Visit the Energy Systems Laboratory Homepage.
Expensive Moisture/Insulation System Problems at Several Central Florida and South Texas Nursing Homes
These nursing homes were designed and built in the 80's and 90's. They experienced similar design and construction deficiencies and expensive repairs. Some of the issues to be discussed in this paper are the interactions of architectural and HVAC shortcomings that result in a synergistic increase in mold, mildew, corrosion and rot. ASHRAE 62 requires 24 hour per day toilet exhaust and fresh air. What do you do to control humidity when the A/C duty cycles when the thermostat is satisfied? There needs to be humidity control designed into the HVAC system. Architects and contractors frequently take a "head in the sand" approach to wall and attic vapor barriers. This needs to be looked at realistically. We have seen several nursing homes whose moisture/sheet rock damage was severe due to design defects that allowed free interchange of hot humid air between the attic and the space inside interior partitions. Allowing air interchange between the attic and outdoors: can cause overheating of water in pipes in attics where temperaturs reach 150° F. increases condensation due to inadequate details in mechanical insulation on ducts and pipes Vinyl wall covering is well known to be a disaster in this climate but interior decorators continue to specify it on various walls. HVAC balance needs to be considered. Frequently the kitchen exhaust design is not coordinated with the HVAC engineer. There needs to be a reasonable balance between air in and air out of the building. When air is allowed to flow through the insulation system R value is reduced to near 0. In order to prevent mold and mildew and expensive failures, along with even more expensive lawsuits, the HVAC system design and the insulation system design must be integrated.
Lotz, W. A. (2000). Expensive Moisture/Insulation System Problems at Several Central Florida and South Texas Nursing Homes. Energy Systems Laboratory (http://esl.tamu.edu); Texas A&M University (http://www.tamu.edu). Available electronically from