Steam Quality Testing

The physical tests for steam quality are a requirement of EN 285 – Steam sterilisers – Large Sterilisers and form part of the recommended test schedule to demonstrate the performance of autoclaves using saturated steam cycles (Porous Load Cycles).

Honeyman Validation designs and installs pure and clean steam systems, and conducts routine steam quality testing, third party systems included.

Steam Quality testing is described in PDA Technical Report Number 1, regarding steam sterilisation. The physical steam quality tests are strictly only applied to autoclaves, although many companies choose to perform the physical tests at other user points such as SIP systems, to get some quantifiable values for the system as a whole.

The three physical tests are as follows

Non Condensable Gas Test – limit ≤3.5%
Dryness Test limit ≥0.95
Superheat limit ≤ 25.0°C

Non condensable gases (NCG)

Non condensable gases are gases that cannot be liquefied by compression under the range of temperature and pressure used during the operating cycle. High levels of NCG’s in steam systems can prevent the attainment of sterilising conditions

Superheat

Super-heated steam is steam whose temperature at any given pressure, is higher than indicated by the vaporisation curve of water. Too little moisture in the steam will allow the steam to become super-heated during expansion.

Steam Dryness Value

Steam Dryness value is a dimensionless quantity, approximating to the dryness fraction, derived to determine whether steam is of the correct dryness for sterilisation purposes. A dryness value of 1.0 represents saturated steam. Excessive moisture in the steam can cause wet autoclave loads in steam sterilisers

To discuss your specific needs regarding steam quality testing and to find out how we can help you, please contact us with your details of your enquiry.