Abstract: An apparatus for controlling a level of gas in a closed environment from a gas supply having a gas sensor for detecting the level of gas in the closed environment. The apparatus has a valve in communication with the gas supply which is automatically opened without human interaction, monitoring and adjustment to release gas from the gas supply into the environment when the level of gas in the environment goes below a first predetermined level and which is automatically closed without human interaction, monitoring and adjustment to stop gas from being released from the gas supply into the environment when the level of gas in the environment goes above a second predetermined level. A method for controlling a level of gas in a closed environment from a gas supply. A refuge chamber.

Abstract: An apparatus for controlling a level of oxygen in a closed environment from an oxygen supply having an oxygen sensor for detecting the level of oxygen in the closed environment. The apparatus has a plurality of relays in communication with the sensor. The apparatus has a valve in communication with the relays and the oxygen supply which is automatically opened with the relays without human interaction, monitoring and adjustment to release oxygen from the oxygen supply into the environment when the level of oxygen in the environment goes below a first predetermined level and which is automatically closed with the relays without human interaction, monitoring and adjustment to stop oxygen from being released from the oxygen supply into the environment when the level of oxygen in the environment goes above a second predetermined level. A method for controlling a level of oxygen in a closed environment from an oxygen supply. A refuge chamber.

Abstract: An apparatus for controlling a level of oxygen in a closed environment from an oxygen supply having an oxygen sensor for detecting the level of oxygen in the closed environment. The apparatus has a plurality of relays in communication with the sensor. The apparatus has a valve in communication with the relays and the oxygen supply which is automatically opened with the relays without human interaction, monitoring and adjustment to release oxygen from the oxygen supply into the environment when the level of oxygen in the environment goes below a first predetermined level and which is automatically closed with the relays without human interaction, monitoring and adjustment to stop oxygen from being released from the oxygen supply into the environment when the level of oxygen in the environment goes above a second predetermined level. A method for controlling a level of oxygen in a closed environment from an oxygen supply. A refuge chamber.

Abstract: An apparatus for controlling a level of oxygen in a closed environment from an oxygen supply having an oxygen sensor for detecting the level of oxygen in the closed environment. The apparatus has a plurality of relays in communication with the sensor. The apparatus has a valve in communication with the relays and the oxygen supply which is automatically opened with the relays without human interaction, monitoring and adjustment to release oxygen from the oxygen supply into the environment when the level of oxygen in the environment goes below a first predetermined level and which is automatically closed with the relays without human interaction, monitoring and adjustment to stop oxygen from being released from the oxygen supply into the environment when the level of oxygen in the environment goes above a second predetermined level. A method for controlling a level of oxygen in a closed environment from an oxygen supply. A refuge chamber.

Abstract: An apparatus for controlling a level of oxygen in a closed environment from an oxygen supply having an oxygen sensor for detecting the level of oxygen in the closed environment. The apparatus has a plurality of relays in communication with the sensor. The apparatus has a valve in communication with the relays and the oxygen supply which is automatically opened with the relays without human interaction, monitoring and adjustment to release oxygen from the oxygen supply into the environment when the level of oxygen in the environment goes below a first predetermined level and which is automatically closed with the relays without human interaction, monitoring and adjustment to stop oxygen from being released from the oxygen supply into the environment when the level of oxygen in the environment goes above a second predetermined level. A method for controlling a level of oxygen in a closed environment from an oxygen supply. A refuge chamber.