As you see from the charts above, the output of galvanic systems follows an exponential decrease in current output similar to the 'half-life' principle, where the current is halved at constant periods of time. End-of-life performance is a critical criterion when designing and specifying a corrosion protection system, as it ensures the system will remain effective at mitigating corrosion for the entire duration.

Legacy GCP specifications tend to focus on the mass of zinc, but this is a gross oversimplification that overlooks other critical performance factors like:

• Service Life expectations

• Efficiency/Utilization Factor of the anode

• Minimum current density delivered over the anode service life - This minimum level is governed by the corrosion risk level of the existing concrete or its environment.

Verify the following information for a product before specifying:

1. The type of activation mechanism must be stated and demonstrated.
2. The distributed anode contains no intentionally added constituents corrosive to reinforcing steel or detrimental to concrete, e.g. chloride, bromide, sulfate, etc.
3. Initial startup current per anode per area at the specified average annual temperature of the structure.
4. Aging term - This is the number of years over which the electric current produced by the installed anode drops to half of the initial measured current.
5. Submittal of monitored performance data for two examples of satisfactory field performance where said aging term has been achieved. 
6. Efficiency and utilization as determined from site performance data of no less than seven years.
7. Anode spacing to achieve specified current density at specified service life
8. The initial mass of zinc and projected consumption over the life of the anode. 
9. Anode units contain zinc cast around (non-galvanized) steel tie wire.
10. Third-party product evaluation, such as from Concrete Innovations Appraisal Service, BBA, etc.
11. Using the information above, model how the alternative design will meet the minimum current density at the end of life of [enter service life here].

To help asset owners and engineers better identify their corrosion protection requirements, we have published sample performance-based specifications for various GCP systems on our technologies pages.

Simply head to the document section of our Galvashield XP, CC, Fusion or DAS technology pages and download our free word doc sample specifications to get started!