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MIL-STD-810, Environmental Engineering Considerations and Laboratory Tests is a United States Military Standard that emphasizes tailoring an equipment's environmental design and test limits to the conditions that it will experience throughout its service life, and establishing chamber test methods that replicate the effects of environments on the equipment rather than imitating the environments themselves. The MIL-STD-810 test series are approved for use by all departments and agencies of the United States Department of Defense (DoD). Although prepared specifically for military applications, the standard is often used for commercial products as well. The current document revision (as of 2012) is MIL-STD-810G which was issued on October 31, 2008. It superseded MIL-STD-810F released on January 1, 2000 and which was last updated on May 5, 2003. The standard's guidance and test methods are intended to: (i) Define environmental stress sequences, durations, and levels of equipment life cycles; (ii) Be used to develop analysis and test criteria tailored to the equipment and its environmental life cycle; (iii) Evaluate equipment's performance when exposed to a life cycle of environmental stresses; (iv) Identify deficiencies, shortcomings, and defects in equipment design, materials, manufacturing processes, packaging techniques, and maintenance methods; and (v) Demonstrate compliance with contractual requirements.
MIL-STD-810 is maintained by a Tri-Service partnership that includes the USAF, the US Army, and the US Navy. The U.S. Army Test and Evaluation Command, or ATEC, serves as Lead Standardization Activity / Preparing Activity, and is chartered under the Defense Standardization Program (DSP) with maintaining the functional expertise and serving as the DoD-wide technical focal point for the standard.
MIL-STD-810 addresses a broad range of environmental conditions that include: low pressure for altitude testing; exposure to high and low temperatures plus temperature shock (both operating and in storage); rain (including wind blown and freezing rain); humidity, fungus, salt fog for rust testing; sand and dust exposure; explosive atmosphere; leakage; acceleration; shock and transport shock; gunfire vibration; and random vibration. The standard describes environmental management and engineering processes that can be of enormous value to generate confidence in the environmental worthiness and overall durability of a system design. The standard contains military acquisition program planning and engineering direction to consider the influences that environmental stresses have on equipment throughout all phases of its service life. The document does not impose design or test specifications. Rather, it describes the environmental tailoring process that results in realistic material designs and test methods based on material system performance requirements.
Finally, there are limitations inherent in laboratory testing that make it imperative to use proper engineering judgement to extrapolate laboratory results to results that may be obtained under actual service conditions. In many cases, real-world environmental stresses (singularly or in combination) cannot be duplicated in test laboratories. Therefore, users should not assume that an item that passes laboratory testing also will pass field/fleet verification tests.
In 1945, the Army Air Force (AAF) released the first specification providing a formal methodology for testing equipment under simulated environmental conditions. That document, entitled AAF Specification 41065, Equipment - General Specification for Environmental Test of, is the direct ancestor of MIL-STD-810. In 1965, the USAF released a technical report with data and information on the origination and development of natural and induced environmental tests intended for aerospace and ground equipment. By using that document, the design engineer obtained a clearer understanding of the interpretation, application, and relationship of environmental testing to military equipment and material.
The Institute of Environmental Sciences and Technology (IEST), a non-profit technical society, released the publication History and Rationale of MIL-STD-810 to capture the thought process behind the evolution of MIL-STD-810. It also provides a development history of test methods, rationale for many procedural changes, tailoring guidance for many test procedures, and insight into the future direction of the standard.
The MIL-STD-810 test series originally addressed generic laboratory environmental testing. The first edition of MIL-STD-810 in 1962 included only a single sentence allowing users to modify tests to reflect environmental conditions. Subsequent editions contained essentially the same phrase, but did not elaborate on the subject until MIL-STD-810D was issued marking one of the more significant revisions of the standard with its focus more on shock and vibration tests that closely mirrored real-world operating environments. MIL-STD-810F further defined test methods while continuing the concept of creating test chambers that simulate conditions likely to be encountered during a product's useful life rather than simply replicating the actual environments. More recently, MIL-STD-810G implements Test Method 527 calling for the use of multiple vibration exciters to perform multi-axis shaking that simultaneously excites all test article resonances and simulates real-world vibrations. This approach replaces the legacy approach of three distinct tests, i.e., shaking a load first in its x axis, then its y axis, and finally in its z axis.
A matrix of the tests and methods of MIL-STD-810 through Revision G is available on the web and quite useful in comparing the changes among the various revisions .
