IMPROVEMENTS RELATING TO THE PROTECTION OF BUILDINGS

摘要

A system for use in protecting buildings from the ingress of subterranean gases by preventing a flow of gas from a gas-containing region to an adjacent region comprises a gas impermeable barrier (10) installed so as to separate the gas-containing region and the adjacent region and provide at least one void between them; a pump (23) communicates with the void for pumping gas into it to create a pressure differential between the void and the gas-containing region, and special valves (29) are provided in flow communication with the void for opening the void to the surrounding atmosphere if the void pressure generated by the pump (23) falls below a minimum value, the valves (29) being installed in such way that air currents in the atmosphere which create a pressure differential between respective open ends thereof ventilate the void when open to the atmosphere.