Appendix A: LMTD Correction Factors

TABLE A.1: Fouling Factors

Temperature of heating medium	? 240 F	240 400 F*
Temperature of water	?125 F	>125 F
Water	Water velocity, ft/s	Water velocity, ft/s
?3 ft	>3 ft	?3 ft	>3 ft
Sea water	0.0005	0.0005	0.001	0.001
Brackish water	0.002	0.001	0.003	0.002
Cooling tower and artificial spray pond
Treated makeup	0.001	0.001	0.002	0.002
Untreated	0.003	0.003	0.005	0.004
City or well water (such as Great Lakes)	0.001	0.001	0.002	0.002
Great Lakes	0.001	0.001	0.002	0.002
River water
Minimum	0.002	0.001	0.003	0.022
Mississippi	0.003	0.002	0.004	0.003
Delaware, Schuylkill	0.003	0.002	0.004	0.003
East River and New York Bay	0.003	0.002	0.004	0.003
Chicago sanitary canal	0.008	0.006	0.010	0.008
Muddy or silty	0.003	0.002	0.004	0.003
Hard (>15 gr/gal)	0.003	0.003	0.005	0.005
Engine jacket	0.001	0.001	0.001	0.001
Distilled	0.0005	0.0005	0.0005	0.0005
Treated boiler feedwater	0.001	0.0005	0.001	0.001
Boiler blowdown	0.002	0.002	0.002	0.002
* Ratings in the last two columns are based on a temperature of the heating medium of 240 to 400 F. If the heating medium temperature is over 400 F, and the cooling medium is known to scale, these ratings should be modified accordingly.

Petroleum Fractions
Oils (industrial)	Cracking units
Fuel oil Clean recirculating oil Machinery and transformer oils Quenching oil Vegetable oils Gases, vapors (industrial)	0.005 0.001 0.001 0.004 0.003	Gas oil feed <500 F ?500 F Naphtha feed: <500 F ?500 F	0.002 0.003 0.002 0.004
Coke-oven...

Petroleum Fractions

Oils (industrial)

Cracking units

Fuel oil

Clean recirculating oil

Machinery and transformer oils

Quenching oil

Vegetable oils

Gases, vapors (industrial)

0.005

0.001

0.004

0.003

Gas oil feed

<500 F

?500 F

Naphtha feed:

<500 F

?500 F

0.002

0.003

0.002

0.004

Coke-oven...

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