Fouling Factor
A fouling factor is an added thermal resistance applied in heat-exchanger design to account for deposits — scale, sludge, biofilm — that build up on heat-transfer surfaces over time. It de-rates the clean performance to a realistic in-service value.
No heat exchanger stays clean in service; layers of mineral scale, corrosion products, dirt or biological growth insulate the surface and cut heat transfer. Designers include a fouling factor — an extra resistance term in the overall heat-transfer coefficient — so the exchanger is sized with enough surface to still meet duty when dirty. Tracking the rising fouling factor over time also signals when cleaning is due.
Related reading
Related terms
Heat Exchanger · Log Mean Temperature Difference (LMTD) · Cycles of Concentration