Condensation and high relative humidity levels are important factors in creating an environment conducive to mold growth and are the primary problems in hot, humid climates. Infiltrated humid air, whether introduced by wind or through the HVAC system, can cause condensation on interior surfaces, including inside building cavities. Infiltration of outside moisture-laden air. In both hot, humid and temperate climates, rainwater leaks are a major source of building moisture and fungal growth problems. Significant amounts of moisture can also result from water leaks within building systems or through the building envelope. Moisture present in building materials and on the site during construction can be a source of problems. First, the building designer must understand the basic causes of moisture intrusion into buildings: To avoid the types of problems seen at the Florida municipal building, engineers and architects must work together to manage moisture. But both architects and engineers must understand the interaction between the building envelope and the HVAC system to manage moisture intrusion in buildings. Rainwater leaks occur in every climate, and in this case study, the leaks alone would probably have led to significant microbial contamination and building evacuation. Unfortunately, the problem faced by this Florida county is not an isolated one. Ultimately, repairs and other associated costs exceeded $20 million. The roof and the HVAC system were also extensively modified. The building's exterior was removed to help correct the problems that allowed rainwater to invade the building envelope (Figure 1). Mold and moisture were the culprits, and in the end, the problem will require more than $20 million to repair. Although brand new, this municipal building was evacuated shortly after it opened because occupants were reporting health complaints. So, only a few years after opening its doors, the building underwent a major overhaul.įigure 1. Once the HVAC system became infected with mold, it dispersed spores throughout the building. The mold was the direct result of excess moisture in the building, which was caused by a combination of rainwater leaks and a heating, ventilating, and air-conditioning (HVAC) system that pulled moist outside air into the building during the hours when the cooling system had cycled off. The architects, engineers, and microbiologists tasked with finding the cause of these symptoms identified a problem that is becoming widespread nationwide-severe fungal contamination of the building. The thickness of a layer can be modified by clicking in the text field of a layer's Thickness column and entering your desired value.Just months after occupying their new, multimillion-dollar municipal building, employees of a Florida county began complaining of chronic sinus problems, allergy attacks, headaches, and asthma-classic signs of sick building syndrome and building-related illness.In this example, we will be adding three interior wall layers to our custom wall type, so go ahead and click on the Interior Layers section heading, then click the Insert Below button until we have a total of four layers: one layer in the Main Layers section and three layers in the Interior Layers section. Additional layers can be added using the Insert Above or Insert Below buttons, and layers can be deleted using the Delete button. Use the Move Up and Move Down buttons to move layers around. The selected wall type’s layers are listed here and are divided into three sections: Exterior, Main, and Interior Layers.In this example, we renamed the wall to "8" Finished Concrete." Replace the wall type name with a short, descriptive name of your choice.Depending on the new wall type you wish to create, you may be able to save time by selecting a similar preexisting wall type from the drop-down list at the top of the Wall Type Definitions dialog and copying it.
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