7 C.F.R. § 42.140

Current through November 30, 2024
Section 42.140 - Operating Characteristic (OC) curves for on-line sampling and inspection
(a) This section contains the Operating Characteristic (OC) curve for each of the sampling plans given in Tables I, I-A, II, II-A, III, and III-A. The OC curve and the corresponding sampling plans are listed by AQL.
(b) Different acceptance and rejection criteria are provided for each AQL. The criteria for each AQL must be obtained from the applicable sampling plan tables.
(c) The curves show the ability of the various sampling plans to distinguish between good and bad lots. This can be illustrated by examining OC curve 6 for an AQL of 0.25 defects per hundred units in the Reduced and Normal Inspection Plans. If the quality of the lots submitted for inspection is poorer than the AQL of 0.25 defects per hundred units, fewer lots will be accepted. For example, OC curve 6 shows that when the quality of lots submitted for inspection is 1.0 defects per hundred units, only 26 percent of the lots are expected to be accepted. Conversely when the quality of the lots submitted for inspection is better than the AQL of 0.25 defects per hundred units, most lots are expected to be accepted. For example, the same OC curve 6 shows that when the quality of lots submitted for inspection is 0.10 defects per hundred units, about 99 percent of the lots are expected to be accepted.
(d) The table of sampling plans that correspond to OC curve 6 can be found over the curves for an AQL of 0.25 defects per hundred units in the Reduced and Normal Inspection Plan. An examination of this table reveals that there is one single and one double sampling plan that have OC curves comparable to OC curve 6. The first plan listed is a single plan requiring the inspection of 500 individual containers. Under this plan the lot is accepted as meeting the requirements for an AQL of 0.25 if there are 3 or less defects in the sample or rejected if there are 4 or more defects in the sample.
(e) The next plan that is listed in the column headed 6 for an AQL of 0.25 is a double sampling plan that requires the initial inspection of 228 individual containers. The lot will be accepted as meeting the requirements of an AQL of 0.25 if there are no defects in the sample, and rejected if there are 3 or more defects in the sample. In the event that the number of defects is between the acceptance (0) and rejection (3) numbers, additional containers must be inspected. In this case, the table indicates that a total of 516 containers must be inspected before a decision can be made to either accept or reject the lot. This will require the inspection of 288 more containers (516 - 228 = 288).

If there are 3 or less defects in the total sample, the lot will be accepted. If there are 4 or more defects in the total sample, the lot will be rejected. The other double sampling plans operate in a similar manner with the only differences being the sample sizes and acceptance and rejection numbers.

Reduced and Normal Inspection Plans-Sampling Plans and Operating Characteristic (OC) Curves for AQL = 0.15 Defects per Hundred Units

[Sampling plans-AQL = 0.15]

Comparable sampling plansIdentification number of OC curve
R1R2R3R4N4N5N6N7N8
ncAcRencAcRencAcRencAcRencAcRencAcRencAcRencAcRencAcRe
Single291284121260131512168122641250023800341,25045
Double1802360212002174022520345604
3612961218012336125402386434

nc = Cumulative sample size. Ac = Acceptance number. Re = Rejection number.

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Tightened Inspection Plans-Sampling Plans and Operating Characteristic (OC) Curves for AQL = 0.15 Defects per Hundred Units

[Sampling plans-AQL = 0.15]

Comparable sampling plans Identification number of OC curves
1234
nc Ac Re nc Ac Re nc Ac Re nc Ac Re
Single2640150012800231,25034
Double360024560357603
51612864231,29634

nc = Cumulative sample size. Ac = Acceptance number. Re = Rejection number.

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Reduced and Normal Inspection Plans-Sampling Plans and Operating Characteristic (OC) Curves for AQL = 0.25 Defects per Hundred Units

[Sampling plans-AQL = 0.25]

Comparable sampling plansIdentification number OC curves
R1N2R3N and R4N and R5N6N7
ncAcRencAcRencAcRencAcRencAcRencAcRencAcRe
Single29128401841216812315235003480045
Double18023602120021680322803
18129612180123482351634

nc = Cumulative sample size. Ac = Acceptance number. Re = Rejection number.

