47.5 MB - The Whole Building Design Guide

Water InfiltrationWhere corrosion is problematic, anodizedaluminum or galvanized doors and frames,and stainless steel frame anchors andhardware are recommended.For primary swinging entry/exit doors,exit door hardware is recommended tominimize the possibility of the doors beingpulled open by wind suction. Exit hardwarewith top and bottom rods is more securethan exit hardware that latches at the jamb.Heavy rain that accompanies high winds (e.g., thunderstorms,tropical storms, and hurricanes) can cause significant winddrivenwater infiltration problems. The magnitude of theproblem increases with the wind speed. Leakage can occur betweenthe door and its frame, the frameand the wall, and between the thresholdand the door. When wind speeds approach120 mph, some leakage should be anticipatedbecause of the very high windpressures and numerous opportunities forleakage path development.The following recommendations should be considered to minimizeinfiltration around exterior doors.Vestibule: Adding a vestibule allows both the inner and outer doorsto be equipped with weatherstripping. The vestibule can be designedwith water-resistant finishes (e.g., concrete or tile) and thefloor can be equipped with a drain. In addition, installing exteriorthreshold trench drains can be helpful (openings must be smallenough to avoid trapping high-heeled shoes). Note that trenchdrains do not eliminate the problem, since water can still penetrateat door edges.Door swing: Out-swinging doors have weatherstripping on the interiorside of the door, where it is less susceptible to degradation,which is an advantage when compared toin-swinging doors. Some interlocking weatherstrippingassemblies are available forout-swinging doors.The successful integration of the door frameand the wall is a special challenge whendesigning doors. See Section 3.3.3.2 for discussionof this juncture.ASTM E 2112 provides information pertaining to the installationof doors, including the use of sill pan flashings with end dams andrear legs (see Figure 3-31). It is recommended that designers useASTM E 2112 as a design resource.3-50 MAKING CRITICAL FACILITIES SAFE FROM High Wind