CSE Pure Power - Summer 2008 - (Page 9)

9 ❮❮ PURE POWER // SUMMER 2008 New NEC Article 708 Critical Operations Power Systems leaves much to the judgment of the engineer designing the COPS. ngineers are asking many questions about the new Article 708, Critical Operations Power Systems (COPS), in the 2008 National Electrical Code (NEC). For example: How do we comply with the documented risk assessment required in Section 708.4? Unlike the other special systems of Chapter 7, there is subtext to the new article that may depend upon mandates from state or federal authorities. Fine Print Note No. 1 reads: “Critical operations power systems are generally installed in vital infrastructure facilities that, if destroyed or incapacitated, would disrupt national security, the economy, public health, or safety, and where enhanced electrical infrastructure for continuity of operation has been deemed necessary by governmental authority.” To NEC traditionalists who believe the NEC should remain a prescriptive installation code for electrical safety in building premises wiring only, this may be unsettling. They want clear, bright-line code that makes their point at construction board of appeals meetings. Even though there are a few sections of the code that address design, along comes Article 708, placed in the special system chapter, with all of these subtleties not seen in the other Chapter 7 articles that govern backup power systems commissioning, maintenance, and testing. It has annexes with new words that seem to make BY MICHAEL A. ANTHONY, PE, ROBERT ARNO, ROBERT SCHUERGER, PE, and EVANGELOS STOYAS, PE COPS terms of art Power reliability and power security are often used interchangeably and have become the focus of an expanding intellectual history involving the combined—but not always harmonious—efforts of standards writers. Annex F, the informative material in the 2008 National Electrical Code that accompanies Article 708, contains a description of these concepts. For the purpose of this article, we reﬁne these concepts further with the use of a simple notational identiﬁer to distinguish between reliability (the measured, scalar quantity) and reliability (the general term). Reliability is a term that reﬂects the overall state of a system, the Fine Print Note of NEC Section 700.12, for example. Reliability is a number, typically expressed as a percentage or a decimal, that reﬂects the probability and frequency of failures and is expressed as a probability over a given duration of time cycles. It appears in the NEC Annex F. In general industry practice, it represents the probability that a product or service will operate properly for a speciﬁed period of time under design operating conditions without failure. It is a time-dependent metric; the longer the time interval, the lower the reliability, regardless of what the system design is. The better the system design, the higher the probability of successful operation for a longer period of time. Availability is always measured in terms of percentage of uptime versus downtime. The closer to 100%, the better. The limited vulnerabilty design concept originated in work by the U.S. Army Corps of Engineers is used to describe a building structure designed to detect potential terrorist threats, isolate resulting damage, and promote survival of personnel affected by an event while propagating continued parallel mission activity. E paperwork as important as wiring (see COPS terms of art, at right). It also raises issues of how these COPS requirements will be ﬁnanced. You can build the cost of a generator into the ﬁrst cost of a building on the basis of NFPA 101. However, is ensuring 72 hours of fuel for it (as required in 708.22-C)—because the COPS is an integral part of the building—considered an operating expense? Conversely, can a homeland security grant help pay for an infrastructure upgrade where the designated critical operations area (DCOA) is an embedded system in a multi-function building? Does testing to compliance with 708.6 mean that third-party agencies need to be paid from a county homeland security grant or from the same municipal budget that covers inspections for general commercial occupancies? These are questions that will be answered as 708 is integrated into other standards and codes. Article 708 crossreferences six other NFPA standards within itself. Progress in the integration process will be measured by how fast we see reciprocal referencing of 708 in other NFPA, International Code Council, Federal Emergency Management Agency (FEMA), and Dept. of Homeland Security documents; and how fast precedents track in white papers and advisories of public utility commissions and county emergency management agencies. Here, we describe the characteristics of an NEC-compliant risk assessment for a single designated critical operations area. We assume it does not trigger a multi-trade infrastructure upgrade of the larger facility within which the COPS is embedded. We www.purepowermagazine.com http://www.purepowermagazine.com

Table of Contents Feed for the Digital Edition of CSE Pure Power - Summer 2008

CSE Pure Power - Summer 2008 Contents In the News Industry Roundup Risk Assessments for COPS Grounding Requires More Power Systems to Protect Healthcare Important Changes Coming in NFPA 70E A Look at Arc-Resistant Switchgear Agencies and Associations New Products Ad Index

CSE Pure Power - Summer 2008

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