre section of the development and will have 345 guest rooms, 30 rooms with 30,000 square feet of meeting and exhibition space and a media resource center. Other amenities will include several restaurants and health and racquet facilities, including tennis courts, an indoor pool, a health spa and an exercise room. It will be able to accommodate groups of up to 600 persons.

"Our business is business meetings," said Gene Keluche, chairman of ICRA, which will operate the Westfields Executive Conference Center when it is completed in March 1989. "We will help plan and coordinate a corporation's entire conference, from the agenda and the air travel to providing secretarial and taping services. We won't be just providing the facilities."

Keluche sees a substantial demand for executive conference centers. He said American companies spend $12 billion annually on corporate conferences, which average 3 to 5 days in length, and the firms are willing to spend a daily average of $200 per executive just for facilities.

Given this market, ICRA is planning to develop, during the next six years, a network of 8 to 10 conference centers within a two-hour flight of all major U.S. and Canadian cities.

International Conference Resorts of America, which operates conference center facilities in Arizona, Texas and Colorado, is a partnership among Henry A. Long Co.; MJ Property Co., a New York-based investment and development firm; and the principals of International Conference Resorts, an Arizona-based firm with experience managing executive conference centers.

In other developments in commercial realty: Federal Home Loan Mortgage Corp. leased 123,912 square feet at Point West Plaza, 8609 Westwood Center Dr., Vienna, from J.A. Loveless Co. Leggatt McCall/Grubb & Ellis Inc. was the leasing agent.

Kaye, Scholer, Fierman, Hays & Handler, a law firm, leased 41,154 square feet at McPherson Building, 901 15th St. NW, from McPherson Building Joint Venture. Coldwell Banker represented Kaye, and Leggatt McCall represented McPherson.

EER Systems Inc., a NASA contractor, leased 50,079 square feet at Greentec 3, Aerospace Rd., Greenbelt, from The Shapiro Companies. Long & Foster was the leasing agent.