Radon is an environmental concern with an easy solution!

Transcription

1 Many people in County are concerned about elevated levels of radon gas in their homes, schools, and workplaces. Although homeowners are aware of how easy it is to test their homes, many may not be aware of how easily radon exposures can be reduced and how common this procedure is in County. If you are interested in determining and reducing your family s exposure to radon, as many of your neighbors have already done, this program will summarize many proven radon testing and reduction techniques. It will also detail some of the resources that are available to help you in selecting radon professionals, or in some cases, to test and fix the problem yourself. However, before we get started on the program, let s find out what your specific interest and knowledge is regarding the radon issue so the program can be somewhat customized to insure that your specific needs are addressed. Let s go around the room and have each of you tell us your name, why you are here, if you have tested and - if you want to - tell us your results. We would also like you to briefly describe your home as to whether it is a slab-on-grade, basement or crawl space, etc., and also if you are in the process of selling your home. Radon is an environmental concern with an easy solution! 1

2 Presented by: Your Company Name and Contact Information This slide can be modified by your PowerPoint program Put in appropriate contact information for you or your firm Phone, website, etc. You can also put additional slides within the program we have prepared for you, to customize it for your audience. It is also not critical that you show all of the slides we have prepared. 2

3 What Is Radon? Radon Radium Uranium Radon is a gas. It is naturally occurring. It cannot be seen or smelled. It enters buildings from the soil beneath them. Radon is a gas that is created in the soils where uranium and radium are found. These elements can be found everywhere in the world, therefore any building has the potential for elevated levels of radon. The more uranium found in the soil, the higher the potential for elevated radon levels within a building constructed above this soil. It is not a question of, Is there radon? but rather, How much radon is there? Radon comes from natural deposits of uranium in the soil. It is not because of a manmade landfill or other suspicious sources. Uranium breaks down to radium, which in turn decays into radon gas. Radon is an inert gas, which means that it does not react or combine with the elements in the ground. Because of this, radon gas can move up through the soil into the atmosphere, where it is easily diluted and presents little concern. However, when it enters a building constructed on top of this soil, it can build up and become a health concern. You cannot see or smell radon. There is no way that your body can sense the presence of radon, yet it can have a detrimental effect on the inhabitants by increasing their likelihood of developing lung cancer. 3

4 How Is Radon Drawn Into A Building? Vacuum Exhaust Exhaust systems Thermal Thermal stack effects Radon pci/l Vacuum (pa.) Days Buildings are typically at a lower pressure than the surrounding air and soil. This causes radon and other soil gases to be drawn into the building. There are several reasons why this occurs. One cause is the effect that exhaust fans have when removing air from a building. When air is exhausted, outside air enters the building to replace it. Much of this replacement air comes in from the underlying soil. When interior temperatures are higher than outside temperatures, thermal effects occur inside of the building. Just as warm air causes a balloon to rise because the surrounding air is cool, warm air rises within a building and is displaced by cold, dense outside air. Some of the outside air, which is displacing and replacing the interior air, comes from the soil. Whenever air enters a building from underneath, radon will most likely come in as well if radon is present in the underlying soil. The forces that draw radon into a structure vary, which in turn effects the entry rate of radon. Measurement devices that average radon levels over long periods of time provide a better indication of the amount of exposure to radon. The minimum duration of any test, the results of which could be used as a basis for determining the need for remediation, is 48 hours. Radon also varies from season to season as a function of climate and the use of the home by occupants (open windows-closed windows). It would be ideal if a year-long test could be conducted, however, such timing would be unrealistic for the purpose of a real estate transaction. Short-term tests are utilized to determine the potential of a home for having elevated levels of radon, independently of how the house is operated. The tests involve closing all windows and doors, except for normal exit and entry, and testing on the lowest occupiable location in the home. This technique has become the method for testing homes during real estate transactions. 4

5 Why Is Radon A Concern? Radon Decay Products Radon Radon Radon decays into radioactive particles known as radon decay products. These particles are easily inhaled and deposited in the lungs where they can damage sensitive lung tissue. Once radon enters a building it is easily dispersed through the air. The radioactive decay process that leads to the creation of radon does not stop. This causes the radon to decay into several radioactive elements called radon decay products. These decay products are made up of different forms of polonium, lead and bismuth. Unlike radon, which is a gas, the radon decay products produced from radon are solid particles. These particles become suspended in the air when they are formed from the decaying radon gas. These particles are extremely small and cannot be seen. Because they are extremely small particles, radon decay products are easily inhaled and can attach to lung tissue. They have very short half-lives which means that they will decay relatively quickly after they are formed. In fact, if they are inhaled, they will decay in the lungs before the lungs have an opportunity to clean themselves. It is the radon decay products that actually present the health risk associated with radon gas. 5

