Date of Award


Document Type


Degree Name

Master of Science


Department of Systems Engineering and Management

First Advisor

Willie F. Harper, Jr., PhD


This study examines the removal of perfluoroalkyl substances (PFAS) from legacy hangar fire suppression systems which utilized PFAS containing aqueous film forming foam (AFFF). Hundreds of these systems are currently in place throughout the Department of Defense, with planned phase-out occurring by 2024. The estimated cost of replacing these systems is $2.1 billion dollars. To mitigate this cost, a triple-rinse method of decontamination has been proposed. This thesis explores the release of PFAS from AFFF systems during a triple-rinse decontamination, and the continued removal of PFAS after a triple-rinse is complete while simultaneously analyzing methylene blue dye as a potential surrogate for PFAS removal from hangar systems. A triple rinse protocol consisting of either three 15-minute rinses, or one 15-minute rinse and two 24-hour rinses, does not completely remove PFAS contamination. Additionally, differences in PFAS removal behavior were observed between varying pipe types within the fire suppression system. There was no significant difference found between efficacy in removing PFAS removal between a 15-minute rinse and various rinse durations between up to 24-hours. Methylene blue dye was found to not be a suitable surrogate. Results indicate that the currently proposed method of a triple-rinse with water will not decontaminate AFFF hangar fire suppression systems.

AFIT Designator



A 12-month embargo was observed.

Approved for public release. Case number on file.