As temperatures rise and another summer begins, it's important to reflect on the unpredictable weather Mother Nature can deliver at a moment's notice. This message is especially critical for standby power system enclosures, which must be designed to withstand loads produced by hurricanes and tropical storm force winds. According to a new white paper, “Understanding IBC Wind Load Requirements for Generating Systems,” written by Allan Bliemeister, senior staff engineer for Kohler Power Systems, building owners and power system specifiers must be keenly familiar with the wind load compliance provisions of the International Building Code (IBC 2000, 2003, 2006, and 2009) with respect to power system equipment. Of equal importance to the design of the power system is the installation and mounting of the enclosure to ensure the product remains connected to the foundation. Following are some important installation guidelines:
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Anchors used for wind load installation must be designed and rated to resist wind loading in accordance with ACI (American Concrete Institute) 355.2-04 and documented in a report by a reputable testing agency (i.e., The Evaluation Service Report issued by the International Code Council). Anchors, brands, and style used for wind loading are essentially the same as those for seismic loading.
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Install anchors in minimum 4,000 psi compressive-strength normal-weight concrete. Concrete aggregate must comply with ASTM C33. Installation in structural lightweight concrete is not permitted unless otherwise approved by the structural engineer of record.
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Install anchors to the required torque specified by the anchor manufacturer to obtain maximum loading.
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Install anchors with spacing and edge distance required to obtain maximum load unless otherwise approved by the structural engineer of record.
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Install wide washers at each anchor location between the anchor head and equipment for tension load distribution. See the applicable installation or dimension drawing for specific anchor information and washer dimensions.
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Equipment installed on a housekeeping pad requires the pad thickness to be at least 1.5 times the anchor embedment depth. All pads must also be securely anchored and dowelled or cast for security and approved by the structural engineer. Rebar reinforcing in the housekeeping pad is required for all installations.
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Rebar reinforcement in concrete must be designed in accordance with ACI 318-05.
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Install wall-mounted equipment to a rebar-reinforced structural concrete wall that is wind load designed and approved by the engineer of record to resist the added wind loads from components being anchored to the wall. When installing, rebar interference must be considered.
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Structural walls, structural floors, and pads must also be designed and approved by the structural engineer of record. The installing contractor is responsible for proper installation of all electrical wiring, piping, ducts, and other connections to the equipment.
The full white paper is available at http://www.kohlerpower.com/common/pdfs/WhitePaper-WindLoadRatings.pdf.