6 Radon Is A Lung Cancer Causing Gas Radon decay products inhaled. Particles irradiate lungs. Irradiation can cause lung cancer. When radon decay products are inhaled they will stick to sensitive lung tissue. Being short-lived, they will break down while they are in the lungs, thereby exposing the lung tissue to radiation. When radon decay products decay, they release alpha, beta and gamma radiation. It is actually the alpha radiation (in the form of particles) from the two radon decay products - polonium 218 and polonium that are the most hazardous. The alpha particles, that come from the decay of radon decay products, will impact the sensitive lung tissue. In most cases they will kill the lung tissue cell, which can be replaced by the body. However, the alpha particles can impact the DNA, or create a chemical reaction that will affect the DNA. When this occurs the cell can become mutated. This is the mechanism by which prolonged exposure to radon and radon decay products can increase the potential of lung cancer. 6

7 Alpha Particles Are Strong Enough To Pit Plastic Photo: Dr. J.F. Burkhart Plastic chip from passive radon test (alpha track) Magnified only 100 times 3 months at EPA Action Level of 4 pci/l The picture above shows a piece of plastic from a radon testing device that was placed in a home for 3 months containing, on the average, 4.0 pci/l of radon. It provides an idea of just how destructive the particles are that are released when the decay products radioactively decay. During the test period, the air in the room would diffuse (no air pump) through a paper filter into a small container where the piece of plastic was housed. When radon and its decay products decay within the container, the resultant alpha particles strike the plastic hard enough to create pits. These pits are large enough to be seen under relatively low magnification (100 power). Note that the plastic is similar to plastics used in some eyewear. Consider, if the alpha particles are forceful enough to create pits in plastic they are certainly forceful enough to impact, penetrate, and damage soft tissue. This is what happens in the lungs. Also consider that the act of breathing causes approximately 20,000 liters of air to be inhaled and exhaled on a daily basis, thus bringing far more radon decay products into the lungs than would have diffused (drifted) through a paper filter and into the plastic casing that housed this piece of plastic. 7

8 What Happens When Radon Decay Products Are Inhaled? OH - H + H 2 O Chromosome 6, P53 gene impacted Highly radioactive particles stick to lung tissue, where they can irradiate sensitive cells. Radiation can alter the cells, increasing the potential for cancer. When radon decay products are inhaled they stick to sensitive lung tissue. Being shortlived, they will break down while they are in the lungs. This exposes the lung tissue to radiation. If the alpha particle which is released hits a live cell, and within the cell it hits the nucleus, and within the nucleus it hits the DNA, and within the DNA it hits and damages the cancer suppressant gene and increased risk for contracting lung cancer can exist. In addition to the alpha particle causing, the alpha particle can also cause ionization of material around the DNA that can also damage it (shown on right of DNA strand). This is the mechanism that radon (and more specifically the radon decay products) can lead to an increased risk of lung cancer. What are the probability of this happening? It is based on how much you are exposed to and for how long. 8

9 Radon Induced Lung Cancer Risk increased equally by both duration and concentration of exposure One dart at a time for a long time, or handfuls of darts over a short time Being exposed to radon does not mean that you will contract lung cancer. To develop lung cancer from radon the radiation released from its decay has to strike a lung cell and within that lung cell it has to strike a specific location. Since the radiation is released in a random manner, the potential for lung cancer increases with exposure, whether that be exposure to a small amount of radon for a long period of time or a high amount of radon for a short period of time. The probability of contracting lung cancer is like a blind folded person tossing darts at dartboard. If the person tosses a single dart at a time, it is probable that it will take a considerable period of time before the person strikes the bulls eye. On the other hand, if the person throws a handful of darts at a time, it is likely that less time will pass before the person strikes the bulls eye. This analogy can be used to understand that the probability of an alpha particle striking a sensitive part of a lung cell in a manner that will cause cancer depends on dose and time of exposure, or Lung cancer risk from radon is a function of: Radon concentration one is exposed to Amount of time one is exposed to it 9

10 Scientific Basis For Radon Risk Estimates Studies on miners Uranium Uranium miners in U.S. and other countries Studies on residential occupants On-going and as a group confirm application of miner data to residential exposures Studies on laboratory animals The effects of radon have been around a long time. Its effects were first noted as an unknown disease in the 1400 s. Lymphosarcoma was first identified in autopsies conducted in 1879 on European miners. In modern times (1950 s to present), a higher than expected occurrence of lung cancer has been noted in uranium miners within the U.S., Czechoslovakia, France and Canada. Excess lung cancers have also been observed in other underground (not uranium) miners in Newfoundland, Sweden, Britain, France, China, and the U.S. The presence of radon at elevated levels in above ground structures, such as homes, commercial buildings and schools was not well known until the mid 1980s. Remember, you cannot see or smell radon. Many homes and schools have been measured with radon levels in excess of underground mine concentrations. Today the effects of radon are well known. The issue is not if radon causes cancer, but rather, how to control the radon exposure in our homes, workplaces, and schools. 10

