EMR Home Assessment and RF shielding
Testing date: August 8 2017
A 700 square foot mobile home build in 1980, located on the border of the Los Osos Oak Preserve. There is a cell tower .72 miles to the East and a second at 1.5 miles. Both have multiple antennas operated by the local telecom service providers. There are other RF sources from the neighbors including wifi routers and cordless phones. The exterior shell of the mobile home is aluminum which reduces the RF penetration. Some of the windows have been upgraded to Low-E glass which also helps. No internal sources of RF and no Smart meter.
Radio frequency penetration
Internal measurements at locations 3,4,5,6 and 14 averaged above 30 μW/m² which places as “severe” concern by Building Biology Standards. The Kitchen window at Location 7 is Low-E and the angle seems to deflect a good portion of the RF radiation away from the interior. Location 8 and 5 were surprisingly high and I believe the radiation source to be both reflected from the cell towers off the neighbors siding and the neighbors cordless phone directly. External measurements are much higher with peak readings at 3500 μW/m² in the 27MHz -> 10GHz ranges. Again showing the aluminum siding and Low-E glass providing some protection as the interior levels were much lower.
Signal Protect window film
We focused on the windows at locations 3,4,5,6 and 14. I recommend Signal Protect clear window film from Safe Living Technologies and to reduce the cost, replacing vinyl window screens on the lower half of the window with metal which does a decent job of shielding RF. The window at location 5 was considered to large and expensive to film, so shielding fabric was purchased from LessEMF to drape in the inside.
Results
Measurements after shielding averaged < 10 μW/m² putting it around 70% reduction and in the Building Biology “slight” concern.
Performing an EMR assessment I detected and grounded a huge electric field. It was located in the bedroom wall and radiating several feet into the room. At 464 V/m the client was motivated to investigate and mitigate. He opened the wall to expose the one ROMEX cable inside. There was no physical damage to the cable, but at the one point the field strength was huge. We created a quick fix by wrapping the offending section in metal screen, crimping on a piece of 14 gauge wire and connecting into the circuit ground. We dropped from 464 to 5 V/m. I would call that a successful reduction. 99%