IR-Free Coupons can be used to determine the true polarized potential of a buried metallic structure without
having to interrupt all sources of current flowing in the soil that have an influence on the structure-to-soil potential.
As indicated in the 2004 NACE Standard (Recommended Practice) on “The Use of Coupons for Cathodic Protection Monitoring
Applications” [RP0104-2004], the size of a CP coupon should simulate the largest anticipated coating holiday size on the
buried structure occurring in the area of the coupon (the area under investigation). Also, the NACE Standard indicates
that the coupon material should be similar to the material of the structure under investigation. Finally, the Standard
indicates that coupons can be in ring, cylindrical, circular-plate, and rectangular-plate shapes.
M. C. Miller manufactures a variety of “standard” coupon designs for the cathodic protection industry and we also encourage
Regarding custom coupons, the following parameters should be specified to M. C. Miller: