Proficiency testing is a means of determining the performance of individual laboratories for specific tests or measurement and an external audit of their quality control procedures. A standard proficiency testing program compares the measuring results obtained by different laboratories on identical samples.
Proficiency Testing Australia (PTA) is one of Australia’s largest, most experienced proficiency testing providers and recognised by International Accreditation New Zealand. The accreditation covers the specific proficiency testing programs listed on the agreed scope of accreditation and meets the requirements of ISO/IEC 17043:2010 Conformity assessment – general requirements for proficiency testing.
PTA is able to service the construction materials industry by offering proficiency testing programs for aggregate, soils, concrete, rocks, cement, asphalt and bitumen.
The purpose of the aggregates proficiency program is to assess a laboratory’s ability to competently perform the tests examined in accordance with the AS 1141 series of standards and to provide laboratories with additional external quality assurance and thus improve overall performance.
Participation in proficiency testing programs satisfies the requirements of ISO/IEC 17025:2017 General requirements for competence of testing and calibration laboratories. This will enable construction materials companies to monitor their performance by comparison with results of other laboratories.
PTA currently runs two programs per year on coarse aggregate and is now in the process of establishing an additional program on fine aggregate.
In the coarse aggregate program, participating laboratories are supplied with one bucket of 14-20mm graded blend of aggregate, and the following tests may be performed on each sample:
• AS 1141.4 Bulk density (Uncompacted and compacted).
• AS 1141.6.1 Particle density and water absorption of coarse aggregate.
• AS 1141.11.1 Particle size distribution – Sieving method.
• AS 1141.12 Material finer than 75µm.
• AS 1141.14 Particle shape by proportional caliper.
• AS 1141.15 Flakiness index.
• AS1141.20.1 ALD Direct measurement 10 mm and greater.
In the fine aggregate program, participating laboratories will be supplied one bucket of 5kg fine aggregate, and the following tests may be performed on each sample:
• AS 1141.5 Particle density and water absorption of fine aggregate.
• AS 1141.24 Aggregate soundness test by exposure to sodium sulphate.
• AS 1141.25.3 Degradation factor – fine aggregate.
• AS 1141.33 Clay and fine silt – Settling method.
• AS1141.34 Organic impurities other than sugar.
The main aim of these programs is to assess the competence of laboratories to undertake this testing. Statistical outliers are identified using a robust z-score technique to detect excessively large variations between the individual laboratory and the overall consensus values. A final report, summarising the information submitted by all of the participants can be viewed on the PTA website at the conclusion of each round of the program. An individual summary sheet about the performance of that laboratory in the program is also sent to each participant.
Each participating laboratory is assigned a code number to allow for confidential treatment of results in all reports and publications produced by PTA.
For more information about the aggregates program, including fees, email ptaenquiry@pta.asn.au or visit the PTA website: pta.asn.au/index.php/programs/confidentiality
Source: Proficiency Testing Australia