Anode Calculation - Caisson.xlsx

1 Description Equipment OD = 1985 mm H= 9000 mm Splash zone Area [3.5 m to -1.00m] Elevation between [-1.00 m -to -4.50 m]

2 Design Parameter 2.1 Cathodic protection criteria : 2.2 Type of CP : 2.3 Design life time (L) : 2.4 Calculation allowance (SF) : 2.5 Resistivity Sea Water (r) :

1.985 m 9m 46.14 m2 34.51 m2

-1.05 volt vs Ag/AgCl Sacrificial anode 25 years 10% 20 ohm.cm

2.6 Current Density (i) : Sea Water :

Initial : 0.150 A/m2 * Refer to DNV RP B401 (2005) Tabel 10-1 and T Mean : 0.070 A/m2 Final : 0.100 A/m2 2.7 Estimate Coating Breakdown (fc) Depth 3.5 to -1m -1 to -4.5 m Initial : 5% 100% Mean : 30% 100% Final : 55% 100% 2.8 Sacrificial Anode Material : Alumunium Alloy (Al-ln-Zn) Anode 2.9 Aluminium Anode Data Element Content (%) Zinc (Zn) 3.0 - 5.0 Indium (In) 0.01 - 0.02 Silicon (Si) 0.5 max Iron (Fe) 0.12 max Size : 900 (L) x 150 (W) x 150 mm (T) A= 135000 mm2 Weight (Wa) : 53.7 kgs (nett) 0.135 m2

CALCULATION 1 Area to be protected Splash zone Area [3.5 m to -1.00m] Elevation between [-1.00 m -to -4.50 m]

46.14 m2 34.51 m2

2 Current Requirement Ic = Ac x ic x fc (Amp) 3.5 to -1m -1 to -4.5 m Total Initial 0.34605 5.1765 5.52255 Mean 0.96894 2.4157 3.38464 Final 2.5377 3.451 5.9887

3 Weight of anode *mean condition W= Ic x L x 8760 305.035457 kgs uxc 4 Number of Anode (By Weight Calculation) N= W/Wa 5.680362324 →

* u and c refer to DNV RP B401 (2005) tabel 10-

6 Anodes

Anode Utilization Factor (u

Anode current capacity/ El

401 (2005) Tabel 10-1 and Tabel 10-2

NV RP B401 (2005) tabel 10-8 and 10-6

Anode Utilization Factor (u)

Anode current capacity/ Electrochemical Capacity (e)