Definitions A| B| C| D| E| F| G| H| I|K|L| M| N| O| P| Q| R| S| T| U| V| W
Abbreviations & Acronyms: A| B|
C| D| E|
F| G| H| I| L| M| N|
O| P |Q |R | S | U| V| W
American
Association of Radon Scientists and Technologists
Absorbed
Dose
Accuracy
Activated
Carbon
Activity
Acute
Effect
Air
Changes per Hour (ACH)
Air
Exchange Rate
Air
Pressure Differentials
Aggregate
Alarm
Alpha
Decay
Alpha
Particle
Alpha
Track Detector
Anchor
Bolt
Asbestos
or Asbestos-Containing Material (ACM)
Atom
Atomic
Number
Atomic
Weight
American Association of Radon Scientists and Technologists - A non-profit organization of radon measurement and testing professionals.
Absorbed Dose - The energy deposited by ionizing radiation per unit mass of material. Units of absorbed dose are the gray (GY) and the rad.
Accuracy - Measure of the correspondence of the measured result of the "true" or target value.
Activated Carbon - A material manufactured from the combustion of fibrous materials such as coconut shells or wood under low oxygen conditions. This process makes "sites" within the material upon which radon can be adsorbed. This material is used in activated carbon measurement devices and in activated carbon adsorption units for removing radon from water.
Activity - Synonymous with RADIOACTIVITY
Acute Effect - An effect that becomes apparent after a discrete brief exposure, rather than being manifested only long after exposure.
Air Changes per Hour (ACH) - The number of times within 1 hour that the volume of air inside a house would nominally be replaced, given the rate at which outdoor air is infiltrating the house. If a house has 1 ACH, it means that all of the air in the house will be nominally replaced in a 1-hour period.
Air Exchange Rate - The rate at which the house air is replaced with outdoor air. Commonly expressed in terms of air changes per hour.
Air Pressure Differentials - Differences in air pressure that exist over short distances, e.g. between the interior of a home and below slab or between inside and outside the building shell. Air moves from areas of higher pressure to lower pressure. Air flow caused by pressure differentials is a major force for radon entry into buildings.
Aggregate - Stone, crushed stone, or other inert material having hard, strong, durable pieces. When used in house construction, it forms the uppermost surface on which the slab is poured, just below the vapor barrier.
Alarm - As used here, a device which gives a visual or auditory signal (such as a light or a buzzer) when the suction or air flow in an ASD system moves outside the acceptable operating range for that system. An alarm may or may not also include a gauge to provide a reading of the actual suction or air flow in the system.
Alpha Decay - The radioactive decay of an atom in which the nucleus loses two protons and two neutrons.
Alpha Particle - A positively charged subatomic particle emitted during decay of certain radioactive elements. For example, an alpha particle is released when radon-222 decays to polonium-218. An alpha particle is indistinguishable from a helium atom nucleus which consists of two protons and two neutrons.
Alpha Track Detector - A long-term detector for radon. It consists of a plastic material or celluloid film, in which alpha radiation leaves damage tracks that can be counted under a microscope after the plastic material is etched in NaOH (sodium hydroxide) solution.
Anchor Bolt - A threaded rod used to fasten the sill plate to the foundation.
Asbestos or Asbestos-Containing Material (ACM) - A fire-proofing material used extensively in general building construction up until its use was severely restricted by the U.S. EPA in 1972 due to exposure concerns. Asbestos fibers target the respiratory system and exposure can increase risks in developing asbestos, lung cancer, and melotheleomia. Radon related diagnostic and mitigation activity may inadvertently release asbestos fibers into the air.
Atom - The smallest particle of an element that exhibits the same chemical properties of the compound itself. Consists of a nucleus (a mass of protons and neutrons) surrounded by electrons.
Atomic Number - The number of protons (positively charged particles) found in the nucleus of an atom. Each element has a distinct atomic number.
Atomic Weight - The weight of an atom which is approximately the number of protons and neutrons in the nucleus. This sum is also called the atomic mass.
Back-Drafting
Backer Rod
Backfill
Background
Measurements
Background Radiation
Balloon
Frame
Baseboard
Basement
Bearing Partition
Bearing Plate
Beir
Beta Decay
Bias
Blind Spikes
Blocking
Blower Door
Bonding Agent
Brick Veneer
Bridging
British Thermal Unit (BTU)
Bronchial Epithelium
Built-Up Roof
Back-Drafting - A condition where the normal movement of combustion products up a flue, resulting from the buoyant forces on the hot gases, is reversed, so that the combustion products can enter the house. Back-drafting of combustion appliances (such as fireplaces and furnaces) can occur when depressurization in the house overwhelms the buoyant force on the hot gases. Back-drafting can also be caused by high air pressures at the chimney or flue termination.
Backer Rod - A semi-rigid foam material resembling a rope of various diameters used to fill around pipes, etc., and to assist in making a sealed penetration. For example, where a pipe is inserted through a concrete slab, a length of backer rod is jammed into the opening around the pipe. Caulking is then applied to the space above the backer rod and between the outside of the pipe and the slab opening. The purpose of the backer rod is to hold the semi-fluid caulk in place until it sets or hardens. It is most important that a sealant only adhere to the two sides of the joint and not the base of the joint (third side). Adhesion to all three sides will prevent the sealant from elongating properly and will cause sealant failure. (Adopted Rule 422.20)
Backfill - Earth replaced around a foundation.
Background Measurements- Background measurements are made with instruments exposed to very low radon concentration environments (such as outdoor air), or can be "blanks", unexposed passive detectors. Background levels are subtracted from samples before calculating sample concentrations.
Background Radiation - Radiation arising from radioactive material other than that under consideration. Background radiation due to cosmic rays and natural radioactivity is always present; there may also be background radiation due to the presence of radioactive substances in building materials.
Balloon Frame - A type of building frame in which the studs extend from sill to eaves without interruption or cross bracing.
Baseboard - The finishing board covering a wall where it meets the floor.
Basement - A type of house construction where the bottom liveable level has a slab (or earthen floor) which averages 3 feet or more below grade level on one or more side of the house.
Bearing Partition - A partition supporting any vertical load other than its own weight.
Bearing Plate - A support member used to distribute weight over a larger area.
Beir- Biological Effects of Ionizing Radiation - A report by the National Research Council that provides the basis for determining lung cancer risks for individuals from the Uranium Miner data.
Beta Decay - Radioactive decay in which a nucleus is transformed by the emission of an electron or positron. In either case, the atomic mass remains unchanged, but the atomic number either increases or decreases by 1.
Bias - The systematic difference between the average value of duplicate measurements true value.
