NFPA. Abbreviation for the National Fire Protection
Nondestructive Testing. A method of inspecting materials
without cutting, drilling or otherwise destroying the
material; usually used to examine steel plates, pipes, and
Nozzle. A spout or connection, usually with a control valve
through which fuel is discharged into a receiving container.
National Pollutant Discharge Elimination System.
Octane Number. A numerical measure of the antiknock
properties of automotive gasoline as measured against standard
reference fuels, under controlled laboratory conditions. Iso-
octane is a reference fuel whose octane number is given a
value of 100.
Off-Spec. Commonly used contraction for off-specification,
usually referring to fuel which is contaminated or otherwise
deficient in quality.
Oil/water Separator. A device used to separate mixtures of
oil and water, usually by the difference in specific gravity
Oily-water Mixture. Mixture in which water comprises more
than half the total. Most such untreated mixtures contain
less than 15 percent oil, some of which may be in emulsified
Operation and maintenance support information.
Operating Storage Tank. Storage tank from which fuel is
issued directly to the final-use vehicle such as a ship or
aircraft, sometimes called day tanks or ready-issue tanks.