After 12 years, Fairfax city and county are renegotiating the service contracts by which city services are handled. But the negotiations are proceeded behind closed doors because of what both sides call the inevitable city-county "adversary" relationship.

Talks on reworking the city's fire service contract are to begin soon, to be followed by discussions in order on seven remaining services: Solid waste, sewer services, court services and jail, and schools.

In each case, according to county spokesman Edmund Castillo, the talks are to be done on a staff level, in private, with their respective governing boards of supervisors. Only at the conclusion of all negotiations will an agreement be released and voted on.

Officials of both governments consider secrecy so crucial to the talks that even proposed dates for the meetings are not released until one is agreed to by both sides. Fairfax City Mayor Nathaniel Young warned that such releases would lead to "date battles" between the two adversary governments.

The county board of supervisors, after a meeting in executive session Monday, asked for another meeting with city council members before negotiations begin. Neither the reason for the request of a further meeting nor the details of related communications between city and county officials would be released.

Castillo said that city and county officials had communicated, but he would say how. "I'm not at liberty to discuss the matters of the negotiations. It's no different thatn if the city or the country were negotiating a contract for a supplier of goods," he said.

When negotiations begin, probably within a week, thecity's negotiator will be City Attorney John H. Rust Jr. Deputy County Executive J. Hamilton Lambert will handle the county negotiations on fire services, Robert Fitgerald, an attorney specially retained by the county, will handle the other service areas.

The plan established two weeks ago calls for the negotiators talking privately, then going back to their respective boards in executive session for instruction, all finally setting each service area alide as they reach agreement. Once all service areas have been discussed and resolved by the negotiators, their tentative agreement will go to the two boards for public debate and decision.

The city-county contracts deal with the cost and quality of public services, and not any private matters. But, say city and county officials, the negotiations must be held secretly.

"It's an adversary proceeding, under any circumstances," Young explained. "When you try to negotiate something, you are trying to get the best for your side. You don't tell the other side everything in negotiations."

Fairfax County Supervisor Martha V. Pennino called the procedures a matter of orderliness, shrewd negotiating, and an attempt to keep the negotiations out of politics.

"These are work sessions. These are not meetings where business is accomplished and decisions are made," she said. "If everything were being discussed and out in the open, you couldn't run it an orderly fashion. There's no attempt to keep the people from knowing what their negotiatings are nothing that the government is doing. It's an information gathering process."

Pennino agreed with Young that the negotiations were an adversary process: "If you put all your cards on the table, the other jurisdiction is going to try for the advantage over the other."

Finally, she called it "wise to keep it out of the political arena." She emphasized, "Negotiations deal with this in a very rational, impartial manner, without political considerations. It's a straight business deal between two governments. If you start doing this in public, it becomes a matter of what's popular andwhat isn't.

The two governments agreed on the major ground rules for the negotiations last month, and said then that they expected to complete that talks "by late fall." A Nov.15 target date has been set.

All existing city-county service agreements date back to 1965, shortly after the town of Fairfax became am independent city. The citywants to take over its own fire protection, while entering a mutual aid agreement with the county so that some areas on the fringe of the city are split between the two fire departments.

In all other contracts, the main issues for renegotiations will be service fees and whether the city should get credit for federal and state grants. The city and county school boards will enter discussions on the school contract, and they may bring up "some things other than strictly money," Young said.