What is the current recommendation by instrument manufacturers for the quality of steam used for reprocessing? Is clean steam (generated by a steam generator using potable water) or pure steam (generated by a steam generator using deionized water) the standard now being recommended? Or is house steam (steam supplied by central boiler) still acceptable? If the recommendation is for clean or pure steam - why?

Hi Lucy
I think the AKI - Red brochure "Proper maintenance of Instruments" answers some of your questions. Among the members of the working Group of AKI are all important Instrument manufacturers of Germany.
You find the downloadable brochure either on our Education page under Periodicals or direct at www.a-k-i.org Click red brochure. On page 44 point 10.1 you find some information on Steam quality e.g. Table B1 the specified steam impurity tolerance. The European Standards for Steam Quality are EN285 and EN554.
I hope this is of some help.
Best regards
Josy

Hi.
"Dry saturated Steam" as defined is the appropriate steam that have many "+" as follow":

1. A small mass carry a big amount of energy.
2. It has excellent penetration property.
3. It is made of water. You find it everywhere, and cheap.
4. Easy to transfer, also long distance.
5. It does not carry any contaminant: no rust, no water droplets, no micro-organism. Nothing!

Dry saturated steam is clean steam. The ASME Code define "Clean steam" as "Dry saturated steam without any additives".

In other words: If your steam is supplied from a central plant room (normal steam boiler made of Carbon steel), and you take all the Good Practice means (seperator, correct pipe diameter, declination of the pipeline, steam traps, air vents etc.), there is no reasom to get poor quality steam.

Since poor steam is a carrier - it causes damage to Carbon steel, Stainless steel and other materials. To protect Carbon steel, we use Soft water. To protect Stainless steel, we use mineral free water.
On the other hand, "over-qualified" water may also cause damage.

Purity of steam is an output of purity of the used water: See how many "waters" are: potable water, public water, tap, treated water, soft, mineral free, clean, distilled, pure, wfi.

miki