At least six of the 16 persons who died in fires in Fairfax County in 1983 "could have been saved by smoke detectors," Fire Chief Warren Isman said yesterday, announcing a new program that will supply detectors to some households free of charge.

The program, run by the Fairfax County fire department and 12 area Rotary clubs, will give away smoke detectors to low-income families, the elderly and handicapped.

According to county figures, 75 percent of homes with incomes over $25,000 have smoke detectors, but only 55 percent of homes with incomes below $25,000 have them.

The program, initiated by the Falls Church Rotary Club, has employed tax records to select 1,200 Fairfax families who might need smoke detectors, and last week letters were mailed to them offering the devices free.

Already, fire officials say, more than 200 families have sent back response forms saying they want the detectors.

Another 75 families declined the offer, saying they already had smoke detectors.

The Rotary clubs are paying the $8.50-per-unit cost of the smoke detectors, which will be distributed through the county's fire stations.

The only requirement imposed on those receiving the detectors, officials said, is that they come pick them up at the fire station closest to their homes.

The units come with the 9-volt batteries that operate them.

The county already requires new single-family homes to be equipped with smoke detectors. Beginning next March, all homes will be required to be equipped with smoke detectors when they are sold.

Isman said any family desiring a smoke detector and unable to afford one can get one by contacting the public affairs office of the county fire department at 691-4385.