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steam quality [steem kwol-i-tee] (n): the measurable aspects of steam used for medical sterilization. Deviations from established processing ranges can result in wet, damaged, or unsterile loads.

Poor steam quality can cause:

Wet Packs and Wet Loads,

Damaged Goods,

Indicator Failures,

Unsterile Loads


Measurements made when there are no problems provide a baseline and assurance of proper conditions.

We measure:

·Steam Dryness


·Noncondensable gases

And we have the know-how to help you fix any problems found to ensure that the steam delivered to your load meets all established parameters needed for proper sterilization.

European Standards require annual steam quality testing; should your sterilization be any less certain? Contact us today to ensure your system is working properly.


Definitions of Steam Quality Parameters and Effects of Their Deviations from Accepted Values

Steam Dryness


The measure of the water content of steam deliverd to the sterilizer chamber.

Acceptable values are 0.9 or greater (<10% water) for non-metallic loads and 0.95 or greater (<5% water) for metallic loads.

Wet steam can cause an unsterile load in two ways:

· Insufficient energy delivered to the load to sterilize.

· “wet packs”, making the sterile barrier material surrounding the load less of a barrier and compromising sterility assurance.



A situation in which the temperature of the steam is higher than the saturation temperature for its actual water content. (The steam is too dry).

Acceptable values are less than 25oC of superheat in free expansion.

Superheat has two potential effects:

· Unsterile loads due to insufficient energy being delivered to the load, since the steam is too dry.

· Damage to the load if the superheat is generated causing the temperature reached by the load to be higher than its materials can withstand.

Non-condensable gases


A measure of air or other gases entrained in the steam. Expressed as a percentage by volume of gas in the steam.

Acceptable levels are less than 3.5% delivered to the chamber.

High non-condensable gas content can cause an unsterile load in two ways

· Insufficient energy delivered to the load to sterilize. Gases deliver substantially less heat energy than steam.

· Pockets of gas can form that provide “islands” of unsterility. Unless the indicator is in such an island, their presence will go undetected.