Testing Compressed Air Lines – Medical Device Manufacturing

If you’re a medical device manufacturer, you need to clean the air systems that clean your components. Here is some advice.

Compressed air is used in many applications for medical device manufacturers. While they are generally used to eliminate contaminates, the compressed air system itself can harbor microorganisms. This can adversely affect the product, so it’s important to routinely test your air lines.

Things to consider when scheduling your periodic testing include:

  • Increases or decreases in production schedules
  • Changes in the seasons
  • Changes and modifications made to equipment
  • Any hardware or dryers/filters replaced
  • System inactivity

The actual test should use air impaction onto growth media by reducing the compressed air pressure using a built-in or external regulator. Then attach a flow meter, adjust the flow to a suitable rate, and attach the prepared Petri plate with the air impaction sampler.

Your test equipment will likely include a Slit Sampler, or slit-to-agar sampler. This puts the Petri plate on a rotating stage to impinge the organisms onto the agar. The plate is then incubated so the microorganisms can grow.

There are a few things to consider when developing a sampling plan:

  • A longer sampling time is appropriate when the air system is static
  • A shorter sample time is appropriate when the air system is in use
  • Broad spectrum, non-selective media will enable the growth of too many organisms and overwhelm the process
  • Selective media, on the other hand, can potentially limit overall growth, giving quantitative counts.

A broad-spectrum agar like Tryptic Soy Agar (AGA) is a recommended medium for the growth of non-fastidious organisms. If you’re trying to isolate a certain type of microorganism, you can use something like Subouraud Dextrose Agar, which cultivates fungi.

If you need cleanroom certification or validation, including a Validation Master Plan, contact Gerbig Engineering Company: 888-628-0056; info@gerbig.com.

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