StacksVerified U.S. regulatory reference

40 CFR Part 266, Appendix VI

Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov
Flow rate (m3/s)Exhaust Temperature (K°)
<325325-349 | 350-399 | 400-449 | 450-499 | 500-599 | 600-699 | 700-799 | 800-999 | 1000-1499 | >1499
<0.50 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0
0.5-0.90 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1
1.0-1.90 | 0 | 0 | 0 | 1 | 1 | 2 | 3 | 3 | 3 | 4
2.0-2.90 | 0 | 1 | 3 | 4 | 4 | 6 | 6 | 7 | 8 | 9
3.0-3.90 | 1 | 2 | 5 | 6 | 7 | 9 | 10 | 11 | 12 | 13
4.0-4.91 | 2 | 4 | 6 | 8 | 10 | 12 | 13 | 14 | 15 | 17
5.0-7.42 | 3 | 5 | 8 | 10 | 12 | 14 | 16 | 17 | 19 | 21
7.5-9.93 | 5 | 8 | 12 | 15 | 17 | 20 | 22 | 22 | 23 | 24
10.0-12.44 | 6 | 10 | 15 | 19 | 21 | 23 | 24 | 25 | 26 | 27
12.5-14.94 | 7 | 12 | 18 | 22 | 23 | 25 | 26 | 27 | 28 | 29
15.0-19.95 | 8 | 13 | 20 | 23 | 24 | 26 | 27 | 28 | 29 | 31
20.0-24.96 | 10 | 17 | 23 | 25 | 27 | 29 | 30 | 31 | 32 | 34
25.0-29.97 | 12 | 20 | 25 | 27 | 29 | 31 | 32 | 33 | 35 | 36
30.0-34.98 | 14 | 22 | 26 | 29 | 31 | 33 | 35 | 36 | 37 | 39
35.0-39.99 | 16 | 23 | 28 | 30 | 32 | 35 | 36 | 37 | 39 | 41
40.0-49.910 | 17 | 24 | 29 | 32 | 34 | 36 | 38 | 39 | 41 | 42
50.0-59.912 | 21 | 26 | 31 | 34 | 36 | 39 | 41 | 42 | 44 | 46
60.0-69.914 | 22 | 27 | 33 | 36 | 39 | 42 | 43 | 45 | 47 | 49
70.0-79.916 | 23 | 29 | 35 | 38 | 41 | 44 | 46 | 47 | 49 | 51
80.0-89.917 | 25 | 30 | 36 | 40 | 42 | 46 | 48 | 49 | 51 | 54
90.0-99.919 | 26 | 31 | 38 | 42 | 44 | 48 | 50 | 51 | 53 | 56
100.0-119.921 | 26 | 32 | 39 | 43 | 46 | 49 | 52 | 53 | 55 | 58
120.0-139.922 | 28 | 35 | 42 | 46 | 49 | 52 | 55 | 56 | 59 | 61
140.0-159.923 | 30 | 36 | 44 | 48 | 51 | 55 | 58 | 59 | 62 | 65
160.0-179.925 | 31 | 38 | 46 | 50 | 54 | 58 | 60 | 62 | 65 | 67
180.0-199.926 | 32 | 40 | 48 | 52 | 56 | 60 | 63 | 65 | 67 | 70
>199.926 | 33 | 41 | 49 | 54 | 58 | 62 | 65 | 67 | 69 | 73

[56 FR 7233, Feb. 21, 1991, as amended at 71 FR 40277, July 14, 2006]