Subject: Re: Electrostatic vs Electronic air cleaner in duct system

From: [email-masked] (Steve )
Date: Tue, 24 Oct 1995 00:22:22 GMT

[email-masked] (Matthew Klein) wrote:

>On 13 Oct 1995 20:27:16 -0700

>Whether he sells electronic air cleaners or not, he is absolutely
>right about the electrostatic filters not being as effective as the
>electronic.  Testing according to the ASHRAE dust spot test have shown
>that the electrostatics have an efficiency of less than 20% while the
>electronics have efficeincies greater than 70%.  If you don't believe
>these tests, which were performed by independent labs, then watch what
>happens with the crud buildup in your system over the next 10 years.
>BTW, I don't sell filters; but I am active on the ASHRAE technical
>committee that is concerned with filtration.
>Matthew Klein, PE
>Indoor Air Quality Solutions

The difference you inidicated Mathew is correct, however electronic
air cleaners (electrostatic two stage preciptitors) are tested with
(ASHRAE 52-76) the initial or average atmospheric dust spot
method,(this is the ONLY method used for EAC's) while electrostatics
are tested using the weight arrestance method (ie: how much weight can
they hold) (ASHRAE 52-76) , this not allowing for a true comparison.
EAC's can not be tested with the arrestance test.  An electrostatic in
field use will very seldom come close to the rated performance since
they require correct air veleocity and low humidity accorss the face
of the surface area to get the "static effect".

Steve Lewellen  ([email-masked])