If you’ve never given much thought to gasket compression (gasket what?), you likely have the mindset of “clamp ‘er in there the best you can”. While this mantra may work for you in certain scenarios, it is definitely not ideal. Achieving the proper gasket compression via the torque placed on the bolts is actually a well-engineered, tested and verified process done with a specific type of gasket material.
However, as we all know, things never stay the same. Sometimes the torque values aren’t followed like they should be, or sometimes a material gets replaced, and flange surfaces change throughout the repetitive heat cycles. When this happens, you have to trust the performance of your gasket material. In some cases, over-compression can happen, and that can lead to problems. What are some of the warning signs of a gasket that is or has ever been compressed beyond what is recommended?
Too Much Compression
1. Material splits or tears
Hopefully seeing this symptom will be a cause for concern for you even if you don’t understand the reason why it is happening. Before reading this blog, you may have always chalked it up to a bad gasket or bad gasket material. You may need to take a closer look at how much compression you are putting on your gasket, especially if it seems to be happening regularly.
Leaking gaskets are never a good thing. If this seems to happen more times than not, too much compression may be the culprit. Check that before scrapping your gaskets and trying something new.
3. Does not recover to it’s original configuration
A used gasket rarely looks as perfect as a new one, but it still should be recognizable. Permanent distortion suggests that a better quality product should be used to survive the conditions. To understand more about what should be expected with compression and recovery, check out our blog “What is Compressibility & Recovery, and Why Do I Care?”
How To Avoid This Issue
As you can see, gasket torque values and the actual compression of your gasket will have an effect on the performance of your application. If you are unable to verify the recommended torque values for the joint, talk to your trusted gasket material supplier. They should be able to (at a minimum) provide you with recommended flange loading and compression for a specific material and guidance in selecting a proper material for your application.
You may also find that you can no longer achieve a seal with the recommended torque values and your current gasket material. If compressibility is an issue, you may need to make a change in your gasket material. Again, your trusted gasket material supplier can guide you through this process.