ADOPTED_FROM:ISO 2859-3:1991
1.1 This part of IS0 2859 specifies generic attribute skip-lot sampling procedures for I’educing the inspection effort on products submitted by those suppliers who have demonstrated their ability to control, in an effective manner, all facets of quality and who consistently produce lots which meet requirements. The reduction in inspection effort is achieved by selecting at random, with a specified probability, whether a lot presented for inspection will be passed without inspection. This procedure extends to the inspection of lots the principle of
random selection already applied within IS0 2859-l to the individuals comprising a lot.
Inspection may take place at the supplier’s or purchaser’s locations or at an interface between operations of a production process. The skip-lot procedures are designed to be used with the attribute lot-by-lot plans described in IS0 2859-l.
NOTE 1 The skip-lot procedures specified in this part of IS0 2859 should be distinguished from Dodge’s skip-lot
plans. See[4],[5] and [6] in annex D.
1.2 Since every product has its own environment and characteristics, options are provided in recognition of the fact that the supplier and responsible authority select the appropriate options to meet the specific needs of the product and its environment.
All choices as a result of this tailoring should be specified in a written document (see annex A).
The procedures specified are applicable to, but not limited to, the inspection of
a) end items, such as complete units or subassemblies;
b) components and raw materials;
c) services;
d) materials in process;
e) supplies in storage;
f) data or records;
g) administrative procedures.
These procedures are intended only for a continuing series of lots or batches and are not to be used for
isolated lots, All lots in the series are expected to be of a similar quality and there should be reason to believe that the lots not inspected are of the same quality as the ones inspected.
This part of IS0 2859 is to be used only for characteristics inspected by attributes as designated in IS0 2859-l. Its application differs from that of reduced inspection in IS0 2859-l. With respect to the inspection of multiple characteristics, the skip-lot procedures will follow the same principles used in the associated IS0 2859-l procedures.
The skip-lot procedures in this part of IS0 2859 can only be implemented if the IS0 2859-l procedures are in use, on normal or reduced inspection, or a combination of normal and reduced inspection, at qeneral inspection levels I, II or Ill.
Multiple sampling plans may only be used during the qualification phase associated with normal inspection. It is strongly recommended that single sampling plans with an acceptance number of zero are not used in this part of IS0 2859 (see 8.1 and clause C.4).
NOTES
2 Reduced inspection is a feature of IS0 2859-l permitting smasher sample sizes than used in normal inspection. 3 Reduced inspection may be used while the product is in the lot-by-lot inspection state, but may not be used
during the skip-lot inspection or skip-lot interrupt states.
4 Skip-lot sampling may be used instead of reduced inspection if it is more cost effective to do so (see annex C).
1.3 When specified by the purchaser, this part of IS0 2859 may be referenced in a purchasing or specification contract, inspection instruction, or other contractual documents. The responsible authority and the inspection agency are to be designated in one of the above documents. The inspection agency may be the responsible authority or an organization delegated to conduct the inspection procedures.
1.4 It is essential that the skip-lot procedures are not applied to the inspection of product characteristics that bear upon the safety of personnel.
| Number of Pages : | 24 |
| Published : | 12/14/2000 |
