ASHRAE help!!!
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  1. #1
    Join Date
    Aug 2009
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    33

    ASHRAE help!!!

    i am trying to purchase 85% efficiency filters for my AHUs at work. But the sales people from filters are keep giving me ASHRAE standard 52.1 certificate which says that MERV-13 are 85%, but according to ASHRAE 52.2 they are <75%. Is ASHRAE 52.1 still accepted by FDA etc?

    Thanx

  2. #2
    z
    The 80-85% efficiency filter you are seeking is generally accepted as a MERV 13. The problem is the numbers are derived by totally different test methods. The 75% you are seeing in the 52.2 test is a percentage of particle capture by particle size. The 80-85% in the 52.1 test is a "dust spot efficiency" which is the discoloration of a "target" exposed to test dust on the downstream side of the filter.

    The 52.1 standard has been "retired" which means it won't be accepted by the FDA.

    For a review of the current ASHRAE filter testing situation see:

    http://allergyclean.com/articles/?p=157

  3. #3
    Join Date
    Aug 2009
    Posts
    33
    Quote Originally Posted by breathe easy View Post
    z
    The 80-85% efficiency filter you are seeking is generally accepted as a MERV 13. The problem is the numbers are derived by totally different test methods. The 75% you are seeing in the 52.2 test is a percentage of particle capture by particle size. The 80-85% in the 52.1 test is a "dust spot efficiency" which is the discoloration of a "target" exposed to test dust on the downstream side of the filter.

    The 52.1 standard has been "retired" which means it won't be accepted by the FDA.

    For a review of the current ASHRAE filter testing situation see:

    http://allergyclean.com/articles/?p=157
    Breath Easy,

    Thank you very much it does clear up lot of confusion. So in order to satisfy FDA we must use ASHRAE standard 52.2 MERV 14 for 85%

  4. #4
    You can use a MERV 13.

  5. #5
    Join Date
    Aug 2009
    Posts
    33
    Quote Originally Posted by breathe easy View Post
    You can use a MERV 13.
    But MERV 13 is <75% for 0.3 micron particle, we are looking for 85% efficiency for that size particle, so MERV-14 would be a better choice right?

  6. #6
    z
    You need to read the article.

    An 80-85% filter tested according to 52.1 has nothing to do with efficiency at 0.3 microns. If for some reason you actually need 85% efficiency at 0.3 microns, the only filter that will provide this is a true HEPA. The 85% you are reading off the ASHRAE 52.2 chart is actually an average for 4 particle sizes between 0.3 and 1 micron. A MERV 14 filter would generally provide less than 70% efficiency at 0.3 microns.

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