What is Foam Tensile Strength?

How far can you stretch before you snap? Only you can answer that question — but when it comes to foam, we can answer that question.  Tensile strength is one of the most important features to look for when choosing the type of foam for your packaging. Here’s what it is and why it matters.

What is Foam Tensile Strength?

To put it simply, foam tensile strength is the measurement of foam’s ability to stretch before breaking. Tensile is just a fancy way of saying tension. So, tensile strength refers to how strong foam’s tension is.

However, note that there’s a similar measurement called tear strength that measures foam’s ability to resist tearing after damage.

Related Content: Tensile Strength vs Tear Strength for Foam Packaging

What Affects Tensile Strength?

Four of the biggest factors that determine foam tensile strength are:

• Density: Foam with higher density often has a higher tensile strength.
• Composition: Different materials and additives affect foam tension strength.
• Structure: Closed-cell foams generally have higher tension strengths than open-cell.
• Manufacturing Process: Curing conditions and treatments after processing determine tensile strength.

How is Foam Tensile Strength Measured?

Measuring foam tensile strength involves a universal testing machine, or tensile testing apparatus, and four simple steps:

1. A piece of foam is cut out.
2. Both ends of the foam are clamped in a testing machine.
3. The machine slowly pulls the foam apart until it breaks, tears, or is otherwise deformed.
4. The machine reports how much force it took to reach that point.

This number is noted on a foam spec sheet in terms of PSI - so the higher the PSI, the more resistant that type of foam is to tearing.

Related Content: 3 Key Takeaways from a Foam Spec Sheet

Why Does Tensile Strength Matter in Foam Packaging?

Foam tensile strength matters in foam packaging because it determines how well a material resists tearing, stretching, and other damages when tension is applied. Depending on your product, packaging, and shipping methods, a high tensile strength may be necessary to ensure no damage during transit.

Tear, Tensile, and Pick and Pluck Foam: CRUSHING IT Ep. 3

This video describes the difference between Tear Strength and Tensile Strength.  Pick and Pluck foam may have a high tensile strength, but the tear strength is very weak, especially when the walls get thin.  

How to Choose the Right Foam for Your Packaging Application

Get it right by working with a foam packaging expert. As a leader in the packaging industry, Foam Industries has set the bar with an unwavering commitment to quality, exceptional client service, and constant innovation. Through our extensive inventory of endlessly customizable products, we ensure you find exactly what you’re looking for.

Contact a Packaging Expert

Foam Industries is a custom protective packaging company specializing in foam – with additional wood and plastic fabrication services. Our custom foam fabrication services are ideal for any type of packaging, display, or support service needed – from design to finished product.