Picture: vibration test on a munitions lot
Last June, EDA’s 2019 ‘Round Robin Test’ was launched with the participation of nine laboratories from seven EDA Member States (Poland, the Netherlands, Finland, France, Germany, Lithuania, Cyprus) as well as from Norway (which has signed an Administrative Agreement with the Agency). The initiative is designed to compare test results obtained in different Member States laboratories working on ammunition safety.
These multinational tests, organised on a yearly basis under the auspices of EDA, are a central tool established by the European Network of National Safety authorities on Ammunition (ENNSA) whose objective is to enhance cooperation and interoperability between national authorities in charge of ammunition safety.
In a Round Robin Test (RTT), the results of different laboratories are all considered to be at the same level of quality: the intent is thus not to verify the accuracy of the results obtained from each and every laboratory by comparing them with the reference exact result, but rather to verify the dispersion of the data and the possibility of using a certain standard to obtain reliable results (within a certain range of errors considered tolerable), under different conditions. Therefore, what is evaluated in an RRT is the standard itself, not the performance of the laboratories. A successful RRT provides the assurance that the standard used is suitable to generate ‘reproducible’ results. A failed test, on the other hand, can help to highlight the need to amend and/or supplement the standard.
Focus on Energetic Materials
This year’s RRT is focused on the characterization of Energetic Materials, which are key components of any kind of ammunition, and more specifically on propellants (single-base nitrocellulose) and high explosives (HMX). All nine participating laboratories will soon receive samples from the same explosive batch and will be required to perform identical tests, all referring to explosive sensitivity and thermal stability, in particular: impact sensitivity, friction sensitivity, Differential Thermal Analysis (DTA),
Differential Scanning Calorimetry (DSC), Heat Flow Calorimetry (HFC), Thermogravimetric Analysis (TGA). The test is led by one of the most experienced European laboratories in this field, the Polish Laboratory of Combat Assets Testing of the Military Institute of Armament Technology (MIAT), located in Zielonka, near Warsaw. Coordinator of this test is Agata Kamieńska-Duda, Head of MIAT’S Ammunition Test Laboratory.
Room for improvement
Bogdan Krysiński, the current chairman of ENNSA, is responsible in MIAT for testing ammunition after long-term storage. He insists on the substantial added value provided by the annual Round Robin Tests initiative but also believes it could be further improved. “The RRT initiative is very valuable in many aspects. First of all, it allows everybody to compare research capabilities among the institutes and exchange experience among the researchers. However, it would be wrong to claim this is enough. Science never stops. Better methods of ammunition performance should be continuously sought for in order to provide a more precise assessment of its safety and operational reliability”, he commented.
“For many types of ammunition and their components it will be probably necessary to introduce a broader scope of testing than that used within the current RRT. Another issue is the need to develop unambiguous templates of documents for the preparation of the tests, as well as for the recording and reporting of the test results. Recent experiences confirm the importance of this. Continuous improvement of the Round Robin Test programme is thus something we should keep in mind for the benefit of all”, he stated.
In 2010 the EDA Steering Board approved the establishment of the European Network of National Safety authorities on Ammunition (ENNSA) with the primary task to facilitate communication among the national bodies which are in charge of ammunition safety. The focus of ENNSA, as agreed by its members, was to explore the harmonisation of ammunition qualification to improve interoperability and increase cooperation among Member States, in parallel with achieving savings across the ammunition production/procurement cycle. One of the basic tools designed for this purpose is the Round Robin Test (RRT) programme. It serves to compare and validate test results obtained in different laboratories of the Member States working within the area of ammunition safety.