MC Miller's IR-Free Coupon Was Built to Your Exacting Specifications!

M.C. Miller listened to you to find out what corrosion and cathodic protection engineers want in a corrosion coupon. You said accuracy, precision, and reliability. You also said you wanted a corrosion coupon that was cost-effective to use.

In development for 10 years, M.C. Miller's IR-free corrosion coupon accurately measures the integrity of pipeline cathodic protection systems without the need to interrupt all current sources. This revolutionary device is designed for easy installation next to existing test stations. It also withstands harsh field environments and eliminates the effects of stray earth currents, producing accurate measurements every time.

Built for Accuracy . . . and Precision

Unlike other corrosion coupons, M.C. Miller's IR-free coupon is designed to evaluate cathodic protection systems without interrupting rectifiers, foreign bonds, or sacrificial anodes. The coupon consists of a bare, cold-rolled steel cylinder head and No. 12 stranded wires, which are inserted along side a 2-inch PVC tube. The PVC tube shields the reference electrode from potential gradients, resulting in accurate, precise cathodic protection measurements. These measurements also meet anticipated federal regulations and industry standards for considering IR drop in structure to soil potential readings.

Built to Last

Like all M.C. Miller products, our IR-free corrosion coupon is built to last. The wire - coupon interface is environmentally sealed to keep the steel, copper, and solder components corrosion free, making the coupon virtually indestructible.

Using an auger, bore a hole to the center of the pipeline, about 4 to 12 inches away from the pipeline. Then lower the coupon into the hole by its wires. Drop native soil in the hole until about 1-1/2 to 2 inches of soil is packed over the coupon, so that it will remain outside of the PVC tube.

Install the PVC tube 1-1/2 to 2 inches above the coupon with the wires outside the tube. Then fill the tube with native soil, which should be saturated with water thoroughly packed to remove excess air. Install the No. 12 green wires along the outside of the PVC tube and insert through a hole at the base of the adjacent test station. Drill a hole in the test station just below grade level to accommodate the wire. Then connect on of the green coupon wires to the structure test wire by direct connection or through a jumper bar at the test station box.

Easy to Use

After the coupon has polarized, insert a half-cell into the top of the PVC tube, contacting the compacted soil above the coupon. Connect an LC-4 selectable voltmeter to the green coupon wire and the half-cell.

An IR-free potential reading is obtained by breaking the connection between the coupon wire and the structure test wire, usually through the jumper bar, interrupting cathodic protection to the coupon. Take a potential measurement one to two seconds after breaking the coupon connection.

Coupon Specifications

• Surface area 1.34 sq. in.
• THHN No. 12 stranded wire
• Silver solder
• 3M potting compound
• Coupons can be customized to your specifications. Optional alloy and surface area designs are encouraged.