11 Comparing Radon Exposures In Mines To Radon Exposures In Homes Radon In Home (pci/l) pci/l Ontario Miner Study Years In Home Curve represents the time- dose exposure where excess lung cancer was observed The graph above represents the probability of contracting lung cancer as a function of time and exposure. This was developed on the basis of a uranium miner study where excess lung cancers were observed as a function of radon decay product concentration and duration of exposure. The radon exposures have been adjusted to reflect the typical availability of radon decay products for inhalation in homes rather than mines, and the typical amount of time an individual spends in a home given evenings, weekends and the impact of television. The left hand axis represents the long-term radon that could be found in a home and the horizontal axis represents the time in that home or a home like it. Any point on the line which represents the combination of radon exposure and time of exposure is where, in this particular study of miners, where a statistically significant number of excess lung cancer cases were observed. For example one would only have to live in a home (or another home like it) at 40 pci/l for a period of roughly 10 years, where the dose to the lungs would have been similar to that which was able to cause a statistically significant increase in lung cancer as was observed in this study. It is also useful to note that the US EPA action level of 4.0 pci/l would cause an equal amount of exposure at a period of time well within a normal life span. This is another example of why the 4.0 pci/l guidance does not represent a safe level, when comparing it to real human effects data. 11

12 EPA & Surgeon General Recommend That People Not Have Exposures Above 4 pci/l On A Long-Term Basis One is advised to take action if a home is at or above 4.0 pci/l Average indoor: 1.3 pci/l Average outdoor: 0.4 pci/l Based upon current and past studies, the EPA established a guidance for non-occupational exposures to radon. This guidance level was arrived at by analyzing both the health risks and the cost of fixing buildings with elevated levels. That is, the 4.0 pci/l guidance is both a health and an economic based number. The 4.0 pci/l guidance is not a safety standard. Levels below 4.0 pci/l still represent some risk. Even the outdoor air contains some radon. So, avoid making comments such as the house tested safe, or there is no radon in the home. Just because a house is below the EPA s action level does not mean that there is no risk at all. The conclusion that radon is a serious health risk is supported not only by the US EPA, but also the American Lung Association, the National Academy of Sciences and the National Council on Radiation Protection, among others. 12

13 How Does Radon Rank As A Cancer Causing Agent? Radon is ranked as a Group A carcinogen Highest Highest ranking for cancer potential Known Known to cause cancer in humans Tobacco Tobacco smoke and tobacco products in same category Provides basis for regulatory and liability concerns! Due to the amount and strength of data that has been collected, radon is placed in the highest category of cancer causing agents. This category is referred to as Group A, which contains materials that are known to cause cancer in humans. Being a Group A carcinogen certainly underscores the reasons there are concerns about radon. Being a Group A carcinogen also strengthens concerns about liability when a home or commercial building is sold. This is why radon testing has become more common at the time of sale. 13

14 25000 How Does Radon Compare To Other Causes Of Death Deaths per year (U.S.) Drunk Driving Radon Falls in Home Drowning Home Fires Source: U.S. EPA Citizen s Guide to Radon, 4th edition, May 2004, Radon: EPA Reassessment of Radon Risk in Homes, June 2003 Other: National Safety Council 2002reports, Centers for Disease Control The comparison above is from the US EPA s Citizens Guide to Radon. It compares the estimated number of deaths in the U.S. due to radon, with other more widely known causes of death. This comparison provides one reason why the EPA and other health organizations are so concerned about the radon issue. Furthermore, because radon is so easy to detect and also easy to fix, one can see why radon detection and remediation has become such a priority. Radon is estimated to cause about 21,000 lung cancer deaths per year, according to EPA's 2003 Assessment of Risks from Radon in Homes (EPA 402-R ). The numbers of deaths from other causes are taken from the Centers for Disease Control and Prevention's National Center for Injury Prevention and Control Report and 2002 National Safety Council Reports. 14

15 National Research Council BEIR VI: February 19, 1998 U.S. Lung Cancer Deaths/yr Never Smokers Smokers Lung cancer due to radon exposure Higher risk among smokers High non-smoker risk Radon is one of the most extensively investigated human carcinogens. Radon is a...public-health problem and makes indoor radon the second leading cause of lung cancer after cigarette smoking. In 1998, the National Research Council's sixth Committee on the Biological Effects of Ionizing Radiation (BEIR VI) released the results of a lengthy study. This study reviewed the epidemiological data available to evaluate the health effects of radon again. The study reviewed data on underground minders exposed to radon and laboratory animals exposed to radon, as well as eight completed case-control studies that investigated lung cancer risks from the radon in homes. The study concluded radon poses a significant risk to the general population. Although the use of tobacco products remains the largest single cause of lung cancer, the risk of lung cancer in non-smokers -- as well as the additional lung cancer risk presented by radon to people who smoke -- is significant. It should be noted that the result of this extensive study estimates a larger risk to the U.S. population that what the previous studies had estimated. Although any study has uncertainties, "This uncertainty did not change the committee's view that indoor radon should be considered as a cause of lung cancer in the general population that is amenable to reduction." 15

