We have a building that houses an open Sludge Press for our onsite wastewater treament facility. The building is (I can go get exact measurements) approximately 60' square with 15' ceilings. IT currently has a large upblast exhaust fan (needs to be repaired or replaced, but the roof deck is rotted out so they can't work up there) that I would esimate is about 36" diameter and probably around 15,000-20,000 CFM.
The walls are cinder block. It's a low pitched roof, that's pitched in one direction. Roof supports are engineered steel trusses (not sure if that's the right term).
A sludge press is a large roll press that has a fine mesh belt and sludge is squeezed between rollers for dewatering. Below the press is an open pool with warm waste water. THe pool I'd estimate is about 20' square. The press is the same width.
The roof deck is... or rather was galvanized steel. I'm fixing the roof deck problem by going with a T&G treated lumber (couldn't find T&G marine grade). I'd going to blast and repaint the trusses.
But I need to resolve the building venting.
How mch ventilation do I need? Short term after the roof is repaired I'm going ot add a 48" square louvered inlet. But I suspect I'll need a MUA unit for winter to temper the air.
How do I calcuate the the amount of MUA??? Do I target a certain ACH?