This NACE standard test method describes a multiple-tube test heat exchanger that can be used by process industry facilities to monitor corrosion and fouling control in cooling tower water systems. Methods for collecting test data to determine average fouling factors and corrosion rates that can be used in predicting the expected service life of a plant exchanger are presented.

This standard was originally prepared in 1986 by NACE Task Group T-7A-10, a component of Unit Committee T-7A on Cooling Water, and was a revision of NACE Publication 5C165, "Standard Heat Exchanger for Cooling Water Tests." It was reaffirmed with editorial changes by T-7A in September 1988. This standard was revised in 1994 by NACE Task Group T-3T-4, a component of Unit Committee T-3T on On-Line Monitoring Technology. It was reaffirmed in 2001 by Specific Technology Group (STG) 11 on Water Treatment and is issued by NACE International under the auspices of STG 11.

1.1 Cooling tower water systems are critical elements in the operation of most process plants. Recirculation of the water used in cooling tower systems reduces fresh-water requirements and makes it economically feasible to adjust the water composition in order to control corrosion and fouling rates. The effectiveness of corrosion and fouling control programs in cooling water systems can be monitored by test heat exchangers mounted in a bypass. Conditions on heat transfer surfaces can then be determined at any time, without removing plant equipment from service.

1.2 The test unit described in this standard should be used whenever cooling tower systems are critical to the process. Data from the test unit can be used to: (a) predict service life of heat exchangers, (b) predict heat transfer coefficients, (c) determine fouling rate, (d) determine relative performance of various treatment programs,

(e) optimize costs of treatment programs, (f) minimize unplanned shutdowns resulting from fouling or corrosion, and (g) determine effect of alloy selection on fouling and corrosion rates.

Historical Document 2001