| 摘要 |
An electrically conductive confined space ventilation conduit formed of a substantially rigid non-metallic conductive material, such as plastic, and a related process for ventilating an enclosure accessed by a manhole or other port. In one embodiment, the conduit has a pair of outer cylindrical sections and a central section having a cross-sectional shape of a crescent or a segment of a circle where it passes through a port to provide a minimum of obstruction for men and equipment passing through the port. Intermediate sections of varying cross-section connect the central section to the cylindrical outer sections so that the outer sections are offset from the axis of the manhole. The central section is preferably configured to obstruct no more than about 10 percent of a standard manhole opening, while causing either no air flow rate reduction, or a reduction of no more than about 10 percent as compared to the flow rate through a cylindrical conduit similar to said outer sections. The conduit is preferably formed of a conductive or electrically dissipative polyethylene polymer material to allow static electricity to be conducted from the conduit to ground. In a preferred embodiment, a connecting device for connecting the conduit to electrical ground is connected to the conduit. A grounding circuit kit and method of grounding the conduit is also disclosed. |
