By Tom and Georgiann Manz, ResCom Radon Solutions www.RadonKC.com
Seeing new homes springing up in the Kansas City area is a great thing. That means more people are going to work each day and families are enjoying new neighborhoods in their new homes.
1. Builders frequently are not properly installing passive radon systems.
2. A passive radon system does not function like an "active" radon mitigation system.
What is a “passive radon system?”For the purpose of definition, a “passive” radon system relies on natural pressure differentials and air currents instead of a fan (used with active radon mitigation systems) to draw radon up from below the home.
According to the EPA, radon resistant construction should include:
-Installing a layer of clean gravel or aggregate beneath the slab or flooring system-Laying polyethylene sheeting on top of the gravel layer
-Including a gas-tight venting pipe from the gravel level through the building to the roof (a passive radon system)-Sealing and caulking the foundation thoroughly
The radon-resistant construction components and a passive radon system help reduce the effect of soil gas pressure under the home. If installed properly, the passive system helps air and soil gasses from beneath the basement floor flow up through the pipe to vent safely to the outdoors.
HOWEVER, studies are showing a passive radon system may very likely not have enough natural air flow to eliminate radon gas to the safest levels – especially if the passive radon system has not been installed correctly.If radon levels are still proven to be unsafe in a home with a passive radon system, a fan can be installed on the existing pipe in the attic to pull the radon gas from under the basement floor into the vent pipe where it can be exhausted outside the house. The addition of a fan and its associated wiring creates an "active" radon system.
Even though passive radon systems are a good first step in new home construction, there are potential unseen problems that may exist – issues that the builders, buyers, or their realtors may not be able to recognize.
Builders typically use their plumbing contractors to install passive radon system vent piping from below the basement floor extending up through the framing, through the attic and out the roof. Since most plumbers do not have specific training in radon system design and operation, they often make critical mistakes that limit or completely negate the purpose and effectiveness of the passive radon system.Passive radon system design flaws include:
1. The installation of the sub-slab suction pipe is not properly connected to the gravel bed.
2. Although 3 inch vent pipe may be used in the basement, it is often reduced to a 2 inch pipe at the main floor level in order to pass more easily through the 2x4 house framing This size reduction eliminates the possibility of using a radon fan for an active system due to the fan’s minimum 3 inch pipe requirement.
3. Vent piping in the attic is frequently installed up through or close to an outer wall not leaving a minimum of 18 inches of clear space in the attic between the ceiling joists and roof rafters. This prohibits installing a radon fan in that location using the existing roof penetration.
4. Horizontal vent pipe runs are often not graded properly to allow condensation to drain through the vent piping back to the sub-slab gravel bed. This becomes evident when the system is activated with a fan and water builds up in the pipe creating a sloshing sound which is annoying to the home owner, reduces the air flow of the radon system, and shortens the life of the fan.Good news – bad news
Many builders in the KC area are installing passive radon systems as a part of their new construction process – the good news. The bad news - many new home buyers (and builders, realtors, and home inspectors) assume that because a house has a passive radon system, they don’t need to be concerned about radon levels and, as a result, do not conduct a life-saving radon test during the home inspection process.Since 40-50% of the homes tested for radon in the Kansas City area have levels above the EPA’s action level of 4.0 pCi/L (picocuries per liter of air), radon testing for all homes should be a major concern for residents.
What is the solution?
1. First and foremost, every home should be tested for radon during the home inspection process!
2. Builders, realtors and buyers need to be aware that having a passive radon system DOES NOT mean a home is radon safe.
3. If unsafe levels of radon are found in a home with a passive system, a certified radon contractor should be called in to examine the existing passive system and install a radon fan in the attic to activate the system.
4. Certified radon contractors should be consulted in the passive design process and in the activation process.
The issue of radon in homes, schools, and work places is a serious health issue. Radon awareness is improving among realtors, builders, and the general population, but we still have a long way to go when you consider over 20,000 people each year needlessly lose their lives to radon-induced lung cancer.How tragic that lives are lost from inhaling a natural-occurring gas that can be easily discovered by a simple air test and eliminated by an inexpensive radon mitigation system. As radon awareness increases through proper information from builders, realtors, and home inspectors, radon deaths will lower and hopefully, one day, be a thing of the past.