Only in the past few years have homeowners added radon to the list of hazards they want to eliminate from the place they live.
Radon is a colorless, odorless, naturally occuring radioactive gas, a by-product of uranium, that comes through the soil. Extensive exposure is linked to lung cancer. It's found in all parts of the country to some extent, though there are some radon "hot spots," including parts of Maryland. In 1988, the U.S. Environmental Protection Agency and the surgeon general advised that all homes be tested for radon.
As a result, more and more houses are being equipped with radon-mitigation systems. But there are few laws regulating the radon-mitigation industry.Homeowners who don't know what to look for can easily end up with a less than ideal radon-elimination system.
The system itself is simple. The most common entry point for radon is the basement. A typical system includes a pipe that runs under the slab and ventilates to the outside. The pipe has an in-line fan that creates negative pressure (suction) in the pipe and exhausts the radon gas.
To get rid of the radon, however, all the parts of the system have to be installed and working properly.
According to Marty Emerick, vice president of Maryland Radon Professional Radon Services, of Eldersburg, these are the attributes of a good system:
*The exhaust fan should be outside the living space -- in the attic, the garage, or outside the house. The basement is considered living space.
*The vent pipe should extend above the roof, where radon quickly dissipates in outside air. (In some older systems, the pipe simply may be vented to the outside. Those systems should be monitored regularly to make sure the radon is being vented.)
*The system should have a monitor or alarm to evaluate pressure. The simplest is a manometer, a device that has a column of liquid to indicate pressure at each end of a U-shaped tube. These devices don't measure radon; they indicate whether the fan is working and negative pressure is being created in the pipe. They're essential however, so the average homeowner can check on the system's operation.
Those are the big three, but Mr. Emerick suggested several other points:
*The installer should use polyurethane caulk between the floor slab and the wall -- a main radon entry point.
*Radon-mitigation pipes should be labeled so all current and future homeowners can tell which ones they are. The circuit that runs the fan should be labeled at the electrical panel box.
*Traps should be installed in any drains connected to a sump pump, so air isn't being pulled in from outside and defeating the radon-exhaust system.
*Homeowners should get an instruction book with the system -- and keep it to pass on to subsequent homeowners.
*The installer should use plastic pipe, which can be glued into a seamless hole so there are no connections to break and leak radon.
Two areas where homeowners can look for regulation to protect themselves are in testing and installation. The EPA has established minimum standards for radon testers -- the Radon Measuring Proficiency Program -- and for radon mitigators -- the Radon Contractor Proficiency Program.
There may be no rules in your locale that require people to operate under the guidelines, but you can generally assure you're getting a serious radon professional by choosing someone who has trained under either program. An RMP or RCP contractor will have an EPA identification card. (In Maryland, RCP radon mitigators also must have a Maryland Home Improvement license.)
Next: A question of furnace efficiency.
Mr. Johnson is construction manager for Neighborhood Housing Services of Baltimore. Ms. Menzie is a home writer for The Sun.
If you have questions, tips or experiences to share about working on houses, write to us c/o HOME WORK, The Sun, 501 N.
Calvert St., Baltimore 21278. Questions of general interest will be answered in the column; comments, tips and experiences will be reported in occasional columns.
Where to get help
The Maryland Department of the Environment recommends that all homes in the state of Maryland be tested for radon, says Leon Rachuba, the health physicist who manages the department's radon program,
The department can provide names of radon testers and mitigators who are listed with the RMP and RCP programs.
For more information, call the state's radon hot line at (800) 872-3666.