The high intensity radio frequency (RFR) fieldsproduced by modern radio and radar transmittingequipment can cause sensitive electroexplosivedevices (EEDs) contained in ordnance systems toactuate prematurely. The Hazards of ElectromagneticRadiation to Ordnance (HERO) problem was firstrecognized in 1958. The prime factors causing theproblem have been increasing ever since. The use ofEEDs in ordnance systems has become essential. Atthe same time, the power output and frequency rangesof radio and radar transmitting equipment have alsoincreased.RFR energy may enter an ordnance item through ahole or crack in its skin or through firing leads, wires,and so on. In general, ordnance systems that aresusceptible to RFR energy are most susceptible duringassembly, disassembly, loading, unloading, andhandling in RFR electromagnetic fields.The most likely results of premature actuation arepropellant ignition or reduction of reliability bydudding. Where out-of-line Safety and Arming (S + A)devices are used; the actuation of EEDs may beundetectable unless the item is disassembled. If theitem does not contain an S + A device, or if RFR energybypasses the S + A device, the warhead may detonate.Ordnance items susceptible to RFR can beassigned one of three HERO classifications, basedupon the probability that they will be adversely a f f e c t e d b y t h e R F R e n v i r o n m e n t . T h o s eclassifications are:1. HERO Safe. An ordnance item sufficientlyshielded or protected to make it immune toadverse effects from RFR when used in itsexpected shipboard RFR environments.2. HERO susceptible. Ordnance containing EEDsproven by tests to be adversely affected by RFRenergy to the point that safety or reliability maybe in jeopardy when the ordnance is used in RFRenvironments.3. HERO unsafe. Any electrically initiatedordnance item that becomes unsafe when:a. Its internal wiring is physically exposed.b. Tests being conducted on the item requireadditional electrical connections to be made.c. Electroexplosive devices (EEDs) havingexposed wire leads are present, handled, orloaded.d. T h e i t e m i s b e i n g a s s e m b l e d o rdisassembled.e. The item is in a disassembled condition.f. The item contains one or more EEDs and hasnot been classified as HERO safe orsusceptible by either a test or designanalysis.To ensure the HERO safety and HERO reliabilityof ordnance systems, the Naval Sea SystemsCommand sponsors an extensive testing program todetermine their susceptibility to RFR energy. HEROrequirements and precautions are provided inNAVSEA OP 3565/NAVAIR 16-1-529/NAVELEX0967-LP-624-6010/Volume II, ElectromagneticRadiation Hazards (U) (Hazards to Ordnance) (U).You will find your ship’s specific requirements in itsHERO Emission Control (EMCON) bill.The commanding officer of each ship or shorestation is responsible for implementing HEROrequirements. He or she must also establish aprocedure to control radiation from radio and radarantennas among personnel handling ordnance andpersonnel controlling radio and radar transmitters. Thecommanding officer does this through a commandinstruction based on the ship’s mission and specialfeatures. This instruction is usually part of the Ship’sOrganization Manual and is the basis for departmentand division instructions
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