Blind Spikes - Detectors exposed to known values and submitted for analysis without being labelled as such. Used to evaluate the accuracy of a laboratory's analytical process.
Blocking - Small wood framing members.
Blower Door - A device consisting of an instrumented fan, which can be mounted in an existing doorway of a house. By determining the air flows through this fan required to achieve different degrees of house depressurization, the blower door permits determination of the tightness of the house shell, and an estimation of the natural filtration rate.
Bonding Agent - A material added to adhesive or on a surface to be bonded to enhance adhesion characteristics of the bonding material.
Brick Veneer - A brick facing laid in front of frame construction.
Bridging - Cross-bracing between floor joists to add stiffness to the floors.
British Thermal Unit (BTU) - Basic heat measurement, equivalent to the amount of heat needed to raise 1 pound of water 1 degree Fahrenheit.
Bronchial Epithelium - The surface layer of cells lining the conducting airways of the respiratory system.
Built-Up Roof - A roofing composed of several layers of felt and asphalt, pitch, or coal tar.
Calibration
Canal Drain
Cantilever
Cavity Wall
Channel Drain
Chases
Check Valve
Chemical Smoke
Chronic Effect
Circuit
Coefficient of Variation
Cold Air Return
Concentration Gradient Diffusion
Confidence
Controlled Calibrations
Convective Movement
Column
Communication
Concrete
Concrete Masonry Unit (CMU)
Condensation
Conductor
Conduit
Cornice
Counterflashing
Course
Crawl Space
Cricket
Cubic Feet per Minute (cfm)
Curie (Ci)
Curtain Wall
Calibration - The determination of deviation from standard of measurement instrument to determine necessary correction factors (calibration factor).
Canal Drain - A means for collecting water in a basement by means of a large gap or channel between the concrete floor and the wall. Collected water may flow to aggregate beneath the slot "French Drain" or to a sump where it can be pumped away.
Cantilever - A beam or girder fixed at one extremity and free at the other. To "cantilever" is to employ the principle of the lever to carry a load.
Cavity Wall - A masonry wall having an air space of about 2".
Channel Drain - A void area between the concrete floor and foundation wall that remains open to collect surface water; typically 2-inches wide (See Canal Drain).
Chases - Open areas that run horizontally or vertically through a structure to accommodate installation of pipes, duct, and electrical wire.
Check Valve - A device installed on an effluent plumbing line to only allow flow discharge in one direction.
Chemical Smoke - A sensitive smoke generated from the reaction of titanium tetrachloride and air.
Chronic Effect - An effect that becomes apparent only some time after exposure, as opposed to an acute effect, which develops with a one-time or short-term exposure.
Circuit - The path for an electric current.
Coefficient of Variation - The standard deviation of a number of samples divided by the average value of those of samples.
Cold Air Return - The registers and ducting which withdraw house air from various parts of the house and direct it to a central forced-air furnace or heat pump. The return ducting is at low pressure relative to the house because the central furnace fan draws air out of the house through this ducting.
Concentration Gradient Diffusion - One of the methods by which radon moves through a material (soil) by diffusion from a higher concentration (source) to areas of lower concentration. The rate of diffusion is generally determined by the porosity of the soil.
Confidence - The degree of trust that a method will achieve the radon reduction estimated.
Controlled Calibrations - A controlled calibration refers to measurements made in a known radon environment (calibration chamber). Generally, detectors that require laboratory analysis (e.g., charcoal canisters and alpha track detectors) are placed in a calibration chamber for a known period of time and then sent to a laboratory for analysis. The laboratory result may then be compared with the known chamber concentration value to check the accuracy of the laboratory, (a "blind calibration"), or used to derive or verify the conversion factors for the detectors (a "spiked sample"). Real-time radon and RDP measuring instruments must be operated in a chamber on a regular basis to calculate the calibration factor.
Convective Movement - As used here, the bulk flow of radon-containing soil gas into the house as the result of pressure differences between the house and the soil. Distinguished from diffusive movement.
Column - A vertical member, generally a beam or post, that supports some of the weight of a building.
Communication - The degree to which the effects of a depressurization at some location under a slab are transmitted to other remote locations under the slab.
Concrete - A masonry mixture of Portland cement, sand and aggregate, and water in proper proportions.
Concrete Masonry Unit (CMU) - Composite material fabricated in modular units, typically used to fabricate foundation walls in conjunction with mortar. Sometimes referred to as block, cinder block, and concrete block.
Condensation - Water formed by warm, moist air contacting a cooler surface.
Conductor - A material permitting passage of electric current.
Conduit - A pipe or trough that carries water, electrical wiring, cables, and so forth.
Cornice - That part of a roof which extends or projects beyond the wall; the architectural treatment thereof, as a "box cornice."
Counterflashing - A flashing used under the regular flashing.
Course - A horizontal row of bricks, tile, stone, building blocks, or similar material.
Crawl Space - An area beneath the living space in some houses, where the floor of the lowest living area is elevated above grade level.
Cricket - A roof device used at intersections to divert water.
Cubic Feet per Minute (cfm) - A measure of the volume of a fluid (liquid or gas) flowing within a fixed period of time.
Curie (Ci) - A standard measurement for radioactivity, specifically the rate of decay for a gram of radium -- 37 billion decays per second. A unit of radioactivity equal to 3.7 x 1010 disintegrations per second.
Curtain Wall - An exterior wall which provides no structural support.
Damper
Daylight Drains
Decay Product
Decay Series
De-Gassing
Degree Day (dd)
Depressurization
Diagnostic Measurements
Differential Pressure Gauge
Diffusive Movement
Downspout
Draftstop
Drainage Board
Drain-Tile Depressurization (DTD)
Driver
Dry Core Drill
Ductwork
Duplicates
Dura-Wall
Damper - A movable plate to regulate the air flow in a duct.
Daylight Drains - A drain pipe that is laid horizontally around the foundation to collect sub-surface water. The drain pipe will continue from the building until it breaks grade and reaches daylight.
Decay Product - Radioactive materials degrade to give rise to decay products, often referred to informally as "daughters" or "progeny." The radon decay products of most concern from a public health standpoint are polonium-214 and polonium-218.
Decay Series - The consecutive members of a family of radioactive isotopes formed by sequential radioactive decay.
De-Gassing - As used here, the release of dissolved radon gas into the house air when radon-containing well water is used in the house.
Degree Day (dd) - The degree day is a unit of heat measurement equal to one degree variation from the standard temperature in the average temperature of one day. If the standard is 65 degrees F and the average outside temperature is 50 degrees F for two days, then the number of degree days is 30, i.e., 15o x 2 days = 30 dd.
