Tag: ASTM E122

ASTM E122 updated for calculating sample size

ASTM E122, Standard Practice for Calculating Sample Size to Estimate, With Specified Precision, the Average for a Characteristic of a Lot or Process, has just been revised.  The new 2017 Edition updates the previous 2009 Edition (with an editorial correction), which is now obsolete.  The standard covers a number of simple methods for calculating unit values for valid sampling.  ASTM E122 is one of our all-time best-selling sampling and process control standards!

Sampling is a proven methodology used extensively in quality and process control.  In order to have valid results, you need to understand how many units need to be used in order to achieve a specified precision.  And accuracy depends both on the units chosen and the time interval.  This practice was developed so you have the tools to measure variability.

It’s been a while since the ASTM E122 was revised.  You’ll find corrections in a number of areas.  First, the scope paragraph is expanded to include information on the system of units for the standard.  Also, a disclaimer assures the user that the standard was developed in accordance with standardization principles accepted by the WTO Technical Barriers to Trade Committee.

A new definition of pooled standard deviation has been included.  A number of equations have been changed.  At the end of the publication, a new clause 12 for keywords has been added.

If you want to have more information on these changes, you should purchase the redline edition of the document from us.  With this option, we provide you with both a clean copy of the 2017 Edition plus a marked-up copy of the 2009 so you can clearly see each modification.  Just go to the Document Center Inc. webstore at www.document-center.com.  Here is a link directly to the order page for ASTM E122.

When you place your order, request the redline in the order comments area.  It will cost you 20% more and save you a lot of time and headaches!

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All time best selling Standards on Sampling and Statistical Process Control

It’s said if you can measure it, you can manage it, and Statistical Process Control is the tool to use!  So it’s no surprise that there are a wide range of standards on the subject.  Here’s our list of the top 10 Standards on Sampling and Statistical Process control.

ASQ-Z1.4, Sampling Procedures and Tables for Inspection by Attributes

ASQ-Z1.9, Sampling Procedures and Tables for Inspection by Variables for Percent Nonconforming

These 2 Standards replace MIL-STD-105 and MIL-STD-414, both of which are now obsolete. Filled with pages of tables for use with a continuous supply, the documents are our current best-selling sampling standards.  The Z1.4 covers go/no go data, the Z1.9 covers measurement.

Zero Acceptance Number Sampling Plans is often used as an alternative to the MIL-STD-105/ASQ-Z1.4 Inspection systems.  It is based on C=0 concept developed by author Nicholas Squeglia back in 1961.  The 5th edition is the current revision of this item.

During the last few years, the ISO standards on this topic have seen greater usage as well.  Top sellers include the ISO-2859 series, the ISO-11462 series, the ISO-3534 series, and the ISO-5725 series.

ISO-2859-10, Sampling procedures for inspection by attributes – Part 10: Introduction to the ISO 2859 series of standards for sampling for inspection by attributes, is a good starting point for the ISO-2859 set.  It provides a general introduction to acceptance sampling by attributes and provides a brief summary of the attribute sampling schemes and plans used in Parts 1 through 5. The standard also provides guidance on the selection of the appropriate inspection system for use in a particular situation.

ISO-11462-1, Guidelines for implementation of statistical process control (SPC) – Part 1: Elements of SPC, and ISO-11462-2, Guidelines for implementation of statistical process control (SPC) – Part 2: Catalog of Tools and Techniques, are two additional useful standards.  They provide concepts, tools and techniques to help an organization in planning, implementation and evaluation of an effective statistical process control (SPC) system.

ISO-5725-1, Accuracy (trueness and precision) of measurement methods and results – Part 1: General principles and definitions, is an introduction to the ISO-5725 series.  It outlines the general principles to be understood when assessing accuracy of measurement methods and results.  It can also be used to establish practical estimations of the various measures by experiment.  The standard may be applied to a very wide range of materials, including liquids, powders and solid objects, manufactured or naturally occurring.

For Statistics – Vocabulary and symbols, the ISO-3534 series covers all the bases:

ISO-3534-1, Part 1: General statistical terms and terms used in probability

ISO-3534-2, Part 2: Applied statistics

ISO-3534-3, Part 3: Design of experiments

ASTM International (formerly the American Society for Testing and Materials) also has a number of standards on the topic of Sampling and Statistical Process Control.  We often sell the following:

ASTM-E122, Standard Practice for Calculating Sample Size to Estimate, With Specified Precision, the Average for a Characteristic of a Lot or Process.  This standard is intended for use in determining the sample size required to estimate, with specified precision, a measure of quality of a lot or process. The practice applies when quality is expressed as either the lot average for a given property, or as the lot fraction not conforming to prescribed standards.

Should you have any questions about the above standards, or need more suggestions to get the information you need, please contact us at www.document-center.com, info@document-center.com, or phone us at 650-591-7600.  We’re always ready to help you out.