A method configured to be executed by a system controller. The method includes obtaining a first metric from a first sensor installed in a first underground vault of a system of interconnected underground vaults, and obtaining a second metric from a second sensor installed in a second underground vault of the system. The first and second underground vaults are in fluid communication with one another via one or more connections. The method also includes locating a gas source based at least in part on one or both of the first and second metrics, and performing an action. The action includes identifying the gas source to one or more users and/or altering a rate of atmospheric turnover in at least a portion of the system.

A method that includes obtaining a sensor reading from a sensor installed inside an underground vault and determining whether the sensor reading is indicative of an alarm state. When the sensor reading is indicative of the alarm state, the method obtains at least one new reading and determines whether the sensor reading includes sensor drift based at least in part on the at least one new reading. The alarm state is established when the sensor reading is determined not to include sensor drift. The sensor drift is removed when the sensor reading is determined to include sensor drift.

A system including an active ventilation device and a system controller. The active ventilation device is installed in an underground vault and generates an exhaust flow from the vault having an exhaust rate. The system controller is configured to determine that a reading received from a selected gas sensor indicates that a manhole event is occurring, and instruct the active ventilation device to change the exhaust rate when the reading indicates that the manhole event is occurring. The system controller is configured to receive at least one sensor reading after the exhaust rate has been changed, determine whether the selected gas sensor is exhibiting drift based at least in part on the sensor reading(s), and perform an action when the system controller determines the selected gas sensor is not exhibiting drift. The action includes notifying a user and/or instructing the active ventilation device to alter the exhaust rate.

A system including an active ventilation device and a system controller. The active ventilation device is installed in an underground vault and generates an exhaust flow from the vault having an exhaust rate. The system controller is configured to determine that a reading received from a selected gas sensor indicates that a manhole event is occurring, and instruct the active ventilation device to change the exhaust rate when the reading indicates that the manhole event is occurring. The system controller is configured to receive at least one sensor reading after the exhaust rate has been changed, determine whether the selected gas sensor is exhibiting drift based at least in part on the sensor reading(s), and perform an action when the system controller determines the selected gas sensor is not exhibiting drift. The action includes notifying a user and/or instructing the active ventilation device to alter the exhaust rate.

Embodiments of a manhole cover safety apparatus having a circular base defining a central opening and a flange that extends outwardly from the circular base. An expandable cover is in rotatable engagement with the flange through a plurality of frame members that are secured to a cover portion which is operable between a deployed position wherein the cover portion covers at least a portion of the circular opening to provide a visual and physical warning of an uncovered manhole and a retracted position wherein the cover portion does not cover the central opening.

A manhole cover system (10) for sealing manholes to minimize water infiltration includes a manhole cover (12) re-movably inserted into a manhole cover frame (14) having a compressible gasket (28) attached thereto. Manhole cover (12) includes a base (16) and a peripheral rim (18). Peripheral rim (18) includes a cover outer peripheral surface (20) and a horizontal cover seat (22). Manhole cover frame (14) includes a frame cover restraint wall (24) and a frame seat (26). During assembly, peripheral rim (18) is removably seated on frame seat (26) of manhole cover frame (14). Compressible gasket (28) forms a seal within a vertical clearance space (32) between cover outer peripheral surface (20) and frame cover restraint wall (24).

A fastener for attaching an identification placard having a post to a lid for a utility vault from a single side of the lid, the fastener includes a body portion for positioning within a hole in the lid, the fastener having tabs for retaining the fastener to the lid and lobes for preventing over insertion of the fastener into the hole in the lid and a bore extending through or partially through the body portion for receipt of and friction retention and/or mechanical interlocking of the post of the identification placard.

A manhole assembly including a base, riser, and cap. The base having an upper surface forming a bench, a bottom surface, and a radially outward surface with penetrations there through; and a radial spigot in the radially outward upper edge of the base. The base having a corrosive-resistant layer covering the channels, bench, and radial spigot. Also disclosed is a riser comprised of a corrosive-resistant polymer pipe having a radially outward surface, an inner surface and a bottom surface in contact with, supported by, and sealed to the radial spigot. The cap having a radial spigot, and access hole; the radial spigot in the radially outward bottom edge of the cap resting upon and sealed to an upper edge of the riser. The radially outward surface of the cap and base are aligned with the radially outward surface of the riser.

A prefabricated former for an underground pump station comprises: a floor former; a plurality of vertical support elements; a side wall secured to and surrounding the plurality of vertical support elements, the side wall having an inner layer and an outer layer defining a cavity therebetween, and an opening at an upper end of the side wall in communication with the cavity for receiving concrete, the side wall extending both above and below the floor former for defining a space above the floor former and a space below the floor former, and an opening being provided between the cavity and the space below the floor former enabling concrete to flow through the cavity and into the space below the floor former; when set, the concrete forming a unitary wall and base.

A safety railing system for an underground utility enclosure includes a utility hatch frame for the underground utility enclosure or a utility hatch cover for the utility hatch frame, and a folding safety railing. The folding safety railing includes a first panel pivotally connected to the utility hatch frame or the utility hatch cover, and a second panel pivotally connected to the first panel. The folding safety railing unfolds so the first and the second panels stand vertically along one or more edges of the utility hatch frame.