Depressurization - In houses, a condition that exists when the air pressure inside the house is slightly lower than the air pressure outside or the soil gas pressure. The lower levels of houses are essentially always depressurized during cold weather, due to the buoyant force on the warm indoor air (creating the natural thermal stack effect). Houses can also be depressurized by winds and by appliances which exhaust indoor air. Radon-containing soil gas is drawn more rapidly into a house under the depressurized condition.
Diagnostic Measurements - A variety of different types of tests that can be conducted prior to or following the installation of a radon reduction system, in order to aid in: deciding which radon reduction technology to utilize; designing the selected system; or evaluating the reasons why an installed system is not performing as anticipated.
Differential Pressure Gauge - A gauge which has two parts. The gauge measures the difference in pressure between the two parts. If one part is left open and the other part is connected via a tube to beneath a concrete slab, the resultant measurements provides the difference in pressure from beneath the slab of the interior of the home. Such gauges can be obtained with large ranges of measurements to thousandths of an inch of meter column as in the case of a micromanometer.
Diffusive Movement - The random movement of individual atoms or molecules, such as radon atoms, in the absence of (or independent of convective movement). Atoms of radon can diffuse through tiny openings, or even through unbroken concrete slabs. Distinguished from convective movement ( See Concentration Gradient Diffusion).
Downspout - A vertical drain pipe for carrying rain water from the gutters.
Draftstop - Fire retardant materials placed around openings through floor and sealing systems to prevent the flow of gases.
Drainage Board - A board with grooves or an open mesh material that is installed next to exterior foundation walls from just below grade line to the footing during construction. The purpose of which is to provide a pathway for surface water to easily run down the side of the wall to the exterior foundation drainage system.
Drain-Tile Depressurization (DTD) - A variation of the ASD technology, where the area around the foundation is depressurized by drawing suction on drain tiles.
Driver - In the context of this document, driver indicates the element that generates negative pressure to power and ASD system. These are fans or blowers.
Dry Core Drill - An electric-powered drill that usually can be used like a small jackhammer, a hammer drill, or a core drill. This type of drill usually does not use cooling water. Generally, a chisel bit is used in the jackhammer mode, a screw bit in the hammer drill mode, or a core bit in the core drill mode.
Ductwork - Any enclosed channel(s) which directs the movement of air or other gas.
Duplicates - Two measurements made side-by-side as a quality control measure. The primary objective is to determine how close the resulting values are to each other, i.e. their precision.
Dura-Wall - Horizontal reinforcing for CMU walls typically placed every sixth course and imbedded in mortar.
Eave
Effective Leakage Area
Elbow
Electret Ion Chamber
Electron
Electron Volt (ev)
Entry Routes
Epithelium
Equilibrium, Secular
Equilibrium Ratio, Dynamic
Exfiltration
Exhaust Fan
Expansion Joint
Eave - The boarder of a roof that overhangs any wall. (Adopted Rule 422.20)
Effective Leakage Area - A parameter determined from blower door testing, giving a measure of the tightness of the house shell. Conceptually, this leakage area reflects the square inches of open area through the house shell, through which air can infiltrate or exfiltrate.
Elbow - An L-shaped pipe fitting. A 90o fitting.
Electret Ion Chamber - A device for measuring radon. Radon diffuses into the chamber where it goes through its normal decay process emitting ionizing radiation. The ions created alter the charge on an electret surface. Measurements of the charge on the electret surface before and after deployment of the device can be used to calculate the radon concentrations in the room in which the detector was placed.
Electron - An elementary constituent of an atom that orbits the nucleus and has a negative charge. Beta decay is radioactive decay in which an electron (or a positron) is emitted from a nucleus.
Electron Volt (ev) - The energy assumed by an electron as it is accelerated through an electric potential difference of one volt. One electron equals 1.6 x 10-19 Joules.
Entry Routes - Openings through the flooring and walls where the house contacts the soil, providing pathways by which soil gas can flow into a house.
Epithelium - A membranous cellular tissue that covers the surface of some organ or part of the body.
Equilibrium, Secular - A state in which the formation of atoms by decay of a parent radioactive isotope is equal to its rate of disintegration by radioactive decay.
Equilibrium Ratio, Dynamic - A total concentration of radon decay products (RDPs) present divided by the concentration that would exist if the RDPs were in radioactive equilibrium with the radon gas concentration which is present. At 100% equilibrium (i.e., at an equilibrium ratio of 1.0), 1 WL of RDPs would be present when the radon concentration was 100 pCi/L. The ratio is never 1.0 in a house. Due to ventilation and plate-out, a commonly assumed equilibrium ratio is 0.5 in which case 1 WL corresponds to 200 pCi/L. However, equilibrium ratios vary with time and location, and ratios of 0.3 to 0.7 are commonly observed. Large buildings, including schools, often contain equilibrium ratios less than 0.5.
Exfiltration - The movement of indoor air out of the house.
Exhaust Fan - A fan oriented so that it blows indoor air out of the house.
Expansion Joint - A joint between a concrete slab or two adjacent slabs that allows the concrete to move independently from the adjacent slab or wall. It is typically a 1/2 inch fibrous board which is impregnated with an asphaltic material. It is laid either between the first and second slab or between the wall and the adjacent floor.
Facade
Face Brick
Fan Curve
Fascia
Field Blank
Fieldstone
Fill Soil
Fire Stopping
Fire Wall
Flashing
Floor Plan
Flowable Caulk
Flue
Follow-Up Measurements
Footing(s)
Forced-Air Furnace (or Heat Pump)
Foundation
French Drain
Frost Line
Furring
Facade - The front or face of a building.
Face Brick - A special brick used for facing a wall. They are more uniform in size than common bricks, are made in a variety of colors and textures, and are weather resistant.
Fan Curve - A plot of the airflow that a specific fan can produce with a given amount of pressure drop. When there is no flow, the fan will exert the maximum suction or pressure it can attain. The maximum airflow the fan can produce exists when there is no resistance (free air), and no pressure drop across the fan. The collection of points representing the airflow at any intermediate pressure produces the fan curve for that fan.
Fascia - A flat banded projection on the face of the cornice.
Field Blank - A quality control measurement made using a detector which has not been exposed to radon or progeny. The purpose of this procedure is to determine the bias associated with the storage and shipping of devices.
Fieldstone - Building stone found loose on the ground (field) regardless of its exact variety.
Fill Soil - The soil that has been graded, placed, and packed directly under where the slab will be poured. Fill soil may be brought from another site or may be native to the area. For a stem wall construction, the fill soil is used to "fill" the space inside the stem walls up to the level at which the bottom of the slab will be poured. In the monolithic construction, the fill soil is the soil into which the footings and onto which the slab will be poured.
