Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

CONTAM User Guide and Program Documentation Version 3.4



William Stuart Dols, Brian Polidoro


This manual describes the computer program CONTAM version 3.4, developed by NIST. CONTAM is a multizone indoor air quality and ventilation analysis program designed to help determine airflows, contaminant concentrations, and occupant exposure in buildings. CONTAM can calculate infiltration and exfiltration airflows between interior zones of the building and the outdoors, room-to-room airflows, and ventilation system airflows. These airflows are the result of pressure differences resulting from driving forces which include mechanical ventilation system fans, wind pressures acting on the exterior of the building, and buoyancy effects induced by temperature differences between zones, including the outdoors. CONTAM can also calculate contaminant concentrations to account for the transport and fate of airborne contaminants due to airflow, chemical and radio-chemical transformation, adsorption and desorption of building materials, filtration, and deposition to and resuspension from building surfaces. CONTAM can be useful in a variety of applications. Its ability to calculate building airflow rates and pressures between zones of the building is useful for assessing the adequacy of ventilation rates in a building, for determining the variation in ventilation rates over time, for determining the distribution of ventilation air within a building, for estimating the impact of envelope air-tightening efforts on infiltration rates, and for evaluating the energy impacts of building airflows. The program has also been used extensively for the design and analysis of smoke management systems. The prediction of contaminant concentrations can be used to determine the indoor air quality performance of buildings before they are constructed and occupied, to investigate the impacts of design decisions related to ventilation system design and building material selection, to evaluate indoor air quality control technologies, and to assess the indoor air quality performance of existing buildings. Predicted contaminant concentrations can also be used to estimate personal exposure based on occupancy patterns and activities, and occupants can also act as contaminant sources as they move throughout the building.
Technical Note (NIST TN) - 1887r1
Report Number


airflow analysis, building controls, building technology, co-simulation, computer program, contaminant dispersal, controls, energy use, indoor air quality, multizone analysis, smoke control, smoke management, ventilation


Dols, W. and Polidoro, B. (2020), CONTAM User Guide and Program Documentation Version 3.4, Technical Note (NIST TN), National Institute of Standards and Technology, Gaithersburg, MD, [online],, (Accessed March 2, 2024)
Created August 3, 2020, Updated February 23, 2023