edVirtus Reference

What Are Hazards of Electromagnetic Radiation to Ordnance (HERO)?

How Can RF Energy Affect Electrically Initiated Explosive Devices?

Hazards of electromagnetic radiation to ordnance, abbreviated HERO, are the potential safety or reliability effects of RF energy on ordnance containing electro-explosive devices or other electrically initiated components.

Wiring, connectors, firing circuits, and conductive structures can act as receiving elements in an RF field. If sufficient energy couples into an initiation circuit, it may heat a bridge wire, disturb electronics, damage a component, or in an extreme case cause unintended functioning.

HERO risk depends on the external electromagnetic environment and the susceptibility of the ordnance in its actual configuration. Frequency, field strength, modulation, antenna proximity, cable geometry, shielding, assembly state, damage, exposed wiring, and maintenance connections can all affect the coupled energy.

Ordnance classifications and terminology are defined by the applicable military or organizational standard. Common classifications distinguish items that have been demonstrated safe from those that are susceptible or must be treated as unsafe in a specified RF environment. A classification is valid only for the tested or analyzed configuration.

HERO assessment uses approved analysis, instrumented tests, system-level immunity testing, and surveys of the RF environment. The objective is to establish operating restrictions or separation distances that keep coupled energy below the criterion for the ordnance item.

Controls can include restricting portable and fixed transmitters, maintaining specified separation distances, using approved shielding and packaging, controlling assembly and maintenance states, applying configuration-specific labels, and de-energizing transmitters during sensitive operations.

Personnel exposure compliance does not establish HERO safety. Ordnance may require lower field levels or greater separation because the consequence of unintended initiation is severe and the relevant receptor is an electrical firing circuit rather than human tissue.

HERO work must follow the controlling explosives-safety and electromagnetic-environment documentation. The brief explains the engineering principle, but it does not replace item-specific classifications, surveys, procedures, or authorized safety advice.