HAM: MOIST 3 1-D heat and moisture transfer model

"MOIST is a user-friendly, personal computer program that predicts the 1D transfer of heat and moisture in building envelopes"

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The National Institute of Standards and Technology (NIST) has developed a computer model, called MOIST, that predicts the transfer of heat and moisture in a multi-layer wall under nonisotherrnal conditions (Burch and Thomas 1991). MOIST calculates the moisture content of the construction layers as a function of time. The model includes one-dimensional moisture transfer by diffusion and capillary flow. The moisture-transfer permeances offered by vapor retarders and paint layers are readily included in simulations. The model accounts for convective moisture transfer by including air cavities which may be coupled to indoor and outdoor air. MOIST has recently been verified by way of comparison to a series of experiments (Zarr, et al. 1994).

Transfer of Heat and Moisture in Building Envelopes (by ORNL)

MOIST is a user-friendly, personal computer program developed by the National Institute of Standards and Technology and the Virginia Polytechnic Institute and State University. MOIST predicts the one-dimensional transfer of heat and moisture in building envelopes. A wall, cathedral ceiling, or low-slope roof construction can be easily defined, and the effects of various parameters on the moisture accumulation within layers of construction can be investigated. For example, the effect of climate on moisture accumulation can be investigated by conducting computer runs for different U.S. and Canadian cities. The need for a vapor barrier can be determined; and, if needed, where it should be placed relative to the other materials. MOIST allows the user to vary easily the building materials and their relative placement and predicts the resulting moisture accumulation within each as a function of time for the selected climate. MOIST permits the evaluation of the effect of the water-vapor resistance offered by paint layers, wallpaper, and vapor retarders. Finally, MOIST can be used to produce moisture control guidelines.

The algorithms in the program can predict moisture transfer for the diffusion regime through the capillary flow regime. The program has a provision to account for convective moisture transfer by including embedded cavities which may be coupled to indoor or outdoor air. The program generates a plot on the computer screen of the average moisture content of the construction layers versus time as the program executes. The program generates output files which may be imported into plotting programs for preparing reports.

• Burch, D., (1995), An analysis of moisture accumulation in the roof cavities of manufactured housing
• used
  Burch, D. M. and Saunders, C. A., (1995), Computer analysis of wall constructions in the moisture control handbook
• use MOIST in Manufactured housing for moisture performance
  Burch, D. M., Saunders, C.A. and TenWolde, A., (1995), Manufactured housing walls that provide satisfactory moisture performance in all climates
• MOIST 3.0 user's manual
  Burch, D.M, (1997), MOIST: A PC program for predicting heat and moisture transfer in building envelopes, Release 3.0
• Burch, D.M. and A.O. Desjarlais, (1995), Water-vapor measurements of low-slope roofing materials
• Burch, D.M. and Walton, G.N, (1997), A mathematical analysis of moisture and heat transfer in the roof cavities of manufactured housing
• experimental verification
  Burch, D.M., R.R. Zarr, and Fanney, A. H., (1995), Experimental verification of a moisture and heat transfer model in the hygroscopic regime
• Hens, H. and Janssens, A., (1993), Inquiry on HAMCAT codes
• empirical verification of MOIST
  Rode, C. and Burch, D.M, (1995), Empirical validation of a transient computer model for combined heat and moisture transfer
• Straube, J.F. and Burnett, E.F.P, (2001), Overview of hygrothermal (HAM) analysis methods
• Tsongas, G., Burch, D., Roos, C., and Cunningham, M. J., (1995), A prarmeteric study of wall moisture contents using a revised variable indoor relative humidity version of the "MOIST" transient heat and moisture transfer model
• Tsongas, G.A., Thornton, B.A., Burch, D.M. and Walton, G.N, (1996), A computer analysis of the moisture performance of roof constructins in the U.S. DOE Moisture Control Handbook
• Zarr, R. R., Burch, D. M. and Fanney, A. H., (1995), Heat and moisture transfer in wood-based wall construction: measured versus predicted
• Zarr, R.R., Kumaran, K. and Lagergren, E.S, (1997), NIST/NRC-Canada interlaboratory comparison of guarded hot plate measurements: 1993-1997

• HAM: 1D-HAM
• HAM: DELPHIN 4, DIM 3.1
• HAM: EMPTIED
• HAM: GLASTA
• HAM: hygIRC
• HAM: Hygran24
• HAM: LATENITE
• HAM: Lund-Gothenburg Group for Computational Building Physics
• HAM: MATCH
• HAM: MOISTURE-EXPERT
• HAM: simple calculations
• HAM: simulation input parameters
• HAM: TCCC2D - Transient Coupled Convection and Concudtion in 2 Dimensions
• HAM: TRATMO
• HAM: WALLDRY
• HAM: WUFI (W?rme- Und Feuchtetransport Instation?r)
• HAM: WUFI-ORNL/IBP
• MOIST 3 property data
• heat and moisture behavior of underground space
• Heat-air-moisture transport program available on the web
• History of HAM (Heat-Air-Moisture)
• History of research models for combined heat and moisture transfer
• IEA/Annex 24: Heat, air and moisture transfer