|
|
TEST METHOD: ASTM G-95:
|
Standard Test Method for Resistance to Cathodic Disbondment by the Attached Cell Method.
|
|
COATING SYSTEM:
|
PROTECTO 401 CERAMIC EPOXY Lining: Plant applied Protecto 401 Ceramic Epoxy lined ductile iron pipe (DIP) cut into 6
inch x 6 inch coupons.
|
|
PROCEDURE:
|
Following ASTM G-95, a five inch tall by four inch diameter section of PVC pipe, ground to the approximate curvature of the internal
surface of the pipe coupon, was attached via RTC silicone caulk. A 0.25 inch holiday was drilled through the coating to metal in
the center of each coupon. A 0.25 inch hole was drilled through one corner of each coupon and fitted with a bolt to provide
attachment of the negative lead from the impressed current cathodic protection power supply. Triplicate coupons were subjected
to simulated cathodic protection by impressing a 1.5 volt potential between the metal and an electrode within the CD cell for a
period of thirty days. The electrolyte used was 3% sodium chloride in tap water.
An additional set of coupons were subjected to the same test regime with the exception that they were maintained at 60øC on a
sand bath. The hot (60°C) cells were covered with plastic wrap to minimize evaporative losses. Evolved hydrogen was able to
escape through the plastic and did not present a problem.
|
The values given are in mm of disbondment increase in diameter from original RADIUS of holiday.
Panel Number:
154 (Room Temp.)
157 (Room Temp.)
156 (Room Temp.)
|
Increase in RADIUS:
0 mm
0 mm
0.5 mm
|
Panel Number:
* 155 hot (60°C)
* 158 hot (60°C)
159 hot (60°C)
|
Increase in RADIUS:
xx
xx
2 mm
|
* Over heated; suffered thermal damage after leaking dry over week end.
CERTIFIED
|
_________________
Dr. George Mills
|
|
|
