MAMF_with 1-21 Revisions

MAMF/MALB Companion Guidance 2021 Understanding Radon 2 for radon should be considered, especially if the building is vacant or there is no water use when testing for radon in air. Radon in water testing is covered in a separate document and is beyond the scope of this testing protocol. More information on radon in drinking water is available at state radon offices, local drinking water safety programs or at federal water safety programs (e.g., EPA’s Drinking Water Hotline (800) 426-4791 Sometimes building materials that contain uranium and radium can produce radon in sufficient amounts to result in elevated radon concentrations in the air. A radiation professional or local radiation program can help you evaluate this possibility. Factors Influencing Radon Entry Many factors contribute to the entry of radon gas into buildings. As a result, building managers cannot know without testing if elevated concentrations of radon are present. The following factors determine why some buildings have elevated radon concentrations and others do not: ● Source Strength: The concentration of radon in the soil gas ; ● Gas Mobility: The permeability of the soil or sub- surface geology under the building; ● Structure and Construction of a building; and, ● Mechanical Systems: The type, design, operation, and maintenance of the heating, ventilating, and air- conditioning system. Source strength: The radon concentration in soil gas under structures can vary greatly from one building to the next. It can even vary greatly under different parts of the same building. Gas mobility: Certain geological features beneath a building, such as cracks, fissures or solution cavities, can serve as a direct connection between the radon-producing minerals and the building’s foundation. Such a direct connection can cause one room or portion of a building to have a radon concentration significantly higher than other nearby areas. The permeability of the soil under a building along with the differences between the air pressure inside a building and the air pressure under a building’s foundation influence the radon entry rate. For example, if the air pressure in the building is greater than the air pressure under the building’s foundation, radon is less likely to enter through the openings of a building’s foundation. If the air pressure in the building is less than the air pressure under the building’s foundation, radon in the soil gas will enter through any openings in the building’s foundation. Structure and construction : Any building can have a radon problem even though building design and construction impact radon entry and ventilation once radon enters. Testing is the only way to know if elevated concentrations of radon are present. Heating, cooling and ventilation systems: Depending on their design and operation, HVAC systems can influence radon concentrations in buildings: ● Ventilation with outdoor air serves to dilute indoor radon concentrations; however, radon gas potency most often overwhelms the practical limits of increasing ventilation to adequately reduce occupant exposure. ● Poor ventilation provides less dilution of indoor radon concentrations. ● Depressurized buildings draw radon inside. ● Pressurizing a building helps keep radon out. The frequency and thoroughness of HVAC maintenance can sometimes play an important role. For example, air intake filters that are not periodically cleaned and changed can significantly reduce the amount of outdoor air needed to dilute indoor contaminants. An understanding of the design, operation and maintenance of a building’s HVAC system and its influence on indoor air is helpful for managing radon problems and other indoor air quality problems in buildings. However, since HVAC systems are only one of many factors that affect radon concentrations in a building, their modifications are often not an effective stand-alone radon mitigation strategy. E. Contacts for Additional Information In the United States: ➢ EPA website http://www.epa.gov/radon ➢ State radon offices: http://www.epa.gov/iaq/whereyoulive.html ➢ Indian Nation radon offices: http://www.epa.gov/epahome/tribal.htm ➢ Regional EPA offices: http://www2.epa.gov/aboutepa/visiting-regional- office ➢ The National Radon Proficiency Program (NRPP): www.nrpp.info ➢ The National Radon Safety Board (NRSB) - Radon Proficiency Program: www.nrsb.org In Canada: ➢ Health Canada https://www.canada.ca/en/health- canada/services/health-risks- safety/radiation/radon.html ➢ Canadian—National Radon Proficiency Program (C-NRPP): https://c-nrpp.ca/