Radon mitigation heater pipe

Abstract

An apparatus and method for radon mitigation using natural convection to remove radon-contaminated air from beneath the slab foundation of a structure, building, or dwelling, comprising a section of vertically mounted convection duct including an internal heat source, an inlet duct extending from said convection duct through the slab into the gas permeable sub-slab layer, an outlet duct extending from said convection duct through the structure and out the roof thereof, the internal heat source comprising a thermally conductive tube disposed concentrically within said convection duct and heated by one or more electrical heater elements to assist the upward airflow of the radon-contaminated air from the structure.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a continuation-in-part of U.S. patent application Ser. No. 10 / 773,076 filed on Feb. 5, 2004, which claims priority from U.S. Provisional Patent Application Ser. No. 60 / 445,135, filed on Feb. 5, 2003.BACKGROUND OF THE INVENTION [0002] The present invention relates generally to devices for radon mitigation in homes and other structures. More specifically, the present invention relates to an improved system for ventilating the foundation of a structure to remove radon gas so that it does not accumulate inside the structure. [0003] Radon is a radioactive gas generated by the natural (radioactive) decay of the uranium that is found in nearly all soils, and can be found all over the United States. The breakdown of uranium in soil, rock and water releases radon into the air we breathe. Radon can get into any type of building—homes, offices, and schools—and cause an elevated indoor radon level. It typically moves up through ...

AI Technical Summary

Benefits of technology

[0013] The present invention provides a simple, low-maintenance device for actively drawing radon-contaminated air from beneath the foundation of a structure, thus mitigating the risk that radon will enter into and accumulate inside of the structure. By using an internally heated section of duct to create a convective flow of air upward from the gas permeable sub-slab layer, expelling the radon-contaminated air above the roof of the structure, the device of the present invention eliminates the need for a fan. Therefore, the device of the present invention is quieter and less prone to failure than a similarly installed fan-powered radon mitigation device. Additionally, because the device of the present invention heats the air that is being withdrawn from beneath the slab, condensation within the ducting is reduced. The heat source utilized in the present invention is of low wattage so that the temperature of the withdrawn air is maintained within the capabilities of the PVC outlet piping and no temperature control mechanism is required.

Problems solved by technology

A radon problem can exist in any home, regardless whether the home is new, old, well sealed, or drafty, and may even occur in a home without a basement.

Like other environmental pollutants, there is some uncertainty about the magnitude of radon health risks.

Because this system usually does not have a fresh air input into the gas permeable layer below the slab, airflow is restricted.

The reliance of this method on a fan causes problems with noise and condensation building up on the inside of the pipe.

The condensation then drips down on the fan, increasing the noise.

Because of the mechanical nature of the fan, its life span is limited.

U.S. Pat. No. 6,524,182 [Kilburn, et al.] discloses a fan-driven system having a sump well inlet and a band-board outlet that is suboptimal, since it does not get the radon-contaminated air sufficiently away from the dwelling.

However, all of these fan-inclusive devices suffer from the drawback of having the fan, a mechanical component that is prone to failure.

Also, these devices do not heat the cool air being drawn from the sub-slab region (or the basement) and are therefore prone to develop condensation in the outlet piping.

For that reason, this device also would not be compatible with PVC piping.

U.S. Pat. No. 1,759,830 [Blanchard] discloses a resistance heater that is in contact with and intended to directly heat the metal walls of a chimney cap, again an application that is incompatible with creating an updraft of airflow in PVC piping.

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