Technical Aids

Useful resources and reference materials for cathodic protection and corrosion control

Cathodic Protection

The corrosion of underground structures is caused by a direct current flowing from one metal surface to another through electrolyte in the adjacent soil. The metal surface discharging the current dissolves metal particles to cause deterioration of the structure. Cathodic protection is a means of stopping the discharge of direct current from the structure or negative (cathodic) metal, by countering with another current from a positive (anodic) metal. This is accomplished by installing anodes in electrical contact with the structure.

  • Anodes:
    • Galvanic (Sacrificial) – Magnesium, Zinc, and Aluminum
    • Impressed Current – High Silicon Cast Iron, Mixed Metal Oxide, Graphite, Platinum
  • Rectifier:
    • Air Cooled, Oil Cooled, Custom
  • Cable/Wire, Connectors, Wire Splice Kits, & Fittings
  • Test Stations, Reference Electrodes, & Testing Equipment

Coatings & Wraps

Stuart Steel offers a wide range of coatings, wraps, and application equipment for corrosion control. These products include: epoxies, hot-applied tar coatings, heat-shrinkable sleeves, cold-applied tapes, mastics, petrolatum and Stuart Rock Stop™. The Stuart Wrapster™, a pipe-wrapping machine developed in 1968, is specifically designed for applying Stuart Super Wrap and other hot or cold-applied plasticized tapes.

Electrical Isolation

Stuart Steel isolation products include dielectric unions and flange insulation kits with gaskets, sleeves and washers. We offer a variety of products to seal and separate the carrier pipe from the casing. They include Stuart Casing Seal Kits, rubber link seals, spacers and casing fillers. tape, transition fittings, couplings and tools associated with corrosion control.

Instruments & Accessories

Electrical metering and instrumentation products include potential meters, reference cells, soil resistance instruments, holiday detectors, pipe locators, and other field monitoring devices.

Stuart Steel Accessories include pipeline pigs for internal cleaning, pipeline marking tape, transition fittings, couplings and tools associated with corrosion control.

Electromotive Force Series

Anodic End Electrode Reaction Standard Electrode
Potential, E (Volts), 25 °C
Magnesium Mg2+ + 2e -2.34
Aluminum Al3+ + 3e -1.67
Zinc Zn3+ + 2e -0.076 *

* Anodic, base or electronegative

Cable and Wire Chart

AWG Diameter in Inches Circular Mills Cross Sectional Area in Sq. Inches LB/1000 Ft.
Copper Aluminum
0000 0.46 211600 0.1662 640.5 194.7
000 0.4096 167800 0.1318 507.8 154.4
00 0.3648 133100 0.1045 402.8 122.4
0 0.3249 105600 0.08291 319.5 97.13
1 0.2893 83690 0.06573 253.3 77
2 0.2576 66360 0.05212 200.9 61.07
3 0.2294 52620 0.04133 159.3 48.43
4 0.2043 41740 0.03278 126.3 38.39
5 0.1819 33090 0.02599 100.2 30.46
6 0.162 26240 0.02061 79.4 24.15
7 0.1443 20820 0.01635 63 19.16
8 0.1285 16510 0.01297 49 15.19
9 0.1144 13090 0.01028 39.6 12.04
10 0.1019 10380 0.00816 31.4 9.55
11 0.0907 8230 0.00646 24.9 7.57
12 0.0808 6530 0.00513 19.8 6.02
13 0.072 5180 0.00407 15.7 4.77
14 0.0641 4110 0.00323 12.4

Resistance and Output Currents of Sacrificial Anodes

Nominal Weight (lb) Anode Package Size (in) Soil Restistivity (ohms) Anode Resistance (ohms) Current output and est. life for structure Potential (volts):
0.3 (mA) (yrs) 0.5 (mA) (yrs) 0.85 (mA) (yrs)
Standard magnesium – AZ63 (Hi alloy) – solution potetial – 1.55 V
17 22×7 5000 23 54 19 46 21 30 33
10000 46 27 37 23 15
20000 92 14 11 8
32 26×8.5 20000 7.7 162 12 136 15 91 22
5000 19 66 30 55 36 37
10000 38 33 60 28 18
50 22×10 2000 7.1 176 17 147 20 98 31
5000 18 69 43 58 39
10000 36 35 29 19
High – potential magnesium – solution potential – 1.73 V
17 38×6 5000 19 75 13 65 15 46 22
10000 39 37 32 31 23 23 43
20000 18 16 11
48 34×8 2000 7.2 199

