Hi,
We are still having problems to install MERV 6 filters upstream VRF evaporators cooling coils, due to the low pressure they can give and luck of enough space to place them.
What if we install some element to avoid the growing of mold and microorganisms in the coil fins?, this device would be feasible to meet the requirements of Standard 62.1?
thank you
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Andrew Mitchell, P.E.
PrincipalMitchell Gulledge Engineering, Inc.
LEEDuser Expert
126 thumbs up
April 3, 2012 - 5:15 pm
Paula, it is not uncommon to have filters of a higher MERV level upstream of all coils in any piece of HVAC equipment. Typically the industry minimum is a MERV-8 for commercial equipment. As for VRF units, they should all have a filter rack on the return as part of the unit design. The intent of paragraph 5.9 is to have air filtered upstream (before it hits the cooling coil) to prevent blockage and mold growth.
Paula Hernandez
MRS.PAH&A
85 thumbs up
April 4, 2012 - 6:59 am
Andrew, I thought this was the reason, and VRV units do have a filter rack, but a MERV 6 ot 8 are not part of the standard unit design, mostly because of it´s low presure capacity.
So, if I can avoid the groing of mold and microorganisms in the fin by some other device like a UV lamp, would it be ok as for Seccion 5.9?
Thank you
Andrew Mitchell, P.E.
PrincipalMitchell Gulledge Engineering, Inc.
LEEDuser Expert
126 thumbs up
April 10, 2012 - 9:30 am
Paula, if you do not provide a minimum of MERV 6 then you do not meet the requirements. It is that simple. Even if it was allowed, it is not good practice. See ASHRAE 62.1-2007 Users Manual; it states that Paragraph 5.9's purpose is also "to reduce the level of airborne particles that may be harmful to humans, such as airborne microorganisms and respirable particles." You cannot simply use your coil as a filter and install UV lights to kill everything caked on it.
Paula Hernandez
MRS.PAH&A
85 thumbs up
April 18, 2012 - 6:17 am
Thank you Andrew, we will try to install them,
Adam Noureddine
NEUCDecember 13, 2012 - 10:22 am
Hello Andrew,
I am working on a residential building oversees seeking LEED Silver (V3). To comply with IEQc.5 we are installing MERV 13 filters on all fresh air intakes. Would we still need to install MERV 6 filters on all fan coils to satisfy ASHRAE 62.1 - 5.9 and therefore IEQp1?
Andrew Mitchell, P.E.
PrincipalMitchell Gulledge Engineering, Inc.
LEEDuser Expert
126 thumbs up
December 13, 2012 - 2:47 pm
Adam, ASHRAE 62.1 Para. 5.9 only applies to coils that serve occupied spaces. In order to comply with IEQp1, all Fan Coils serving occupied spaces must be filtered with a minimum of MERV-6. In order to achieve IEQc5 they will need MERV-13 filters. This is only for occupied spaces. If not occupied then there is no requirement but filters are highly advised.
Dylan Connelly
Mechanical EngineerIntegral Group
LEEDuser Expert
472 thumbs up
January 3, 2013 - 7:47 pm
Andrew is correct. Just to further clarify:
You need to install MERV 6 filters in the fan coil units in addition to the MERV 13 filters in the fresh air supply fans (for IEQc5). The reason is that typically fan coil units have local air return in addition to the fresh air supply. That local return air needs to be filtered by MERV-6 filters prior to a wetted coil to meet the requirements of ASHRAE. Then for IEQc5, the fresh air supply fans need MERV 13 filters.
If the fan coil units are pulling in their own fresh air supply then they just need MERV 13 filters for IEQc5.
Andrew Mitchell, P.E.
PrincipalMitchell Gulledge Engineering, Inc.
LEEDuser Expert
126 thumbs up
January 4, 2013 - 4:27 pm
Dylan, thanks for the clarification. When I saw your response I initially thought there was something odd so I looked up all of the addenda. ID#100000426 does exclude the return air from the MERV-13 requirement. I think this will help on some of our projects in my office where systems are decoupled.