What is ISO 3951‑1 about?
ISO 3951‑1 is the first part of the multi-series international standard that focuses on single sampling plans indexed by acceptance quality limit with inspection for a single quality characteristic. ISO 3951‑1 is primarily designed for use under the following conditions:
- Where the inspection procedure is to be applied to a continuing series of lots of discrete products all supplied by one producer using one production process
- Where only a single quality characteristic, x, of these products are taken into consideration, which must be measurable on a continuous scale
- Where production is stable (under statistical control) and the quality characteristic, x, is distributed according to a normal distribution or a close approximation to the normal distribution
Who is ISO 3951‑1 for?
ISO 3951‑1 on single sampling plans indexed by acceptance quality limit with inspection for a single quality characteristic is useful for:
- Chemical laboratories
- Chemical Industries
- Metallic coating industries
Why should you use ISO 3951‑1?
ISO 3951‑1 specifies an acceptance sampling system of single sampling plans for inspection by variables. ISO 3951‑1 is indexed in terms of the acceptance quality limit (AQL) and is designed for users who have simple requirements.
The objectives of the methods laid down in ISO 3951‑1 are to ensure that lots of acceptable quality have a high probability of acceptance and that the probability of not accepting inferior lots is as high as practicable. This is achieved using the switching rules, which provide the following:
- An automatic protection to the consumer (using a switch to tightened inspection or discontinuation of sampling inspection) should a deterioration in quality be detected
- An incentive (at the discretion of the responsible authority) to reduce inspection costs (using a switch to a smaller sample size) should consistently good quality be achieved.
ISO 3951‑1 is intended for application to a single quality characteristic that is measurable on a continuous scale.