Pipe Coverage Data Sheet

Nominal Size
(Inches)
Actual Pipe (Inches) Pipe Surface Square Feet (1000 ft.) Tape Width (Inches) Minimum Tape Overlap (Inches) Tape Required for 1000 Lineal Ft. Pipe (Squares)
0.5 0.84 220 2 0.25 2.52
0.75 1.05 275 2 0.25 3.14
1 1.315 344 2 0.25 3.94
1.25 1.66 435 2 0.25 4.98
1.5 1.9 497 2 0.25 5.68
2 2.375 622 4 0.375 6.87
2.5 2.875 753 4 0.375 8.31
3 3.5 916 4 0.375 10.1
3.5 4 1047 4 0.375 11.6
4 4.5 1178 6 0.5 12.9
4.5 5 1309 6 0.5 14.3
5 5.563 1456 6 0.5 15.9
6 6.625 1734 6 0.5 19
8 8.625 2258 9 0.5 24
10 10.75 2814 9 0.5 29.8
12 12.75 3338 9 0.5 35.6
14 14 3665 12 0.75 39.1
16 16 4189 12 0.75 44.7
18 18 4713 18 1 50
20 20 5236 18 1 55.5
22 22 5760 18 1 61
24 24 6283 18 1 66.5
26 26 6807 18 1 72.1
28 28 7330 18 1 77.6
30 30 7854 18 1 83.2
32 32 8378 18 1 88.7
34 34 8901 18 1 94.3
36 36 9425 18 1 99.8
42 42 10990 18 1 116.4
48 48 12560 18 1 133
54 54 14139 18 1 149.7
60 60 15710 18 1 166.3

Bolts

Nom Dia Flange OD Flange Thickness Dia. B.C. Bolt Hole Dia. Bold Dia. No. of Bolts Length of Bolt Thread Length
6 11 1 9.5 0.875 0.75 8 4 1.75
8 13.5 1.125 11.75 0.875 0.75 8 4 1.75
12 19 1.25 17 1 0.875 12 4.5 2
16 23.5 1.4375 21.25 1.125 1 16 5 2.25
20 27.5 1.6875 25 1.25 1.125 20 5.5 2.5
24 32 1.875 29.5 1.375 1.25 20 6 2.75
30 38.75 2.125 36 1.375 1.25 28 6.5 3
36 46 2.375 42.75 1.625 1.5 32 7.5 3.5
48 59.5 2.75 56 1.625 1.5 44 8 3.5
60 73 3.125 69.25 1.875 1.75 52 9 4
66 80 3.375 76 1.875 1.75 52 9.5 4
72 86.5 3.5 82.5 1.875 1.75 60 10 4

A Galvanic Series of Certain Metals and Alloys Arranged In Order of Corrosivity

ANODIC (Least Noble) End Material
Magnesium
Magnesium alloys
Zinc
Aluminum 25
Cadmium
Aluminum 17ST
Steel or iron
Cast iron
Chromium-iron (active)
Ni-Resist
18-8 Chromium-nickel-iron (active)
18-8-3 Chromium-nickel-molybdenum-iron (active)
Lead-tin solders
Lead
Tin
Nickel (active)
Inconel (active)
Hastelloy C (active)
Brasses
Copper
Bronzes
Copper-nickel alloys
Monel
Silver Solder
Nickel (passive)
Inconel (passive)
Chromium-iron (passive)
18-8 Chromium-nickel iron (passive)
18-8-3 Chromium-nickel-molybdenum-iron (passive)
Hastelloy C (passive)
Silver
Carbon and graphite
Platinum
Gold
CATHODIC (Most Noble)

Electrochemical
Equivalent of Metals

Material Theoretical Pounds of Metal Removed Per Ampere Year
Magnesium 8.76
Aluminum 6.47
Zinc 23.5
Chromium 12.5
Iron 20.1
Cadmium 40.5
Cobalt 21.2
Nickel 21.1
Tin 42.7
Lead 74.2
Copper (Cu2+) 22.8
Copper (Cu+) 45.7
Carbon (C+) 4.23
Carbon (C4+) 2.16

Supercoat Coating Coverage

Per US Gallon
Mils Sq. Ft.
2 802.1
3 534.7
4 401.0
5 320.8
6 267.4
7 229.2
8 200.5
9 178.2
10 160.4
12 133.7
14 114.6
16 100.3
18 89.1
20 80.2
22 72.9
24 66.8

100% solids, theoretical no wastage
Mils = 0.001 inch thickness

Diamond Rockstop Coverage Table

Coverage Information Stuart Diamond Rockstop
Pipe Diameter” 6 8 10 12 14 16 18 20 22 24 26 30 36 42 48
Rolls 500 sqft 4.7 6.3 7.9 9.4 11.0 12.6 14.1 15.7 17.3 18.8 20.4 23.6 28.3 33.0 37.7
© Stuart Steel Protection.
All Rights Reserved.
Terms of Use
Website by Asenka

Mailing Address:
P.O. Box 476
So. Bound Brook, NJ 08880
Email: info@stuartsteel.com
Phone: 732-469-5544
Fax: 732-469-9270

Warehouse Address:
New Jersey
411 Elizabeth Ave.
Somerset, NJ 08873

Tennessee
1005 Main Street
Humboldt, TN 38343