The following table traces the specification's evolution in terms of environmental tailoring to meet a specific user's needs.
|Version of MIL-STD-810||Date||Focus on Environmental Considerations|
|MIL-STD-810||14-June-1962||One sentence under “Purpose” states that the laboratory test methods serve as a guide to those who prepare environmental portions of detail specifications. One sentence on tailoring.|
|MIL-STD-810A ||23-Jun-1964||Same as MIL-STD-810.|
|MIL-STD-810B||15-Jun-1967||One sentence under “Purpose/Scope” states that the standard establishes methods for determining the resistance of equipment to the effects of natural and induced environments peculiar to military operations. One sentence on tailoring.|
|MIL-STD-810C||03-Oct-1975||Same as MIL-STD-810B|
|MIL-STD-810D||19-Jul-1983||A section on tailoring explains how to consider environmental issues throughout the materiel development process. Includes diagrams on the environmental tailoring process and on environmental life cycle histories of various classes of military hardware.|
|MIL-STD-810E||14-Jul-1989||Same as 810D with addition of a flow diagram, “How to Use MIL-STD-810E,” that shows how Data Item Descriptions relate to each other in the acquisition process and who is responsible for preparing them.|
|MIL-STD-810F||01-Jan-2000||New 54-page “Part One” explains how to implement the environmental tailoring process throughout the material acquisition cycle, focusing separately on the roles of the different users. Includes Environmental Engineering Program Guide. The guidance goes beyond laboratory testing to encompass natural environment field/fleet testing. Alternatives to testing hardware prototypes (e.g., modeling and simulation) are recognized as standard environmental engineering test practices.|
Part One of MIL-STD-810G describes management, engineering, and technical roles in the environmental design and test tailoring process. It focuses on the process of tailoring design and test criteria to the specific environmental conditions an equipment item is likely to encounter during its service life. New appendices support the succinctly presented text of Part One. It describes the tailoring process (i.e., systematically considering detrimental effects that various environmental factors may have on a specific equipment throughout its service life) and applies this process throughout the equipment's life cycle to meet user and interoperability needs.
Part Two of MIL-STD-810G contains the environmental laboratory test methods to be applied using the test tailoring guidelines described in Part One of the document. With the exception of Test Method 528, these methods are not mandatory, but rather the appropriate method is selected and tailored to generate the most relevant test data possible. Each test method in Part Two contains some environmental data and references, and it identifies particular tailoring opportunities. Each test method supports the test engineer by describing preferred laboratory test facilities and methodologies. These environmental management and engineering processes can be of enormous value to generate confidence in the environmental worthiness and overall durability of equipment and material. Still, the user must recognize that there are limitations inherent in laboratory testing that make it imperative to use engineering judgment when extrapolating from laboratory results to results that may be obtained under actual service conditions. In many cases, real-world environmental stresses (singularly or in combination) cannot be duplicated practically or reliably in test laboratories. Therefore, users should not assume that a system or component that passes laboratory tests of this standard also would pass field/fleet verification trials.
Specific examples of Test Methods called out in MIL-STD-810G are listed below:
Part Three contains a compendium of climatic data and guidance assembled from several sources, including AR 70-38, Research, Development, Test and Evaluation of Materiel for Extreme Climatic Conditions (1979), a draft version of AR 70-38 (1990) that was developed using Air Land Battlefield Environment (ALBE) report information, Environmental Factors and Standards for Atmospheric Obscurants, Climate, and Terrain (1987), and MIL-HDBK-310, Global Climatic Data for Developing Military Products. It also provides planning guidance for realistic consideration (i.e., starting points) of climatic conditions in various regions throughout the world.
MIL-STD-810 is a flexible standard that allows users to tailor test methods to fit the application. As a result, a vendor's claims of "...compliance to MIL-STD-810..." can be misleading. Because no commercial organization or agency certifies compliance, commercial vendors can create the test methods or approaches to fit their product. Suppliers can—and some do—take significant latitude with how they test their products, and how they report the test results. When queried, many manufacturers will admit no testing has actually been done and that the product is only designed/engineered/built-to comply with the standard. This is because many of the tests described can be expensive to perform and usually require special facilities. Consumers who require rugged products should verify which test methods that compliance is claimed against and which parameter limits were selected for testing. Also, if some testing was actually done they would have to specify: (i) against which test methods of the standard the compliance is claimed; (ii) to which parameter limits the items were actually tested; and (iii) whether the testing was done internally or externally by an independent testing facility.
Specific examples of laboratories where test methods called out in MIL-STD-810G are performed: