Do quidelines exist that describe the chemical and bacterial quality of the water that is used for the prodution of steam in the steam sterilizer?

Griet Missant
Elisabeth ziekenhuis
Belgium

Dear Mrs. Missant,

Within the EN 285 you can find a table (EN 285 - 92, ANNEX B, feed water) which can be used as a tool to determine the chemical water quality which is recommended.

For the bacterial water quality it is a different story, as this depending of many circumstances in the feed water line but also in the environment of the feed water buffer tank. If the supply of the feed water to the buffer tank is well designed, the feed water bio burden will be very low or even not present.
The risk factor is the long storage of the water in a buffer tank where it is heated up by the environment in the technical area of the steriliser. This has often an ambient temperature up to 30 - 35°C. If there is regular refreshing of the water due to the daily routine processes the risk of getting a too high bacterial contamination is not presumable. Next to that many sterilisers do have degassing provisions to remove dissolved gasses from the feed water. This is normally achieved at temperatures 85 - 90°C which means that the risk for bacteria growth in the feed water tank is not likely. However if there is not such a feature in the feed water tank, you could drain your feed water tank over the weekend, to minimise the period of time that the water is standing still.
If you have any doubts over your own situation you could ask the microbiologist in your hospital to do a test trail to find out how the situation is in your steriliser feed water tank.

I hope this answer is satisfactory but if you have any questions, please do not hesitate to contact me directly.

Best Regards,

Henk Ras
Sanamij B.V. - Rotterdam

Website: www.sanamij.com

Hi.

A very good answer you can get by the HTM2010 and HTM2031 refering "Sterilization" and "Clean steam" in the British approach. Makes sense, easy to read, the best education literature I know.

Michael Meyer - QAM
Tuttnauer Co.

Dear Griet,

In the latest issue of "The ISSM Journal", Apr - Jun 2003 Vol.7 No.4 appeared 2 articles on RO water:
"Implications on using RO water in thermal washer-desinfectors" by Peter Hooper and "Practical Aspects of Reverse Osmosis Design for Sterile Services Applications" by Martyn Fisher.
Maybe these also can help you,

See you,
Wim