CONTAM logo.

Multi-zone (nodal) airflow and contaminant transport analysis program. CONTAM consists of two components � a graphical user interface (GUI) and a simulation engine. The GUI is centered on a SketchPad that provides for the input of building topology via a set of drawing tools geared towards producing schematic representations of building floor plans. Drawing tools are used to draw walls, ducts and simplified control networks as well as to create iconic representations of building elements including flow paths, source/sinks and occupants. These drawing tools were designed to provide a robust means to create a well-formed multi-zone description of a building to be used by the simulation engine. Once a building representations is developed it is �passed� to the simulation engine to calculate zone pressures, airflow rates and contaminant concentrations. It can perform steady-state, transient, and steady periodic (one day) analyses. The interface also provides a means to graphically review results.

CONTAM Version 2.0 contains several new features including: non-trace contaminants, unlimited number of contaminants, contaminant-related libraries, separate weather and ambient contaminant files, building controls, scheduled zone temperatures, improved solver to reduce simulation times and several user interface related features to improve usability. CONTAM Version 2.1 provides the capability to incorporate data from exterior airflow and pollutant transport models, e.g., CFD, plume and puff dispersion models, to utilize detailed ambient wind pressure and contaminant data fields. Screen Shots


airflow analysis; building controls; contaminant dispersal; indoor air quality, multizone analysis, smoke control, smoke management, ventilation


Several multi-zone modeling validation studies have been performed. Results of these studies are available throughout the literature. The following reference provides a good starting point: Emmerich, S.J. Validation of Multizone IAQ Modeling of Residential-Scale Buildings: A Review. ASHRAE Transactions, vol. 107 pt. 2, 2001. American Society of Heating, Refrigeration and Air-Conditioning Engineers. Several other studies are provided in the Publications section of the NIST IAQ Analysis website.

Expertise Required

Familiarity with buildings, building ventilation, and pollutant sources.


More than 3,000 copies downloaded.


Mechanical, environmental, and smoke control engineers; building designers; state and Federal agency staff; university faculty; researchers; private consultants.


A graphical, schematic representation of the building as a series of walls that makeup the zones, zone temperatures, airflow leakage paths through walls and floors, ductwork and ventilation system flows, contaminant source strengths, filter efficiencies, ambient weather and contaminant data, building controls and schedules.


On-screen display of all pressure drops and flows superimposed on the graphic building description; on-screen graphs of transient airflows and contaminant concentrations; formatted reports of same; files suitable for import into spreadsheet programs consisting of zone pressures, contaminant concentrations and ages of air, inter-zonal airflow rates and whole building air change rates.

Computer Platform

The GUI (ContamW) runs under Windows 95/98, NT/2000, and XP as well as under Windows emulators on MacIntosh computers. The simulation engine (ContamX) runs under Windows, but can be compiled to run under Linux as well.

Programming Language



Flexible graphic interface simplifies description of complex buildings, fast and reliable solution algorithms handle large complex geometries very quickly, flexible units, and interactive help. Used by many companies for designing smoke control systems.


Absolute accuracy of computed flows and pressures limited by the wide range of data on leakage characteristics of building components and uncertainties in wind pressures. Accuracy of contaminant migration limited by treating each building space as a well-mixed zone.



National Institute of Standards and Technology


100 Bureau Drive, Stop 8633
Gaithersburg, Maryland 20899-8633
United States


(301) 975-6421


(301) 975-4409




Program and user manual are public domain and freely available at