How the ASTM Interlaboratory Study Program Can Help You
Since the inception of ASTM International’s Interlaboratory Study Program in 2005, more than 135 individual programs have been registered by committee members. Some programs have been simple, others quite intricate, but all have come with their own unique challenges and obstacles to overcome.
The ASTM technical committee members who manage their committee’s ILS often do an excellent job of setting up the studies, but sometimes they hit a roadblock they simply can’t overcome. One advantage of the ILS program is that ASTM staff can pick up and assist at any point in a program, from coming up with the original design at the outset of a program, to provide statistical support. ASTM members can contact staff and choose the specific help they need, cafeteria style.
For Dennis Hetzner of Committee E04 on Metallurgy, laboratories were on the menu. Although he had his protocol and samples all ready to go, Hetzner had little luck obtaining volunteer labs for the study. In order for an interlaboratory study to produce a viable precision and bias statement, usable data must be received from a minimum of six labs, so finding additional help was vital to the success of the program.
In response to the committee’s need, the ASTM ILS staff sent a lab solicitation to the members of Committee E04, and received about a dozen replies from laboratories that were interested in volunteering for the study. Still, Hetzner was concerned that even 12 labs might be too low a number.
Every study goes through a certain amount of attrition, as even labs that genuinely want to participate might find themselves unable to complete the study due to time constraints or scheduling conflicts. It seemed unlikely that any more labs would be coming from the E04 talent pool, so the ILS staff sought help from Committee A01 on Steel, Stainless Steel and Related Alloys. When all was said and done, Hetzner had more than 40 labs volunteering to help with the study.
Shipment of Samples
Andrew Rutkiewic of ASTM International Committee E12 on Color and Appearance had already figured out most of the details for his ILS program, including the preparation of a set of painted panels to use as samples, but did not have a good way to ship them. The program was designed to test the finish on the samples, so it was vital that the panels remain absolutely pristine as they moved from lab to lab.
Compounding the issue was the fact that some of the labs taking part in the study were overseas, ensuring that the samples would encounter some fairly rugged handling. A container that would accommodate the samples while preserving their integrity simply did not exist, so the ILS team had one made. After some research, the ASTM ILS department managed to find a plastics manufacturer capable of constructing a reusable storage and shipping container that would not only fully protect the panels, but also be easy for lab techs to handle. The container worked perfectly and the samples arrived at each of their destinations intact.
Rutkiewic knew the main obstacle facing his ILS program from the very beginning, but it was not until Alexander Salenikovich’s study was in full swing that a problem arose. The ILS he was managing for his committee, D07 on Wood, required samples of structural lumber to be shipped to a number of laboratories in both the United States and Canada, round-robin style. The specimens were enormous, but surprisingly that was not what ultimately caused a hang-up. After successfully traveling among several different labs across the northwestern United States, the lumber samples made their way into Canada, where they were tested at another six laboratories, after which they vanished. The next American lab on the round robin schedule had yet to receive them, but the last Canadian lab to test them no longer had them.
ASTM’s ILS team quickly moved to track down the errant shipment, finally discovering that a simple misunderstanding with the paperwork had left the lumber stranded at the border. An expediter regularly used by ASTM was called upon to step in and clear up the issue, which solved the problem quickly and sent the specimens on their way back to Idaho.
Getting the Right Materials
Even when materials are readily available, they can cause issues with an interlaboratory study. Randy Dickerman’s ILS for Committee F03 on Gaskets involved testing the blowout pressure of room temperature vulcanized elastomers and required the use of certain fixtures meant to mimic the function of a T-joint in a car’s engine block. Most of the participating labs had fixtures that would have been appropriate to the task, but using them could have added unwanted and uncontrollable variables to the procedure, making it difficult to determine if a blowout occurred because of the sealant or because of some variation in the fixture.
A study is only as good as the data it captures, so keeping known variables to an absolute minimum can be the difference between useful information and a waste of time and money. To maintain the integrity of the study and ensure that the variability of the method was what was being tested, the ILS and Committee F03 had a set of aluminum fixtures specially machined to ensure that they adhered to the template published in the standard in every way possible.
While most committees that register ILS programs need help with finances, samples or shipping, some need a slightly different kind of support. Committee E12’s Marina Batzke already had a study up and running when she asked for some help crunching numbers. Typically, the ILS staff prepares precision and bias statements once all study data has been received, but Batzke was hoping to have some information to present at an upcoming committee meeting, so a P&B was developed using the data from just a handful of labs. This process was repeated a few months later for another meeting, but it was quickly becoming clear that unless more labs were added to the study, the data would never be as illuminating or accurate as it could be. A few more laboratories were recruited to help with the testing, which greatly improved the statistical validity of the study.
It’s a certainty that the interlaboratory studies of 2007 will offer an entirely new set of challenges for the committee members who register them, but ASTM’s ILS staff will be ready and waiting to help out however and whenever they’re needed. We eagerly anticipate the challenges of the coming year. Our capabilities keep growing, and we are looking forward to continuing our work with the 51 committees that have already registered studies. ASTM staff is also excited about building new relationships with many more committees as we continue to develop this vibrant program. //