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Tightened Inspection Plans-Sampling Plans and Operation Characteristics (OC) Curves for AQL = 0.25 Defects per Hundred Units

[Sampling plans-AQL = 0.25]

Comparable sampling plans Identification number of OC curves
12345
nc Ac Re nc Ac Re nc Ac Re nc Ac Re nc Ac Re
Single168013151250023800341,25045
Double168022280345604
348125162386434

nc = Cumulative sample size. Ac = Acceptance number. Re = Rejection number.

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Reduced and Normal Inspection Plans-Sampling Plans and Operating Characteristic (OC) Curves for AQL = 0.50 Defects per Hundred Units

[Sampling plans-AQL = 0.50]

Comparable sampling plansIdentification number of OC curves
R1N and R2N and R3N and R4N5N6
ncAcRencAcRencAcRencAcRencAcRencAcRe
Single2912841216823315345005680078
Double18023602120031680422805
36129612180233483451656

nc = Cumulative sample size. Ac = Acceptance number. Re = Rejection number.

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Tightened Inspection Plans-Sampling Plans and Operating Characteristic (OC) Curves for AQL = 0.50 Defects per Hundred Units

[Sampling plans-AQL = 0.50]

Comparable sampling plans Identification number of OC curves
12345
nc Ac Re nc Ac Re nc Ac Re nc Ac Re nc Ac Re
Single168123152350034800451,25067
Double12002168032280345615
18012348235163486445

nc = Cumulative sample size. Ac = Acceptance number. Re = Rejection number.

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Reduced and Normal Inspection Plans-Sampling Plans and Operating Characteristic (OC) Curves for AQL = 1.00 Defects per Hundred Units

[Sampling plans-AQL = 1.00]

Comparable sampling plansIdentification number of OC curves
R1N and R2N and R3N and R4N5N6
ncAcRencAcRencAcRencAcRencAcRencAcRe
Single2912842316845315675009108001314
Double18023603120251681522827
361296231804534878516910

nc = Cumulative sample size. Ac = Acceptance number. Re = Rejection number.

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Tightened Inspection Plans-Sampling Plans and Operating Characteristic (OC) Curves for AQL = 1.00 Defects per Hundred Units

[Sampling plans-AQL = 1.00]

Comparable sampling plans Identification number of OC curves
1 2 3 4 5
nc Ac Re nc Ac Re nc Ac Re nc Ac Re nc Ac Re
Single168233153450056800781,2501011
Double12003168042280545626
18023348345165686489

nc = Cumulative sample size Ac = Acceptance number. Re = Rejection number.

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Reduced and Normal Inspection Plans-Sampling Plans and Operating Characteristic (OC) Curves for AQL = 1.50 Defects per Hundred Units

[Sampling plans-AQL = 1.50]

Comparable sampling plansIdentification number of OC curves
R1N and R2N and R3N and R4N5N6
ncAcRencAcRencAcRencAcRencAcRencAcRe
Single29128434168563158950012138001819
Double18023604120261682722839
36129634180563489105161213

nc = Cumulative sample size. Ac = Acceptance number. Re = Rejection number.

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Tightened Inspection Plans-Sampling Plans and Operating Characteristic (OC) Curves for AQL = 1.50 Defects per Hundred Units

[Sampling plans-AQL = 1.50]

Comparable sampling plans Identification number of OC curves
1 2 3 4 5
nc Ac Re nc Ac Re nc Ac Re nc Ac Re nc Ac Re
Single168453156750091080013141,2501920
Double120251681522827456510
18045348785169108641415

nc = Cumulative sample size. Ac = Acceptance number. Re = Rejection number.

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Reduced and Normal Inspection Plans-Sampling Plans and Operating Characteristic (OC) Curves for AQL = 2.50 Defects per Hundred Units

[Sampling plans-AQL = 2.50]

Comparable sampling plansIdentification number of OC curves
R1N and R2N and R3N and R4N5N6
ncAcRencAcRencAcRencAcRencAcRencAcRe
Single2923844516878315131450018198002728
Double1803360412037168510228511
362396451808934814155161920

nc = Cumulative sample size. Ac = Acceptance number. Re = Rejection number.

