40 CFR Part 1068, Appendix A

Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗

The following tables describe sampling plans for selective enforcement audits, as described in § 1068.420:

Projected family sales	Code letter 1	Minimum number of tests	Maximum number of tests
To pass	To fail
20-50	AA	3	5 \| 20
20-99	A	4	6 \| 30
100-299	B	5	6 \| 40
300-499	C	5	6 \| 50
500 +	D	5	6 \| 60

1 A manufacturer may optionally use either the sampling plan for code letter “AA” or sampling plan for code letter “A” for Selective Enforcement Audits of families with annual sales between 20 and 50 engines/equipment. Additionally, the manufacturer may switch between these plans during the audit.

Stage a	AA	A	B	C	D
Pass #	Fail #	Pass #	Fail #	Pass #	Fail # \| Pass # \| Fail # \| Pass #
1					\| \| \| \|
2					\| \| \| \|
3	0				\| \| \| \|
4	0	\| 0			\| \| \|
5	1	5	0	\| 0	\| 0 \| \| 0
6	1	6	1	6	1 \| 6 \| 0 \| 6 \| 0 \| 6
7	2	6	1	7	1 \| 7 \| 1 \| 7 \| 1 \| 7
8	2	7	2	7	2 \| 7 \| 2 \| 7 \| 2 \| 8
9	3	7	2	8	2 \| 8 \| 2 \| 8 \| 2 \| 8
10	3	8	3	8	3 \| 8 \| 3 \| 9 \| 3 \| 9
11	4	8	3	8	3 \| 9 \| 3 \| 9 \| 3 \| 9
12	4	9	4	9	4 \| 9 \| 4 \| 10 \| 4 \| 10
13	5	9	5	10	4 \| 10 \| 4 \| 10 \| 4 \| 10
14	5	10	5	10	5 \| 10 \| 5 \| 11 \| 5 \| 11
15	6	10	6	11	5 \| 11 \| 5 \| 11 \| 5 \| 11
16	6	10	6	11	6 \| 12 \| 6 \| 12 \| 6 \| 12
17	7	10	7	12	6 \| 12 \| 6 \| 12 \| 6 \| 12
18	8	10	7	12	7 \| 13 \| 7 \| 13 \| 7 \| 13
19	8	10	8	13	8 \| 13 \| 7 \| 13 \| 7 \| 13
20	9	10	8	13	8 \| 14 \| 8 \| 14 \| 8 \| 14
21	\|	9	14	9	14 \| 8 \| 14 \| 8 \| 14
22	\|	10	14	9	15 \| 9 \| 15 \| 9 \| 15
23	\|	10	15	10	15 \| 10 \| 15 \| 9 \| 15
24	\|	11	15	10	16 \| 10 \| 16 \| 10 \| 16
25	\|	11	16	11	16 \| 11 \| 16 \| 11 \| 16
26	\|	12	16	11	17 \| 11 \| 17 \| 11 \| 17
27	\|	12	17	12	17 \| 12 \| 17 \| 12 \| 17
28	\|	13	17	12	18 \| 12 \| 18 \| 12 \| 18
29	\|	14	17	13	18 \| 13 \| 18 \| 13 \| 19
30	\|	16	17	13	19 \| 13 \| 19 \| 13 \| 19
31	\|	\|	14	19	14 \| 19 \| 14 \| 20
32	\|	\|	14	20	14 \| 20 \| 14 \| 20
33	\|	\|	15	20	15 \| 20 \| 15 \| 21
34	\|	\|	16	21	15 \| 21 \| 15 \| 21
35	\|	\|	16	21	16 \| 21 \| 16 \| 22
36	\|	\|	17	22	16 \| 22 \| 16 \| 22
37	\|	\|	17	22	17 \| 22 \| 17 \| 23
38	\|	\|	18	22	18 \| 23 \| 17 \| 23
39	\|	\|	18	22	18 \| 23 \| 18 \| 24
40	\|	\|	21	22	19 \| 24 \| 18 \| 24
41	\|	\|	\|	19	24 \| 19 \| 25
42	\|	\|	\|	20	25 \| 19 \| 26
43	\|	\|	\|	20	25 \| 20 \| 26
44	\|	\|	\|	21	26 \| 21 \| 27
45	\|	\|	\|	21	27 \| 21 \| 27
46	\|	\|	\|	22	27 \| 22 \| 28
47	\|	\|	\|	22	27 \| 22 \| 28
48	\|	\|	\|	23	27 \| 23 \| 29
49	\|	\|	\|	23	27 \| 23 \| 29
50	\|	\|	\|	26	27 \| 24 \| 30
51	\|	\|	\|	\|	24 \| 30
52	\|	\|	\|	\|	25 \| 31
53	\|	\|	\|	\|	25 \| 31
54	\|	\|	\|	\|	26 \| 32
55	\|	\|	\|	\|	26 \| 32
56	\|	\|	\|	\|	27 \| 33
57	\|	\|	\|	\|	27 \| 33
58	\|	\|	\|	\|	28 \| 33
59	\|	\|	\|	\|	28 \| 33
60	\|	\|	\|	\|	32 \| 33

a Stage refers to the cumulative number of engines/equipment tested.