The antiquated and deteriorating fire alarm system at the Pentagon, repeatedly branded a potential danger to employes and property in the world's largest office building, is scheduled to be replaced this summer.

A spokesman for the General Services Administration, which operates the building, said last week that Congress has approved a $4.5 million overhaul of the 43-year-old alarm system, now considered a "top project" for GSA.

Although the Pentagon's fire alarm system does not comply with the federal fire safety code, GSA officials in the past have stressed that there is no imminent danger to life or property in the facility.

A design for the new system is expected to be completed in April, and a contract could be awarded in June, GSA spokesman Dale Bruce said.

The decision to pay for a new alarm system followed a 1983 GSA report urging "immediate action" to replace the current system. The report cited potential safety problems and noted that the system had become so obsolete that replacement parts are nearly impossible to get and must be custom-made at great expense.

The report was the fifth in 12 years to criticize the current alarm system, which consists of wall box alarms and pull handles.

Arlington County Fire Chief Thomas M. Hawkins said his department, which responds to Pentagon fires with the Army's Fort Myer fire department near the Pentagon, has been urging the GSA to replace the system for years.

Hawkins said the Pentagon needs both sprinklers and smoke detectors, as well as an improved internal communications system for firefighters to use when battling blazes there. Currently, Hawkins said, the firefighters have to use telephones to contact various floors or personnel in the building, which has 22,000 employes.

"We've been constantly on them and trying to convince them they should do certain things because of potential fire problems," he said, referring to what firefighters consider improper storage areas and insufficient fire-protection training for Pentagon personnel. "They need to bring that building, as much as possible, up to the modern-day fire code."

There are no official figures on fires at the Pentagon, but most have been small ones and involved no loss of lives.