Water Separation Efficiency

Canonical Definition

The percentage of emulsified water removed from diesel fuel by a fuel filter/water separator element in a single pass under standardised test conditions, measured per ISO 16332. Test conditions specify A2 Fine test dust at a defined concentration, water injected as a fine dispersion at 0.5% by volume, and rated flow rate. ISO 16332 Grade A performance requires ≥95% water separation; Grade B requires ≥90%. Water separation efficiency is measured independently from particle filtration efficiency — a filter element with high particle Beta ratio may have poor water separation efficiency if it lacks a dedicated coalescing media stage.

Engineering Context

Water separation efficiency governs the residual water concentration achievable in fuel downstream of the filter assembly under rated operating conditions. For HPCR injection systems requiring low water content at the injector inlet in high-humidity or contaminated-fuel environments, the coalescing element must be rated for the required grade. HYDROCORE staged fuel-conditioning and separation is engineered around sequential mechanisms — coalescing droplets, gravity settling, and hydrophobic repulsion of residual fine droplets — matched to the approved application.

Applicable Standards

Protection Systems

Related Terms