Case 5.  Warehouse Accounting Office in Sacramento, California...

Clients' Concerns:  An office area close to the main electrical meter and distribution panel in this large warehouse was experiencing annoying interference problems on some of the computer screens.  The clients suspected that the problem might be due to electromagnetic interference (EMI) from either the main electrical panel or the nearby electrical transformer.  They also wished to minimize EMF levels for employees. 

Source of the Magnetic Fields:  Our measurements confirmed that strong magnetic fields from the main electric meter and distribution panel in the warehouse were the chief cause of the high EMFs and computer interference in the nearby accounting office.  (Please click image for a full-sized picture of the meter panel.  In this picture, you can also see a layer of shielding material that we installed onto the wall directly behind the meter panel to reduce the levels.)

Solution Implemented:  The most cost effective mitigation for this particular case was to install several layers of magnetic shielding alloy onto the walls near the electric meter equipment.  This picture shows one layer of shielding material as it is being stapled to the existing wall inside the accounting office.  The final shield design included multiple layers of 6 mil thick shielding material mounted on two walls inside the office, and another layer of shielding mounted to the wall directly behind the electrical equipment.  (Please click image for a full-sized picture.) 

This picture shows some of the shielding before it was covered with standard sheetrock and painted.  To minimize costs, the shielding material was installed during an already planned remodel of the accounting office.  (Click image for full-sized picture.)