Corrosion Coupons – OVERVIEW
Corrosion coupons allow for “on-line” monitoring of the corrosivity within a water system. Accurate monitoring of corrosion rates is important for a variety of reasons, but perhaps the most important of these is for estimating the service life of process equipment for a specific installation in order to minimize downtime associated with unexpected equipment failure. By observing the mils-per-year corrosion rate of an exposed coupon in a system it is possible to estimate the life expectancy of components in a system that are made of the same material as the coupon being measured. Testing typically will last for at least one week, but it is most informative if testing is done at regular intervals over a period of time.
It is important to mount corrosion coupons so they are electrically isolated from other metals and so that there is very little movement (if any) as water flows over them. Care should be taken to ensure that mounting fixtures and hardware will not create additional corrosion and that they will not fail in the environment tested.The corrosion rate in a system is determined by calculating the amount of corrosion that occurs on the corrosion coupon during the time period that the coupon is installed in the system.
Following is the formula that is used for this calculation.
Corrosion Rate = (Coupon Weight Loss (g) x K) ÷ (Alloy Density (g/cm³) x Exposed Area x Exposure Time (hours))
For more information about Corrosion Coupons, please call or e-mail Aqua Clear. This is one of the many water treatment services that we offer and we would be happy to work with you to perform a corrosion evaluation of your water system.
Please click here to e-mail or call 858.270.7655 to schedule an on-site evaluation. We welcome the opportunty to discuss your water treatment and/or water purification needs.