View all text of Subjgrp 234 [§ 43.103 - § 43.106]

§ 43.106 - Choosing AQL's and sampling plans.

(a) The selection of AQL's and sampling plans for given lot sizes depends on too many factors to permit the issuance of a “pre-selected” standard set of plans for specified lot sizes. Each user of the standards of this subpart should select AQL's and sampling plans that are tailored to best meet his needs.

(b) Some of the factors that must be considered prior to selecting the AQL's are:

(1) Class of defects such as major and minor: Major defects would generally require lower AQL's than those for minor defects;

(2) Process capabilities under good commercial practice with respect to the defects in question: For example, if under normal production processes, the defect level cannot be kept below 2.0 percent defective, the selection of an AQL of 0.15 percent defective, although desirable for the defects in question, may not be practical;

(3) Consumer preferences: These may require higher AQL's or permit lower AQL's than process capabilities would indicate; and

(4) Time and cost required to sample and inspect a lot under various AQL's: The smaller the AQL the more time and cost of inspection.

(c) Some of the factors that may be considered prior to selecting the sampling plans for given lot sizes are:

(1) The applicable AQL(s): The AQL dictates, among other things, the smallest sample size that can be used and the size of the “jumps” from one sample size to the next larger one;

(2) The relative ability of the plans to discriminate between “good” and “bad” lots: Although several plans in these standards have the same AQL, they differ in their ability to reject lots worse than the AQL's. The OC curve in the standards of this subpart provide the basis for determining the discriminating ability of each plan;

(3) The amount, time, and cost of sampling required;

(4) The size and value of the lots relative to the producer and consumer protection a sampling plan affords: One may be willing to take larger risks of passing “bad” lots that are small or of lesser value than they would for larger more valuable lots;

(5) The knowledge about the lot(s) to be submitted for inspection: Lots consisting of product produced under essentially the same conditions may require smaller sample sizes than those consisting of product produced by different shifts and different raw stock for example; and

(6) The record of the quality level of previously submitted lots: The sample size can be smaller for lots submitted from a supplier with a consistent record of quality levels significantly better than the specified AQL(s) than sample sizes for the supplier whose records show considerable variability in quality, “borderline” supplies or product worse than the AQL.

Master Table of Single and Double Sampling Plans 1

Sample size code letter Sample size Acceptable quality levels 0.065 0.10 0.15 0.25 0.40 0.65 1.0 1.5 2.5 4.0 5.0 6.5 8.5 10.0 12.5 15.0 Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re AAn1=1 0 1 An1=2 0 1 Bn1=3 0 1 0 3 1 2 nt=8 2 3 Cn1=4 0 1 1 2 Dn1=5 0 1 1 2 En1=6 1 22 3 EEn1=7 2 3 Fn1=9 0 1 1 2 2 3 3 4 Gn1=11 1 2 2 3 3 4 Hn1=13 0 1 2 3 3 4 4 5 Jn1=21 0 1 0 2 0 2 2 3 1 4 3 4 3 5 4 5 5 6 6 7 nt=31 1 2 2 3 3 4 5 6 Kn1=29 0 1 0 2 1 2 2 3 1 4 3 4 4 5 3 7 5 6 6 7 7 8 nt=65 1 2 6 7 9 10 Ln1=48 0 1 0 2 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 10 11 11 12 nt=72 1 2 Mn1=84 0 1 0 2 0 3 2 3 3 4 4 5 6 7 7 8 9 10 11 12 13 14 15 16 18 19 nt=120 1 2 nt=132 2 3 Nn1=126 0 1 0 2 0 3 2 3 3 4 4 5 6 7 9 10 10 11 13 14 16 17 18 19 22 23 26 27 nt=180 1 2 nt=210 2 3 Pn1=200 0 1 0 2 0 3 2 3 3 4 4 5 6 7 9 10 13 14 15 16 19 20 24 25 27 28 33 34 39 40 nt=284 1 2 nt=326 2 3 Qn1=315 0 1 0 2 0 2 3 3 4 4 5 6 7 8 9 13 14 19 20 22 23 28 29 35 36 41 42 50 51 59 60 nt=435 1 2 nt=519 2 3 Rn1=500 0 2 0 3 2 3 3 4 4 5 6 7 9 10 12 13 18 19 28 29 33 34 42 43 53 54 62 63 76 77 90 91 nt=644 1 2 nt=836 2 3 Sn1=800 0 3 2 3 3 4 4 5 6 7 9 10 13 14 18 19 27 28 42 4350 510 64 65 82 83 95 96117 118140 141 nt=1304 2 3 Tn1=1250 2 3 3 4 4 5 6 7 9 10 13 14 19 20 26 27 41 42 63 64 76 77 Un1=2000 3 4 4 5 6 7 9 10 13 14 19 20 28 29 39 40 62 63 96 97

1 Double plans are indicated by 2 sample sizes, n1 (first) and nt (total). Ac=Acceptance number Re=Rejection number.

Sampling Plans and Operating Characteristic (OC) Curves for AQL=0.065 Percent Defective (or AQL=0.065 Defects per Hundred Units)

[Sampling plans—AQL=0.065]

Comparable sampling plans Identification letter of OC curve Q R S, T U ncAc Re ncAc Re ncAc Re ncAc Re Single31501624121250232,0003 Double5000280003 64412130423

