FLOOD07643 - Laserfiche WebLink

Home Browse Search

==t ~ ~ I f CHAPTER 3 TEMPORARY AND PERMANENT CLOSURES FOR OPENINGS IN EXISTING STRUCTURES Description Structures whose exterior is generally impermeable to water can be made to keep flood water out by installing watertight closures to openings such as doorways and windows, While some seepage will probably always occur, it can be reduced by applying a sealant to walls and floors and by providing a floor drain where practical. Closures may be temporary or permanent. Temporary closures are installed only during a flood threat and therefore need warning time for installation. Specific measures which may be taken are described below. Doorway Closures - Exterior doors do not normally seal tight enough to prevent seepage around the door jamb. Installation of a rubber type gasket and the means to press the door against the gasket to create a tight seal would be adequate for low heads (0 - 1 feet). A more certain means is the use of flood shields. Shields are normally of aluminum, steel or wood and made to the height and width desired. In commercial/industrial structures they may be permanently installed at the doorway on hinges or rollers for swinging or sliding into place, or more often, particularly for residential structures, they may be stored nearby for installation on brackets or anchor bolts at the time of a flood. The shield seals against the door jamb with a rubber type gasket. Doorways not used are sometimes closed permanently with concrete blocks, bricks, or other relatively impermeable materials. Window Closures - Normal window glass will take little hydrostatic pressure and is especially vulnerable to breakage by floating debris. Flood shields are commonly used to protect windows and prevent water from entering. As with doorway shields they may be permanently installed on hinges or rollers at the opening or stored elsewhere and installed temporarily during floods. Another alternative is to install heavy duty plexiglass or glass block (for basement windows) which can normally withstand hydrostatic pressures of several feet. large display windows in commercial structures are sometimes protected by installing weep holes at the base of the window. This allows water on the inside to equalize the hydrostatic pressure on the window, but it is prevented from entering the remainder of the structure by parapet walls. Windows not needed can be permanently closed with blocks, brick or other impermeable material. Seals - Waterproofing sealants are sometimes applied to generally impermeable walls and floors to further reduce seepage. Sealants are particularly effective on brick veneer, cement block, r~inforced concrete and similar masonry type surfaces. Cracks in the masonry can be filled by caulking. Sewer Lines - Sanitary sewer backflow can be prevented by installation of a gate valve and by installing valves in floor drains. Sump Pump - Some seepage is likely to enter a structure even though it is termed "watertight". It is desirable, therefore, to have a sump pump available to remove seepage. The pump discharge should be located above the design flood elevation. The above measures are those generally used to keep water out of a structure~ They can be used in any combination depending upon specific site conditons. Figure 3-1 illustrates the use of these measures. 12