Are you over-spec’d? When to Choose High vs. Low Compression Set Foam
Not every application requires high-performance foam. Not every gasket needs to bounce back perfectly after months or years under compression. Yet, many engineers and buyers default to low compression set foams, assuming they’re always the safer choice. In reality, that can end up costing you more in the long run.
Compression set is just one performance property to consider when selecting a gasket material. If cost savings is a priority, a higher compression set foam may offer a better overall value without taking anything away from critical functionality.
Why pay more when you don’t have to?
In the following, we’ll dig into when a low compression set is essential for meeting standards and when it can be skipped for a more economical alternative.
What is compression set and why does it matter for gasket performance?
Compression set tells us how much a material permanently deforms under compression. Low compression set materials spring back close to their original shape when released from pressure. High compression set materials don’t fully recover. Instead, they may remain closer to their flattened state. In other words, they take a set. Low compression set can prevent gasket failure in certain applications.
To understand why a compression set matters, it helps to revisit the role of a gasket. A gasket joins two dissimilar materials, and it often creates the closest thing to a bonded seal without welding or permanent adhesion. A properly designed gasket can create a highly effective seal when matched to the right environment.
Compression set matters most when the material is sealing out moisture, sustaining pressure or subjected to repeated flexing (such as a gasket that’s opened and closed frequently).
But if the gasket is compressed and left in place, recovery may not matter at all.
Performance vs cost: Weighing the gasket options
Low compression set materials, such as high-performance urethane or silicone foams, are known for their resilience, but they come with premium pricing. When the application demands a higher level of recovery, the cost is justified. But in other cases, a higher compression set material, such as an open-cell polyurethane or neoprene blend, may deliver the performance you need but at a significantly lower price.
When is a low compression set essential?
Without question, in some applications there’s no good alternative to a low compression set material. There are times when the ability to recover to its original form is non-negotiable. Here are just a few:
Here are a few examples where low compression set is critical:
- Enclosures that open and close repeatedly
- Applications requiring tight, reliable sealing under a long-term load
- Exposure to high heat or harsh chemical environments
- EMI shielding applications where recovery ensures consistent performance
For a real-world example, read our case study, Identifying the Right Gasket Material to Restore Function to a Gas Detector.
If the material is compressed, released and recompressed throughout its life, or if a dependable seal is essential to performance and safety, then low compression materials are worth the higher cost.
When is a high compression set material good enough?
In many applications, a material can take a set and still function just as well. Consider these examples:
- Static gaskets that are compressed once and never reopened
- Vibration damping or spacing applications where shape retention isn’t critical
- Short-lifecycle products or components that are regularly serviced
In cases like these, a high compression set material may offer all the functionality you need—at a fraction of the cost.
Let us help you find the best fit
Not sure if you’re over-spec’d? Our team at SRP can help you compare materials, understand the performance tradeoffs and determine whether a lower-cost option fits the bill. You might be surprised at how much you can save without sacrificing the performance you need. Contact us for a customized review of your materials.