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

Sampling Plans and Operating Characteristic (OC) Curves for AQL=0.10 Percent Defective (or AQL=0.10 Defects per Hundred Units)

[Sampling plans—AQL=0.10]

Comparable sampling plans Identification letter of OC curve P Q R, S T U ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re Single2000140812800231,250342,0004 Double3150250003 4351283623

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

Sampling Plans and Operating Characteristic (OC) Curves for AQL=0.15 Percent Defective (or AQL=0.15 Defects per Hundred Units)

[Sampling plans—AQL=0.15]

Comparable sampling plans Identification letter of OC curve N P Q R, S T U ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re Single126012641250023800341,250452,00067 Double2000231503 2841251923

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

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

[Sampling plans—AQL=0.25]

Comparable sampling plans Identification letter of OC curve M N P, Q R S T U ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re Single8401168123152350034800451250672000910 Double1260220003 1801232623

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

Sampling Plans and Operating Characteristic (OC) Curves for AQL=0.40 Percent Defective (or AQL=0.40 Defects per Hundred Units)

[Sampling plans—AQL=0.40]

Comparable sampling plans Identification letter of OC curve L M N, P Q R S T U ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re Single48011081220023315345004580067125091020001310 Double840212603 1201221023

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

Sampling Plans and Operating Characteristic (OC) Curves for AQL=0.65 Percent Defective (or AQL=0.65 Defects per Hundred Units)

[Sampling plans—AQL=0.65]

Comparable sampling plans Identification letter of OC curve K L M, N P Q R S T U ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re Single29016612126232003431545500678009101250131420001920 Double48028403 721213223

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

Sampling Plans and Operating Characteristic (OC) Curves for AQL=1.0 Percent Defective (or AQL=1.0 Defects per Hundred Units)

[Sampling plans—AQL=1.0]

Comparable sampling plans Identification letter of OC curve J K, L M N P ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re Single2101481284231263420045 Double2902 6512
Q R S T U ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re Single3156750091080013141250192020002829

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

Sampling Plans and Operating Characteristic (OC) Curves for AQL=1.5 Percent Defective (or AQL=1.5 Defects per Hundred Units)

[Sampling plans—AQL=1.5]

Comparable sampling plans Identification letter of OC curve H J, K L M N P ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re Single13012912482384341264520067 Double2102 3112
Q R S T U ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re Single31589500121380018191,25026272,0003940

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

Sampling Plans and Operating Characteristic (OC) Curves for AQL=2.5 Percent Defective (or AQL=2.5 Defects per Hundred Units)

[Sampling plans—AQL=2.5]

Comparable sampling plans Identification letter of OC curve F J, K L M N P ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re Single90129234834844512667200910 Double2102 3123
Q R S T U ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re Single3151314500181980027281,25041422,0006263

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

Sampling Plans and Operating Characteristic (OC) Curves for AQL=4.0 Percent Defective (or AQL=4.0 Defects per Hundred Units)

[Sampling plans—AQL=4.0]

Comparable sampling plans Identification letter of OC curve D G J K L M N ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re Single5011112212348458467126910 Double2914 6567
P Q R S T U ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re Single200131431519205002829800424312506364200096

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

Sampling Plans and Operating Characteristic (OC) Curves for AQL=5.0 Percent Defective (or AQL=5.0 Defects per Hundred Units)

[Sampling plans—AQL=5.0]

Comparable sampling plans Identification letter of OC curve C F J, K L M N ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re Single4011122934485684781261011 Double2114 3134
P Q R S T ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re Single200151631522235003334800505112507677

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

Sampling Plans and Operating Characteristic (OC) Curves for AQL=6.5 Percent Defective (or AQL=6.5 Defects per Hundred Units)

[Sampling plans—AQL=6.5]

Comparable sampling plans Identification letter of OC curve B E H J K L ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re Single3016121323213429454867
M N P Q R S ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re Single8491012613142001920315282950042438006465

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

Sampling Plans and Operating Characteristic (OC) Curves for AQL=8.5 Percent Defective (or AQL=8.5 Defects per Hundred Units)

[Sampling plans—AQL=8.5]

Comparable sampling plans Identification letter of OC curve D G J K, L M ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re Single51211232445487884111 Double21352937 315665910
N P Q R S ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re Single12616172002425315353650053548008283

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

Sampling Plans and Operating Characteristic (OC) Curves for AQL=10.0 Percent Defective (or AQL=10.0 Defects per Hundred Units)

[Sampling plans—AQL=10.0]

Comparable sampling plans Identification letter of OC curve A C F H J K L ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re Single2014129231334214529564889
M N P Q R S ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re Single84131412618192002728315414250062638009596

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

Sampling Plans and Operating Characteristics (OC) Curves for AQL=12.5 Percent Defective (or AQL=12.5 Defects per Hundred Units)

[Sampling plans—AQL=12.5]

Identification letter of OC curve Comparable sampling plans B, EE G J K L M ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re Single723113421562967481011841516 Double303 823
N P Q R S ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re Single1262223200333431550515007677800117118

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

Sampling Plans and Operating Characteristic (OC) Curves for AQL=15.0 Percent Defective (or AQL=15.0 Defects per Hundred Units)

[Sampling plans—AQL=15.0]

Comparable sampling plans Identification letter of OC curve AA B E F H J K ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re Single101312623934134521672978
L M N P Q R S ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re ncAc Re Single4811128418191262627200394031559605009091800140141

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