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Community and Q&A

Should I connect radon vent to the airtight basin lid?

alumniu | Posted in General Questions on

I recently installed a sump basin with an airtight lid connected to interior & exterior drain tile with the intention of using it to vent radon also.

The plumbing inspector told me that I could not vent off of the basin, and that I would have to install a vertical pipe off of the interior drain tile. (could even be directly adjacent to the sump basin)

The reasoning being that in order to service the sump pump, that the radon line would need to be disconnected to remove the cover, and this vent line may not get reconnected.

Is this good practice? Is this worth arguing with the inspector to connect it to the basin lid?

New house build in Northern IL, climate zone 5.

I saw that in another radon related question that Eric Bjornson (not sure of qualifications) said…
“It might be worth noting that we would rarely recommend using the sump pit as a suction point for sub slab depressurization if the soil drainage system (weeping tiles) terminates at the sump pit. A sub slab depressurization system is designed to create a low pressure condition under the slab. Using the sump pit as a suction point causes the low pressure field to be extended to soil surrounding the foundation often resulting in higher than desired airflow requirements meaning the need for a higher power fan and resulting energy penalties particularly in cold climates.”


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  1. GBA Editor
    Martin Holladay | | #1

    The reason that radon mitigation specialists don't like to use sump lids as suction points is that this approach complicates sump pump maintenance.

    You'll hear different opinions on this issue. According to the Nebraska Department of Health and Human Services, "A radon mitigation system will collect and remove soil air from below your basement floor from either: (a) a sump pit, if one is present, or (b) a five-inch suction point (the size of a common CD) that will be drilled through the floor in an unfinished storage area or your utility room. If your home has a sump pit, then an airtight lid should be installed so radon and soil moisture vapor cannot intrude into your basement. A radon mitigation system can then be constructed to pull the soil air from within the sealed sump pit. Systems that pulled soil air from a sealed sump pit are very effective at lowering the indoor radon level."

    However, regulations promulgated by the state of Illinois warn of the need for special fittings if this approach is taken: "Sump pits shall not be used as the primary suction point for mitigation systems except in accordance with subsection (h)(7)(J). ... All joints and connections in radon mitigation systems using plastic vent pipes shall be permanently sealed with adhesives as specified by the manufacturer of the pipe material used, with 2 exceptions: i) If secondary suction points are installed in sump pits, the system shall be designed with removable or flexible couplings to facilitate removal of the sump pit cover and for sump pump maintenance..."

    Note that this requirement refers to "secondary suction points" -- the assumption is that the primary suction point is elsewhere.

    Some airtight sump manufacturers make special sumps designed to be connected to radon vents; here is one: Radon Vented Sump.

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