Fire Stopping - Obstructions across air passages in buildings to prevent the spread of hot gases and flames; horizontal blocking between wall studs.
Fire Wall - A wall system installed to separate areas to protect from fire and smoke.
Flashing - The sheet metal work used to prevent leakage over windows and doors, around chimneys and other roof penetrations, and at the intersections of different wall surfaces and roof planes.
Floor Plan - A diagram of a floor of a building.
Flowable Caulk - Refers to caulks (often urethane caulks) which are sufficiently fluid such that they will tend to flow like a viscous liquid prior to curing. Flowable caulks have the advantage of flowing into cracks and irregularities in the opening being sealed, thus forming an effective seal.
Flue - A passage in the chimney to convey smoke to the outer air.
Follow-Up Measurements - Measurements made to evaluate typical long-term radon concentrations. They are conducted after an initial measurement indicates the potential for unacceptable radon levels.
Footing(s) - A concrete or stone base which supports a foundation wall and which is used to distribute the weight of the house over the soil or subgrade underlying the house. The bases upon which the foundation and posts rest.
Forced-Air Furnace (or Heat Pump) - A central furnace or heat pump that functions by recirculating the house air through a heat exchanger in the furnace. Distinguished from a central hot-water space heating system or electric resistance heating.
Foundation - The supporting wall of a building below the first-floor level.
French Drain - A means for collecting drainage water around a house for the purpose of diversion. In its early forms, this was a trench of large aggregate along or below a foundation that would allow water collected in the trench to soak down through the soil. More modern improvements on this design lead to "canal" or "channel drains" inside of a basement to facilitate interim water to flow to the aggregate or a sump. Another improvement was to place perfected pipe in a rock-filled trench around the inside or outside of the footing to collect and divert water.
Frost Line - The depth of frost penetration in soil.
Furring - Wood strips fastened to a wall or ceiling for the purpose of attaching wallboards or ceiling tile.
Gable
Gamma Radiation
Geiger Counter
Grab Sampling
Grade (above or below)
Grade or Grade Line
Granular Activated Carbon (GAC)
Gross Alpha
Ground Fault Interrupter Switch
Grout
Gutter
Gypsum
Board
Gable - See eave. (Adopted Rule 422.20)
Gamma Radiation - Short-wavelength electromagnetic radiation of nuclear origin, with energies between 10 keV to 9 MeV.
Geiger Counter - A device for detecting beta and gamma radiation.
Grab Sampling - The collection of a sample over a very short period of time (usually a few minutes). Is essentially an instantaneous measurement, and only indicates values existing at the time of sampling. Generally only useful for diagnostic purposes.
Grade (above or below) - Term describing the level of the ground surrounding a house. In construction, typically refers to the surface of the ground. Things can be located at grade, below grade, or above grade relative to the surface of the ground.
Grade or Grade Line - The level of the ground around a building.
Granular Activated Carbon (GAC) - A unique material made from wood, coal, or other carbon base that has been carbonized (charcoal) and activated to develop a vast internal pore structure and adsorption. Used in activated charcoal canisters and in radon in water reduction devices.
Gross Alpha - A measure of the total alpha activity of a water sample, excluding radon. It can serve as a rough indication of the radium and uranium concentrations present in a water sample.
Ground Fault Interrupter Switch - A switch which is installed in the power cord leading to masonry drills, which are being used to drill or core holes through concrete slabs. If the drill bit touches anything metal beneath the slab (such as a gas line), the switch opens, shutting off the power to the drill before further damage can be done to the sub-slab line. A GFI circuit is also found in areas where water may be present, such as a garage or bathroom.
Grout - Cementitious material with non-shrink properties placed under a member resting on a concrete wall to provide a flat bearing surface.
Gutter - A trough or depression for carrying off water.
Gypsum Board - Board made of plaster with a covering of paper. Also plaster board.
Half-Life
Header
Headjoint Area
Heat Exchanger
Heat Recovery Ventilators
Heat Transfer Efficiency
Henry's
Constant
Half-Life - The time required for half the atoms of a radioactive substance present at the beginning to be disintegrated. For instance, beginning with 100 units, there would be 50 units not disintegrated at the end of the first half-life, 25 at the end of the second, and so forth.
Header - A beam perpendicular to the joists into which they are framed.
Headjoint Area - The vertical joint located between two CMUs.
Heat Exchanger - A device used to transfer heat from one stream to another. In air-to-air heat exchangers for residential use, heat from exhausted indoor air is transferred to incoming outdoor air, without mixing the two streams.
Heat Recovery Ventilators - Also known as air-to-air heater exchangers or heat exchangers.
Heat Transfer Efficiency - The efficiency at which heat can be transferred from one medium to another. In the context of this manual it is the percentage of heat (expressed in BTUs/pound) which can be recovered from an air stream exhausted from a home through an air to air heat exchanger to the incoming air supply stream.
Henry's Constant - The ratio of the air to water concentrations of a gas or volatile compound.
IDNS
Infiltrations
Indoor Radon Abatement Act
Interior Footing Drains
Investigatory Measurements
Ion
Ionization
Ionizing Radiation
Isotope
IDNS-ILLINOIS DEPARTMENT OF NUCLEAR SAFETY
Infiltrations - The unwanted admittance of air through cracks and pores. The movement of outdoor air or soil gas into a house. The infiltration which occurs when all doors and windows are closed is referred to in this document as the natural closed-house infiltration rate. The reverse of exfiltration.
Indoor Radon Abatement Act - Passed is 1988 as Title III of the Toxic Substances Control Act, this law establishes as a national goal - but not as a requirement - that air within buildings "should be as free of radon as the ambient air outside of buildings." The law directed EPA to conduct a variety of activities, and to fund three year programs for States and Regional Radon Training Centers.
Interior Footing Drains - A perforated pipe located on the interior of the foundation typically in a porous fill material. The pipe runs continuously around the interior foundation and terminates in a sump or may travel to the exterior and be connected to a daylight drain.
Investigatory Measurements - Measurements of various types made to determine the sources and entry routes of radon into a structure.
Ion - An electrically charged atom in which the number of electrons does not equal the number of protons. The ion can have either a positive or negative electrical charge depending on whether it has an excess or a deficit number of electrons.
Ionization - The process whereby a neutral atom or molecule becomes negatively or positively charged by acquiring or losing (an) electron(s).
Ionizing Radiation - Any type of radiation capable of producing ionization in materials it contacts; includes high-energy charged particles such as alpha and beta rays, and nonparticulate radiation such as gamma rays and X-rays. In contrast to radiation (e.g., visible light and micro-radio waves) in which the waves do not ionize atoms.