16 Radon Is A Serious National Health Problem American Lung Association American Medical Association Environmental Protection Agency National Academy of Sciences National Council on Radiation Protection and Measurement U.S. Surgeon General World Health Organization The U.S. EPA s concerns about radon are shared by many other independent health based agencies. During the mid 1980s, the EPA was perceived by some as taking a Chicken Little attitude towards radon. That is, they were accused of making too much out of the issue. After all, radon is something that you cannot see or smell. It has been with us for a long time - so what s the big deal? However, after several other health based organizations reviewed the data that the National Academy of Sciences used to develop the EPA s health risk assessments, they joined the EPA as Cooperative Partners to assist in educating the public about this significant environmental health concern. In addition to the entities listed on the slide, the EPA is joined by many cooperative partners such as the National Association of Counties, The American Lung Association, The National Environmental Health Association. 16

17 Is This The Only State Where Radon Concerns Exist? No! Many parts of the country have radon concerns. Map developed as basis for radon control techniques in new construction. Since the late 1980 s, radon measurements have been taken throughout the United States. This data has been collected and compared to geological formations to yield the map shown above. This map was originally developed for the purpose of establishing the degree of radon reduction methods that should be incorporated into the construction of new homes and buildings. However, it has served as a tool for focusing public awareness efforts on radon. It has also become a tool for relocation companies and lenders to develop their radon testing policies. The zone classifications are based upon being able to predict the likelihood of finding certain ranges of radon concentrations when conducting short-term measurements (as is often done at the time of a real estate transaction). Key: Zone 1: Equal to, or greater than, 4.0 pci/l Zone 2: Between 2.0 pci/l and 4.0 pci/l Zone 3: Less than 2.0 pci/l In comparing zones on the map above, one should remember that the US EPA and Surgeon General recommend that people not be exposed, on a long-term basis, to levels of radon in excess of 4.0 pci/l. Additionally, one should realize that significant variations can occur within a county and there is no substitute for testing to verify individual conditions. 17

18 Radon Distribution Radon enters from beneath foundation and travels upward. Diluted with outdoor air infiltrating building If radon is less than 4 pci/l in lower level, one can say with reasonable confidence that upper floors are also less than 4 pci/l. The majority of radon enters a structure from its underlying soil. Once it enters the building it moves upward in the structure where it can be diluted with fresh outdoor air. This is why radon is typically at its highest concentration in the lower portion of a building. If one finds radon to be at low concentrations in the lower portion of a building, one can say with reasonable, assurance that even lower concentrations exist on upper floors. This is why most radon testing at the time of sale occurs in the lowest occupiable portion of the home. 18

19 Average Contributions From Radon Sources In U.S. Homes Soil Gas 85-90% Water < 1% Emanation 2-5% Diffusion 1-4% Radium Containing Soil The movement of soil gas into a home is the predominant entry route. These are averages - a particular home can be different! Although most radon in U.S. homes comes from the soil from beneath them, some radon can also enter by other means. Radon in Water: Radon in the ground can dissolve into ground water. When this ground water is brought into a building directly (without the benefit of being held in an atmospheric holding tank) the dissolved gas is released from the water. As a rule of thumb for residential structures on private wells, if a well contained 10,000 pci/l of radon in the water the amount of radon entering the building from normal water usage, after dilution by normal residential ventilation, would add 1 pci/l of radon into the air in the building above and beyond that which comes from the soil. There are no current U.S. standards regarding the amount of radon allowed in public drinking water supplies. However, standards have been proposed. Emanation: Some radon can emanate off the surface of building materials that contain radium, however this is very rare. Diffusion: High concentrations of radon beneath a slab can cause migrate through concrete even if there are no cracks in the slab. The flow of radon is so small that normal ventilation rates of a building will dissipate this. Radon from the soil beneath the home is typically the most significant source. 19

20 Testing Is Easy And Inexpensive Of all of the environmental concerns that we could be faced with, radon is one of the least expensive to measure. In fact, it is so simple that radon test kits are available for homeowner use. However, there are cases where a radon professional should be hired to perform the test, such as when an objective third party is needed, as in the case of a real estate transaction. 20

21 Short And Long-Term Testing Devices Help Determine the Need for, and Effectiveness of, Radon Mitigation This slide shows two types of passive devices that are commonly used to measure radon. These are referred to as passive devices, since no power is needed for them to take a sample in a building. These devices yield a single average value of radon in pico Curies per liter of air for the period they were deployed and for the location in which they were placed. There are two basic types of these passive devices that are commonly used by homeowners: Short-term: These are shown on the left and commonly consist of carbon containing devices that will absorb radon. After they are used, they should be immediately shipped to the laboratory for analysis. These are used with the house closed up during the entire test (except for normal entry and exit) to determine the potential for radon in the home. Note that the minimum duration of a test is for 48 hours. The instructions that accompany these should be followed. Long-term: A common example of a long-term test device is shown on the right. It is called an alpha track detector and is used for tests that last longer than 90 days. These are used to determine, for example, a year long average of radon in your home with the home being operated in a normal manner (not closed up). These are good for determining an average annual exposure. Note that there are also active devices that can measure changes in radon concentrations and other variables, but are most commonly used by professional radon testers. 21

