Speaking from experience, it's primarily due to 'tradition.' All of your combi-nozzles and rate control valves are rated and marked in GPM (Gallons per minute) and hose is purchased and stored as 50' sections. NFPA specifications for the hose required on a first due engine are in feet.
A department can't decide to use metric alone. The entire industry first would need to support at the minimum both standards.
A department can't decide to use metric alone. The entire industry first would need to support at the minimum both standards.