Progress in the development of HEMP protection standards for C3I facilities

A brief summary is presented of US Department of Defense (DOD) efforts for standardizing a high electromagnetic pulse (HEMP) radiation hardening approach for critical fixed ground-based command, control, and communication and intelligence (FGBC³I) facilities. The approach adopted by DOD for hardening FGBC³I facilities is called the low-risk hardening approach. This approach relies principally upon an electromagnetic barrier to prevent unacceptable electrical transients from reaching potentially vulnerable system components. The barrier consists of (1) an electromagnetic shield (steel or copper) which fully encloses all mission-critical components, and (2) treatment of each electrical penetration of the shield and each aperture in the shield to attenuate the transmission of conducted transients adequately. The number of shield penetrations and apertures is strictly controlled to facilitate validation testing. The low-risk hardening approach is illustrated. The hardening approach will be promulgated in MIL-STD-188-125 scheduled to appear in early 1990