22 Closed House Conditions For All Short-Term Tests All exterior doors and windows closed, except for normal entry and exit Internal-external external air exchange systems off Total Total internal recycle is allowed Combustion or make-up air must not be closed Permanent radon mitigation systems remain on Short-term tests are usually 2 to 7 days long and are done under "closed-house" conditions. Closed house conditions mean that the house is closed up for at least 12 hours before the test and for the duration of the test. Exterior windows and doors are kept shut, except for normal walking in and out of the doors (don't leave them open). Fans and blowers which move air from the outside of the house to the inside, or exhaust inside air to the outside, are turned off. Whole house fans should be off and air conditioners should be put on recycle" or "max.-cool," but not on the "fresh air" setting. Of course, you can live in the house during the testing. Since it is sometimes difficult to keep all the windows closed during warm weather, try to schedule the testing period when it will not be inconvenient or uncomfortable to keep the house closed up. If you must test during warm weather, keep the air-conditioning on, but simply put it on total recycle rather than the "fresh air" setting. On the other hand, "swamp coolers" or evaporative coolers that blow air into the home should be turned off during the test. The test device should be placed about table height (2 to 5 feet above the floor but no closer to the floor than 20 inches) and left undisturbed for the duration of the test. The test device should not be placed in direct sunlight or on hot or cold surfaces. The test device should not be placed in a moist environment such as the bathroom, the kitchen, or the laundry room. Finally, the test device should not be placed directly in moving air, such as in front of a fan or an air duct. Note: Closing up the room in which the test device is placed and opening doors and windows in the rest of the house is not following proper test procedures and can give erroneous readings. This can falsely report the radon too high, or even worse, too low. 22

23 Test Location Depends On Purpose Lowest lived in Suitable for Occupancy Non-Real Estate Real Estate Lowest lived in Bedroom YES Bedroom YES Closet NO Bedroom YES Bathroom NO Kitchen NO Living Room YES Garage NO Choose occupied room Keep away from drafts and moisture The location of a radon test may depend upon whether the test is being done for a real estate transaction or not. Since the purpose of the first, short-term test is to identify homes that are clearly below 4.0 pci/l, it is necessary to place the test device in a part of the home that would be expected to have the highest radon level. Then, if the reading comes back below 4.0 pci/l, there is good reason to believe that the rest of the home also has a low radon level. Furthermore, if the closed house test protocols were followed, there is good reason to believe that a low short-term test result (below 4.0 pci/l) means that the average radon throughout the year will probably not be above 4.0 pci/l. Therefore, in order to have confidence in the radon reading, the device should be placed in the lowest occupied space of the home. A finished basement is normally chosen in those parts of the country that typically have basements. After the lowest occupied area of the home is selected, the device should be placed in a room in that area that is frequently occupied, but where high humidity in the air would not be expected. Examples of good locations would be bedrooms, dining rooms, and family rooms. Never place the device in a closet, crawl-space, storage area, kitchen, garage or bathroom. In the case of a real estate transaction one would place it in the lowest portion of the house suitable for occupancy without rennovations. Remember real estate tests determine the radon potential of a home, independent of how future homeowners may operate or occupy the house. 23

24 Test Placement Within A Room Exterior wall No (openings) 12 inches min. 20 inches min. 3 feet min. 3 feet from windows or exterior doors At least 20 inches above floor 4 inches from other objects Where it won t be disturbed A proper location should be selected to obtain a good measurement of the radon in the home. The measurement should represent the breathing space of the home. The minimum distances for a test device are at least 20 inches from the floor, 4 inches from another object, 12 inches from an exterior wall, and 3 feet from an outside window. You can place it near an interior wall, like on a book shelf, but keep it at least 4 inches from the wall or back of the shelf to allow for good air movement to all sides of the device. Devices that are designed to be hung by a string should be no closer than 12 inches from the ceiling. No test device should be placed in rooms with excess humidity. They also should not be placed in a location where drafts will hit them. If you can feel a breeze on the back side of your hand don't place the device there. A device should not be placed where direct sunlight can strike it, nor should it be placed on hot surfaces such as a water heater. 24

