Steam Sterilization Cycles, Part 4: Rapid Cool Cycles

While not every research facility conducts the same research, most every research facility is interested in improving their overall efficiencies, which includes optimum throughput capacity when it comes to using their steam autoclaves. To help your facility achieve maximum return from your autoclave, we introduce the fourth article in CSS’ series about Steam Sterilization Cycles—part of an ongoing effort to help you leverage the appropriate cycle types for your unique applications.

In this article, we explore the Rapid Cool Cycles:

The Rapid Cool Cycles are important because by the end of most steam sterilization cycles, the temperature of your load is above 200°F (93.3° C). And as such, the autoclave operator must wear heat resistant gloves and other Personal Protection Equipment (PPE) in order to remove the load safely. Then, after the hot items are removed, the operator must wait for these items to cool down on the bench before they can be used.

But this wait time can be problematic and there are a myriad of reasons why you may want to cool the load in a manner that is quicker than traditional “bench top” cooling:

• To have safer handling of the load.
• To decrease the wait-time between when the items (e.g. utensils, liquids, glassware, etc.) are removed from the sterilizer and when they are safe to use for research experiments.
• To undergo rapid product life-cycle testing. In this particular scenario, commonly used in medical device (e.g. implants) material compatibility studies, the temperature of the load is required to continually cycle between sterilization (i.e. 250°F) and room temperature (say, 75°F) for extended periods of time as defined by the validation protocol. So, accelerating this cooling process can greatly shorten the total amount of validation time required to complete these studies—thereby increasing overall facility efficiencies.

Given this desire by many facilities to accelerate the cooling process (which is typically via convection to the surrounding air), steam sterilizers can be configured with convenient “Rapid Cool Cycles.”

There are two common types of Rapid Cool Cycles available: Spray and Jacket.

Rapid Spray-Cool Cycle

The Rapid Spray-Cool Cycle directly cools the load by spraying cold water on the items within the chamber at the end of the sterilization cycle. Rapid Spray-Cool is most applicable for customers with non-porous products or items that do not need to be dry when removed from the sterilizer. The cold water reduces the radiant heating effect on the product and cools it through convection. The appropriate quality of water should be used to maintain the integrity and sterility of the product.

Rapid Jacket-Cool Cycle

Unlike the Rapid Spray-Cool Cycle, this cycle does not directly cool the load with water. Instead, cold water circulates around the jacket of the sterilizer to reduce radiant heat and cool the load faster. Since the cold water remains in the jacket and never in contact with the load, it does not need to be sterile. This cycle is ideal for loads that cannot be wet when removed from the chamber or for items such as open glassware containers.

At CSS, we hope articles like this will help your lab increase its overall productivity, allowing you to create the most suitable sterilization cycles for any load type you run. So stay tuned—we’ll be regularly adding more articles. If there is anything you need to know in the meantime, please contact us with your questions—we have a team of sterilization experts waiting and prepared to help.