Unit Designators

As a result of the mutual-aid agreements in place in the metropolitan Washington D.C. area, a standard numbering system was put into place for area fire department. All units have a 3-digit designator, with the first digit denoting what agency the unit is from.

• 100 series Arlington County, Virginia (includes City of Falls Church)
• 200 series City of Alexandria, Virginia
• 300 series Metropolitan Washington Airport Authority (includes Reagan National Airport and Dulles International Airport)
• 400 series Fairfax County, Virginia (includes City of Fairfax, Town of Herndon, Town of Vienna, and Fort Belvoir)
• 500 series Prince William County, Virginia
• 600 series Loudoun County, Virginia
• 700 series Montgomery County, Maryland

Fairfax County uses 400 series designators. All units in Fairfax County start with a 4, (e.g. Engine 413), however when additional apparatus are in service, two units of the same type from the same station need to be identified separately. For example, at our fire station the front-line engine is designated Engine 413 and the volunteer engine, when staffed, is designated Engine 413-B.

One additional variance to the unit designators in Fairfax County occurs when volunteer ambulances are placed in service. A reserve ambulance that is completely or partially staffed by volunteers that are trained only as EMTs will be designated Ambulance 413-E.

Here are the unit designators for apparatus operating out of Fire Station 13:

Frontline Units
• Ambulance 413
• BC 402
• Engine 413

Reserve Units
• Ambulance 413-B or 413-E
• Engine 413-B
• Canteen 413
• Chief 413 or Utility 413

© 2008 Dunn Loring Volunteer Fire and Rescue Department. All rights reserved. Information presented is for informational purposes only. Dunn Loring Volunteer Fire and Rescue Department is a non-profit, 501(c)3 organization.