Wet Packs Prevention Protocol

Keckler Medical occasionally hears feedback from end users regarding condensate issues (wet packs) following sterilization. A wet load required that the sterilized materials be rejected and re-sterilized. This, in turn, can cause surgery delays and lost revenue in Healthcare settings.

Wet packs are the most difficult and complex technical issue to resolve in steam sterilization because of the numerous potential causes of excess condensation.

When working to identify the source of the problem, the following troubleshooting protocol is used by JMK based on over 40 years of experience.
Check the most common suspect first – steam quality.

JMK’s experience, along with that of numerous other sterilization experts, has shown that poor steam quality accounts for >95% of all wet packs issues!

Steam Quality

The first thing that end users must evaluate is the quality of the steam supplied to the sterilizer. Poor quality steam is defined as less than 97% (greater than 3% water content by weight) and can lead to excessive condensate formation within the sterilizer.
Things to check and evaluate:
  • Determine if excessive demand is being placed on the in-house boiler. Excess demand can cause carryover of water into the steam supply system
  • Examine the steam supply system for potential areas of condensate formation such as dead legs or improperly trapped or insulated piping
  • If the sterilizer is not physically close to the boiler, condensate will form and will need to be removed from the piping before the steam reaches the sterilizer. This is accomplished by properly located steam traps and filters along the route of the steam piping
  • Insulating the steam piping will help rescue heat losses and in turn reduce condensate formation.
  • Check the jacket steam trap and check valve at the drain port to ensure they are functioning properly.
If it is positively determined that the steam supply is not the source of excess condensate, the next step is to evaluate what is being loaded into the sterilizer.

Load and Load Configuration

Another potential cause of wet packs is the load itself. Overly dense packing is frequently a cause of excessive condensation which cannot then be completely “flashed off’ by subsequent steam injections. Large quantities of hard-goods or complex packaging can prevent proper steam circulation. Proper load packing procedures are thoroughly described by AAMI and should be followed.
When steam enters the chamber and contacts the product, the steam will condense on the product when a portion of its heat energy (latent heat of condensation) is transferred to the load being sterilized.
The resulting condensate will fall to the chamber floor and be discharged through the drain system. Proper removal of the excess water is crucial to prevent insulating the load from the steam.