25 Interpreting Radon Results (Non Real Estate Transactions) Short-Term Test Equal to, or greater than 4 pci/l? No No Mitigation Yes Follow-up Test Repeat Short-Term Long-Term Test No Mitigation Recommended No Average of 1st and 2nd results at or above 4 pci/l? Yes Mitigate Home Yes Results of long-term test at or above 4pCi/L? No No Mitigation Recommended How do you interpret the measurement results to determine if you should mitigate (fix) your home? The first step is to conduct an initial short-term test in the lowest occupied portion of your home. If the result of this is less than 4.0 pci/l, you can assume that on an annual basis the home will be less than 4.0 pci/l. It is also true that if you tested the lower portion of the home, radon concentrations on upper floors will also be lower than the measured result of the single test. If, on the other hand, a result of 4.0 pci/l or greater is obtained you should confirm this with another test. If your initial results were quite elevated (greater than 10 pci/l) you should retest rather soon by conducting another short-term (closed building) test placed in the same location as the first test. Average the first and second test results and if it is equal to or above 4.0 pci/l you should take steps to mitigate the house. If your initial test was equal to or greater than 4.0 pci/l, but less than 10 pci/l, then you should also perform a follow-up measurement, but in this case the urgency is not as great. You can perform a long-term test of greater than 90 days or preferably for a year. This long-term test would be placed in the same location as your initial short-term test but you would not need to maintain closed house conditions. You will base your decision to mitigate on the results of the long-term test alone. Don't average the long-term result with the initial short-term result. 25

26 Passive Device Use in Real Estate Testing Activated charcoal devices shown as an example. Deployed simultaneously Placed 4 inches apart Results are averaged If average is equal to, or greater than 4 pci/l, mitigation is recommended. Simultaneous Testing Method: A common radon measurement method described in the U.S. EPA Protocols for real estate transactions is the simultaneous testing method. The process is as follows: External doors and windows are closed, except for normal entry and exit, for 12 hours prior to the initiation of the test. Two test devices are placed four inches apart in the lowest potentially occupiable portion of the home for 48 hours. External doors and windows are closed, except for normal entry and exit, throughout the test. The results of the two tests are averaged together to determine the need for mitigation. The results of the two tests should be very close to each other. Simultaneous testing allows the tester to perform a second check on the detectors to safeguard against errors. Because only two and a half days are needed to conduct the test (independent of laboratory results) the simultaneous method is the approach most often used in real estate transactions. 26

27 Continuous Monitor Use in Real Estate Testing Single device Must measure and report in hourly increments and be calibrated If average is equal to, or greater than 4 pci/l, mitigation is recommended Variations can detect tampering Continuous Monitors: The continuous monitor is another method described in the U.S. EPA Protocols for radon measurements for real estate transactions. The process is as follows: External doors and windows are closed, except for normal entry and exit, for 12 hours prior to the initiation of the test. A single continuous monitor is placed in the lowest potentially occupiable portion of the home for a minimum of 48 hours. External doors and windows are closed, except for normal entry and exit, throughout the test. The decision to remediate the home would be based upon the average reading of the hourly reported results, after the first four hours of measurements have been disregarded (this allows for devices to reach equilibrium after being set in a home). Note that this is the only methodology that allows for the decisions to be made upon the results of a single test device! In order for one of these to be used in this manner it must have the capability of measuring and reporting results in increments of one hour or less. This allows the tester to spot unusual swings due to weather or occupant behavior (including test tampering). 27

28 Homes With Radon Concerns Can Be Fixed! Active soil depressurization is a means of creating a vacuum beneath a slab or plastic sheet and collecting the radon before it enters a building. Active soil depressurization has proven to be a very cost-effective and reliable technique for radon reduction, by collecting the radon from beneath the building before it can enter. How this technique is applied depends upon the type of foundation. Crawl spaces: A high density polyethylene sheet is laid on the soil. A perforated pipe or drain mat is placed beneath the plastic. This pipe is connected to solid PVC piping and fan, which creates a vacuum beneath the plastic. The seams are sealed, and the edges are sealed to the foundation walls. This effectively collects the radon and exhausts it to a safe location outside. Slab-on-grade: One or more holes are cut through the slab. A pit is hollowed out beneath the slab. A PVC pipe is inserted into the hole(s). This pipe is routed to a fan which creates a vacuum beneath the slab. The number of suction points needed is a function of the permeability of the soil beneath the slab and how many intervening footings exist within the building. These systems can be simple or complex depending upon the design of the building. Operating costs of these fans are negligible due to their low power consumption (90 watts per fan). 28

29 Can t We Just Seal The Cracks? Radon can enter through very small openings. Without affecting house pressures, sealing is not a stand-alone alone technique. Radon can enter through the smallest of openings in the foundation due to the vacuums in buildings (negative pressure differentials). There are many openings that will allow radon to enter: Plumbing penetrations Electrical service penetrations Openings under tubs and showers. Many of these openings are often hidden within walls and are difficult to access as shown in the picture above. It is impossible to cost-effectively access and seal all foundation openings. Even if you were able to seal all openings, stress cracks that would occur in the future would provide openings that the radon could then pass through. Unless one counters the negative pressures that cause radon laden soil gas to enter caulking and sealing is not a stand-alone technique. 29

