A few years ago MCAS Quantico upgraded the hangars and apron used by HMX-1 "NIghthawks".
The squadron that operates the helicopters designated as Marine One. Eric'sons construction division installed approximately 6000ft of slotted drains in the apron. Supplied over 2000ft of 20B24DIF frame and grate for the AFFF (Aqueous Fire Fighting Foam) fire suppression trench inside the hangar. The AFFF system is a series of trenches arranged in the hangar floor.
It utilizes a particular grated nozzle set at specific intervals in the trench drain runs.
This nozzle when activated sprays a fire suppressing foam under the aircraft putting out the fire.
The foam fire fighting material then drains thru the DuraTrench frame and grate and ultimately to underground storag