Consulting-Specifying Engineer - June 2008 - (Page 60)

Codes & Standards 24/7 facilities. There are a number of electrical design alternatives above code minimum that can help reduce potential patient disruption. A new code requirement in NEC 210.4 (A) and (B) has a distinct effect on hospital circuiting. The new code requires that all multi-wire circuits have a common means to disconnect the phase conductors via a multi-pole circuit breaker or a combination of single-pole circuit breakers using an approved tie handle. If circuit neutrals are shared between patient bed locations, it could cause disruption during maintenance or project work. A new design standard in electrical healthcare design is that emerging circuits should have dedicated neutrals for all patient care area receptacle circuits. This will allow performance of maintenance and modifications in one patient room without affecting other patients. All receptacles in patient care areas are required by 517.18 (B) to be hospital-grade receptacles. A hospital-grade receptacle is manufactured to take much more abuse than a commercial receptacle and has a higher plug retention force. Because the entire hospital can become a patient care area in an emergency condition, electrical designers might want to consider using only hospital-grade receptacles throughout the hospital. An automatic transfer switch (ATS) is required to connect an emergency power branch to either the normal service or the generator source. During emergency power system testing, the short power outage that occurs while transferring between sources can cause electronic equipment to reset or restart. This can be disruptive to patient care. Using an ATS design that has a closed transition transfer can eliminate the transfer “blip” when going between two active sources. Code minimum Single generator Beyond minimums All ATS require scheduled maintenance. This can be difficult and disruptive to hospital operations. To avoid this disruption, specify ATS that have the bypass/isolation feature. This allows the automatic switch to be bypassed so that maintenance can be performed on the switch without affecting hospital operation. Care insurance for a fully operational hospital If healthcare facility administrators want the facility to remain fully operational following a natural disaster, cataclysmic accident, or a terrorist attack, here’s the perfect situation in which to flex the minimums of the NEC. In preparing a facility for a multi-day extended outage, it is important to consider the areas where going beyond code minimums has a real affect on keeping a hospital fully operational. Issues like cooling, potential generator failure, and fuel supplies are areas that need thoughtful decisions. The accompanying chart indicates a list of design decisions that go beyond the code. Codes are critically necessary in today’s healthcare design. But they are not the end of the discussion—only the beginning. Understanding the hospital’s mission and the manner in which they function will allow you as an engineer to know how to work together with the facility team to design a hospital that has patient safety and care at the center of the design and potentially help create a fully operational hospital even following a disaster. Stover is principal and electrical engineer with FreemanWhite, an A/E firm specializing in healthcare projects. Benefit Provide multiple generators to serve the Allows for rigorous testing and for required emergency load with N+1 redundancy for the loads to remain in service in the event of a genrequired loads. erator failure. Three automatic transfer Provide additional ATS on the critical and Multiple equipment branch ATS allow the facilswitches (ATS) for required equipment branches. ity to control which systems have power in the branches of emergency event of decreased emergency power system power output. Normal and emergency power provided in the emergency department, operating room, critical care area, and imaging departments. Use an additional critical branch as the code permits to serve critical care, diagnostic, operating suite, and emergency department loads that are typically fed by the normal power branch. In order for these areas of a hospital to be fully operational during an outage, it is important that all of the loads are capable of being fed from the emergency power system. Using multiple critical branches makes this possible. In the vast majority of outages, refueling would be possible within a 5-day time frame. Without cooling, within hours some hospital service lines will have to be shutdown; after a day or two, patients would need to be evacuated. The fully operational hospital must have cooling on emergency power. Provide 2 days of generator Provide 4 to 5 days of fuel capacity on site. fuel. No cooling on emergency power Provide cooling on emergency power. 60 Consulting-Specifying Engineer • JUNE 2008

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Consulting-Specifying Engineer - June 2008 Contents Viewpoint Letters News M/E Roundtable No Gambling Allowed on Smoke Control in Las Vegas Be Prepared: Hospital Protections for Catastrophic Events Ready for Retail Commissioning Documents: Necessary Evil Codes & Standards Codes & Standards Case Study Equipment Lifecycles New Products Advertiser Index Green Space

Consulting-Specifying Engineer - June 2008

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