The Invisible Worksite Hazard – AM Broadcast RF Signals

There are over 5000 AM broadcast stations located throughout the United States. For most construction trades, the hazards related to their RF emissions are not a factor, being limited to fenced and signed areas a few yards in radius about the base of the broadcast tower. However, trades using cranes, pile drivers, and other heavy equipment with long booms and cables are at much greater risk. The radio “profile” of this equipment can effectively capture and amplify the waves, and present a physical and personnel hazard as much as two miles away from a station – and the tower may not even be visible from the worksite.

Recently, a contractor had to shut down a New Orleans bulkhead project when sling cables supporting a hydraulic vibrator from a 165’ boom began arcing and burning. Personnel on the barge and divers in the water were reporting burns. After consultation with LBA engineers, contractor personnel checked and cleared the site of possible problems with welders, shore power, generators, etc., but the problem persisted. An engineer was mobilized to the site where he was able to precisely locate the relationship to AM stations, and coordinate office computations of impact on the contractor’s equipment. Measurements confirmed influences from three station of sufficient magnitude to cause the problems being experienced. Working with the project engineer, the LBA engineer was able to devise rigging and work protocols that eliminated all RF safety hazards from the project, which was able then to resume.

In another case, a contractor found that a large water tank project was located only a few hundred feet from a directional AM station. Workers were getting burned and rigging cables were arcing. Subsequent LBA studies examined health issues and advised on remediation. Also, LBA found the tank to significantly alter the operation of the AM station due to its proximity, raising serious liability and Federal Communications Commission compliance issues for both owners and contractors. Specialized permanent electronic add-ons to the structure were determined by LBA to be required to comply with Federal Law to protect the AM station.

Yes, your construction equipment can also disrupt AM station signals!  Read more here.