Industrial Hygiene at 5G Speeds — Preliminary Field Measurements

1437 

Professional Poster 

R Adams¹

¹Ramboll, Portland, OR

Mr Robert Adams  
Ramboll

The purpose of this assessment was to measure the potential for exposures to radiofrequency radiation (RF) electromagnetic fields (EMF) to exceed OELs when utility service personnel work in proximity to 5G antennas. Additionally, another goal of the RF exposure assessments was to delineate within three dimensional space around the 5G antennas, safe approach boundaries or exclusion zones, outside of which the RF EMF exposure is below the OELs. Both quantitative and qualitative evaluations of the work environment relative to the potential for exposures to RF from the multiple distances around installed and operational 5G antennas were performed.

Fifth generation (5G) wireless antennas, like the current fourth generation (4G) antennas, will emit energy in the RF spectrum but at frequencies above 1 gigahertz (GHz) and potentially greater than 60 GHz. The demands for 5G mobile transmission speeds are expected to increase over the coming years as the rollout of this new technology progresses. There is limited scientific research available specific to 5G wireless technology. However, the principal concerns related to health effects, techniques and equipment for measurement, methods for doing predictive measurements, and exposure standards for RF have been documented and understood for decades. The main difference with respect to 5G wireless is that the frequency spectrum that is to be used has not been previously available for commercial telecommunications purposes. Another factor that the IH needs to be aware of is the potential for other sources of RF EMF to be present, as these new antennas will likely be mounted in the vicinity of existing wireless and radio/TV communication antennas and transmitters, as well as power lines, that also emit RF.

Measurements of power density (PD) were made at outdoor utility/ telecommunications poles where utility workers engaged in maintenance of telecommunications and wired infrastructure in proximity to fifth generation wireless systems (5G) antennas, operating in the range of >1 gigahertz (GHz) to around 50 GHz, that had been installed by wireless phone carriers in three US cities (Sacramento, Indianapolis, and Houston). The purpose of this exposure assessment was to evaluate the potential RF EMF exposures and compare PD measurements to regulatory or authoritative OELs. Specifically, the measurements were compared to the Federal Communications Commission (FCC) Maximum Permissible Exposure (MPE) limits for occupational exposures, the American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV) and the IEEE International Committee on Electromagnetic Safety (IEEE) MPE. RF measurements were collected using a NARDA Broadband Field Meter NBM-520 and EF 9051 probe, which measures the PD in milliwatts per square centimeter (mW/cm^2) of non-ionizing radiation in the >1 GHz to 50 GHz range. The probe was calibrated at several frequencies, and the correction values are stored in an erasable programmable read-only memory (EPROM) chip in the probe and automatically considered by the NBM-520 instrument. NARDA instruments are calibrated at their labs which are accredited by the relevant national accreditation agencies and meet the general requirements for competence for calibration laboratories outlined in ISO/IEC 17025.7F RF EMF measurements were taken by a pole man at the following distances: 6', 3', 1.5', 0.8' and at the 5G antenna (at the source) at different directions including right, left, front, back, top, and bottom,

The majority of the RF EMF data sets obtained during this initial assessment of the 5G wireless rollout suggests that maintenance, construction, or utility workers can work at distances as close as 30 cm (1 ft) from operating 5G antennas and not exceed the a maximum permissible exposure (for 60-minute time weighted average) of 1 mW/cm2. However, the potential for interference from high powered transmission lines near 5G antenna installations may cause erroneous readings as well as the presence of other antennas and transmitters are likely to add to these levels. Additionally, nearby reflecting surfaces can create regions of field intensification, or hot spots. Preliminary data suggests that there is a need to consider there may be quite large variations in the power density depending on the power output of the 5G antenna, operating frequency, orientation relative to the location of the worker, and number of antennas in an array. Additionally, predictive data models suggest, when 5G antennas are operated at full power, and there are multiple antennas in an array, exposures to RF energy could be higher than the measured results from this initial assessment, requiring greater distances from the source to stay below OELs. As the 5G rollout continues, additional investigation appears to be prudent. Companies that may have workers that will be required to work in proximity to 5G antennas should consider the establishment of RF EMF safety programs, provide training for workers prior to assignment in work areas with 5G (or any other wireless antennas or transmitters), and use personnel monitoring, especially for work that will take place around live antennas or transmitters.

Construction

Exposure Assessment Strategies

Radiation (Ionizing and Nonionizing)