Aging equipment, an outdated electrical distribution system, and a facility originally designed for other purposes contributed to elevated arc flash incident energy values throughout the 20,000 sq. ft. facility of Pompano Beach, Fla.-based Micro Typing Systems, Inc. The company is a wholly owned subsidiary of Ortho-Clinical Diagnostics, Inc. (a Johnson & Johnson company) and manufacturer of the ID-Micro Typing System Gel Test (a card containing a gel that indicates a patient’s blood type), along with reagents for various blood work applications such as antibody screening and identification.
Ortho-Clinical Diagnostics purchased Micro Typing Systems in March 2002, and one of the first orders of business was work on the electrical distribution system to mitigate the potential of an arcing fault incident. Current flow through air during an arcing fault releases a high amount of energy in the form of heat and pressure, and the subsequent arc flash usually will result in extensive equipment damage and severe worker injury or death.
Jackie Shay, Micro Typing Systems director of facilities and projects, commissioned an arc-flash analysis study by Schneider Electric’s Square D Services (www.squared-services.com). The goal was to determine the arc flash incident energy value at each piece of equipment and the appropriate levels of personal protective equipment (PPE).
The first step was to gather detailed data about the electrical distribution system, everything from the lengths of conductors to the size of panelboards to the types of circuit breakers in use. The system was then modeled in a software analysis program that calculates arc flash potential energy levels. Those energy levels determine the amount of PPE anyone working on the system must wear, including personnel from regular contractor JMD Incorporated Electrical Contractors, Miramar, Fla.
The findings indicated issues with the electrical distribution system caused mostly by the age of the facility (built in 1980, before arc flash mitigation was a design objective). For example, based on the 2004 NFPA 70E standard, several areas in the system were rated Hazard/Risk Category 4 or above, meaning anyone working on it must wear multiple layers of flame-resistant clothing and other specialized equipment, even for minor work like a lockout/tagout procedure. The facility also used six fused switches at the service entrance because it was originally a multiple-tenant building.
The analysis made a series of recommendations for upgrading the electrical distribution system to make it more efficient and safer. Work began the Friday after Thanksgiving 2006, and was completed 72 hours later – a difficult task considering the electrical room is roughly 4 ft. by 8 ft., limiting the number of workers that could enter the room at one time. Work was performed by Square D Field Services and Tirone Electric Inc., Hollywood, Fla.
The six fused switches were replaced with two panelboards, one for the main incoming breaker and main generator breaker (for emergency power), the other for distribution. Two solid-state circuit breakers with electronic trip units in the main panelboard provide flexibility to reduce the NFPA Hazard/Risk Category to Level 0 on the distribution panelboard. Seven thermal-magnetic breakers are used in the distribution panel.
The two panelboards are connected by cable, so they’re assigned separate NFPA Hazard/Risk Category arc flash ratings. As a result of the new design, the entire plant, except for the main panelboard, is rated at Hazard/Risk Category 0, meaning workers need wear only one layer of untreated natural fiber clothing. The main panelboard continues to be rated above a Hazard/Risk Category 4 because of the available fault current and fault-clearing characteristics of the utility overcurrent protective devices.
A power meter installed in the main panel and connected to a computer allows Shay to track incoming power quality. The facility previously suffered brownouts, and Shay wanted to confirm her suspicions that they were caused by problems on the utility side of the meter, not her side.
Now the company has a safer electrical distribution system and the ability to monitor incoming power, along with a completely updated single-line electrical distribution system diagram. What’s more, Shay purchased the proper PPE that JMD personnel use when they’re on site; it’s stored in a locker for convenience.
“It was a good investment,” Shay says. “We love the ability to trend our incoming power, and we now have protective equipment that provides the optimal level of safety and brings our contractor into compliance when they are on-site.”