A militant coalition of teachers, firefighters and county government employes told the Fairfax County superivisors last night that the 8.5 percent raises proposed for them would result in "the largest loss to inflation which county employes have ever suffered in a single year."

Speakers for the coalition urged a 13.3 percent raise. That amount would only barely help county workers stay even with inflation, said Rick Nelson, president of the Fairfax County Federation of Teachers, which claims membership of about 500 of the county's 7,000 teachers.

The Board of Supervisors is unlikely, according to observers, to provide the money for the higher raises, but the speakers at last night's budget hearing before the supervisors were undaunted.

Nelson told a reporter after speaking that "we make a damn good case. We deserve more than that stupid 8.5 percent. They've got the money. . . . It's a question of where their priorities are."

The 8.5 percent pay raise was agreed on last fall by school officials and representatives of the Fairfax Education Association, which represents most county teachers. County officials subsequently adopted that figure for an across-the-board raise included in their proposed budget for all county workers.

Members of the group that spoke last night stressed workers' needs in the face of double-digit inflation, saying many can't afford to live in the affluent county.

Privately, they criticized the education association for agreeing to the 8.5 percent raise. "The FEA continues to care only about themselves," said Glenn Benarick, president of the Fairfax County Professional Firefighters, Local 2068.

FEA President Gerry Gripper countered by saying that "any public employes' group in this country had the right to" negotiate salaries. "The FEA was the only employe group to do so. Where were these other groups last spring?"