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  • Revision:2015 Edition, 2015
  • Published Date:January 2015
  • Status:Active, Most Current
  • Document Language:English
  • Published By:Institute of Electrical and Electronics Engineers (IEEE)
  • Page Count:46
  • ANSI Approved:Yes
  • DoD Adopted:No

  • This recommended practice presents a rationale for developingemission limits and immunity test levels and recommends that thesefacets are representative of current practice and user needs.Emission limits generally are written by national and internationalstandards bodies. Emission limits for the most part are specifiedby regulators, which is the case in the U.S. and Canada. Suchregulatory limits take precedence, even if the limits are differentfrom those considered in this document. In the U.S. and Canada,product immunity is not regulated except for some safety equipment.In this way, adequate immunity is more a quality aspect of theproduct as if it does not operate in its intended RF environment,the user would deem it of poor quality. It should be noted that theentire document does not impose normative requirements, butrecommends options.


    The main purpose of this recommended practice is to aidmanufacturers who might need to modify the emissions their productsgenerate (as long as regulatory limits are met) to meet for exampleintra-system needs for their products. There might also be a needto have different (higher) immunity test levels than what istypically required if the product will be used in severeelectromagnetic environments. As the use of electronics isconstantly changing (e.g., the Smart Grid [B10]1), the testmethods, immunity test levels, and emission limits likewise need tobe periodically reviewed to assure that EMC is maintained. In fact,these EMC considerations might have to be tailored for specificdesigns and go beyond regulatory requirements to ensure properproduct operation at the user location, which is exposed to amyriad of RF environments and where it is likely that there areother electronic products that might suffer interference from RFgenerated by the product. The emissions and immunity measurementtechnique used can have an impact on the accuracy, repeatability,and reproducibility of the test results. Emissions from productsshould be controlled to protect radio services by not causinginterference, and at the same time, products should have sufficientimmunity to be able to operate as intended in the RF environmentsexpected in locations where the products are intended to beused.

    As part of the development of emission limits and immunity testlevels, the following topics are discussed in this recommendedpractice:

    a) The general properties of both man-made and naturalenvironmental electromagnetic noise (disturbances), as this willimpact the product immunity test levels and immunity tests that areneeded so that a product performs within manufacturer’sspecifications in the intended use environments

    b) Selection, capabilities, and use of proper emissionsmeasurement instrumentation.

    c) The test instrumentation used to simulate the RF environmentto which products are expected to be exposed so that the productswork properly with minimal customer EMC complaints.

    d) A defensible rationale that can be used in selecting aconsistent set of limits for emissions and test levels forimmunity,2 subject to good engineering practice and cost-effectiveEMC management, taking into account any regulatory requirements.Topic a) through topic

    d) of this subclause are intended to be applicable to individualproducts as well as systems of various sizes and, if properlyapplied, provide guidance for obtaining both intrasystem andintersystem electromagnetic compatibility. This recommendedpractice assists manufacturers in specifying their own emissionslimits (but as a minimum meeting regulatory and user requirements)and test levels as appropriate for their product to functionproperly and to not cause any undesired interference.

    NOTE—Emission limits and immunity test levels along with thenecessary measurement techniques described herein are proposed forgeneral use to the extent that they are not covered in regulationsor in customer requirements.