Isotope -An atom of an element characterized by the number of neutrons in the nucleus. All atoms of a given element have the same number of protons, but the number of neutrons can vary among isotopes of the same element.
Kusnetz Method - A method of determining radon decay product concentrations (working level measurements) in air from grab samples. The decay products from a known volume of air are collected on a filter, and the alpha activity on the filter counted at specified time intervals. The results are in working levels, and do not provide concentrations of the individual decay products.
Lab
Blank
Lally Column
Lifetime Risk
Linear Dose Model
Lintel
Liter (L)
Lognormal Distribution
Lower Limit of Detection
Lab Blank - A quality control measurement made to determine the counts that would be reported by an analytical system without the detector having been exposed.
Lally Column - A structural steel column which can be hollow or filled with concrete.
Lifetime Risk - The lifetime probability of dying of a specific disease.
Linear Dose Model - The dose-risk model that assumes that the excess risk is linearly proportional to the dose.
Lintel - The horizontal member supporting the wall over an opening such as a window or doorway.
Liter (L) - A metric unit of volume equal to 1000 cubic centimeters, or 1.057 quarts.
Lognormal Distribution - A distribution of measurements which does not exhibit a normal (Gaussian) distribution, but whose logarithms exhibit such a distribution.
Lower Limit of Detection - The smallest amount of sample activity that will yield a net count, for which there is confidence at a predetermined level that activity is present.
Make-Up
Air; Outdoor source of draft air (to address combustion appliance back-drafting)
Material Safety Data Sheets
Magnehelics Gauge
Manometer
Masonry
Mass Number
Maximum Contaminant Level
Medium
Micromanometer
Microrem
Mitigation
Modified Tsivoglou Technique
Mortar
Make-Up Air; Outdoor source of draft air (to address combustion appliance back-drafting) - As used here, an outdoor supply of fresh air provided into the house to provide the required draft air (and combustion air) needed for proper movement of products of combustion up the flues of combustion appliances. Such make-up air may be needed in cases where an ASD system is found to be creating back-drafting of combustion appliances through depressurization of the house. The term "make-up air" can also be used to describe the supply of outdoor air into the house in general, to prevent house depressurization by combustion appliances and exhaust fans, in cases where an ASD system has not been installed. "Make-up air" can also be used to refer to fresh air drawn into the cold air return of forced-air furnace systems, to ventilate and perhaps even pressurize the house.
Material Safety Data Sheets - Informational documents required by law from manufacturers. They detail hazardous aspects and first aid information regarding the material.
Magnehelics Gauge - A pressure gauge manufactured by the Dwyer Instrument Co., which displays pressures on a calibrated face. Such gauges are sometimes used as permanently-mounted pressure gauges on ASD installations.
Manometer - A pressure-sensing device that displays pressure differences between two locations by the level of a colored liquid. Two types of such manometers (including a U-tube and a curved inclined manometer) are commonly used as pressure gauges and permanently mounted on ASD installations.
Masonry - Material such as stone, brick, and block.
Mass Number - The sum of the number of protons and neutrons in the nucleus of an atom.
Maximum Contaminant Level - The maximum concentration allowed in air or water as required by statute.
Medium - A substance regarded as the means of transmission of a force or effect. (In this manual, medium refers to the sub-slab fill material).
Micromanometer - A differential pressure measurement device that reads in the thousandths of an inch of meter column.
Microrem - A unit of measure of "dose equivalence," which reflects the health risk resulting from a given absorbed dose of radiation. A microrem (urea) is one millionth of a rem (roentgen equivalent man).
Mitigation - means the act of repairing or altering a building or building design for the purpose in whole or in part of reduing the concentration of radon in the indoor atmosphere. [420 ILCS 44/15]
Modified Tsivoglou Technique - A method of determining radon decay product concentrations (working level measurements) in air from grab samples. The decay products from a known volume of air are collected on a filter, and the alpha activity on the filter counted at specified time intervals (different intervals than for the Kusnetz method). Results are then used to calculate concentrations of three radon decay products and the working level.
Mortar - A mixture of cement, sand, and water, used as a bonding agent for masonry components.
Neutral
Pressure Plane
Neutron
Non-Flowable Caulk, Gun-Grade Caulk
Nucleus
Nuclide
Neutral Pressure Plane - A roughly horizontal plane through a house, defining the level at which the pressure indoors equals the pressure outdoors. During cold weather, when the thermal stack effect is occurring, indoor pressures below the neutral plane will be lower than outdoors, so that outdoor air and soil gas will infiltrate. Above the neutral plane, indoor pressures will be higher than outdoors, so that house air will exfiltrate.
Neutron - One of the two major components of the atomic nucleus. The neutron weighs about as much as the proton, the other major component, and is electrically neutral.
Non-Flowable Caulk, Gun-Grade Caulk - Refers to caulks which are sufficiently viscous, such that the caulk bead will tend to retain its shape prior to curing. They are distinguished from flowable caulks. Non-flowable caulks are less effective at settling into cracks and irregularities in the opening being sealed, but are required in cases where the opening does not provide a channel to contain the fluid movement of the flowable caulks, or where the opening is on a vertical surface.
Nucleus - The central portion of an atom where the protons and neutrons are found.
Nuclide - A specific type of atom characterized by its nuclear properties (i.e., the number of protons and neutrons, and the energy state).
Organization (RMP) - An individual, sole proprietorship, partnership, corporation, college or university, government agency, laboratory, or institution. The RMP Program treats separate address locations and separate applications are required for each.
Overhang - The horizontal distance that a roof projects beyond a wall.
Parging
(pargeting)
Partition
Pascal
Passive Construction
Percent Difference
Perimeter Drain
Permeability (sub-slab)
Picocurie
(pCi)
Picocurie per Liter (pCi/L)
Pier
Pilaster
Pitch
Pitot Tube
Plank
Plate
Plating
Out
Plenum
Plumb
Post and Beam
Poured Concrete Wall
Porosity
Precision
Precision Error
Pressure Isobar
Pressure Driven Airflow (Convective Movement)
Pressure Field Extension (PFE)
Pressure Field Mapping
Primer
Purlin
Polyvinyl
Chloride (PVC)
Proton
Parging (pargeting) - Cement mortar applied to a masonry wall.
Partition - An interior wall (Wall: an exterior wall).
Pascal - A unit of pressure. 1000 pascals (Pa) are equivalent to 4.0219 inches of water column pressure at 20 degrees C.
Passive Construction - A system installed in new construction that relies solely on the convective flow of air upward in the vent pipe for sub-slab depressurization and consists of a vertical vent pipe routed through conditioned space from the suction pit to 12 inches above the roof.
