OA Filters

[ascj]

I have a pharma locations with some 100% OA AHU's up on the roof. The big complaint is insects and particles getting into the air stream. We use quality pleated filters and vacuum out the unit every 3 months.

The problem is there is nothing on the outdoor air hood. I was thinking about some sort of screen on the hood. Kinda like the cottonwood screens that I have seen on some condenser coils.

What you think?

[pecmsg]

All my fans are 100% OA. There is a screen ¼” size just to keep large items out of the unit, then a pre-filter, then a 12” deep bag or HEPA filter depending on discharge location. All filter racks have rubber seals to prevent air bypassing them.

Hope it helps

[ascj]

All my fans are 100% OA. There is a screen ¼” size just to keep large items out of the unit, then a pre-filter, then a 12” deep bag or HEPA filter depending on discharge location. All filter racks have rubber seals to prevent air bypassing them.

Hope it helps

Bags and Hepa's are not happening....since there is no room or track for them and they really don't need them. There is no outdoor air filters...just a hood. I was thinking of using some screens.

Here's a link- http://www.airsolutioncompany.com/co...er_screens.asp

[pecmsg]

Remember anything that small will restrict air flow. Try one and measure the pressure drop. Personally I think things are getting around the filters.

Seal up the filter rack and see what happens.

[ascj]

Remember anything that small will restrict air flow. Try one and measure the pressure drop. Personally I think things are getting around the filters.

Seal up the filter rack and see what happens.

I have room for more pressure drop. I'm at 80% on the VFD's.

I agree stuff is getting around the filters. I just can't seem to get them tight enough. Also, I'm tired off vacuuming and sweeping the return section between the filters and OA hood. It's about 12' by 5' area and has all sorts of nooks and crannies.