A B C D
2 low high    
3 0.35 1.2 ft3/min, flowrate for EPA Method 5(?)  
4 28.3168 28.3168 liters per ft3  
5 9.91088 33.98016 liters per minute this appears to match approx flowrates for EPA Method 5 according to Table 5.1 in:
6 0.0075 0.0075 grains per dscf https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwjYltzHvKrNAhVQ92MKHbkqDSoQFgghMAA&url=https%3A%2F%2Fwww3.epa.gov%2Fttnemc01%2Fpromgate%2Fm-05.pdf&usg=AFQjCNGTaCXQFoTGJZHbD5QP60TN9zTvVw
7 0.002625 0.009 grains per minute  
8 0.1575 0.54 grains per hour  
9 64.7989 64.7989 mg per grain  
10 10.20582675 34.991406 mg per hour  
12 According to George's document, 3 mg of sample is detectable.
13 At the flowrates above, it looks like a 1 hr test would gather more than 3mg of sample if emissions are at the proposed limit. So, a 1 hr test would be able to show whether a facility is meeting the limit or not.

calc

  A B C
3 0.0075 gr/dscf proposed baghouse outlet limit
4 64.7989 mg/grain  
5 0.48599175 mg/dscf  
6 35.3147 ft3/m3  
7 17.16265285 mg/m3  
8 1.00E+06 ng/mg  
9 1.72E+07 ng/m3 outlet concentration
11 0.08 ng/m3 ambient limit for hex chrome, the most stringent in the rule
13 2.15E+08 dilution factor needed to make air safe if outlet conc is at proposed limit

emissions calc