RF Abatement of a Class A Office Space
RF Abatement – Summary
RF Issues: Cell Phone Antenna-sourced RF Radiation on Neighboring Rooftop
Problem in detail: Client’s Class A downtown San Francisco office space was being strongly affected by three moderately large cell antennas directed squarely at the office. They were mounted on a neighboring rooftop, roughly 100 feet away as measured on Google Earth. The mostly glass siding of the Class A office space offered no shielding against the RF radiation from such large cell antennas at such a close distance. While the client had not noted health problems for any particular office workers, they had noted that their phone lines and networking lines had extremely high levels of static, making their phone systems almost unusable. Their WiFi networking range was also greatly diminished, likely due to interference.
Mapping the RF radiation strength in the rooms of the Class A office space yielded:
Nearly all the rooms on the side facing the neighboring rooftop’s cell antennas were well in excess of 10,000 uW/m2. Various health related groups consider RF radiation power density levels over 1000 uW/m2 to be of high concern.
Other factors to consider: There appeared to be an anti-shatter film on the building’s glass. The office also had a high air conditioning bill.
RF Abatement Project Management:
- Various window films were researched and categorized for the applications of providing security and anti-shatter qualities with a low heat gain coefficient and, above all, RF-shielding capabilities. Our research yielded a film that provided all of these qualities for 60% less cost than traditional RF-shielding window films.
- Window film application professionals were invited to bid on the project with quality vs cost comparisons showcased to the client.
- The window film application professional removed all traces of the old window film and applied the new RF-shielding window film.
- Shortly after the window film was applied, RF radiation levels were verified to have diminished.
RF Abatement Results after Implementation:
Office personnel reported that phone line static was reduced to barely noticeable when listening with an intent ear for static. Below are the quantified values of measured RF radiation power density levels.
|Before installation of RF-shielding window film||After installation of RF-shielding window film||Percentage Reduction|
|Rooms facing cell antennas||31,000 microWatts per meter^2 (uW/m2)||990 uW/m2||96.8%|
|38,000 uW/m2||1850 uW/m2||95.1%|
|Not taken||1140 uW/m2||—|
|45,000 uW/m2||2610 uW/m2||94.2%|
|59,000 uW/m2||2870 uW/m2||95.1%|
|15,530 uW/m2||1080 uW/m2||93%|
|15,810 uW/m2||1210 uW/m2||92.3%|
|11,720 uW/m2||720 uW/m2||93.9%|
|4960 uW/m2||450 uW/m2||90.9%|
As shown above, the reduction due to the RF-shielding window film was very effective. The minimum reduction experienced was 90.9%
and the average reduction was 93.9%. While it is possible to reduce RF radiation power density further through other means, the main objective of this RF mitigation was met. The high RF radiation power density that was affecting the phone lines and WiFi networking was reduced to much more manageable levels, eliminating RF interference (static) on phone lines and improving WiFi networking functionality.
By: Cameron Freres, Environmental Inspector, EMF Consultant & Building Biologist Environmental Consultant
BPI BA, BBEC, EMRS, CDPH LA