A term used to describe certain types of tightness tests conducted on underground tank-and-piping systems.
To qualify as a precision test a tightness test must take into account several variables, particularly product temperature at differing liquid depths and tank-end deflection.
The term, precision test, was originally used in Underground Leakage of Flammable and Combustible Liquids, NFPA 329, a publication of the National Fire Protection Association. In its current edition, however, the publication has dropped use of the term. Even so, some tank regulations continue to require that tank testing be accomplished through "precision test" methods.