47.5 MB - The Whole Building Design Guide

Boiler and exhaust stack attachment: To avoid wind damage to boilerand exhaust stacks, wind loads on stacks should be calculated andguy-wires should be designed and constructed to resist the loads.Toppled stacks, as shown at the hospital in Figure 3-76, can allowwater to enter the building at the stack penetration, damage theroof membrane, and become wind-borne debris. The designershould advise the building owner that guy-wires should be inspectedannually to ensure they are taut.Figure 3-76:Three of the five stacksthat did not have guywireswere blown down.Hurricane Marilyn (U.S.Virgin Islands, 1995)Access panel attachment: Equipment access panels frequently blowoff. To minimize this, job-site modifications, such as attachinghasps and locking devices like carabiners, are recommended.The modification details need to be customized. Detailed designmay be needed after the equipment has been delivered to the jobsite. Modification details should be approved by the equipmentmanufacturer.Equipment screens: Screens around rooftop equipment are frequentlyblown away (see Figure 3-77). Screens should be designedto resist the wind load derived from ASCE 7. Since the effect ofscreens on equipment wind loads is unknown, the equipment attachmentbehind the screens should be designed to resist thedesign load.MAKING CRITICAL FACILITIES SAFE FROM High Wind3-89