light water

• lightwater
• light-water

light water (uncountable)

1. (inorganic chemistry) Water in its standard form of H₂O, containing two protium (¹H) hydrogen atoms, as opposed to heavy water (which contains deuterium, ²H). (Natural water contains some deuterium, but not much; so it can safely be called light water.)
2. Foam formed by water and a fluorocarbon surfactant, used in firefighting because it floats on flammable liquids lighter than water.
   • 2001, Roger C. Mardon, An Illustrated History of Fire Engines, →ISBN, page 112:

     The light water (AFFF) of the TACR was to be backed up by fluorinated protein foam instead of standard protein foam.

   • 2014, John R. Ridley, Safety at Work, →ISBN, page 504:

     These fires can be extinguished with water spray, alcohol-resistant foam, light water, vaporising liquids ("Halons"), carbon dioxide and dry powder.

   • 2015, Phil Hughes, Ed Ferrett, Introduction to Health and Safety at Work, →ISBN:

     They can be extinguished by carbon dioxide, dry powder, water spray, light water and vaporising liquid

(protium water):

• ¹H₂O
• protium water
• protium oxide
• diprotium oxide
• protium monoxide
• diprotium monoxide
• protiated water
• fully-protiated water

(protium water):

• H₂O
• water
• protiated water

(protium water):

• heavy water
• semi-heavy water
• super-heavy water

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