AS 1038.16:2005 pdf – Coal and coke- Analysis and testing Part 16: Assessment and reporting of results

AS 1038.16:2005 pdf – Coal and coke- Analysis and testing Part 16: Assessment and reporting of results.
4.1 General
The quality of results oblained by use of methods referred to in this Standard will he maximized when attention is given to each phase of the analytical procedure. from initial selection of sample to final reporting. The general requirements of quality assurance systems reIeant to laboratory testing operations are given in ISO/IEC 17025. Statistical quality control techniques should also he applied as detailed below.
4.2 Sample collection
Incorrect methods of sample collection iIl negate all future care that is taken sith subsequent operations of sample preparation and analysis. Standard procedures arc given in AS 2617. AS 4264.1. AS 4264.2 and AS 4264.3 for the sampling of coal and coke. Special treatment of the sample within the laboratory for a particular method is detailed within the relevant Standard in the AS 1038 or AS 2434 series or associated Standards.
5 ASSESSING THE ACCURACY OF TEST RESULTS
5.1 General
A single test result, or a number of test results obtained tinder repeatability conditions. provides no information as to the accuracy of the result(s). To assess the accuracy. it is necessary to obtain a result, hereafter referred to as the reference result, concurrently on a suitable reference material and then to compare that result with the certified or reference value.
5.2 Reference material
Standards Australia has prepared several reference niaterials, e.g. coal and coal ash, that have certified or verified characteristics. In the absence of suitable certified or verified materials, a sample that has well accepted results because of repeated testing over a period of time by several different laboratories may serve for alidation. It is important for any such reference material to maintain long-term stability. To minimize matrix effects, the chemical and physical composition of the certified reference material or other validated reference material should match. as closely as possible. that of the sample.
5.3 Accuracy of the reference result
If the reference value for the reference material is denoted by m. and the laboratory’s test result from n replicate tests is determined to be v. the difference should be tested as follows:
Additional information on test result precision may be determined through regular testing of a quality control sample. A reference material, such as that described in Clause 5.2 can be used for this purpose. If no such material is available, a stable and homogenous material should be obtained. AQ sample should be tested with each batch of samples tested.
When sufficient data for the QC sample has been collected. usually about 15 measurements. the average and standard deviation of the results should be determined.