Mapping Electromagnetic Interference (EMI) Boundaries in 3-D BIM

Early Modeling Saves Upfront and Operational Costs
Published 6-17-2015
  • 2-D BIM

    This two-dimensional image depicts the same research facility as the 3-D video above.

    Courtesy of Field Management Services, Inc.

Just as building information modeling (BIM) can prevent contractors from laying one exhaust duct in the path of another, BIM can ensure that research-critical tools, sensitive to electromagnetic interference (EMI), are not destined for a room next to the elevator.

BIM applies information technology to coordinating the many different components, skills, and processes required to plan and construct or remodel a building, from commercial facilities to research laboratories. Field Management Services, Inc., (FMS) uses BIM to apply these benefits to EMI analysis and mitigation, and to integrate EMI measures into the many other construction requirements.

“EMI clash detection easily shows where EMI levels exceed specs for a particular tool,” says Davidson Scott, director of engineering at FMS. “You set a space for a controlled EMI environment, and as the design evolves, you can track threats to the protected low-EMI space.”

The use of BIM is becoming ubiquitous in the design and construction of complex facilities that require tighter systems integration. According to a study by McGraw-Hill Construction, 74 percent of contractors and 70 percent of architects in North America were employing BIM by 2012, an increase of nearly 50 percent for contractors in just three years.

“There is a deep penetration of BIM in the industry,” says Scott. “If you’re not involved in BIM in some way, it’s very hard to stay in this business.”

A latecomer to the use of BIM, EMI mitigation has been considered a small niche discipline, more of an afterthought than an early design consideration. But the evolving needs of complex research facilities, often located on dense campuses and in urban settings, are bringing EMI challenges and their costs to the forefront. At the same time, new technologies make it easier to integrate increasingly rich EMI data into existing BIM models.

“New techniques allow EMI to be communicated through BIM, so you can get useful information out of your BIM investment that will include EMI domains,” says Scott. “People like to say EMI is as much art as science, but with the proper calculation tools, you’re able to be more data-driven.”

The three aspects of EMI—DC environment [Click here for video], electrical power (AC) [Click here for video], and radio frequency (RF) environment—may be in different layers of BIM, but 3-D BIM models contain all the layers of information necessary to map EMI sources:

  • Electrical layers (AC/ELF)
  • Telecom/security (RF) layers
  • Vertical lift layers (DC/Geomagnetic EMI)
  • Mechanical layers (AC/ELF/RF/DC EMI)

A BIM model can also incorporate external data, such as the location of a potentially disruptive power line or mass transit route.

“On the RF realm, if you’ve got a digital TV station putting out a megawatt of power a half-mile away, you can model that and put it into the BIM,” he says.

The location of the EMI-sensitive equipment is then integrated into the BIM to determine where to set the EMI clash-detection boundaries.

“With 3-D modeling, you can understand the spacial relationship, even within a room,” says Scott. “You get only a single level in the room with a 2-D depiction; 3-D is necessary because if you have a microscope column, for instance, the environment may be very different at the bottom of the column than at the top, and these are important things to understand.”

The earlier these calculations are done, the better.

“One dollar spent using low-EMI modeling to find a problem in the design phase avoids $20 of cost if you don’t find the problem until the assembly phase, and $60 if that problem is not discovered until the facility operational phase,” says Scott.

A BIM-derived EMI assessment enables tighter design cycle inputs and comprehensive assessment of EMI-impacting infrastructure, for example the whole electrical system of a building rather than only part of it. Models can be run in hours or days rather than weeks, and when the design changes, it is fully communicated to the EMI consultant so the impacts can be assessed in a timely manner.

The benefits carry forward through the life of the building, as the EMI data in BIM can be updated and deployed for future fit-outs and renovations.

“Part of achieving a low-EMI environment is keeping it,” says Scott. “If you’ve got the right elements in your BIM, those elements fall right out into a configuration management database.

By Lisa Wesel

This report is based on a presentation Scott made at the Core Facilities 2015 conference. All videos are available courtesy of Field Management Services, Inc.