Consulting-Specifying Engineer - August 2007 - (Page 30)

Electrical Design for Ta Buildings: Designing electrical systems for high-rise buildings is an exercise in engineering coordination and cooperation. BY MARK BENDIX, P.ENG., Senior Director, Operations, Giffels Assocs. Ltd., Toronto T here has been a sharp increase in the development of extra tall buildings, usually multi-purpose and often consisting of a retail and/or entertainment podium and towers of commercial offices, hotels and residential facilities. A good example is the iconic Emirates Towers complex in Dubai, comprised of a below grade parking area, a retail podium and one tower of commercial office space. The other tower houses The Photography courtesy of Giffels Assocs. Ltd. Jumeirah Emirates Towers Hotel. The complex electrical systems installed in these tall buildings present to the engineer a number of design challenges, including space constraints, limitations of physical structure and the integration of multiple systems. To successfully overcome these challenges, careful planning, collaboration with other professionals and coordination of systems are essential. First of all, every tall building is supplied with multiple sources of electricity, including feeds for normal power, usually supplied by the local electrical utility company (LEUC), and an emergency or standby source of power, usually supplied from on-site enginegenerator sets. The LEUC supplies the building with medium-voltage power from one or more utility sub-stations. Ideally, the supplies are fed from multiple sub-stations to increase the reliability of the main electrical system. The utility supply will enter the building from below grade and usually terminates in a main switch room. Often, the location of this electrical room depends on the demands of the LEUC. A significant concern is that each LEUC has its own idiosyncrasies. In some jurisdictions, the LEUC has no requirements for the main switch room at all, and it can be located anywhere within a basement area. In other jurisdictions, the LEUC may require that the main isolation equipment (switchgear or ring-main units) be located as close as possible to the outside wall where the service enters the building. Other LEUCs, such as the Dubai Electricity and Water Authority (DEWA), in the case of Dubai, may demand that this isolation equipment be located in a room at street level, directly accessible from the outside or in a completely separate building at the site property line. Therefore, it is essential that the electrical engineer contacts the LEUC as early as possible to determine if there are specific requirements for the service entrance equipment and its location. At this early stage, the engineer also should determine the codes and standards that the LEUC requires for electrical system design. The engineer will likely find that the LEUC has a set of additional design requirements specific to local conditions and local practices. Often these are not obvious, and if the engineer does not uncover these early, it can be costly to the engineer and to the owner. 30 Consulting-Specifying Engineer • AUGUST, 2007

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

Contents M/E Roundtable Giants 100 Pullout Poster Giants Stand Tall: CSE Giants 100 Report Electrical Design for Tall Buildings HVAC and Fire Safety for Elevator Systems How to Beat the Codes GAS Technology Supplement Recovering Waste Heat from Boilers New Applications for Tankless Water Heating Systmes Techniques Improve for Powder Coating MDF New Tools Available for Heat Treating Steel Direct Drive Engines

Consulting-Specifying Engineer - August 2007

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