Richard,  Brilliant and very clearly written.  I would only argue with the very first line which is:

"Laboratory ventilation is very different from commercial and industrial systems.

While I agree that lab ventilation is very different from commercial, heating and air-conditioning ventilation, I do not agree that it is different from industrial ventilation.  Lab ventilation is industrial ventilation.  I have a problem with the heating and air-conditioning standards being used when there is a better code developed by the American Conference of Governmental Industrial Hygienists (ACGIH) which should be used instead.

Every problem you describe is exactly the same problem in industrial ventilation design.  I can't speak for large industrial systems for refineries and major manufacturing, but I know they are identical for: wood shops; foundries; welding and metal working shops; sculpture, ceramic, and fine art studios; and theatrical scene, prop, and costume shops.  Now we are seeing the same problems in the new fab labs which are full of 3D printers, CNC routers, laser cutters, water jet cutters, and other new technology.

And I love the picture which could be titled  "how not to design a canopy hood."

Monona

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