Radon Control Techniques

Techniques to control radon in residence can be broadly classified as follows:

Source removal (new construction considerations)

Source control

Sealing major radon source

Sealing radon entry routes (see Figure 5.28.3)

Subslab ventilation (Figure 5.28.4)

FIG. 5.28.3 Major radon entry routes into detached houses (Reprinted from U.S. Environmental Protection Agency (EPA), 1986, Reduction techniques for detached houses, EPA 625/5-86/019, Research Triangle Park, N.C.: U.S. EPA.)

Outside fan draws radon away from house

Outside fan draws radon away from house

FIG. 5.28.4 Individual pipe variation of subslab ventilation. (Reprinted from U.S. EPA, 1986.)
FIG. 5.28.6 Two variations of wall ventilation: the baseboard method and the single-point pipe method.

Drain-tile soil ventilation (Figure 5.28.5)

Active ventilation of hollow block basement walls (see

Figure 5.28.6) Avoidance of house depressurization Ventilation of indoor radon concentration Natural circulation Forced-air ventilation Heat recovery ventilation

However, the effectiveness of indoor air ventilation decreases with increased ventilation rates. Also, the radon source concentration and radon entry rate can reach a fi nite level where high ventilation rates are not productive (see Figure 5.28.7).

Table 5.28.1 summarizes the methods of reducing the radon level in a residence. No two houses have identical radon problems. Therefore, a routine method for reducing radon levels does not exist. Most homes usually require more than one of the nine methods listed to significantly reduce their radon levels. Before deciding on an approach, a homeowner should consider the unique characteristics of the house and consult a contractor specializing in the remediation of radon problems.

FIG. 5.28.5 Drain-tile soil ventilation system draining to remote discharge area.

50% reduction in radon concentration results from a two-fold increase (0.25 to 0.5 p ach) in ventilation.

50% reduction in radon concentration results from a two-fold increase (0.25 to 0.5 p ach) in ventilation.

75% reduction results from a four-fold increase in ventilation.

90% reduction results from an eight-fold increase in ventilation.

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