Coping with radon. Venting: viable, fairly cheap solution

For homeowners who find unsafe levels of radon gas in their houses, there is good news and bad news. First, the good news: ``It seems that every house can be fixed,'' says Lee Grodzins, a nuclear physicist at the Massachusetts Institute of Technology who has worked with radon for three years. It probably won't be very expensive: from a few hundred dollars to less than $2,000 - no more than the cost of a coat of paint.

Now for the bad news: remedies currently include unsightly plastic piping.

But ``the greatest advances,'' Dr. Grodzins says, are expected to be in ways of removing radon. ``I believe that in the next few years we're going to see the engineers look at this problem and find solutions that are invisible.''

Enormous progress has been made over the past two years toward reducing radon levels, as is illustrated by information available at the recent annual convention of the American Association of Radon Scientists and Technologists.

Contractors told of successfully using small-diameter pipes to remove radon and of having kept radon out of a house by sucking radon-filled air through the fine sands beneath a house - techniques not previously thought feasible.

One corporation, RAD Systems, is developing a device the size of a furnace that would remove radon from house air by passing it over beds of activated charcoal and cleaning the charcoal by blowing outside air over it. Results from the initial test were promising, and four more test systems are being constructed.

But such changes are in the future, albeit perhaps the near future. For today, Grodzins says, if a homeowner learns from careful testing that the radon level in his house poses a problem, the first step is to see if a way can be found to stop the gas from entering the house.

The first move is to find out where radon enters the building - ``often there is only one entry point,'' he says - and to try to stop it, as by sealing a basement crack or plugging an unneeded drain. ``That's the easy solution,'' he says, in a view with which other specialists concur. It also is the least visible and the cheapest.

If that doesn't get rid of the radon, he says, ``the next level'' of solution is to ``pull the air from beneath the foundation'' by venting it with pipes and a fan.

In the few instances in which venting beneath the basement is unsuccessful, the next step is to exchange inside and outside air much faster than the rate of the average house, which Grodzins says is about one air change an hour. It can be increased to four or five times an hour. In an effort to hold down these costs, heat exchangers can be added to the system; they cost about $1,000.

The new system being developed by RAD may prove a desirable alternative to fast air exchange. ``Basically what you're doing,'' Grodzins says, ``is that you're using the outside air in effect to clean the inside air. ...''