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Description / Abstract:
This document is concerned with the fact that an electric
blasting cap (initiator) might explode unexpectedly when a nearby
radio transmitter is turned on. A cap can absorb electrical energy
from a free-space electromagnetic field of the type produced by
radio and radar transmitters. This document provides
recommendations for limiting the amount of electrical energy
absorbed and recommended methods for determining safe distances
from radio and radar transmitting antennas when one is using
electric blasting caps. Safety is determined by comparing the RF
power pickup to the blasting cap’s no-fire power level. This
criterion is valid over the frequency range 3 kHz to 300 GHz that
is commonly discussed in connection with RF safety. Radio frequency
transmitters that a blaster might encounter occupy only a small
portion of this frequency range. Specifically, this document
explains how to determine safe distances from RF transmitters with
spectrum bands from 10 kHz to 12 GHz, including VHF and UHF
television antennas, FM and AM radio transmitting antennas, radar,
navigation beacons, and portable communication devices.
This document excludes criteria for the use of electro-explosive
devices (EEDs) with electrically conductive enclosures or weapons
containers, and it does not include sufficient information on
hazards deriving from electrostatics or from electromagnetic fields
generated by other sources of energy, such as electrical storms,
electromechanical equipment, electrical power plants, or power
transmission lines. This document does not apply to the use of
non-electric detonators.