This NACE standard describes a variety of devices used for on-line monitoring of fouling, corrosion, and other parameters in recirculating cooling tower water systems. Methods, are presented for collecting test data to determine fouling and corrosion rates that can be used for, but are not limited to, (1) predicting the expected service life of heat-exchange equipment, (2) optimizing the cooling system operation, (3) detecting operating problems and upset conditions, (4) monitoring corrective actions taken when such conditions occur, (5) assisting in problem solving, and (6) evaluating alternate chemical treatment programs. This standard is intended for the use of operators of open recirculating cooling water systems and those organizations that supply treatment materials and consulting services to them.

This standard was originally prepared in 1989 by NACE Task Group T-3T-1, a component of Unit Committee T-3T on On-Line Monitoring Technology, and revised in 1995 by T-3T-4. It was revised in 2002 by NACE Task Group (TG) 241 on On-Line Monitoring of Cooling Waters and Cooling Water Test Units. TG 241 is administered by Specific Technology Group (STG) 11 on Water Treatment. This standard is issued by NACE International under the auspices of STG 11.

1.1 The purpose of this standard is to describe technologies applicable to the on-line monitoring of cooling water systems. The standard focuses on those technologies that provide data on a short-term basis (minutes to hours) and provide output in a form that may be used by the operator to deal with changing conditions in real time.

1.2 For the purpose of this standard, an on-line monitor for a cooling water system is defined as a device, or combination of devices, that measures corrosion rates and determines changes in heat transfer coefficients (fouling factors) by measuring pertinent parameters under steady-state conditions that simulate critical conditions in an operating heat exchanger in a reliable and objective manner and with acceptable precision and accuracy. (Nomenclature and abbreviations used in this standard are defined in Appendix A.) Historical Document 2002