Ceiling program. Four sections at 68.5 x 134, per the distributor catalogs that surfaced this model. Diffusion media across that plane does two jobs at once: final filtration of the heated makeup air and velocity smoothing so the downdraft lands evenly over a long cabin. Order all four sections together; mixing old and new sections skews airflow toward the fresh media.

Exhaust side. Downdraft means the floor takes the overspray. Pit or basement exhaust media below the grating is the loading stage, and on a 7.5 meter cabin the pit run is long, so walk the whole grating when you inspect rather than checking one end. Pit media dimensions vary by installation and are confirmed at fitment check.

AMU prefilter, read this before ordering. Our catalog notes that some older Blowtherm units take an AMU prefilter without a header. Header and headerless bags are not interchangeable in the same frame, so check which style your air makeup unit holds before you order that position, or send a photo with your fitment check and we will identify it.

The compliance load on a long downdraft sits at the floor. EPA 6H requires demonstrated 98 percent capture efficiency at the exhaust filter stage for shops spraying target HAP coatings, and it expects filters present and maintained whenever the booth sprays. OSHA 1910.94(c) requires the ventilation system to hold design airflow, which a blinded pit run defeats. NFPA 33 governs the accumulation side: spent pit media loaded with overspray is combustible and needs scheduled removal and proper disposal. Because the BITA 7.5 meter often runs commercial and fleet work, inspectors tend to visit; dated delivery records for every change-out make those visits short.