Rough-in of Radon Control Components In New Construction of 1 & 2 Family ANSI/AARST RRNC 2020 Dwellings and Townhouses 2 SECTION 201 DEFINITIONS 201.1 Definitions. Terms not defined herein shall have their ordinary meaning within the context of their use. Ordinary meaning shall be defined in "Webster's Eleventh New Collegiate Dictionary." ACCESS (limited). Point of entry to fan location that allows service personnel to reach an ASD fan or intended fan location for the purpose of installing or replacing an ASD fan . Such access does not require walkways, service platforms, level working spaces, receptacle and lighting outlets or clear and unobstructed passageways with continuous solid flooring such as are typically required for appliances that require periodic maintenance, servicing and inspection. ACTIVE SOIL DEPRESSURIZATION (ASD). A radon control system involving fan-powered soil depressurization, including but not limited to sub-slab depressurization and sub-membrane depressurization. ASD FAN. A type of fan that is designed and rated by the manufacturer for continuous duty and for use in an ASD system. BACKWATER VALVE. A mechanical device that will allow water to flow in one direction while preventing airflow in the opposite direction. BECQUERELS PER CUBICMETER [Bq/m 3 ]. A unit of measure for the amount of radioactivity in one cubic meter of air. CONVERSION: 1.0 Bq/m 3 = 0.027 pCi/L . COMBINATION FOUNDATIONS. Buildings constructed with more than one foundation type, such as, basement and crawlspace or basement and slab-on-grade. CRAWL SPACE. A foundation type with an open area beneath the livable space of a dwelling that typically has either a concrete slab or earthen floor. The crawl space can have an open height of a few inches to several feet. The crawl space may or may not be ventilated to the outdoors. CUBIC FEET PER MINUTE (cfm). A measure of the flow rate of a fluid, such as air. CONVERSION: 1.0 cfm = 1.7 m 3 /hr . CUBIC METERS PER HOUR [m 3 /hr]. A measure of the flow rate of a fluid, such as air. CONVERSION: 1.0 m 3 /hr = 0.6 cfm . DEPRESSURIZATION. A negative pressure induced in one area with respect to another. DIAGNOSTIC TESTS. Procedures, including communication tests and other tests, used to identify or characterize conditions under, beside and within buildings that could contribute to radon entry or elevated radon concentrations or that could provide information regarding the performance of a radon control system . DWELLING. Any building that contains one or two units that are intended to be occupied for living purposes. GEOTEXTILE MATTING. A product suitable for soil contact, that provides a void space laterally through the material to allow air movement. The void space is created through a matrix of woven mesh, “egg crate” support of a fabric enclosure or similar means. Also known as soil gas collector matting, geotextile vent strip or vapor matting. GRAVEL. A mixture of crushed rock or naturally occurring pebbles. Commercially, it is classified according to the size of the particles. INCHES OF WATER COLUMN (in. WC). A measure of pressure. CONVERSION: 1 in. WC = 249 Pascals . KARST. An area underlain by limestone in which erosion has produced fissures, sinkholes, underground streams, or caverns.