Pressure decay filtering

1. What is pressure decay test?
2. What is the difference between bubble point and diffusion test?
3. What is the principle of filter integrity?
4. What is the purpose of filter integrity testing?

What is pressure decay test?

In simplest terms, the pressure decay test fills a pressure vessel with air until it reaches its target pressure, cuts the air source to isolate the pressure, and measures the decay (loss) of that pressure over a set period of time; any loss in pressure indicates a leak.

What is the difference between bubble point and diffusion test?

The bubble point test addresses the issues associated with the diffusion test. This test applies an increasing pressure of air on the upstream side of the filter while monitoring the flow rate of air that is diffusing through the saturated filter membrane.

What is the principle of filter integrity?

The gas diffusional flow rate for a filter is proportional to the differential pressure and the total surface area of the filter. At a pressure approximately 80% of the minimum bubble point, the gas which diffuses through the membrane is measured to determine a filter's integrity.

What is the purpose of filter integrity testing?

The goal of filtration integrity testing is to ensure performance and reduce risk. Manufacturers perform destructive tests to validate the claims of their filter's performance.