Class 100/grade A velocity

which is accurage method to check velocity, below 6" of HEPA or at working place?. if any regulaotory reference please specify

I think the both of them should be executed for your HAVC system.
If you have no time to do up them, I think the positon at the table is more important.

Have a good day.

thanks godisfree,
have a good day

ravi asalkar