Screen Printers Open - A Forum for Screen Printing and Embroidery

The only way a flash dryer can damage your home is if left on over a shirt or a shirt board and you leave and then fire will damage your home.
The concrete will be fine, it cant get hot enough to damage concrete.
You really should not have much smoke when curing plastisol. If you have a lot of smoke then you are overcuring your shirts. Remember 320 degrees and your ink is cured. But that 320 degrees has to be thru the entire ink layer, thats very important when curing a thick layer of white ink on a dark shirt.

I've had my flash sitting over the same spot on a concrete floor for 11 yrs and it's the cleanest spot on the floor because nobody walk there.
If you're curing the shirt over your pallets I'd be more concerned about warping the pallets than hurting the concrete floor. When using a flash
to cure you should so it over an ironing board or something similar. As for smoke there should be none or very little if you are smoking up your garage
your heating up the shirts to much. All thou some 50/50 will give off smoke at lower temps.

The flash unit can't damage your floor but you're gonna drip a lot of ink on the floor, no matter how careful you are. Keep a can of mineral spirits or solvent and a rag handy and get in the habit of wiping up spilled ink right away. If you let it sit it will start to harden up and could stain your floor. (And you'll step in it and track ink all over the place including into your house. Been there, done that...)