5 Pressure Mistakes That Cause Inflatable Seal Bursts
If your inflatable seals are bursting, here’s the truth: it’s usually not the seal.
It’s pressure management.
In pharma, semiconductors, isolators, and other high-precision environments, even a small pressure mistake can trigger downtime, failed validations, and expensive rework.
The good news?
Almost every burst happens because of five predictable and completely avoidable mistakes.
Let’s break them down and fix them.
1. Overinflation Beyond Design Limits
This is the #1 pressure mistake engineers make.
If a seal is rated for 100 psi and you inflate it to 110 psi, you overstretch the elastomer and reinforcement.
It’s like blowing up a balloon just a little too much.
Startup pressure spikes make this even worse and often lead to sudden burst failures.
How to avoid it:
- Follow manufacturer pressure ratings (don’t assume).
- Calibrate controllers regularly.
- Install relief valves so excess pressure vents automatically.
A single relief valve can prevent the majority of burst failures.
2. Inflating the Seal Without Groove Support
Inflating a seal outside its groove is like inflating a balloon in mid-air; it expands unevenly and tears.
A groove gives the seal structural support, helping it expand in a controlled way. Without it, internal pressure pushes outward uncontrollably, causing instant failure.
How to avoid it:
- Never test or inflate a seal outside the assembly.
- Use a machined mock-up groove that mirrors your actual installation.
No groove = no test. Non-negotiable.
3. Ignoring Pressure Spikes and Transients
Pressure spikes are silent killers.
They last only milliseconds, but that’s enough to overload a seal especially during valve closures, pump kicks, backflow events, or sudden flow changes.
Even if your average pressure looks safe, spikes can make seals brittle over time.
How to avoid it:
- Use pressure regulators to smooth spikes.
- Choose reinforced fabrics like Kevlar for high-stress applications.
- Conduct proactive inspections for early fatigue.
Always design for the spike, not the average.
4. Rapid Cycling Without Controls
Fast inflation–deflation cycles fatigue rubber the same way rapid bending fatigues metal.
Microcracks form.
Then they grow.
Then the seal bursts usually without any warning.
Dynamic equipment suffers the most because seals aren’t given time to stabilize between cycles.
How to avoid it:
- Add flow regulators so inflation takes 8–10 seconds.
- Reduce cycle frequency wherever possible.
- Use reinforced seals in repetitive-stress environments.
Slower inflation = dramatically longer seal life.
5. Wrong Material for Pressure, Temperature, or Media
Even the best design will fail if the material doesn’t match your application’s:
- Pressure
- Temperature
- Cleaning agents (steam, CIP, aggressive media)
Unreinforced seals often fail faster under high pressure or extreme temperature swings. Material mismatch is one of the most overlooked causes of seal failure.
How to avoid it:
- Use reinforced seals for high-pressure conditions.
- Match elastomer materials to your media and cleaning processes.
- Validate compatibility before production.
Choosing the right material = predictable, reliable performance.
In the End
Inflatable seals shouldn’t burst.
With proper pressure handling, they become silent, reliable performers helping you pass validations, avoid unexpected failures, and keep operations running smoothly.
If your application is high-pressure, unique, or mission-critical, Western Rubbers can help you spec the right seal design from day one.
We’ve seen every pressure mistake in the book and we know exactly how to prevent them.
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