Corrosion coupons

Corrosion Coupons

For Evaluation of Existing or Potential Corrosion Problems



1. Keep the metal specimens in the special envelopes prior to installation.


2. Install the unit so that the specimen is always completely submerged and is parallel to the direction of water flow. Install the specimen through a Tee in the service line if possible (see Figure 1). If complete submergence is not possible in the service line, use the loop arrangement illustrated in Figure 3.


3 In the absence of specific recommendations for a special application, install the test unit where flow is continuous. Except when testing for a specific trouble area, avoid locations where extreme flow velocities are experienced. For example, avoid high flow areas such as immediately downstream of a steam trap or centrifugal pump discharge. Also avoid low flow areas such as condensate receivers, storage tanks, cooling tower sumps, etceteras.


4. Use only mounting screws supplied with each coupon. Use steel screws with steel coupons and brass screws with copper coupons.


5. Leave coupon in the system for at least 30 days. At the end of the test period, return the test coupon in the special envelope to GC³ Specialty Chemicals, Inc. for evaluation. Include the coupon identification number, test location, date installed, date removed, description of water treatment program, etceteras, when returning coupon.



Cut or trim a previously weighed coupon to fit into a pipe line.

Jam coupon against the inside wall of pipe.

Handle the coupon more than is necessary for installation and removal.

Use excessive amounts of pipe dope. Teflon tape is recommended for use on all pipe thread fittings.

Locate coupon where oils are likely to accumulate.