Percent Difference - The difference between two measurements with similar devices divided by the average of the two measurements--expressed as a percentage.
Perimeter Drain - A water drainage system that is routed around a footing either inside or outside the perimeter of a house. Typically refers to a perfected pipe laid in a rock filled trench designed to collect and drain water off a hillside or to a sump. Highly effective drain tile depressurization system that utilizes these to create a negative pressure field around and beneath the home.
Permeability (sub-slab) - A measure of the ease with which a fluid (liquid or gas) can flow through a porous medium. Sub-slab permeability generally refers to the ease with which soil gas can flow underneath a concrete slab. High permeability facilitates gas movement under the slab, and hence generally facilitates the implementation of sub-slab depressurization systems for remediation.
Picocurie (pCi) - A Curie is a standard measurement for radioactivity, specifically the rate of decay for a gram of radium--37 billion decays per second. A picoCurie (pCi) is one trillionth of a Curie.
Picocurie per Liter (pCi/L) -means 2.2 disintegrations per minute of radioactive material per liter of air. (Adopted Rule 422.20)
Pier - A rectangular masonry support, either free standing or built into a wall.
Pilaster - A rectangular support or pier projecting partially from a wall and treated architecturally as a column, with a base, shaft, and capital.
Pitch - A term applied to the amount of roof slope. It is found by dividing the height by the span. Also a liquid material used in roofing.
Pitot Tube - A device for measuring air velocity.
Plank - Lumber 2" and over in thickness.
Plate - A horizontal member in a wall framework, which rafters, joists, studs, and so forth, rest on or are secured to, as in "sole plate," "sill plate," "topplate."
Plating Out - The process whereby small particles or dust attach to walls, carpets, furniture, lung tissue, and so forth.
Plenum - A cavity of air space through which air is moved. Plenum may be used to evenly distribute heat.
Post and Beam - A type of building frame in which cross beams rest directly upon vertical posts.
Poured Concrete Wall - A foundation wall constructed by pouring concrete within forms that are removed after construction. The most common alternative to hollow-block walls.
Porosity - A surface that has the ability to allow air or fluids to pass.
Precision - Degree of mutual agreement among individual measurements made under prescribed conditions, e.g., standard deviation among replicate measurements.
Precision Error - The uncertainty associated with the ability of a given instrument to provide the same results with repeated measurements.
Pressure Isobar - A curve that connects all the points of exactly the same pressure. When sub-slab suction is imposed at a given place, the pressure that can be measured at various points under the slab generally decreases as the distance from the nearest suction hole increases. The pressure contour outlines the area within which the suction is expected to be greater than or equal to the value at the contour.
Pressure Driven Airflow (Convective Movement) - One of the methods by which radon moves through soil from areas of higher to lower air pressure.
Pressure Field Extension (PFE) - means the distance that a pressure change is induced in the sub-slab area, measured from a single or multiple suction points. (See also Communication Test.) (Adopted Rule 422.20)
Pressure Field Mapping - Process of annotating pressures beneath a slab.
Primer - A transitional material application that prepares the surface for subsequent bonding or coating.
Purlin - A horizontal roof framing member, laid perpendicular to main trusses and supporting the roof.
Polyvinyl Chloride (PVC) - A polymeric plastic material which is resistant to deterioration (e.g., by soil chemicals) and used in a wide variety of products. It is used to make rigid piping that is commonly used e.g., in residential sewer lines, and as the piping for ASD systems. Flexible PVC couplings can be used to join section of rigid PVC piping.
Proton - A fundamental unit of matter having a positive charge and a mass number of one.
Quality Assurance - A complete program designed to produce results which are valid, scientifically defensible, and of known precision, bias, and accuracy.
Quality Control - Measurements made to ensure and monitor data quality.
Radiant
Heating
Radioactive Decay Series
Radioactivity
Radionuclide
Radium
Radon (Radon Decay Products)
Radon Ready Construction
Radon Source Strength
Reading Prong
Re-entrainment
Reinforced Concrete
Reinforcing Rod
Reinforcing Wire
Relative
Bias
Relative Measurement Error
Relative Precision (or Coefficient Variation)
Relative Humidity
Ribbon
Ridge
Rim Joist
Roll Roofing
Roof Boards (roofers)
Rotary
Hammer Drill
Radiant Heating - Heating by radiating rays without air movement.
Radioactive Decay Series - A series of isotopes that result following the decay of a parent radionuclide. There are three natural radioactive decay series, uranium-238, uranium-235, and thorium-232.
Radioactivity - The release of particles of energy from an atom as it decays. Units of activity are the Becquerel (Bq) and the Curie (Ci).
Radionuclide - Any naturally occurring or artificially produced radioactive element or isotope; i.e., one which will release subatomic particles and/or energy, transforming into another element.
Radium - A highly radioactive white shining element found in pitchblende, carnotite, and other uranium-containing minerals. It emits alpha particles and gamma rays to form radon.
Radon (Radon Decay Products) - means a gaseous radioactive decay product of uranium or thorium. [420 ILCS 44/15]
Radon Ready Construction- Certain modifications that are made during the construction of a home that would allow for the installation of an active radon mitigation system. Typically these would be aspects of construction that would allow for good negative pressure field extension beneath the slab, such as a layer of large aggregate beneath the slab.
Radon Source Strength - The intensity, power, or concentration of radon action from its point of origin.
Reading Prong - A geographical area stretching throughout Pennsylvania, New Jersey, and New York known to have a large number of homes with high radon concentrations.
Re-entrainment - means the unintended re-entry into a building of radon that is being exhausted from the vent of a radon mitigation system. (Adopted Rule 422.20)
Reinforced Concrete - Concrete containing more than 0.2 percent of reinforcing steel.
Reinforcing Rod - A steel bar used to reinforce concrete and CMU construction. Bar size is indicated in eighth-inch increments, i.e., No. 3 bar is 3/8" diam. Commonly referred to as Rebar.
Reinforcing Wire - Steel wire mesh placed in the concrete material to enhance tensile strength of the material after curing; typical material used is 6" x 6" - 10 x 10 gauge. Commonly referred to as Rewire.
Relative Bias - The estimated bias divided by the true or reference value and expressed as a percentage.
Relative Measurement Error - The standard deviation of a sample of individual measurement errors.
Relative Precision (or Coefficient Variation) - The estimated precision/standard deviation divided by the sample mean and expressed as a percentage. Also called relative standard deviation.
Relative Humidity - Ratio of the amount of water vapor in air to the maximum possible amount at the same temperature.
Ribbon - A wood strip let into the studding to provide a bearing surface for joists.