30 Treating Crawl Spaces Length of perforated pipe on soil High density, 4 mil. cross-linked or 6 mil polyethylene Seal to walls, seams and at pads Large earthen areas such as crawl spaces are best treated by laying down a sheet of plastic with a perforated collection pipe beneath it which is later connected to the radon vent riser. The edges of the plastic are sealed to the foundation wall. Seams and penetrations are sealed as well. The minimum thickness of plastic is a 6 mil polyethylene sheet. However, this material is not very durable if the crawl space will be accessed frequently or if occupants would like to use this area as storage. Typically, a more durable, 4 mil, cross-linked polyethylene is preferred due to is high strength and durability. The high density plastic is also available in white making the crawl space a lot brighter and usable for storage. The location of the riser can be anywhere in the crawl space. It does not need to be in the center. So plan on placing it anywhere in the crawl that will be convenient for crawl space access and convenient for routing the pipe up through the house. Use a minimum 10 feet length of 3 inch corrugated and perforated ADS pipe. Beneath plastic sheeting. 30

31 Perforated Pipe Connected To Suction System Perforated pipe connected to solid Sch.. 40 PVC pipe Riser routed to fan Pipe labeled Plastic helps dry out crawl space and reduce mildew and odors After the plastic has been installed, a solid PVC pipe is connected to the perforated pipe beneath the plastic. The PVC pipe is then routed to the radon fan. The system also helps reduce moisture in the crawl space, thereby reducing mold and mildew odors. 31

32 System Depressurization Fan Installed in attic, garage, or outside Must not be installed inside of house Quiet 90 watt fan runs continuously 11 year expected life The suction piping is connected to a radon fan that must be located either in an unoccupied attic, a garage, or outside the home. These fans are quiet and use less than 90 watts of electricity. Because radon is constantly generated in the soil beneath the home, the fans must operate continuously. 32

33 System Discharges Away From Building Openings Discharge should be high to avoid radon entering building Minimum of 10 feet above grade 10 feet from openings, 2 feet below discharge Above eave Rain cap not recommended 1/4 inch bird screen US EPA Mitigation Standards The fan discharge is then routed up through the roof or up along an outside wall to a high point on the house. The exhaust should be pointed up to force the collected radon up and away from the home. It is very important that the discharge not be near the ground, or the radon might re-enter the structure and increase the level of radon in the home. Radon concentrations in excess of 2000 pci/l have been measured in these discharges. Rain caps interfere with system efficiency and are not needed. However, screens should be placed on the discharge to keep birds and squirrels from entering the pipe. Parameters for proper system installation are dictated by the U.S. EPA radon Mitigation Standards which can be found at: 33

34 A System Performance Indicator Is Needed A system indicator should also be installed to warn the homeowner of any system malfunctions. This is very important since a homeowner will not be able to sense an increase of radon concentrations in the home if the system malfunctions. If the plastic becomes torn and a significant amount of interior air is lost, the gas appliances could backdraft, which is a very serious concern. In fact, the proper operation of the flues must be checked for back drafting after the installation of any radon system. The device on the left will sense a change in power draw on the fan associated with changes in air flow that could be caused by the pipe being broken (drawing in more air) or a blockage in the pipe (decreasing air flow). The one on the right measures vacuum in the suction portion of the piping that will also change as a function of pipes being broken or plugged. 34

35 Suction Point For Slabs And Basements Hole cut through slab Pit dug out PVC pipe connected to hole Pipe routed to fan May require more than one suction point For a home that has a slab-on-grade or a basement, the suction is applied beneath the slab. In this case the slab itself acts much like the plastic sheet in a crawl space system. The only difference with a slab system versus a crawl space system is that you will not have the benefit of a perforated pipe beneath the slab. Consequently, one relies upon the permeability of the soil beneath the slab to allow for good lateral air movement. If the soil is very tight, or if there are obstructions under the slabs such as intermediate foundations, more than one suction point may be needed. If more than one suction point is needed they can generally be tied to a common depressurization fan. The balance of the system (i.e. piping, fan, discharge, and indicator) is identical to the crawl space system shown previously. 35

36 Radon Collection Via Drainage Systems Upper Floor of Home Sump Pit Piping to Roof Cost-effective Care should be taken to avoid conflicts with water collection Soil Gas Perforated Foundation Drain Soil Gas Homes that have sumps or French drains for control of rain water can be effectively mitigated utilizing the sump to collect radon from the underlying soil. In this case a lid with vent piping is placed on the sump pit and a radon fan is used to depressurize the soil under the slab through the sump. The radon is collected and exhausted safely outside the home. 36

