AC-2738 (RP-254) -- Latent Loads in Low-Humidity Rooms Due to Moisture PDF

Significant latent loads exist in cold rooms and other low humidity areas due to moisture which infiltrates the space through doors, windows, conveyor entrances, cracks, seams, Data joints, and through permeable building materials. are available to estimate infiltration through building materials, but techniques for estimating infiltration from other sources are not well defined and industry practice varies widely. This research project specifically addressed the problem of moisture infiltration through openings and through duct seams where ducts pass through unconditioned space. Actual moisture infiltration through openings, and moisture infiltration into air ducts passing through moist air, were determined experimentally for various humidity, temperature, and air outflow conditions. A simple convection theory is presented from which the moisture infiltration through openings can be estimated for a wide range of temperature and humidity. It is also shown that moisture infiltration through openings can be significantly reduced by proper design of the opening and by using an air curtain.