Hot-Dip Galvanized Steel Offers Superior Initial and Long-Term Economic Advantages

Sometimes thought to be more cost prohibitive, at least initially, than other corrosion protection solutions, the American Galvanizers Association (AGA) has conducted a cost case study wherein the initial and lifecycle costs of hot-dip galvanized steel were compared to other methods. Let’s take a look at the findings.

AGA Cost Case Study

The parameters:

  • Typical mix of steel shapes/sizes
  • 50,000 square foot short-span bridge
  • 75-year design life
  • Moderately Industrial (C3) Environment

Using the AGA Life-Cycle Cost Calculator, a quantitative analysis was conducted comparing hot-dip galvanizing to four paint systems, as well as a duplex system and metallizing with defined maintenance schedules.

Initial Cost:

Including materials (paint, metallizing, etc.), the number of coats, the surface prep cleaning method (painted systems: SP-10; duplex: SP-16/ASTM D6386; metallizing: standard near white metal), where the application was performed, and labor costs versus galvanizing’s all-inclusive price:

Coating System

$/ft2

Total

Hot-Dip Galvanizing

$1.76

$   88,000

Epoxy/Epoxy

$2.92

$ 146,150

Epoxy/Polyurethane

$3.35

$ 167,650

Inorganic Zinc/Epoxy

$3.17

$ 158,650

Inorganic Zinc/Epoxy/Polyurethane

$4.53

$ 226,300

Galvanizing/Epoxy/Polyurethane (Duplex)

$5.28

$ 263,950

Metallizing

$8.37

$ 418,550

These findings indicate that when all the costs are considered, galvanizing is often less expensive and at the very least, exceedingly competitive with other coating systems.

Life Cycle Cost:

Utilizing a practical maintenance cycle over the prescribed 75-year lifetime of the project based on Net Future Value (NFV) and Net Present Value (NPV) calculations at 3% inflation and 2% interest, and accounting for a very unlikely needed maintenance paint with an inorganic zinc at year 70 for the galvanized steel:

Coating System

$/ft2

Total

Hot-Dip Galvanizing

$ 4.29

$   214,500

Galvanizing/Epoxy/Polyurethane (Duplex)

$22.84

$1,142,000

Inorganic Zinc/Epoxy

$39.92

$1,996,000

Inorganic Zinc/Epoxy/Polyurethane

$41.53

$2,076,500

Epoxy/Epoxy

$51.91

$2,595,500

Epoxy/Polyurethane

$61.63

$3,031,500

Metallizing

$62.80

$3,140,000

Even with the one maintenance cycle near the end of the life of the project, hot-dip galvanizing was proven to have a significantly more economical lifecycle than that of the other coating systems.

Galvanized Steel Protects Your Investment

To maximize return on investment, it’s critical that buyers ensure the longevity of their purchase. Enhanced over 200 years, galvanizing is a process that best protects steel for long-lasting, corrosion-free performance. In fact, galvanized components can potentially last up to a century without the need for costly maintenance, delivering a significantly lower lifecycle cost, especially when compared to alternatives like stainless steel, aluminum, and epoxy coating. And research suggests that non-galvanized structures incur indirect costs as much as 11 times higher than those that utilize galvanized products. In an economy where steel prices are expected only to rise, buyers are wise to protect their investment and achieve cost savings by galvanizing.

GalvXtra Hot-Dip Galvanizing

AZZ’s GalvXtra four-step, hot-dip galvanizing process uses a proprietary formulation of molten metals to deliver consistent, high-quality zinc coatings on ferrous materials. At the preparation stage, steel arrives at AZZ’s galvanizing plant and is inspected to ensure that drainage and venting requirements are met. Then, the metal is cleaned by immersion in a hot alkali solution, acid pickled to remove rust or scale, and fluxed to eliminate surface oxides. Next, the steel is hot-dip galvanized—submerged in a bath of molten zinc to form a shield of zinc/iron intermetallic layers on all surfaces. Finally, the newly galvanized steel is cleaned, weighed, and carefully inspected with calibrated instrumentation to ensure quality standards.

Trust Your Steel to AZZ

AZZ performs hot-dip galvanizing for steel components used in a wide range of applications, including agriculture, bridge & highway, construction, electrical utility, industrial, original equipment manufacturers, petrochemical, recreational, and transportation. Backed by 60 years of experience in the materials industry, AZZ offers exceptional galvanizing service at over 40 locations across the U.S. and Canada. Click to learn more about protecting your steel investment.