Abstract: A skirt supports an access hatch at a predetermined height as the hatch is formed in concrete. The skirt can be permanently embedded in the concrete. The skirt includes a rigid frame defining a central opening, the frame has an inner surface and an outer surface opposite the inner surface. The frame defines a height between the upper edge and the lower edge. The height of the skirt is predetermined such that the combined height of the skirt and the hatch approximate the desired thickness of the concrete slab. The skirt may include an alignment tab extending from the frame at an angle with respect to the frame, with the alignment tab extending above the upper edge of the frame to guide the hatch into alignment with the upper edge of the frame as the hatch is moved into position on the skirt.

Abstract: A controlled pressure release vault panel assembly is capable of functioning as a second, or auxiliary, relief port to allow the escape of fluid from the vault in the event of pressure build-up inside the vault or in an explosion event. The vault panel assembly may define an opening that includes a manhole cover assembly. The manhole cover assembly may also be vented, and may function as a primary vent. The vault panel assembly may include a retention assembly extending from the vault panel underneath a portion of the vault, enabling a limited range of motion of the vault panel for the escape of fluid and allowing the reseating of the vault pane on the vault once the pressure inside the vault approaches ambient pressures.

Abstract: A removable hydrant nozzle with a locking arrangement for securing the nozzle in a nozzle opening. The locking arrangement includes an axially movable slide configured to selectively engage a portion of the hydrant adjacent the nozzle opening, such as a lug mouth in a quarter-turn fitting. The slide is mounted to a slide housing and is spring loaded. In use, the slide automatically retracts as the nozzle is inserted into the nozzle opening and automatically extends into locking engagement with the mouth when the nozzle becomes fully seated. Once engaged, the slide prevents removal of the nozzle until manually disengaged. The slide may be movably mounted on a pair of shoulder bolts. The slide may include a paddle that extends outwardly where it is accessible to the operator. The nozzle may include a handle and a seal fitted onto the inner axial end of the nozzle.

Abstract: A removable hydrant nozzle with a locking arrangement for securing the nozzle in a nozzle opening. The locking arrangement includes an axially movable slide configured to selectively engage a portion of the hydrant adjacent the nozzle opening, such as a lug mouth in a quarter-turn fitting. The slide is mounted to a slide housing and is spring loaded. In use, the slide automatically retracts as the nozzle is inserted into the nozzle opening and automatically extends into locking engagement with the mouth when the nozzle becomes fully seated. Once engaged, the slide prevents removal of the nozzle until manually disengaged. The slide may be movably mounted on a pair of shoulder bolts. The slide may include a paddle that extends outwardly where it is accessible to the operator. The nozzle may include a handle and a seal fitted onto the inner axial end of the nozzle.

Abstract: A manhole cover assembly configured to behave as a relief valve in an explosion event, opening so that fluid, such as air or explosive gas, may vent from an underground area. The manhole cover assembly may include a manhole cover and a frame, and may be configured to limit movement of the manhole cover with respect to the frame in response to increased pressure on the manhole cover. In one embodiment, the manhole cover may include legs that are configured to enable a range of movement of a portion of the cover such that the cover can be unseated at an angle with respect to the frame to allow fluids to escape from the underground area.

Abstract: A manhole frame assembly according to one embodiment of the present invention generally includes an upper frame and a lower frame, and is adapted to support a manhole cover. The upper frame may be allowed to float with respect to the lower frame, enabling the upper frame to move during installation, or as the surrounding structure moves, or both. By being capable of movement, the upper frame may potentially prevent uneven transitions between the manhole frame assembly and the surface of the surrounding structure.

Abstract: A manhole cover assembly configured to behave as a relief valve in an explosion event, opening so that fluid, such as air or explosive gas, may vent from an underground area. The manhole cover assembly may include a manhole cover and a frame, and may be configured to limit movement of the manhole cover with respect to the frame in response to increased pressure on the manhole cover. In one embodiment, the manhole cover may include legs having angled surfaces adapted to substantially center or guide the manhole cover in the frame while the manhole cover displaces to release pressure. In another embodiment, one or more legs slidable within the manhole cover to enable configuring the manhole cover between a restraint mode and a removal mode.

Abstract: A manhole cover includes a cover panel formed from a first material, which may be a generally lightweight material, and an insert formed within a cutout in the first material. The insert may be formed from a higher strength material and may include one or more openings for receiving conventional cover removal tools. In one embodiment, the manhole cover includes a cover panel having a peripheral edge and defining a diameter, and further defining an opening or cutout that is spaced from the peripheral edge. The insert is disposed in the opening. The insert may include an upper surface and a lower surface opposite the upper surface, the insert defining first and second openings in the upper surface, with the first opening shaped to receive a first removal tool and the second opening shaped to receive a second removal tool.

Abstract: A manhole cover assembly configured to behave as a relief valve in an explosion event, opening so that fluid, such as air or explosive gas, may vent from an underground area. The manhole cover assembly may include a manhole cover and a frame, and may be configured to limit movement of the manhole cover with respect to the frame in response to increased pressure on the manhole cover. In one embodiment, the manhole cover may include legs having angled surfaces adapted to substantially center or guide the manhole cover in the frame while the manhole cover displaces to release pressure. In another embodiment, one or more legs may be at least one of pivotable with respect to the manhole cover and slidable within the manhole cover to enable configuring the manhole cover between a restraint mode and a removal mode.