A new era has arrived for electrical equipment safety. The days of suiting up in personal protective equipment (PPE) and hoping for the best are over. Updates to the National Fire Protection Association (NFPA) safety guidelines mean organizations must try to eliminate the risk before coming in contact with the equipment.
The revised guidelines and demand for more efficient maintenance practices have led to new condition monitoring approaches. Thermal imaging cameras have become essential inspection tools to detect heat in the form of infrared (IR) energy. But electrical equipment must be energized to conduct IR inspections. The NFPA 70E Standard for Electrical Safety in the Workplace guidelines stipulates that organizations must deenergize the equipment if there’s a way to complete the job without disconnecting the machine.
Adding IR windows to panel covers or electrical cabinets allows technicians to perform thermal imaging inspections on energized equipment, says Brent Lammert, vice president of business development for FLIR Systems Inc.’s Volume segment. The windows, which are available in round or rectangular shapes, protect workers against arc flash accidents because they add a barrier between the worker and the connected equipment.
“With thermography, we can’t see through a cabinet. We need to see the connections directly, and we can’t do it with power off because we won’t see a hot spot,” Lammert explains. “So we need to do it either open door and energized with the proper PPE on or we can install IR windows. “That allows us to minimize the risk and isolate the person from the hazard.”
Hierarchy of Control
One of the key aspects of the NFPA 70E update is the addition of a risk assessment procedure. The risk assessment involves identification of hazards, assessment of the risks and implantation of risk control based on the NFPA’s “hierarchy of risk control methods.”
Elimination of the risk sits atop the hierarchy and is considered the most effective control method. The remaining control strategies ranked in order from most to least effective include:
- Engineering controls
- Administrative controls
IR windows also can be considered a substitution or engineering control procedure, depending on a facility’s risk assessment. IR windows may fall under substitution if workers identify the opening of panels as the hazard. The windows would qualify as an effective substitution for opening the panels, Lammert says. If the hazard is high voltage inside the panel, the windows could be considered an engineering control.
“Either way, you’re much higher up that hierarchy of controls than you are with PPE, and that’s a point of emphasis for NFPA—trying to get as high up on that hierarchy of controls toward elimination,” Lammert says.
PPE sits at the bottom of the hierarchy because NFPA doesn’t consider it to be a preventive measure. Instead, PPE is intended to make an injury survivable, Lammert notes.
Thermal imaging solutions provider FLIR added new IR windows in 2018 to its existing product line to increase accessibility to more components. The IRW-xPC and IRW-xPS are impact-resistant rectangular polymer windows that provide the largest viewing area available to monitor inside energized electrical equipment.
The rectangular viewing area and polymer lens material allow for large window designs and a greater viewing area. The windows also can operate in harsh environments with features, such as impact-resistant optics and the ability to withstand exposure to elements, including acids, alkalis, UV, moisture, humidity, vibration, and high-frequency noise.
Installing IR windows is not a complex process. Lammert compares it to adding a conduit to a panel. Users only need to insert a threaded base through a hole and tighten a screw-on ring nut. FLIR provides a sizing table to help organizations determine the correct hole size. The sizing tools help users understand how much area they can view through a given window.
One data center that installed FLIR IR windows completed the installation in less than three hours using cut-out templates and cutting tools provided by FLIR.
Safer and More Efficient
After installing the windows, facilities typically experience faster, less costly inspections than they realized using open-door thermography, Lammert says. When IR windows are not present, thermal imaging typically requires up to two additional workers to remove and reinstall the doors. The technician may also need time to dress in bulky PPE gear, Lammert says.
“The thermographer also has to wait for the covers to come off or go back on before actually inspecting,” Lammert says.
IR windows also help workers inspect electrical equipment more frequently and potentially more components if the voltage was too high for an open-door inspection.
“Frequency and a long list of components that can be inspected yields much better reliability,” Lammert says.