Systems and methods for venting gas in the event of an explosion in a space covered by a manhole cover

Abstract

A closure is adapted to limit damage from a gas explosion in an underground space. The closure includes a telescoping sleeve having a plurality of vents extending radially through the sleeve. The sleeve defines a manhole extending axially through the sleeve so a person can enter the underground space through the manhole. A manhole cover is moveable to a closed position in which the cover is supported on an upper end of the sleeve and covers the manhole. The sleeve can be received in an opening of a frame of a manhole installation so the sleeve is moveable by gas pressure to an extended position in which gas from the underground space can be vented through the sleeve to an aboveground space. If desired, the sleeve can be installed in an existing manhole installation to upgrade the installation to have an explosion mitigation capability without replacing the conventional manhole cover.

Dependencies are inferred from the claim text.