Low EMI Elevator Design Supports Strategic Siting of Research Instrumentation

The siting of sensitive instruments in a research facility requires awareness of the electromagnetic field (EMF) environment and the various types and locations of emission sources. Some of the most difficult electromagnetic interference (EMI) challenges include DC and geomagnetic sources such as cars, trucks, subways, and trains, as well as facility elevators. The EMI footprint from the movement of an elevator through the earth’s magnetic field can exclude large areas of a facility from housing sensitive tools and instruments. Field Management Services (FMS) has pioneered an approach that fundamentally reduces the EMF emission footprint of elevators so that more siting options are available. Traction elevator designs typically utilize a steel elevator car and offsetting counterweights, usually composed of steel. This type of elevator design causes significant coupling to the geomagnetic field from each of the two ferromagnetic masses per elevator, the elevator car and the counterweight. On a recent project where elevator locations were fixed, FMS proposed utilizing non-ferrous counterweights and replacing as much steel in the elevator car as possible with non-magnetic materials. The design modifications reduced the 1mG (10nT) EMI footprint by more than 3,000 sf and the 0.1mG (0.1nT) environment by more than 8,000 sf, thus providing more available real estate for the siting of sensitive instrumentation.