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Re: GBlist: Hospital & Lab Air Filtering



Carol D'Agostino wrote:
> 
> Does anyone know the names and contact info of any companies who
> install the high efficiency air filtering systems in hosptials
> and labs?  I would appreciate any input.
> 
> Also, what is the best filtering medium for PERC and/or TRICH.  A
> 
> Carol
> caroldag@liii.com
> __________________________________________________________________
> This greenbuilding dialogue is sponsored by Oikos (www.oikos.com)
> and Environmental Building News (www.ebuild.com). For instructions
> send e-mail to greenbuilding-request@crest.org.
> __________________________________________________________________

Most Hospital codes require 85% to 90% efficient final filters on air HVAC systems serving sensitive areas or 
where invasive procedures are conducted. This includes labs. I do not know the specific recomendations for the 
PERC and TRICH, but would first contact the hosptal epidemiologist. Filter vendor data is a good starting 
point for effectivness against specific infectious media.  The CDC probably has some recommedations, too.

However, HEPA filters are generally used for infectious disease control.  They are 99.+ efficient and remove 
most everthing, but not all.  HEPA filters should have 60% pre filters to prevent premature filter loading.

A few years ago I conducted an evaluation of portable filtering options for a northern New Hampshire community 
 hospital (read: low budget) who wished to deal with infectous multi drug resistant (MDR) TB patients. The 
purpose was to find alternatives to an expensive central air handler upgrade to accommadate two small MDR TB 
rooms.

All of the portable filtering devices (then on the market) were evaluated.  Of those, my recommendation to my 
client was a portable filtering device from a company called Natures' Quarters in Connecticut (do not have 
phone number avail).  This company offered a sturdy unit of heavy gage metal (look at the total unit wieght 
for clues), on wheels, a recirculating blower fitted with 30% filters, 60% filters then the HEPA filters.  
They were the only Mfr offering 60% pre filters.  In addition, they included a set of UV sterilization lights 
with the air flow parallel to the 4 foot UV lamps. Some competitors used UV, but the air had very little 
contact time through the UV light phase.  The effectivness of UV lighting for health care HVAC sterilization 
is an area of controversy, from what I have been able to determine. UV sterilization lights are not "common 
practice" for Hospital applications at this time, but I sense this is gradually changing.

Based on the above criteria, and the pricing which offered best value (about $3000 for 400+ cfm unit), Natures 
Quarters was recommended.  Note there are many other code required issues that go along with this, such as 
room pressure, humidifier locations relative the the filters, manometers,etc.

Consideration must be given to how the maintenance people will be protected when replacing filters. Sometimes 
a bag-in bag-out device is specified, but this can be expensive. The Hospital mentioned took the unit outside, 
on still days, and replaced filters there with personnel using HEPA type masks.

The units have performed well for the hospital.

Tom Anderson
__________________________________________________________________
This greenbuilding dialogue is sponsored by Oikos (www.oikos.com)
and Environmental Building News (www.ebuild.com). For instructions
send e-mail to greenbuilding-request@crest.org.
__________________________________________________________________


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