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Tightened Inspection Plans-Sampling Plans and Operating Characteristic (OC) Curves for AQL = 2.50 Defects per Hundred Units

[Sampling plans-AQL = 2.50]

Comparable sampling plans Identification number of OC curves
1 2 3 4 5
nc Ac Re nc Ac Re nc Ac Re nc Ac Re nc Ac Re
Single1685631589500121380018191,2502627
Double120261682722839456813
1805634891051612138641920

nc = Cumulative sample size. Ac = Acceptance number. Re = Rejection number.

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Reduced and Normal Inspection Plans-Sampling Plans and Operating Characteristic (OC) Curves for AQL = 4.00 Defects per Hundred Units

[Sampling plans-AQL = 4.00]

Comparable sampling plansIdentification number of OC curves
R1N and R2N and R3N and R4N5N6
ncAcRencAcRencAcRencAcRencAcRencAcRe
Single293484671681112315192050028298004243
Double18133605120610168713228817
36459678180121334821225162930

nc = Cumulative sample size. Ac = Acceptance number. Re = Rejection number.

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Tightened Inspection Plans-Sampling Plans and Operating Characteristic (OC) Curves for AQL = 4.00 Defects per Hundred Units

[Sampling plans-AQL = 4.00]

Comparable sampling plans Identification number of OC curves
12345
nc Ac Re nc Ac Re nc Ac Re nc Ac Re nc Ac Re
Single168783151314500181980027281,2504142
Double120371685102285114561219
18089348141551619208642930

nc = Cumulative sample size. Ac = Acceptance number. Re = Rejection number.

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Reduced and Normal Inspection Plans-Sampling Plans and Operating Characteristic (OC) Curves for AQL = 2.50 Defects per Hundred Units

[Sampling plans-AQL = 6.50]

Comparable sampling plansIdentification number of OC curves
R1N and R2N and R3N and R4N5N6
ncAcRencAcRencAcRencAcRencAcRencAcRe
Single2945849101681617315282950042438006465
Double18143627120101416812182281524
3656961011180171834831325164344

nc = Cumulative sample size. Ac = Acceptance number. Re = Rejection number.

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Tightened Inspection Plans-Sampling Plans and Operating Characteristic (OC) Curves for AQL = 6.50 Defects per Hundred Units

[Sampling plans-AQL = 6.50]

Comparable sampling plans Identification number of OC curves
12345
nc Ac Re nc Ac Re nc Ac Re nc Ac Re nc Ac Re
Single16811123151920500282980042431,2506364
Double1206101687132288174562128
1801213348212251629308644445

nc = Cumulative sample size. Ac = Acceptance number. Re = Rejection number.

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Reduced and Normal Inspection Plans-Sampling Plans and Operating Characteristic (OC) Curves for AQL = 10.00 Defects per Hundred Units

[Sampling plans-AQL = 10.00]

Comparable sampling plansIdentification number of OC curves
R1N and R2N and R3N and R4N5N6
ncAcRencAcRencAcRencAcRencAcRencAcRe
Single29568413141682324315414250062638009596
Double18253639120141916819262282334
3667961516180252634845465166465

nc = Cumulative sample size. Ac = Acceptance number. Re = Rejection number.

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Tightened Inspection Plans-Sampling Plans and Operating Characteristic (OC) Curves for AQL = 10.00 Defects per Hundred Units

[Sampling plans-AQL = 10.00]

Comparable sampling plans Identification number of OC curves
12345
nc Ac Re nc Ac Re nc Ac Re nc Ac Re nc Ac Re
Single16816173152829500424380064651,2509697
Double1201014168121822815244563241
1801718348313251643448646970

nc = Cumulative sampling size. Ac = Acceptance number. Re = Rejection number.

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7 C.F.R. §42.140

31 FR 4687, Mar. 19, 1966; 31 FR 4949, Mar. 25, 1966, as amended at 36 FR 18457, Sept. 15, 1971. Redesignated at 41 FR 42640, Sept. 28, 1976 and 42 FR 32514, June 27, 1977, further redesignated at 45 FR 69424, Oct. 21, 1980 and 46 FR 63203, Dec. 31, 1981