1. Field of the Invention
This invention relates generally to a gas accretion and removal system and in particular, to a combination form-drain structure with collecting and venting-exhausting substructures that are used to remediate gaseous accretions located mainly below grade or in subterranean portions of building structures. The collection structure relates to permanent, in-situ footing/foundation forms and cojoined collecting networks which are both hollow and foraminous; while, vent and exhaust structures relate to nonforaminous manifolds, conduits and both power ventilation and natural (chimney) subsystems.
2. Background Information
Among other noxious gases, radon has been identified as a factor which increases the risk of cancer. The Environmental Protective Agency (EPA) has identified certain areas of the country which, due to geological conditions, have high levels of radon present. Additionally, it has determined the maximum allowable level for human safety to be four (4) picocuries per liter (pCi/L). Because of this requirement, in many areas of the country, radon testing is routine whenever a residence is sold. Irrespective of whether a structure is to be used as a residence, radon remediation could reasonably be required anytime a structure is identified as a radon or noxious gas accretion area.
Some states require testing and remediation if the radon level exceeds 11 picocuries per liter. Based on one of the instant inventor's discussions with EPA and other industry sources, he is confident in predicting that Housing and Urban Development/Federal Housing Administration (HUD/FHA) will soon adopt this radon testing requirement in a uniform enforcement code since mortgages sold in the secondary market must meet HUD/FHA standards.
Quite similar to the radon problem, other noxious gases may accumulate, in structures or in subterranean locations, which can pose general health or safety problems. The instant inventors, therefore, have devised a method and apparatus, for remediating concentrations of unwanted gases or fumes, and which are to be used at the inception of construction or development. By adapting a dual function form-drain structure with a third function, that of providing sub-slab (or subterranean) ventilation, they have developed and provided an elegant and cost-effective remediation system that is installed concurrently with the erection of most structures. Thus, the instant invention may be viewed as either an improvement to an existing form-drain system or, alternatively, a "defugation" system, the latter being a system for removing overheated air or noxious gases.
3. Discussion of Relevant Art
A building foundation form having an integral drain is disclosed in U.S. Pat. No. 5,120,162, issued on Jun. 9, 1992. One of the instant inventors developed this apparatus which cofeatures a concrete footing/foundation retainment and an integral (unitary) drainage means. A rigid, environmentally non-degradable and free-standing footing/foundation concrete retainment form emulates an ordinary plank, but features a hollow core through each component thereof that communicates through a singular foraminous surface with the soil in which the form-drain is situate. Notwithstanding the importance of the mainline foraminous components, the transition and connecting pieces of the form-drain network are of particular importance in that these necessary components of the form drain system disclosed in '162 are an important cofeature of the instant invention. For this reason, U.S. Pat. No. 5,120,162 is hereby incorporated in this application, by reference.
As will be noted hereinafter, only one component of '162, a corner connector, is disclosed having diverse structure (i.e., not necessarily of the type and style of conduit exemplary of the invention proper). Another patent, U.S. Pat. No. 994,155, bears some resemblance to the above. However, '155 is noteworthy because it discloses an irrigation apparatus, that is, a subterranean or at least surface-situated, network of foraminous ducts or pipes that are connected to a vertically ascending pipe, which is connected thereafter to a water holding tank. Intuitively, this differs from '162 in that its function is diametrically the opposite and there is no disclosure or teaching for the use of this double sided, perforated irrigation duct as a concrete form. Most distinctive, however, is the operative feature of '155 wherein water or liquid fluid is introduced to the vertical conduit and allowed to gravity-flow into the foraminous ducting network and out the foramens thereof. Similar to '162 is U.S. Pat. No. 3,017,722, which discloses a hollow, single-sided foraminous stringer. It is used only in the outer peripheral portion of a concrete form and, in itself bears only a single bottom port for drainage to a header box and ultimately, to a sump. It is clearly the intention of the patentee of '722 to provide an exterior peripheral stringer which serves to partially drain a footing; its interior peripheral counterpart is removed and is simply not intended to function as the analogous interior peripheral structure of '162 and the instant invention.
A form and drain tile composite is disclosed in U.S. Pat. No. 3,613,323, issued on Oct. 19, 1971. Although disclosing a primary conduit having foramens at one side, this teaching is noteworthy only in that it lacks the very connective and transition pieces that are essential to the instant invention. Further, '323 deliberately teaches the covering of top-side ports, should the ports not be fitted with stakes for transfixing the main conduits to the ground. U.S. Pat. No. 3,613,323 is also silent as to whether the form-drain is adaptive to a gas scavaging and removal system. Finally, U.S. Pat. No. 4,185,429, issued on Jan. 29, 1980, discloses an apparatus for waterproofing a basement or similar structure. Although not intended as a footing per se, this patent discloses a drainage system which could be adapted for the use taught by the instant inventors, but for certain contradistinctions: the structure is meant to be positioned at an interior wall of a structure, above the footing; it has multiple holes on the upper surface thereof, but suggests no means for manifolding the holes in order to collect gaseous accretions; nor is there any suggestion made by the patentee that the drainage network be placed predominantly below the slab, adjacent to and interior of the footing as a single crossrun or a grid/network.
4. State of the Art
Currently, remediation of noxious gases consists in providing air flow around the basement slab (or crawl space) of a building so that heavier-than-air gases (e.g. methane, carbon monoxide dioxide, hydrocarbon fuels and/or radon) are dispersed outside the living space. Hereinafter, the inventors shall refer only to radon; however, it should be understood by the reader that any of the foregoing gases may also be considered as hazards of the type to be removed by the instant invention. The one notable distinction between radon and any of the other gases is that the hazardous component of the former is filterable, while the others may be scavenged only by the use of activated charcoal, captivating media, or the like. It is in the radioactive decay of radon, with the adherence of internally hazardous, radioactive daughter products to minute dust particles, including living tissue, that radon outgassing becomes a health concern. Thus, one sees the elegance of a system which removes the parent radon from a structure before it ever enters the living area and spawns its deadly daughter products. Contrary to good economization is the current practice of ventilating a living space, once the radon accumulates, because there is an energy loss factor in removing conditioned air.
Thus, the state-of-the-art does provide workable radon remediation systems, but at an enormous cost, comparatively speaking, in view of the concepts and apparatus offered by the instant inventors.