Recommended Practice for Determining Safe Distances from Radio Frequency Transmitting Antennas When Using Electric Blasting Caps During Explosive Operations
|Publication Date:||11 November 2002|
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.