Radon Testing

Rick Bunzel - Mountain View Property Inspection

When most people think of lung cancer, they think of cigarettes. But, do you know what the second leading cause of lung cancer is in the Colorado? Radon. Radon usually comes from certain rocks that contain radioactive particles releasing radon gas. When radon gas decays, radon atoms can change to other atoms than can become embedded in your lungs. Though estimates vary, approximately 14,000 people die each year as a result of radon induced lung cancer. Radon is a gas that cannot be smelled or tasted. Experts have become much more sophisticated in understanding radon exposure over the past ten years. Radon is not unique to Colorado or states bordering on the Rockies, much of the east coast including New York, Connecticut, New Jersey and Pennsylvania have radon levels as high we do. Boulder County, as well as many other counties in Colorado, is ranked by the EPA as having one of the highest probabilities of radon levels over the limit of 4 picocuries (PCi/l). Reviewing the radon tests I have done over the past two years supports the EPA ranking. The average reading I am seeing in the Front Range is around 8 picocuries and the highest reading I've seen was 48 picocuries.

Many times customers will ask if I know the average reading for a given neighborhood and the reality is that radon levels are unique to each home. I don't even try to predict readings due to the number of variables that influence readings. A good example was testing two town homes in the same structure in Longmont's Prospect neighborhood. Tests were started at the same time and units were placed in similar locations in the lower levels of the town homes. The readings came in more than 5 picocuries apart. This is a classic example of units within the same structure having different radon levels.

In real estate transactions short term testing is the common test. Short term is a minimum of 48 hours up to 90 days, although most tests are between 48 and 72 hours. The three types of devices used today for radon testing are; Charcoal canisters, E-Perm, and Continuous Reading Monitors (CRM).

Charcoal canisters and similar charcoal-containing devices are used for short-term tests lasting a minimum of 48 hours and up to 7 days. These units can be purchased at Home Depot for under $20. They contain a quantity of granular activated carbon that absorbs the radon gas entering the canister from the surrounding air. At the end of the test period, the canister is sealed and returned to the manufacturer for analysis, who then reports the results to the buyer. These canisters have three drawbacks: higher moisture levels can influence the readings, the last 12 hours of exposure will have the greatest influence on the readings, and they normally have to be mailed to a lab for processing which causes a delay in getting the results.

Electret Passive Environmental Radon Canisters (E-PERM) are a passive radon detection system consisting of a charged teflon disk (electret), and an ionization chamber. The radon gas exposure will decrease the charge of the teflon disk and that change is read by a machine. These units provide a better overall average and are not influenced by moisture. They also do not require electricity and are ideal for testing homes where the utilities have been turned off. The drawback is that this unit will not detect environmental tampering such as windows being opened during the test and in most cases have to be read by a qualified lab.

Continuous Reading Monitors (CRM) - These monitors are considered "state of the art." They are hi-tech units that measure the radon in a tube called a scintillation cell/photomultiplier. This device counts the flashes of light the decaying process produces. The number of flashes of light corresponds to a specific quantity of radon. These units provide hour-by-hour readings as well as time, temperature, barometric pressure and movement. The additional readings are used to detect tampering or environmental changes that could influence the readings. CRM units will give readings immediately upon pickup.

Colorado does not regulate testing or mitigation but a good test provider will carry a certification. The EPA recognizes the National Environmental Health Association (NEHA) National Radon Proficiency Program's "Residential Radon Gas Measurement Provider" certification. This certification program ensures that those who are offering testing have a demonstrated knowledge of radon measurement protocols for the placement, retrieval of radon measurement devices and to interpret results obtained in residential settings. This would be the certification that Home Inspectors such as myself would have. NEHA also certifies Residential Radon Mitigators.

Although real estate disclosures encourage buyers to get a radon test with every real estate transaction, it is not always necessary. EPA guidelines recommend testing any time there is living space below grade. The exception to this guideline is when there is heating and AC equipment below grade such as in a ranch home with a crawl space. HVAC ducts are never airtight and will tend to draw the radon gas into the system and circulate it into the living spaces of the home. However, the placement guidelines remain the same. Placement should be in a living space at least 20" off the floor and away from windows and doors that may used during the test. Windows and doors need to be closed at least 12 hours prior to the test and for the duration of the test. Normal in and out traffic is OK, but doors should not remain open for any length of time. Air conditioning systems can be run as long as they don't bring in outside air. Swamp coolers cannot be run. If it is doubtful the occupants will honor the test conditions, then the test should be postponed until the conditions can be maintained.

If the home presently has a mitigation system or has been recently tested, then there is no need to retest. However, if the home has a mitigation system but no documentation as to its age or condition, I will recommend a test to ensure it is performing properly. It is not unusual to see these systems fail the test. In homes with a structural wood floor in the basement, the under floor ventilation systems are sometimes confused with a radon mitigation system. They are not the same although the ventilation will help reduce the radon level but not to acceptable levels. The only way to be sure is to test.

Many clients are puzzled by the lack of radon testing particularly with newer homes. This is mostly due to builders who do not want to be bothered with radon issues and have contract clauses that absolve them of any liability. In fact, many builders will not allow radon tests prior to transfer of ownership to the buyers. They do not want to be responsible for the cost of mitigating radon. For more information on radon in our area go to http://www.mvpinspection.com/radon.html

Rick Bunzel is the Principle Inspector at Mountain View Property Inspections and is Residential Radon Gas Measurement Provider certified. If you have questions or comments, Rick Bunzel can be contacted at Mountain View Property Inspections @ 303-443-9063 or MVPInspection@comcast.net