<HTML dir=ltr><HEAD><TITLE>Re: rack power question</TITLE>
<META http-equiv=Content-Type content="text/html; charset=unicode">
<META content="MSHTML 6.00.2900.3268" name=GENERATOR></HEAD>
<BODY>
<DIV id=idOWAReplyText93141 dir=ltr>
<DIV dir=ltr><FONT face=Arial color=#000000 size=2>Paul,</FONT></DIV>
<DIV dir=ltr><FONT face=Arial size=2></FONT> </DIV>
<DIV dir=ltr><FONT face=Arial size=2>Using a multi-stage filter system with the large partical filters in front and an ionizing stage to remove smaller but still large enough particals to cause dust. Clean room filters would be an overkill.</FONT></DIV>
<DIV dir=ltr><FONT face=Arial size=2></FONT> </DIV>
<DIV dir=ltr><FONT face=Arial size=2>John (ISDN) Lee</FONT></DIV></DIV>
<DIV dir=ltr><BR>
<HR tabIndex=-1>
<FONT face=Tahoma size=2><B>From:</B> owner-nanog@merit.edu on behalf of Paul Vixie<BR><B>Sent:</B> Tue 3/25/2008 2:17 AM<BR><B>To:</B> nanog@merit.edu<BR><B>Subject:</B> Re: rack power question<BR></FONT><BR></DIV>
<DIV><BR>
<P><FONT size=2>this has been, to me, one of the most fascinating nanog threads in years.<BR><BR>at the moment my own datacenter problem is filtration. isc lives in a place<BR>where outside air is quite cool enough for server inlet seven or more months<BR>out of the year. we've also got quite high ceilings. a 2HP roof fan will<BR>move 10000 cubic feet per minute. we've got enough make-up air for that.<BR>but, the filters on the make-up air have to be cleaned several times a week,<BR>and at the moment that's a manual operation.<BR><BR>mechanical systems, by comparison, only push 20% make-up air, and the filters<BR>seem to last a month or more between maintainance events. i'm stuck with the<BR>same question that vexes the U S Army when they send the M1A1 into sandstorms,<BR>or that caused a lot of shutdowns in NYC in the days after 9/11: what kind of<BR>automation can i deploy that will precipitate the particulates so that air<BR>can move (for cooling) and so that air won't bring grit (which is conductive)?<BR>--<BR>Paul Vixie<BR></FONT></P></DIV></BODY></HTML>