Consulting-Specifying Engineer - September 2007 - (Page 25)

M/E Roundtable depends a great deal on the system loads and control scheme. If the gensets are controlled just to meet the power load, and the waste heat is used incidentally, then a pre-integrated system will probably work fine. But in more complicated systems where the engines need to meet a thermal load as well, a custom approach is required. CSE : What are some of the pre integrated emergency power systems familiar to you? AHUJA: Cummins/Onan, Russelectric, GE, Cutler Hammer and Siemens. AMANN: Several of the major generator manufacturers are now offering pre-integrated emergency and standby power systems. These include systems that they provision complete with enclosures, switchboards, transfer equipment and controls. They range from simple, single-generator systems, to more sophisticated paralleled arrangements that may connect to the utility grid or co-generate. In some cases, the system also includes a UPS System, with rotating UPS (uniterruptible power supply) systems the most prevalent. FLICKINGER: We have utilized Square D, General Electric, Siemens and ValTec (VTI). We have had some challenges with AHJs accepting integrated emergency power systems primarily due the equipment listing for a given installation. The AHJs usually don’t question the individual component listing, but rather the entire system AIC (available interupt current) rating for the equipment. Additionally, when utilizing integrated equipment for emergency systems, consideration should be given to NFPA 110-7.2.2 for Level 1 EPSS (emergency power supply system) equipment, which must be in a separate room from the normal equipment if rated over 150 volts to ground and equal or greater than 1,000 amps. CSE : What are some of the problems encountered when attempting to evaluate the merits of competing systems? AHUJA: Customers should consider labor costs vs. first costs, local union markup on pre-integrated systems and concern on support due to dependence on one manufacturer for various components of system. FLICKINGER: We have not experienced many challenges with respect to the various manufacturers. Their equipment must reflect all the components on our one-line, comply with the specifications, physically fit within the space requirements, and be UL listed. AMANN: We encourage many of our clients to pre-order or pre-purchase their generators, switchgear and transfer equipment. In this instance, we can evaluate the relative merits and features available from each vendor. This works fine with the pre-integrated systems as well. But if the job is a traditional plan-and-spec bid, it is very difficult to evaluate substitutions that a contractor may submit in a time frame that works effectively for the project. CSE : Do you perceive a growing reliance on pre - assembled sys tems by consulting engineers? AHUJA: Right now it is case-by-case by consulting engineers. Design-build contractors will promote pre-assembled systems to save labor cost and coordination of deliveries on all vendors to build the system at the site. Acceptance with consulting engineers will grow if contractors can show economical advantage and local unions do not discourage use in the field. AMANN: On projects where they fit the bill, certainly engineers will gravitate to pre-integrated systems. It relieves the engineer of some responsibility in assuring the components are compatible, and that the controls match up between the various components. FLICKINGER: Not really. If space considerations and time constraints require Reliable power control Whether your project is a simple standby system or mission-critical power for 24/7 reliability, Cummins Power Generation Inc. has the transfer and control equipment to meet your needs and budget. > Automatic transfer switches > Switchgear > Digital control For more information, contact your local Cummins Power Generation distributor or visit www.cumminspower.com/ powercontrol Our energy working for you.TM © 2007 Cummins Power Generation Inc. Input #216 at csemag.com/quickResponse http://www.cumminspower.com/powercontrol http://www.cumminspower.com/powercontrol http://csemag.com/quickResponse

Table of Contents Feed for the Digital Edition of Consulting-Specifying Engineer - September 2007

Contents M/E Roundtable Cover Story: Airborne Superbugs Third-Party Liability Back to School Product Spotlight Codes & Standards Professional Practices How To New Products Jobs/Cliassifieds Specifier’s Notebook Pure Power Supplement New Technologies, Same Old Transmission Problems Wireless Battery Recharging Solar Concentration Renewables Tracking System A Mighty Wind The Importance of Load Bank Testing Quality Power for Security Systems

Consulting-Specifying Engineer - September 2007

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