Head 08 : Pressure due to elevation of water. Equals 0.433 pounds per square inch (PSI) per foot of elevation. Back pressure. (Approximately 0.5 PSI is required to lift water 1 foot in elevation).
Air National Guard ANG website (and US Forest Service website), Glossary of wildfire terms, Except where noted, terms are taken from: Fireline Handbook 1998, National Wildfire Coordinating Group NWCG Handbook 3 (PMS 410-1), Glossary of Wildfire Terms (additional glossary Sites included on firefighting terms and firefighting equipment), Air National Guard, The Pentagon, USA 1998. http://en.wikipedia.org/wiki/Glossary_of_wildfire_ terms, (For Fr - Amer) {2}