1. n. 
A test to measure static filtration behavior of water mud at ambient (room) temperature and 100-psi differential pressure, usually performed according to specifications set by API, using a static filter press. The filter medium is filter paper with 7.1 sq. in. filtering area. A half-size cell is sometimes used, in which case the filtrate volume is doubled.
See: filtercake, filter medium, filter press, filter-cake quality, filter-cake thickness, filtrate, filtrate tracer, filtrate volume, filtration, fluid-loss control, fluid-loss-control material, relative filtrate volume, spurt loss, static filtration