The Postal Service recently marked the third anniversary of its first fully-operational Flats Sequencing System (FSS) at the Dulles, VA, Processing and Distribution Center (P&DC) — a milestone in the way the Postal Service sorts flats.

Each FSS can sort mail in delivery point sequence (DPS) at a rate of 16,500 pieces an hour, or 280,500 pieces per day to more than 125,000 delivery addresses — allowing letter carriers to start delivering mail earlier in the day.

The first FSS arrived at the Dulles facility Nov. 30, 2007, and sorted flats for the Reston, VA, Carrier Annex — the first delivery office in the nation to receive its flat mail completely in DPS. Today the Dulles P&DC has four FSS machines, processing mail for 95 ZIP codes assigned to 51 delivery units.

“FSS processed 5.6 million pieces last week,” said Isaac Cronkite, Dulles P&DC acting senior plant manager. “The machines set records for weekend and monthly processing in November.”

FSS technology also has helped the Northern Virginia District reduce costs. The district has eliminated 150 letter carrier routes, reduced letter carriers’ base delivery time by more than 400,000 hours each year and lowered rural carriers’ delivery time by more than 75,000 hours annually. Reducing routes produced additional savings by making it possible to reassign long life vehicles to rural carrier routes.

“FSS has removed a significant number of workhours and we continue to see improvements weekly,” said Northern Virginia District Manager Michael Furey. “These savings will allow us to pay for the machines quickly.”

The Postal Service plans to have 100 FSS machines deployed and operational at 47 locations nationwide by the summer of 2011. Currently about 20 machines are fully operational at eight sites.