Inertization Method For Reducing The Risk Of Fire

• US 20080011492A1
• Filed: 11/23/2004
• Published: 01/17/2008
• Est. Priority Date: 12/29/2003
• Status: Active Grant

• Current Assignee: Amrona AG
• Original Assignee: Amrona AG
• Inventors: Wagner, Ernst-Werner
• Granted Patent: US 7,854,270 B2
• Time in Patent Office: Days
• US Class Current: 169/45
• CPC Class Codes: A62C 99/0009 Methods of extinguishing or preventing the spread of fire by cooling down or suffocating the flames

Abstract

In the event of a failure of a fire prevention or extinguishing system, an inertization method reduces the fire risk in an enclosed protected area, where the oxygen content in the area can be maintained on a control concentration that lies below an operating concentration for a certain time period, so that the emergency operation phase is sufficiently long to prevent the ignition and/or re-ignition of combustible materials therein. The control concentration is maintained for an emergency operation period by a redundant secondary source. Alternatively, the control concentration and the operating concentration, while forming a safety margin, can be lowered so far below the design concentration that in the event of a primary source failure, the growth curve of the oxygen content reaches a limit concentration determined for the area in a predefined period, which is sufficiently long to continue to prevent the ignition and/or re-ignition of the combustible materials.

Claims

1-10. -10. (canceled)

11. An inertization method for reducing the risk of fire in an enclosed protected area, in which the oxygen content in the protected area is maintained for a defined period at a control concentration (RK) below an operating concentration (BK) by feeding an oxygen-displacing gas from a primary source;

wherein in the event of a failure of the primary source, the control concentration (RK) is maintained by means of a secondary source for an emergency operating period when the operating concentration (BK) is equal to or substantially equal to a design concentration (AK) defined for the protected area, or wherein the control concentration (RK) and the operating concentration (BK), forming a failure safety margin (ASA), are lowered so far below the design concentration (AK) defined for the protected area that the growth curve of the oxygen content, reaches a limit concentration (GK) defined for the protected area only in a predefined time when the primary source fails.

12. An inertization method according to claim 11, wherein the failure safety margin (ASA) is determined by taking an air change rate applicable for the protected area, including an n₅₀ value for the protected area, and/or the pressure differential between the protected area and the surrounding area into consideration.

13. An inertization method according to claim 11, wherein the design concentration (AK) is lowered by a safety margin (S) to below the limit concentration (GK) defined for the protected area.

14. An inertization method according to claim 11, comprising

a detector for detecting a fire parameter, wherein the oxygen content in the protected area is lowered quickly to the control concentration upon detecting an incipient fire or a fire when the oxygen content was previously at a higher level.

15. An inertization method according to claim 11, wherein the control range is about ±

0.2% by volume oxygen content around the control concentration (RK).

16. An inertization method according to claim 11, wherein the oxygen content in the protected area is controlled with respect to the air change rate, including the n₅₀ value of the protected area, and/or the pressure differential between the protected area and the surrounding area.

17. An inertization method according to claim 11, wherein the extinguishing agent for maintaining the control concentration (RK) in the protected area is calculated with respect to the air change rate of the target area, including the n₅₀ value of the protected area, and/or the pressure differential between the target area and the surrounding area.

18. A device for implementing the method according to claim 17, wherein the primary source is at least a machine that produces oxygen-displacing gas, a cylinder array, a buffer volume or a deoxydation machine.