Metal Corrosion Rates
(Revised May 2024)

Just how long will that tank last sitting in a field? You can make an educated guess as the ISO 9223 standard has an equation that lets you figure out total damage to metals and metallic alloys exposed to outdoor environments; and it is:

D = A * TB

Where:

D: Penetration Depth of Total Damage
A: Damage experienced in First Year of Exposure
T: Exposure Time (Years)
B: Metal-Environment Time Exponent. There are two versions of B - B1 and B2. B1 is generated from regression analysis of flat panel long-term testing, while B2 is two standard deviations above B1 and is intended to be used for identifying an upper limit of corrosion damage.

NOTE: 1,000 μm = 1 mm

Carbon Steel
B1 = 0.523
B2 = 0.575

Zinc
B1 = 0.813
B2 = 0.873

Copper
B1 = 0.667
B2 = 0.726

Dry Indoors Location (C1)

<1.3 μm

<0.1 μm

<0.1 μm

Desert Location or Urban Area (non polluted) (C2)

1.3 to 25 μm
13.15 μm avg

0.1 – 0.7 μm
0.4 μm avg

0.1 – 0.6 μm
0.35 μm avg

Mild Marine/Mild Industrial Location (C3)

25-50 μm
37.5 μm avg

0.7 – 2.1 μm
1.4 μm avg

0.6 – 1.3 μm
0.95 μm avg

Marine Location (Calm Sea) (C4)

50-80 μm
65 μm avg

2.1 – 4.2 μm
3.15 μm avg

1.3 – 2.8 μm
2.05 μm avg

Marine Location (Beach Surf) (C5)

80-200 μm
140 μm avg

4.2 – 8.4 μm
8.3 avg

2.8 – 5.6 μm
4.2 μm avg

Ocean / Offshore (CX - Extreme)

200-700 μm
450 μm avg

8.4 – 25 μm
16.7 μm avg

5.6 – 10 μm
7.8 μm avg

Pre-Built Calculator


Metal/Environment Time Exponent (B)
Damage from First Year of Exposure (μm)
Exposure Time (years) (T)

Penetration Depth (D) (μm)
Penetration Depth (D) (mm)