Structure of models for the prediction of airflow and contaminant dispersal in buildings.

This paper treats the structure of models for predicting interzonal airflow and contaminant dispersal in buildings. It will discuss the mathematical structure of such models, the use of modem data structures, the application of structured program techniques and the use of object-oriented structures for the development of users interfaces and building description processes. Two computer models developed at National Institute of Standards and Technology (NIST) will be used as examples of how these techniques can be applied to air flow analysis and contaminant dispersal: NBSAVIS - a building description processor for multizone buildings, and CONTAM88 - an interzonal airflow and contaminant dispersal analysis program. NBSAVIS treats the building as a collection of physical objects which have flow and leakage characteristics and creates a building idealization (flow paths, zones and contaminant source data) from the physical description of the building. It will be demonstrated that with the proper data structure, general interfaces which are both user-friendly and physically correct can be developed. CONTAM88 combines previously developed interzonal airflow and contaminant dispersal analysis programs AIRMOV, CONTAM86 and CONTAM87 into one model which includes such features as contaminant reactions, pressure induced contaminant sources for modeling radon entry and plateout and disposition of contaminants onto surfaces. An example is presented on the use of these programs for airflow and contaminant dispersal analysis in a large apartment building.