The Federal Office Systems Expo is an office-equipment bazaar. The exposition, Tuesday through Thursday at the Sheraton Washington Hotel, will bring 150 exhibitors together to display wares to equipment users, especially bureaucrats. And the promoter claims it will draw 12,000 persons.

But FOSE is also a story about local business. The promoter is Robert Harrar, founder of Lanham, Md.-based National Trade Productions Inc., who started FOSE in 1977 to tap the indigenous office equipment market created by the federal government.

FOSE is now the mainstay of NTP. According to 31-year-old Harrar, NTP puts on 10 other trade shows around the United States. Harrar said that in 1981, the company broke the million-dollar revenue mark for the first time, taking in $1.3 million.

This year, Harrar said, he has tripled his promotional spending to attract more exhibitors. The extra spending is an investment in his 1983 FOSE, when it will move to the new D.C. Convention Center.

"We tripled our promotion budget because in the convention center, we're going to have triple the space," Harrar said.

As a trade show, FOSE is not targeted to the general public. It is a nuts-and-bolts show of word processors, telephone exchanges, microfiche filing systems and office furniture. It is also office services. Muzak, for example is one of the regulars at the show.

FOSE '82 boasts some big-name exhibitors. Among others, there will be IBM, Kodak, 3M, Bell & Howell, AT&T, Xerox and Exxon.

Although the government market inspired the show, NTP has found that the many private associations and large companies that are moving into Washington have become an important part of his--and the exhibitors'--audience.

In 1981, according to a survey conducted by Exhibit Surveys Inc. of Middletown, N.J., 53 percent of the people who came to FOSE were not government workers.

"We were starting to have an identity crisis," Harrar recalled. "Were we federal, or were we commercial, or were we both?"

This year, Harrar says he is playing down the word "federal" in promotions. The government's presence "was very important to exhibitors, and we couldn't drop that," Harrar said. So NTP is trying to integrate the federal and commercial.

In tandem with the exposition, a three-day conference called "The Technology Connection" is being conducted by the graduate school of the Department of Agriculture and the six federal office management councils, which exchange information on equipment and productivity.

As part of the conference, Egils Milberg, director of the Office of Productivity, Technology and Innovation of the Department of Commerce, will give the keynote address on increasing productivity and on administration policies.

In addition, Rep. Stanley Lundine (D-N.Y.) will address the conference about the human side of productivity growth.

Registration is required for the conference, which costs $225 for government workers and $250 for others.

General admission to the exposition costs $5.