Ridge - The top edge of the roof where two slopes meet.
Rim Joist - The perimeter horizontal timber or beam supporting a floor or a ceiling.
Roll Roofing - Roofing material of fiber asphalt.
Roof Boards (Roofers) - The rough boarding over the roof framework, over which is laid the roof covering.
Rotary Hammer Drill - An electric-powered drill that usually uses solid bits (rather than core bits). Its action may be a piston-driven action like a lightweight jackhammer or as a drill with the hammer-like action.
R-Value - Capacity of a substance to impede the flow of heat. The term is used to describe insulative properties of construction materials (also see Thermal Resistance).
Saddle
Scaling Baseline Hole
Schedule
Scintillation Cell
Screening Measurement
Sensitivity Checks
Sill
Sill Sealer
Skeletal New Construction System
Slab-on-Grade
Sleeper
Smoke Stick
Soak Away
Soffit
Soil Gas
Sole
Spiked Samples
Split Level House
Stack
Stack Effect
Standard Deviation
Stem Wall
Stringer
Studs
Subfloor
Sub-Slab Communication
Sub-Slab Depressurization (Active)
Sub-Slab Depressurization (Passive)
Sub-Slab Flow Curve
Suction Hole/Point
Sump
Sump
Pump
Sub
Membrane Depressurization
Saddle - A small, double-sloping roof to carry the water away from the back of the chimneys (see Cricket).
Scaling Baseline Hole - A hole within about 12 in. of a suction test hole (during a diagnostic test) at which a pressure measurement can be taken. During a vacuum cleaner diagnostic test procedure, the vacuum is adjusted such that the negative pressure on the sealing baseline hole is at the midpoint of the operating range of the proposed ASP fan.
Schedule - In this context, it refers to the wall thickness of a pipe used for radon venting.
Scintillation Cell - A metal cylinder or flask coated with a material that will fluoresce or scintillate (give of a light flash) when contacted by alpha radiation. This device is used to measure radon concentrations in air samples collected in the cell.
Screening Measurement - A short-term measurement made under worst case conditions to determine whether a home is likely to have a radon problem. A screening measurement is not intended to define average exposures and, therefore, should not be the basis for mitigation decision, unless confirmed with a second screening measurement or followed up with a long-term measurement.
Sensitivity Checks - Sensitivity checks are used in the RMP Program to determine the lower limit of detection for a particular measurement system. Background radiation and inherent instrument design often limit the ability to measure very low concentrations of radon.
Sill - The stone or wood member across the bottom of a door or window opening. Also the bottom member on which a building frame rests (sill plate).
Sill Sealer - A compressive material placed between the masonry foundation wall and the wood plate to reduce air infiltration.
Skeletal New Construction System - A system installed in new construction that is designed for the installation of a vent fan and may consist of multiple vent pipes, including vertical and angled runs not necessarily routed through conditioned space, that may be joined to a single termination above the roof or may terminate separately above the roof.
Slab-on-grade - A type of house construction in which the bottom floor of a house is a concrete layer (typically about 4 in. thick and in direct contact with the underlying aggregate or soil), which is no more than 1 ft. below grade level on any side of the house.
Sleeper - A wood member placed over or imbedded in the concrete or earthen floor to provide a nailing base for a wood floor.
Smoke Stick - A small tube, several inches long, which releases a small stream of non-thermal smoke when a rubber bulb at one end of the tube is compressed. Can be used to visually define bulk air movement in a small area, such as the direction of airflow through small openings in slabs and foundation walls.
Soak Away - See Daylight Drain.
Soffit - The undersurface of a cornice, molding, or beam.
Soil Gas - means the gas mixture resent in soil which may contain radon. (Adopted Rule 422.20)
Sole - The horizontal framing member directly under the studs.
Spiked Samples - See Blind Spikes.
Split Level House - Designation of a type of house with floor levels so staggered that each level is about a half story above or below the adjacent one, with stairs between.
Stack Effect - means the overall upward movement of air inside a building that results from heated air rising and escaping through openings in the building envelope, thus causing indoor air pressure in the lower portions of a building to be lower than the pressure in the soil beneath or surrounding the building foundation. ( Adopted Rule 422.20)
Standard Deviation - A measurement of the scatter of several sample values around their average.
Stem Wall - The one or more courses of block (or equivalent height of poured concrete) that is placed above the buried footings comprising the foundation of the house. If the slab is poured inside the stem well, it is considered to be a "floating" slab. More typically, the top course of the stem wall is an "L" or "chair" block with a 4-in. notch cut through half of the thickness of the block so that the slab is poured into forms that cover the entire top of the stem wall.
Stringer - The sides of a flight of stairs, the supporting member cut to receive the treads and risers.
Studs - Vertical members which form the framework of a partition or wall.
Subfloor - The rough flooring under the finish floor.
Sub-Slab Communication - The effect of creating vacuum beneath a slab and being able to detect the vacuum at various locations under the slab.
Sub-Slab Depressurization (Active) - A radon control technique designed to achieve lower sub-slab pressure relative to indoor air pressure by use of a fan-powered vent drawing air from beneath the concrete slab.
Sub-Slab Depressurization (Passive) - A radon control technique designed to achieve lower sub-slab air pressure relative to indoor air pressure by use of a vent pipe (without a fan) routed through the conditioned space of a building and connecting the sub-slab area to the outdoor air. This system relies primarily on the convective flow of warmed air upward in the vent to draw air from beneath the concrete slab.
Sub-Slab Flow Curve - A graph representing the functional relationship between the amount of suction applied on a soil and the flow that results from that suction. If gravel with large pore spaces is the sub-slab medium, then just a small suction will generally produce a fairly large flow; loose sand would produce less flow for the same suction; a more tightly packed soil would produce even lower flows for equivalent suction. Therefore, the sub-slab flow curve would rise more sharply for more permeable media and more gradually for more tightly packed media.
Suction Hole/Point - The hole cut through a concrete slab from which either a vacuum cleaner (for diagnostic purposes) or a mitigation fan will evacuate the sub-slab soil gas.
Sump - A pit through a basement floor slab designed to collect water and thus avoid water problems in the basement. Water is often directed into the sump by drain tiles around the inside or outside of the footings.
Sump Pump - A pump to move collected water out of the sump pit to an above-grade discharge remote from the house.
Sub Membrane Depressurization - Where a sheeting material such as polyethylene is laid on an earthen floor, sealed to the sidewalls, and a vacuum is created beneath it to collect radon.
