Steel Gauge Thickness Chart: How to Pick the Right One

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Summary:

• The steel gauge thickness chart is confusing because the higher the gauge, the lower the thickness. Also, the increments of thickness change are inconsistent from one gauge to the next.
• The origins of gauge measurement explain the reasoning behind the confusing aspects of gauge measurement.
• Understanding gauge thickness allows you to quickly determine if a storage or shipping container meets the necessary regulations. 

Most places measure using the metric system, some use inches and feet, but steel is measured with gauges. The gauge is a unique and confusing measurement because it does not have a dimensional measurement associated with it. It also goes backward, so a lower gauge is thicker than a higher gauge. 

Since there are rules for shipping and storing hazardous materials in steel containers, knowing what gauge is right for your needs is imperative. Learn how to read a steel gauge thickness chart to ensure you get the appropriate steel 55-gallon drums and other shipping and storage containers.

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The Origin of the Gauge Chart

Gauges originated as a measure of thickness when there was no universal measure of thickness available to the British wire producers who invented gauges. The origins of gauge measurement explain why thickness decreases as gauge increases. The explanation for why gauges do not change at a constant rate in thickness measurement or weight measurement is also found in the origin of the gauge chart.

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Inverse thickness to gauge explanation

In early wire production, measuring thickness was difficult due to the small sizes and imperfect measuring tools. Instead of quantifying thickness for the sale of their wire, producers sold wire by weight. They still needed an indication of wire diameter, so they created gauge numbers. 

One gauge represented one drawing of a wire. Every draw reduces the diameter of a wire. The more drawings, the larger the gauge and the smaller the diameter. This explains why large gauge numbers indicate thinner steel thickness.  

Inconsistent weight and thickness increments

As you move from one gauge to the next, the thickness and weight of the material change at inconsistent rates. For example, on the steel gauge chart, the difference in thickness from 4 gauge steel and 5 is .015 mm, while from 5 to 6, it is .0149 mm. At the high end of the gauge chart, the thickness differences get more pronounced between each consecutive gauge. 

This is because wire drawing had metallurgical limits that reduced the effectiveness of each consecutive draw. After a wire draw, the next wire draw cannot reduce the thickness to the same amount as the previous draw. Despite the inconsistent increments, the standardization method grew popular and has never been replaced.

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Picking the Right Gauge

The majority of steel products are between 16 and 24 gauges. In inches, that is .0635 inches thick to .0276 inches thick for galvanized steel. Carbon steel, stainless steel and aluminum steel have slightly different measurements because they are not the same weight, altering their gauge-to-thickness conversion. 

To follow the rules for steel thickness, you just need to know how gauges relate to each other and how to look up thickness on steel gauge charts.  

For instance, if you need flammable cabinets to store flammable liquids or solids, you need to understand the requirements. Adequate durability, measured in gauge rating, is a requirement for fire-resistant storage cabinets. Flammable cabinets must be made of at least 18 gauge steel. 

If you see a flammable cabinet online listed at 18 gauge or lower, you know it fulfills the requirements set forth by OSHA. 

Also, if you know how to read a gauge chart, you can check to ensure a steel cabinet is 18 gauge or under with just the thickness measurement. If the cabinet lists its galvanized steel thickness at .0516 inches (1.311 mm) or thicker, then when you check the gauge chart, you will see it meets OSHA requirements for 18 gauge steel. 

The key to knowing which gauge is right for you is knowing the OSHA, UN, ANSI and other regulatory groups’ requirements for specific material storage and shipping. Beyond steel thickness requirements, there are also hazmat placard labeling rules and many rules regarding what materials can be stored next to others. 

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Get the Right Gauge for Your Needs

Whether you need to ship hazardous materials across international lines or store flammable liquids, you must purchase the correct steel gauge. Once you understand the dated gauge measurement system, you just need to know the regulations for your materials. 

Contact Air Sea Containers to learn more about appropriate containers for specific materials or to purchase packaging for your shipment.