Hi, everyone

We have new researcher who would like to have a cleanroom installed inside their research lab, so that a portion of the lab is a relatively particle-free environment (ISO 7).  They believe this can be achieved with a softwall modular cleanroom such as this one: https://www.terrauniversal.com/cleanroom-softwall-extended-valuline-6600-66-vl-1214.html

The remainder of the lab space (i.e. outside of the modular cleanroom) is a wet chemistry lab with its own fume hood. There will be some chemical use inside the cleanroom, which will have also have its own fume hood inside of it.  Volatile chemicals to be used (and are common to both cleanroom and the rest of the lab) will be acetone, isopropyl alcohol, heptane and toluene, which will be all handled inside the respective fume hoods.  The modular softwall cleanroom would take the air from the lab and pass it through HEPA filters using the ceiling-mounted fan filter units (FFUs), and push it through the cleanroom space and back out into the lab underneath the vinyl curtains.  

We’ve run into an issue where the lab designer will not accept the idea of using modular softwall cleanroom, claiming that per ASHRAE 62.1, Class 3 air (air with significant contamination) cannot be recirculated, even to another Class 3 air space.  They are proposing a hard wall cleanroom with a separate ventilation zone from the rest of the lab, supplying the cleanroom with HEPA-filtered, conditioned outside air to keep it a positively pressurized space w.r.t. the lab.  A fraction of the air will be recirculated back into the cleanroom through the HEPA filter, and the remainder of the exhausted air being sent out of the building’s lab exhaust stack.

I looked up Table 6-1 in ASHRAE 62.1, which lists "university/college laboratories” as having Class 2 air (air with moderate contamination), and not Class 3. It is not clear to me if "university/college laboratories” refers solely to instructional labs, or if it includes research laboratories.  The difference being is that Class 2 air can be recirculated to other Class 2 or Class 3 spaces. It seems to me that the entire lab, including the cleanroom within it, would be a single volume of air, which in any case is ventilated to 6 air changes per hour, per ventilation requirements for a lab.

My questions:

1. Does anyone know what the appropriate Air Class is for such a research space? It seems to me, setting aside fugitive emissions, with chemical manipulations being done inside the lab fume hood, it would take an upset condition, i.e. chemical spill outside of the fume hood, to create a Class 3 air space.
2. Does anyone have an experience with a modular cleanroom they can share with me? In particular, can anyone provide their experience of a modular soft or hard wall cleanroom where there is chemical usage and a fume hood installed inside it?

Thank you!