The wide commercial acceptance of valve-regulated lead/acid batteries for stand-by power applications over the last decade
has involved the use of a novel separator material that is based on glass microfibre. The fibre material's exceptionally small
diameter (0.5-1 p~m), high porosity (95%), zero contact angle, high anisotropy and good compressibility makes it significantly
different from conventional flooded separators and, therefore, worthy of detailed study. Nevertheless, very little has been
published on the mechanisms by which the electrolyte is retained and the oxygen transported within these nearly saturated
recombination systems. This paper reviews critically some of the present methods for characterizing the glass-microfibre materials
and suggests improved testing methods that reflect more accurately the subsequent effects on battery performance.