Engineering Reference

Heat Exchanger Fouling Factors Reference

Typical fouling resistance (Rd) values for common process fluids in shell-and-tube heat exchangers. Fouling resistances derate the clean U-value for preliminary sizing.

TypeEngineering reference — data table with context

Purpose

This reference provides typical fouling resistance (Rd) values for common process fluids in shell-and-tube heat exchangers. Fouling resistances are used to derate the clean overall heat transfer coefficient (U-value) to account for deposit buildup on heat transfer surfaces over time.

Caution

These are typical fouling resistances for preliminary sizing.

Actual fouling rates depend on operating conditions, water treatment, maintenance practices, fluid composition, and temperature. Project standards, vendor specifications, or client requirements override these generic values. Do not use this table as a final design basis.

How fouling affects the U-value

Fouling adds thermal resistance to the heat transfer surface. The relationship between clean and fouled U-values is:

Fouled U-value

1/U_dirty = 1/U_clean + Rd_hot + Rd_cold

Where Rd_hot and Rd_cold are the fouling resistances on the hot and cold sides respectively. If both sides foul, the total fouling resistance is the sum. This always reduces U below the clean value, meaning more area is required for the same duty.

Typical fouling resistances

Fluid	Rd (m²·K/W)	Rd (h·ft²·°F/BTU)	Source
Cooling water (treated, tower)	0.000176	0.001	TEMA 10th Ed., Table RGP-T2.4
Cooling water (untreated, river)	0.000352	0.002	TEMA 10th Ed., Table RGP-T2.4
Seawater (below 50 °C)	0.000088	0.0005	TEMA 10th Ed., Table RGP-T2.4
Seawater (above 50 °C)	0.000176	0.001	TEMA 10th Ed., Table RGP-T2.4
Boiler feedwater (treated)	0.000088	0.0005	TEMA 10th Ed., Table RGP-T2.4
Steam (clean, oil-free)	0.000088	0.0005	TEMA 10th Ed., Table RGP-T2.4
Light hydrocarbons (clean)	0.000176	0.001	TEMA 10th Ed., Table RGP-T2.4
Heavy hydrocarbons	0.000352	0.002	TEMA 10th Ed., Table RGP-T2.4
Fuel oil / residuum	0.000881	0.005	TEMA 10th Ed., Table RGP-T2.4
Vegetable oils	0.000528	0.003	Perry's 9th Ed., Table 11-10
Aqueous salt solutions	0.000352	0.002	TEMA 10th Ed., Table RGP-T2.4
Process air	0.000352	0.002	Coulson & Richardson Vol. 6
Natural gas (clean)	0.000176	0.001	TEMA 10th Ed., Table RGP-T2.4
Hydrogen (clean)	0.000088	0.0005	TEMA 10th Ed., Table RGP-T2.4

Values are per side. For a two-side calculation, add hot-side and cold-side fouling resistances.

Units

•SI: m²·K/W — square metre kelvin per watt
•Imperial: h·ft²·°F/BTU — hour square foot degree Fahrenheit per BTU
•Conversion: 1 m²·K/W = 5.678 h·ft²·°F/BTU

Assumptions

•Values assume typical industrial operating conditions and reasonable maintenance intervals.
•Water fouling values assume standard water treatment programs are in place.
•Hydrocarbon fouling values assume no coke formation or polymerisation.
•These are asymptotic fouling resistances, not initial or time-averaged values.

Boundaries and exclusions

•No slurry fouling — slurry services require specific project data.
•No scaling or crystallisation fouling from supersaturated solutions.
•No biological fouling factors — these depend heavily on biocide treatment.
•Plate heat exchanger fouling is typically lower than these shell-and-tube values due to higher shear rates.

How to use this in calculations

01Identify the hot-side and cold-side fluids from the table above.
02Sum the hot-side and cold-side Rd values for total fouling resistance. Or use the Fouling Factor Selector to estimate the fouled U-value directly.
03Apply to the clean U-value: 1/U_dirty = 1/U_clean + Rd_total. See Typical U-Values Reference.
04Use U_dirty in the area calculation: A = Q / (U_dirty × LMTD). Use the Heat Exchanger Area Calculator to compute the required area, and the LMTD Calculator for ΔTₘ.

Sources

•TEMA Standards, 10th Edition, Table RGP-T2.4 — Fouling Resistances
•Perry's Chemical Engineers' Handbook, 9th Edition, Table 11-10
•Coulson & Richardson's Chemical Engineering, Volume 6