Termite
Shield
Thermal Bypass
Thermal Resistance
Tight House
Time Integrated Sampling
Thermo-Luminescent Detector
Trap
Threshold Hypothesis
Truss
Termite Shield - Sheet metal extending beyond the interior face of a foundation wall at the sill plate, used to block the passage of termites.
Thermal Bypass - Any opening through the floors between stories of a house (or through the ceiling between the living area and the attic), which facilitates the upward movement of house air under the influence of stack effect.
Thermal Resistance - The ability of a substance to impede the flow of heat (also see R-Value).
Tight House - A house with a low air exchange rate. If 0.5 to 0.9 air changes per hour is typical of modern housing, a tight house would be one with an exchange rate well below 0.5 ACH.
Time Integrated Sampling - Sampling conducted over a specific time period (from a few days to a year or more) with results reported as an average value for that period.
Thermo-Luminescent Detector - A device that will absorb radiation and when heated to a specific temperature will emit an amount of light in proportion to the amount of radiation it was exposed to. This device has been used to measure quantities of radon gas.
Trap - A device providing a liquid seal to prevent passage of air and odor.
Threshold Hypothesis - The hypothesis that there is a small "threshold" dose below which radiation causes no injury; the assumption is that the body can repair any damage due to doses below the threshold.
Truss - A braced framework capable of spanning greater distances than the individual components.
Unattached
Fraction
Uranium-238
Urethane
Caulk
Urethane
Caulk Unattached
Fraction - Refers to radon decay products which have not yet adhered
to other, larger dust particles in the air (or to other surfaces, such
as walls). Unattached RDPs might result in a higher lung cancer risk
than will RDPs that are attached to larger particles, because they can
selectively deposit in small areas of the lung.
Uranium-238 - The first radionuclide in the decay chain, which includes radium 226 and radon 222. Uranium-238 has a 4.5 billion year half-life and is naturally occurring in the earth's crust.
Urethane Caulk - See Flowable Caulk. Available in two grades of consistency: self-leveling or flowable and vertical grade.
Vapor
Barrier
Ventilation Rate
Volatile Organic Compound (VOC)
Vapor Barrier - A product or system designed to limit the free passage of a gas (typically water vapor) through a building envelope component (wall, ceiling, or floor). Such products and systems may be continuous or noncontinuous discrete elements, which are sealed together to form a continuous barrier against air (or vapor) infiltration (most commonly, a plastic sheet under a house slab).
Ventilation Rate - The rate at which outdoor air enters the house, displacing house air. The ventilation rate depends on the tightness of the house shell, weather conditions, and the operation of appliances (such as fans) influencing air movement. Commonly expressed in terms of air changes per four or cubic feet per minute. The ventilation rate includes both natural ventilation (infiltration) and mechanical ventilation.
Volatile Organic Compound (VOC) - An organic compound that can slowly vaporize and enter the air at room temperature. VOCs can present hazardous conditions when used.
Wallboard
Wall Ties
Warm Air Supply
Water-Cooled Core Drill
Water Column (WC)
Weatherstrip
Weep Hole
Wind Induced Airflow
Working Level (WL)
Working
Level Month
Wallboard - A large, flat sheet of gypsum or wood pulp used for interior walls.
Wall Ties - A small strip of metal, built into two parts of a cavity wall to bond them together (for instance, tying a brick veneer wall in with the wood frame wall).
Warm Air Supply - The ducting and registers which direct heated house air from the forced-air furnace, to the various parts of the house. The supply ducting is at elevated pressure relative to the house because the central furnace fan is blowing air through this ducting.
Water-Cooled Core Drill - An electric-powered heavy drill that can be used to drill cores out of concrete slabs. Because of the heat produced by the core bit cutting through the concrete, water is sprayed or dripped onto the bit while it is cutting in order to keep it cool. To some degree, the water also acts as a lubricant between the bit and concrete.
Water Column (WC) - A term used to describe air pressure in hydrostatic terms; i.e., the height (in in., mm) of a column of water that would exert an equivalent pressure to the pressure being measured.
Weatherstrip - A strip of metal or fabric fastened along the edges of windows and doors to reduce drafts and heat loss.
Weep Hole - An opening at the bottom of a masonry faced wall to allow the drainage of moisture.
Wind Induced Airflow - The movement of air that results when wind creates higher or lower air pressures around and inside a building. For example, wind can produce elevated air pressures on the windward side of a house, and lower air pressures on the leeward side. Elevated air pressure in soil can force soil gas into a building; lower air pressure in a house can draw soil gas into a building.
Working Level (WL) - means any combination of short-lived radon progeny in 1 liter of air that will result in the ultimate emission 1.3 x 105 MeV of potential alpha energy. The short-lived radon progeny are for radon-222, polonium-218, lead-214, bismuth-214 and polonium-214. (Adopted Rule 422.20)
Working Level Month - means a unit of exposure used to express the accumulated human exposure to radon decay products. It is calculated by multiplying the average working level to which a person has been exposed by the number of hours exposed and dividing the product by 170. (Adopted Rule 422.20)
a - alpha radiation
AARST - American Association of Radon Scientists and Technologists
AC - Activated Carbon
ACH - Air changes per hour
ACM - Asbestos containing material
ASD - Active soil depressurization
ATD - Alpha Track Detector
BEIR - Biological Effects of Ionizing Radiation
Btu - British thermal unit
cfm - Cubic feet per minute
COV - Coefficient of Variation
CRM - Continuous radon monitor
CWLM - Continuous working level monitor
dd - Degree day
DTD - Drain tile depressurization
ELA - Effective Leakage Area
EPA - Environmental Protection Agency
ER - Equilibrium ratio
ev - Electron volt
FAU - Forced Air Unit, such as a forced air furnace
GAC - Granular Activated Carbon
GFI - Ground Fault Interrupter
HRV - Heat Recovery Ventilator
IDNS - Illinois Department of Nuclear Safety
in. - inches
IRAA - Indoor Radon Abatement Act
LLD - Lower Level of Detection
MCL - Maximum Contaminant Level
MSDS - Material safety data sheets
MSHA- Mine Safety and Health Administration
NRC - Nuclear regulatory Commission
NIOSH - National Institute of Occupational Safety and Health
OSHA - Occupational Safety and Health Administration
pCi - picoCurie
pCi/L - picoCuries per liter
PFE - Pressure field extension
PVC - Polyvinyl chloride
QC - Quality Control
Rn - Radon
RDP - Radon Decay Product
RVD - Radon vent duct
Sch - Schedule- refers to wall thickness of pipe.
SMD - Sub membrane depressurization
SSD - Sub slab depressurization
UMTRA - Uranium Mill Tailings Recovery Act
VOC - Volatile Organic Compound
WL - Working level
WLM - Working Level Month