Since we can take it as a given that the developers of point-based building criteria want to ensure occupant health, they should recognize the potential scenarios for the positively pressurized side of radon mitigation systems to leak into conditioned space where that might affect occupant health.

If any fan that is ultimately installed should not be placed within conditioned space, builders should not be given points for pre-installing piping that either may make less safely accessed roof-mounted radon fans needed or will simply make the roughed-in piping unusable.

Instead, in such buildings as Sam describes, the proper directions for pre-installing radon piping need to be conveyed to the builders and to their evaluators to avoid this problem.

Have those directions been officially communicated by AARST at least to the directors of the major building programs, such as those that Sam mentions? If so, documentation of such communications could be provided to mitigators called in to activate builder-installed RRNC in such buildings.

I think that the essential question here is:
Is an unoccupied attic conditioned in such a way that air in that space is more likely to find its way into the livable areas of the building than would the air in unoccupied and unconditioned attic spaces in buildings having them?
1) If yes, then the proscription against radon fan installation in such conditioned spaces is well-founded and builders shouldn’t be awarded points for installing roughed-in piping there.
2) If not, then that proscription in this kind of case may need revisiting.

Since such a conditioned attic space is built to be within the same building envelope as the rooms below it, I’ll admit to a gut feeling (without knowing the evidence) that it is probably more likely to communicate with airspace in the rest of the building.

Yours,

Kevin Stewart
Director of Environmental Health
American Lung Association of the Mid-Atlantic

In the few of those situation we have encountered, several of them we mounted the fan on the roof, and had and electrical contractor wire it. Its not pretty, but the client thought it was better than a retro fit on the exterior.

We have discussed mounting fans on roofs and between the risk and benefits we have adopted a guideline to just retrofit the systems on the exterior.
1. We don't want any liability of damaging or causing issues with roofs, newer roofs have warranties so we don't want to be owning any of those future issues or warranties.
2. In NJ it is so costly and time consuming to license an in installer; and they are so valuable and limited in supply, that we cant afford to risk having of our men fall off a roof or get hurt by installing the fans up there.

While I once believed in the EPA style systems, our Canadian system of installing fans in the basement and sidewall discharge (ground level has been very successful in lowering radon levels for our clients. Before you jump all over me we do require sch 40 pipe above grade (basement floor), as there is no such thing as 3 or 4 inch schedule 20 pipe. Discharge studies have found that after 3 feet discharge radiation is back to background and no freezing issues.
In ten years of business i have only changed out three fans due to failure and all three of them were in attic style systems (just bad luck possibly). I never thought I would say this but somewhere along the line i have become a fan of sidewall ground level discharge radon systems.

Never seen a leak on any of 2000 plus indoor fan systems! Plumbers don’t have leaks, why would a radon mitigator?

The original issue with band joist exhaust was that during the EPA House Evaluation Program in an area with very high home levels - "hundreds" - we were seeing reintrainment back into the structure. You could watch the levels drop as a quick fix of extending the exhaust pipe out with a dryer hose away from the house. For these homes, this was not a theoretical issue, but a reality.

I am not sure how that is happened during EPA House evaluation as we in Canada have installed 10,000's of systems using band joist or rim joist discharges with houses passing both short term and long term follow-up testing. I agree that the US EPA style systems are inherently safer as they have no pressurized piping within the building envelope, this allows for many installers to have little or no construction, pi[ping or building envelope experience to effectively mitigate homes in moderate climates. Most dispersion studies i have read show dispersion effectively back to background within 3-4 feet even within the plume path so it baffles me how reintrainment (even with very high levels, how this could have happened during EPA home tests. Radon is a science and a sometimes and maybe world.
Here in Canada we do have some extremely cold spells and up the side of the home or up through the roof systems with low- moderate flow just freeze up solid doing our clients no good at all, I never though i would say this, side wall discharge and fans indoors just works better in our climate.

These were high homes, so that could certainly impact it. Are the dispersion studies looking at existing homes where the foundation is surrounded by shrubs/ foundation plantings? This was in the mid-80's so plantings were well established as the homes were built in the 60's or earlier.
I agree that freezing up is an issue in Canada and the northern US. However, I think it is important to understand historically why the move away from the band/rim joist was made and the switch to mirror the plumbing exhaust took place.

Larainne I am suggesting that we (as North American mitigators) have a dilemma we have one standard in US and a very different standard in Canada. Your way works really well (post testing in real estate transactions) show this and Canadian (post testing for concerned home owners) show this. Post testing is part of what we are required to do as a mitigator. Having two significantly different ways of pipe routing for mitigating is confusing for non educated clients. While i was initially a staunch supporter of EPA style systems, I must produce a product that does not cause my clients significant grief during the winter months. I often wonder if research was re-conducted if these issues would reemerge. Radon at 5.3 pCi/l is 4 parts / quadrillion or 4 parts X 10 ⁻¹⁵ it does not take a lot of air mixing to diffuse that back to background.