How do Military standards and testing differ to Commercial EMC test standards?

Both civil and military EMC standards are designed around the same principal, to prove that the equipment under test is fit for purpose and to operate in its intended environment.

However, military environment tend to be more hostile and therefore military EMC test levels are usually more severe. For example, the civil radiated immunity requirement for equipment intended for use in an industrial environment is a field strength of 10 V/m where as for military testing this can be 200 V/m and higher.

The driving force behind Commercial Test Standards and testing is EU legislation. A piece of commercial equipment will be tested to the correct product specific, product family or generic harmonised EU test standards. To ensure that a test in the UK to BS EN55011 will be just as relevant and acceptable as a test in Germany to DIN EN 55011 and in some cases to outside of the EU so that it’s also as relevant and acceptable as a test in Australia to AS/NZS CISPR 11.

The driving force behind Military testing are usually contractual requirements. A piece of military equipment will be tested to either the relevant countries own Military Test Standards (Def Stan for the UK, Mil Std for the US) or to the military standard that the country has chosen to adopt. In addition to this military equipment may then be subject to additional testing from product specific specifications.  For example, military aircraft may be subject to tests from the RTCA airborne test specifications as well as Def Stan or Mil Std. For larger military projects, specific product EMC Test Standards may be developed and written to cover that product only, an example of this is the EFA specs for the Euro-fighter project.

If we have a multi role piece of military hardware that is airborne, ship borne and also fitted to land vehicles then a complete set of Def Stan testing would be the very minimum required. If this product is also being marketed to the US, then a gap analysis of Def Stan to Mil Std specifications may be required to identify areas that Mil Std differs from Def Stan. On top of this, tests from the RTCA specifications will be relevant for the airborne version and Commercial Maritime test standards may be relevant for the ship borne version.

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