New York Utility Satellite Facility Magnetic Shield

In August 2001 VitaTech completed a comprehensive AC ELF (extremely low frequency) EMF study of a future 7,200 sq. ft. Information Technology (IT) office area to be located on the 2nd floor at a New York utility satellite facility directly beneath two 138 kV and one 69 kV transmission lines. VitaTech recorded and simulated magnetic flux density levels under various transmission line load conditions within and around the site to evaluate the magnetic shielding requirments. Our client required a 5 mG performance objective measured 1-meter above the floor and 1-m away from windows under average and peak transmission line loads. VitaTech recommended installing a 25,000 square-foot interior AC ELF magnetic shield covering the 2nd floor ceilings, walls and floors. In October 2001 VitaTech was awarded a contract to design, install, test and certify the recommended 5-mG shield.

Our specialized EMF shield installation crew of six with 85,000 lbs. of shielding materials arrived at the work site in October 2001. VitaTech recorded the before shield levels throughout the 2nd floor area while the installation work commenced. Forty-seven (47) consecutive days later the 25,000 sq. ft. shield was completely installed, welded and tested.

An after shield site survey was performed in December 2002. The AC ELF magnetic shield installed by VitaTech complied with the 5-mG and less guarantee measured 1-meter from the shielded floors, walls, windows and ceilings over 95% of the four shielded 2nd floor areas during average and peak loads. Several places inside the four shielded areas approached 0.0 mG.

Project Data

Figure 1
3-D Contour Plot of Site Before AC ELF Magnetic Shield Installed

Figure 2
3-D Contour Plot of Site After AC ELF Magnetic Shield Installed

Slideshow

Magnetic Shield Images

Before Shield
25,000 square-foot Interior of a utility satellite facility. Building was built in 1929 and was composed of tongue-n-groove wooden floors with wooden joists and rafters.

After Shield
The windows were left untreated but still maintained an acceptable rate of decay from the overhead transmission lines. Many areas throughout the facility averaged 0.00 mG.