37 Radon Mitigation Works! Radon (pci/l) Mitigation System Off EPA Guidance Mitigation System ON 16:00 19:00 22:00 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00 2:00 5:00 8:00 Hour After a mitigation system is installed the radon levels are reduced very quickly, as can be seen from the graph above. Of course one cannot assume that these kinds of reductions will occur and that they should be verified with short-term testing, conducted in a similar manner as the premitigation testing. Post-mitigation testing should start no sooner than 24-hours nor later than 30 days after the installation. This should be a short-term test to quickly determine the efficacy of the system. Once the levels have been confirmed, a test should be conducted at least once every twoyears thereafter. Based upon research and a long history of experience mitigation contractors are not only willing to provide guarantees that radon levels will be reduced to less than 4 pci/l but also willing to provide long-term warranties. 37

38 RADON VENT New Homes Can Be Built With Radon Control Systems RADON VENT The figure above illustrates the basic concept of radon control systems installed during the construction of a home. The key to these systems is to insure that soil gases and radon can move easily from underneath the building toward a single riser pipe that is routed up through the home and exits through the roof. In the case of a concrete floor in a basement or slab-on-grade home, this could consist of a 4 inch layer of 3/4 inch washed gravel being placed prior to and beneath the planned slab. Other options are a gas collection system consisting of a loop of buried perforated pipe inside the footing, or matting laid on the sub-grade dirt under the slab. In any case, these mechanisms will allow the soil gases to be easily collected. The pipe riser should be routed through the interior of the building to allow the riser to be warmed, thus creating a natural stack effect. When this riser is combined with the easy gas collecting capabilities of the system installed beneath the slab, it can draw significant amounts of radon from beneath the home. The performance of this natural convection system is enhanced by sealing openings in the slab and walls so the air drawn up through the system comes from beneath the building rather than from within the building. These passive systems are further enhanced by routing the pipe through the warmest spaces in the home (like the chase where the furnace and hot water flues are located.) The radon vent should not be connected to any combustion flues or soil vents. This passive approach is not an option with existing homes because of the need for the permeable system that is specially designed and installed beneath the slab only during construction. Allowance is always made for future installation of a fan should testing indicate that this additional step is necessary. 38

39 Some Radon Can Also Enter Building From Water Supply Rn Rn Ra Rn w Radon enters water in ground and outgasses in building. Concern primarily isolated to private wells. Typically adds minor amount to air compared to that from soil gas. Radon in the ground can dissolve into ground water. When this ground water is brought into a building directly (without the benefit of being held in an atmospheric holding tank) the dissolved gas is released from the water. The amount of water used in a building, along with the amount of radon in the water, will determine the amount of radon brought into the building. Given typical water usage rates and radon concentrations found in wells, this entry mechanism only accounts for approximately 1-2% of the radon that enters homes in the U.S. The vast majority of radon comes from the soil beneath the home. Most remediation efforts concentrate on reducing the entry of radon laden soil gas, rather than treating water. As a rule of thumb, in a residential structure with a private well containing 10,000 pci/l of radon in the water, 1pCi/L of radon is added from normal water usage after dilution by typical residential ventilation. This is above and beyond that which comes from the soil. The US EPA has recommended maximum contaminant levels (MCL) ranging from a low of 300 pci/l to as high as 4,000 pci/l of water in community water supplies. Although these regulations will not impact private wells, this fact does not reduce a homeowners concern if they buy a home with a private well. The actual MCL will depend upon the extent of which the state or utility promotes the reduction of radon in air risks. Homeowners are becoming increasingly concerned about the quality of drinking water. 39

40 National Environmental Health Association's National Radon Proficiency Program Measurement and mitigation contractors certified by NEHA have been trained and carry ID cards. Lists of certified individuals and labs can be found and other helpful information at: or As of September 30, 1998 EPA charged the Conference of Radiation Control program Directors to select an organization to operate a private credentialing program for the certification of radon measurement and mitigation professionals. The National Environmental Health Association was selected to perform this function. To be NEHA certified one must: Attend training, Pass an exam, Agree to follow the US EPA s Radon protocols and Standards, Comply with local codes and regulations Comply with local regulations regarding radon contractors. This is an ID of an individual verifying that he or she is NEHA certified Radon Contractor. It is not always a requirement that individuals performing this work be certified within this program, but to assure yourself that an appropriate test is conducted or mitigation system installed, one would be well advised to suggest a listed individual. A list of certified measurement and mitigation professionals can be found at the web address cited on the slide. 40

41 EPA Documents Citizen s Guide Real Estate Guide Consumer s Guide What it is & how to test Testing at time of sale How to fix radon CERTI A Citizens Guide to Radon: The EPA has published a small pamphlet that summarizes the health effects of radon as well as simple self-testing procedures. Additional copies of this may be obtained from your state radon program or from the NEHA website at it can also be downloaded from the US EPA website shown on the slide. Home Buyers and Sellers Guide to Radon The EPA has published this pamphlet to provide information to homebuyers and sellers about testing for radon at the time of sale. Consumer s Guide to Radon Reduction: The EPA offers a booklet that is useful in explaining radon mitigation. This would be a good document to provide to clients who have questions, rather than speculating on repairs yourself. You should have copies of these to hand out. 41