How Long Does Galvanized Steel in Soil Last? 3 Influencing Factors
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When it comes to galvanized steel in soil, there are a lot of factors at work. Soil is not a uniform environment. Different compositions may cause corrosion rates to vary dramatically, so it’s critical that you understand the subtleties of how galvanized steel in soil works.
Despite the variations in soil, galvanized steel is still the best choice for use underground because the zinc coating provides superior rust protection.
At South Atlantic and Southern Grounding, we don’t rely on guesswork. We know the service life of galvanized steel in soil depends upon conditions and facts—all of which you need to consider for your next venture. In this blog, we’ll look at 3 influential factors and how they affect your project.
You can rest assured that you’ll be investing in quality: All of our ground rods are UL Certified/NEC Qualified. When you’re ready for a reliable quote without any surprise surcharges, we invite you to contact us to see how we have you covered.
What Factors Determine How Long Galvanized Steel Lasts in Soil?
We’ve already discussed how long the galvanized steel lasts depends upon the quality and composition of the soil. Three of the influential factors include:
- Soil chemistry
- Moisture and oxygen
- Zinc coating thickness
We’ll examine them further.
What Types of Soil Can Cause Galvanized Steel to Corrode Faster?
When considering how long galvanized steel lasts in soil, it’s vital to understand that corrosion requires moisture and ionic conductivity. Therefore, the soil chemistry heavily influences the rate of corrosion. This is why electrically conductive soils accelerate corrosion. These factors all interact; no one variable stands alone.
Depending on the factors in play, galvanized steel can last 10-20 years in the ground.
Soil that can cause galvanized steel to corrode faster:
- Acidic soils and low pH environments
- High chloride or sulfate content soils
- Organic-rich soils and microbial activity
- Soils contaminated by industrial or agricultural chemicals
- Why electrically conductive soils accelerate corrosion
The Influence of Moisture Levels and Drainage Conditions
Moisture-rich soil can accelerate the corrosion process. However, if the soil is well-drained, this can limit the corrosion rate. Fluctuating groundwater is another element that can increase the corrosion risk.
Other elements of influence include freeze-thaw cycles that affect soil density and moisture movement.
How Does Zinc Coating Thickness Affect Galvanized Steel in Soil?
As we’ve mentioned earlier, galvanization is the most effective and economical way to provide long-lasting rust protection in even the harshest environments. It’s why it is the natural choice for a wide array of ventures, from DOT projects to art installations.
A thicker zinc coating equals a longer service life.
When installing, remember that it’s vital to ensure that there’s no mechanical damage that can reduce the protection. Improper handling can shorten the lifespan before service even begins.
What Is the Expected Lifespan of Galvanized Steel in Different Soil Types?
Most galvanized steel is covered with 3.9 to 5 mils of zinc. At this thickness, it will last between 35 and 50 years in the most aggressive soils. In less aggressive soils, it could last for 75 years or more.
If you’d like more information, the American Galvanizers Association (AGA) has compiled detailed corrosion data and service life estimates for hot-dip galvanized steel in soil. It can be found on the AGA website.
Are There Ways to Limit Corrosion of Galvanized Steel in Soil?
Yes, there are several ways in which you can limit the corrosion of galvanized steel when it is placed in soil. These include:
- Ensuring you select the right zinc thickness for the soil
- Using barrier coatings
- Making drainage improvements around the buried steel
- Using design strategies to reduce moisture retention
What Are Some Applications Where Galvanized Steel Performs Well in Soil
Some examples of when galvanized steel performs well in soil include:
- Fencing, such as sign posts
- Guardrails
- Utility supports
- Foundations
- Anchors
- Agricultural uses
South Atlantic: Let Us Give You Peace of Mind With Quality Galvanized Steel for Your Next Project
Quality is critical to everything we do at South Atlantic; but it’s not our sole focus. We are also carefully attuned to the needs of our clients. We treat you as individuals because we know no two projects are alike.
With easy ordering and quick service, you won’t have to worry about missing critical deadlines. Contact us for a no-hassle quote and discover the many ways we’ve got you covered.
Key Takeaways
- Soil conditions vary widely, and those differences have a significant impact on how galvanized steel performs underground.
- Despite soil variability, galvanized steel remains one of the most reliable and economical choices for corrosion protection in soil.
- The service life of galvanized steel in soil depends primarily on soil chemistry, moisture and oxygen availability, and zinc coating thickness.
- Electrically conductive soils, including acidic, chloride-rich, sulfate-rich, and contaminated soils, accelerate corrosion.
- Moisture levels, drainage quality, groundwater fluctuations, and freeze-thaw cycles all influence corrosion rates in buried steel.
- Thicker zinc coatings provide longer service life and greater protection in aggressive soil environments.
- Mechanical damage during installation can significantly reduce the lifespan of galvanized steel before service begins.
- Galvanized steel with a 3.9 to 5 mil zinc coating can last 35 to 50 years in aggressive soils and 75 years or more in less corrosive soils.
- Corrosion rates can be reduced through proper zinc thickness selection, improved drainage, barrier coatings, and thoughtful design.
- Galvanized steel performs well in soil for applications such as fencing, guardrails, utility supports, foundations, anchors, and agricultural uses.
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Sources:
American Galvanizers Association, “Performance of Galvanized Steel in Different Environments,” https://galvanizeit.org/knowledgebase/article/performance-of-galvanized-steel-in-different-environments#:~:text=There%20are%20critical%20limits%20for,in%20soil%20(Figure%202).
American Galvanizers Association, “How Long Does HDG Last in Soil?” https://galvanizeit.org/hot-dip-galvanizing/how-long-does-hdg-last/in-soil
American Galvanizers Association, “Estimating Galvanized Steels Service Life in Soil,” https://galvanizeit.org/knowledgebase/article/estimating-galvanized-steel-s-service-life-in-soil
Galvanizers Association of Australia, “ Hot-Dip Galvanized Steel Embedded in Soil,” https://www.galserv.com.au/wp-content/uploads/2023/04/AN-42.2-Hot-dip-galvanized-steel-embedded-in-soil.pdf
