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The Proficiency Sample Programs (PSP and XPS)
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Fine Aggregate Gradation Standards
AMRL Fine Aggregate Gradation Standards No. 151, 152, 159 and 160 are now available for sale. These standards are intended to be used for performance verification of 200-mm (8-inch) and 300-mm (12-inch) diameter U.S.A. Standard Series sieves of the following sizes: 2.36-mm, 1.18-mm, 600-µm, 300-µm, 150-µm, and 75-µm (Nos. 8, 16, 30, 50, 100, and 200). Each standard test specimen consists of approximately 300 grams of material. The standard test specimens, a certificate of analysis, and instructions for their use are available for $50 for a package of five specimens. Please contact psp@amrl.net or call 301-975-5450.
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Extra Proficiency Samples (XPS) Program
In limited quantities, AMRL is now offering proficiency samples for sale for other uses such as training or certification of technicians, testing or equipment verification, inter-laboratory studies, etc.
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PSP Program Description
The Proficiency Sample Program provides participating laboratories with a means to:
1. check both the instrument and the operator under actual testing conditions
2. compare individual test results with the average of a large body of results so that corrective action may be taken where wide discrepancies occur
3. evaluate the quality of test results, thereby reducing the risk of dispute due to testing errors
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Results of Optional Special Study for Surface Dry Penetration of Asphalt Emulsion Residue
The 2010 round of testing for Emulsified Asphalt (samples 51 and 52) included an optional study regarding the effect of surfactant interference when testing the penetration of the residue of emulsified asphalt. Results can be viewed by clicking on the following links:
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How and when do I respond to low ratings on a proficiency sample?
Within 60 days of the date on the final report, an accredited laboratory receiving a +/- 2, +/- 1, or zero rating must send the results of their investigation of the root cause to their Quality Analyst by fax, mail, or email. A standard Proficiency Sample Corrective Action Report Form is available. Keep a copy for your own records.
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How do I save an electronic copy of my ratings sheet?
Sign in and access your ratings sheet on the website. To save the ratings page as a file on your computer click on "File" and "Save As" and designate the location to which you want the file saved.
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What do the ratings for “repeatability (within-lab)” mean?
Repeatability is an estimate of the variation in results that you might expect if you repeated the same test over and over in your laboratory. The within-lab rating is based on the difference between the two individual lab results, but also subtracts out any actual differences between the two sample materials (the manner is similar to what we have always done when computing single operator statistics for the compilation of statistics).
An “individual within-lab value" is determined for each lab as follows:
(1). Individual Within-Lab Value = [(Yi-Xi)-(Yavg-Xavg)]/(square root of 2)
(2). The standard deviation of those values is the repeatability (or within-lab) standard deviation, 1S.
(3). The "Within-Lab Ratings" are determined using the "Individual Within-Lab Values" and the "Within-Lab Standard Deviation, 1S" to determine within-lab Z-Scores. Then, the same rating scheme is used as for the individual samples.
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Do laboratories that receive low ratings for “repeatability (within-lab)” need to respond to AMRL?
No. You should examine why your within-lab results may not be as consistent in your laboratory as in other laboratories, but you are not required to submit a response to AMRL at this time.
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How can I submit my results?
You may submit your results online (account needed) or you may fax or mail us your results.
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How do I get started?
Submit an Enrollment Request.
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How have labs performed in the past?
AMRL provides Reports and a Compilation of Statistics from previous samples.
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What tests am I required to perform on a sample?
A non-accredited laboratory may perform any (or all) of the AASHTO or ASTM tests on a sample pair. Accredited laboratories must perform all offered test methods within the scope of their accreditation (i.e. every accredited test).
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What are the requirements for participating laboratories?
To participate, a laboratory must be equipped to perform some or all of the standard AASHTO or ASTM tests on soils, aggregates, asphalt binder, asphalt emulsion, or hot mix asphalt.
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Reminder: Please be sure to always include your PSP
Enrollment number on your datasheet.
This enables us to properly identify your laboratory. We will
be happy to assist you if you do not know your PSP Enrollment number. Please
contact us at:
psp@amrl.net
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