We will be introducing a new weekly article series about what so-called "environmental tests" are applied in the defense industry in our PALS News section. This article series will be planned with each test per article containing information regarding the subjected test and its effects on design to be able to pass these tests. This introduction article will be focusing on general information that needs to be taken into account before each subject.
MIL-STD-810 is the most commonly known and applied standard in the defense sector, although many others exist. The reason is that MIL-STD-810 was written by the Department of Defense (a.k.a. DoD) of the USA. All defense products and parts need to be interchangeable at some level amongst NATO members. This and many other military standards of the DoD are asked to be complied with by many products manufactured. There are many articles about the subject on the internet. We will try to share more feasible, useful information, such as how to read it. How to apply it?
WHAT IS IT?
MIL-STD-810 is “ENVIRONMENTAL ENGINEERING CONSIDERATIONS AND LABORATORY TESTS”. Everyone somehow knows its name and it is about tests. But please note the name goes as and I quote “engineering considerations” before “Laboratory Tests”. So it is a guidance for;
• Materiel Acquisition Managers whose responsibilities is ensuring material will function as required in intended operational environments,
• Environmental Test Specialist who assist the designers throughout the process to tailor their materiel designs and test designs to environmental conditions during the material's service life,
• Design/Test Engineers and Test Facility Operators who need to meet environmental condition materials intended service life,
As technology advances, design and test capabilities and manufacturing processes become more refined. Thus the standard is revised and revisions go as A, B. Although the current revision in force is H, as it takes time to get an approval of revisions in bureaucracy, older revisions such as G or F can be asked to apply as well.
Each environmental test is called a method, and some methods may contain procedures defining each method. This article series will be intended to subject all methods in the MIL-STD-810G are given in the table below.
WHAT IS TAILORING?
This standard was written to be applied to many products. Please note that this standard may apply to, i.e., an armored ground personnel carrier, or as in PALS’ case, to the PDA-150-MIL transportable, automatic satellite acquisitioning communication system as well. So it has to be "tailored" to each and every product itself. This means this standard does not impose test or design specifications but rather describes tailoring in order to result in a more realistic design or test process based on the product's intended performance requirements.
In more simple words, performance requirements are different for each product. If you happen to be a purchase, environmental conditions, or design specialist, I.e., we will take the low temperature for this example, one of the many performance goals for PDA-150-MIL was to automatically acquire satellite signal under the -30 degree Celsius condition applied. But for PAC-550, it was being able to control PDA-150-MIL from all interfaces within the same condition. In conclusion, MIL-STD-810 is tailored differently for each of them. In all phases of determining performance criteria, designing to pass the test, manufacturing, conducting tests to qualify the criteria, and purchasing by the defense sector responsible.
For more information:
QUALIFICATION TEST PROCEDURE (QTP) OR TEST PLAN
A test plan or qualification test procedure must be prepared according to tailoring. Meaning success (pass/fail) criteria of material need to be set first. Performance test procedures need to be defined and written in detail. Environmental test procedures can be referred to as standards with the tailoring of when and how to conduct performance tests as the environmental test procedure states. Please keep in mind that environmental tests and performance tests are conducted by environmental condition test experts who may or may not be familiar with the product. QTP must be written in detail, step-by-step.
To be continued…
DID YOU KNOW?
PALS Electronics has experts on all subjects of test engineering, mechanical or electronic design, environmental condition engineer, system engineer etc. PALS provides consulting, training, tailoring, test plan, test engineering, test services in all phases of your project. Please feel free if you have any questions or inquiries from https://pals.com.tr/contact
by System Integration Engineer, Özdemir Öztürk