Fire Protection System For Arch Supported Membrane Structures

Abstract

A fire protection system for an arch supported membrane structure comprising a plurality of hollow arches containing a cooling medium. The arches can be made water tight so that they can serve as water mains to supply a sprinkler or deluge system above or below the roof membrane.

Description

BACKGROUND OF INVENTION

Hollow arches can be used to support membrane structures such as described in my U.S. Pat. Nos. 3,388,711 (June 18, 1968), 3,465,764 (Sept. 9, 1969), and my application Ser. No. 93,293 filed Nov. 27, 1970, now abandoned.

These arches can have slip joints that can be made water tight, or sufficiently so, that they can serve as water mains to supply a sprinkler or deluge system above and below the roof membranes.

Heat sensing devices attached or located in the structure can operate valves to fill the arches with a liquid, to keep arches cool and prevent collapse.

Sprinklers and other deluge systems can be operatively attached to the arch mains to spray the roof and/or the structure interior.

The arch supply mains can be directly connected to a reliable liquid source and kept under pressure all the time or connected through a manual or automatic valve to turn on or off the liquid supply to the sprinkler and/or deluge systems.

When these structures are used for public gatherings such as expositions, meetings, sports and the like, or when they are used to shelter expensive equipment such as aircraft, war supplies, or to shelter inflammable materials, there is great concern about a method to control such a conflagration especially to prevent collapse of the structure. By using hollow arch members such as described in my patent application Ser. No. 317,509 filed Dec. 22, 1972, the arches not only are kept cool by water, or another liquid used to reduce the fire, but they also can serve as fire mains to which sprinklers, deluge nozzles or branch lines can be attached.

SUMMARY OF INVENTION

The principal object of this invention is to provide a fire protection system for Arch Supported Membrane Structures to make them safe for public occupancy and to provide a means for cooling the arches to prevent collapse of the structure in a conflagration.

Another object of the invention is to use the arches as water supply mains to a sprinkler and/or deluge system and at the same time keep the arches cool to prevent their collapse in a conflagration.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a typical arch supported membrane structure with arches used to supply the roof deluge system.

FIG. 2 is a cut-away partial view of the above structure showing sprinklers attached to the arches and to branch lines from the arches which may be necessary on large structures.

FIG. 3 illustrates a typical hollow arch cross-section with a membrane attachment.

FIG. 4 illustrates a water main connection to an arch at the base through a control valve that automatically opens to charge the fire protection system. This can be a manually operated valve if desired.

FIG. 5 is a schematic control circuit to operate the automatic valve by heat sensors.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 illustrates a typical arch supported membrane structure with inclined arches 1 and an intermediate arch support 2. All of the arches can be hollow to supply a fire extinguishing fluid such as water and, are attached by 3 to, and supported by, a common base. The flexible membrane 4 is attached to and extends between the arches 1 and 2 and if the structure is enclosed a membrane 5 extends from the exterior arch 1 to the base. The hollow arches are connected to a fluid supply directly or through a valve 6 which is between the arch 1 or 2 and the main supply line 7.

In FIG. 2, two modules of a vertical arch supported structure are illustrated showing sprinklers 8 or deluge nozzles directly attached to the hollow arch supply mains 9 that are in turn connected directly to a supply source 10 or through a valve 11 to the supply main 12. Spray nozzles 13 can be located above the roof membrane as well as below it 8.

In FIG. 3, typical square or hollow cross-sections of arches 14 are illustrated to show the membrane attachment and the spray nozzles 13 directly attached to the arch for covered area when the arches are close enough together. If the arches are too far apart to get effective coverage with the spray devices, branch lines 15 may be connected to the arch mains.

The spray devices can be automatic in operation with temperature actuation when the system is pressurized from the supply system.

In FIG. 4 the arch main is directly connected 16 to a supply main, indirectly connected through a manually operated valve 17 or indirectly connected through an automatic valve 18. The latter system is usually used where there is danger of freezing and the arch mains remain unfilled or not pressurized by the extinguishing fluid until a heat sensor 19 reacts to a temperature rise, see FIG. 1.

In FIG. 5, a schematic electrical control circuit that is actuated by such a heat sensor 19 is shown. In a simple circuit, the heat sensor can close a bi-metal circuit which energizes a relay and closes a circuit that actuates a solenoid valve 18 on the supply line. Where such valves are used, the system is commonly called a "dry" system. If the contents under the spray nozzles would be badly damaged due to a failure in which water leakage occurred, such as a library, this system is frequently used.

The spray nozzles 13, FIG. 1, 2, & 3, above he membrane can be pressure operated so that they will automatically release a spray when a high pressure is reached. When the spray system below the roof membrane is operated by a temperature rise, the roof system can be conveniently used to wash off the roof and cleanse it of dirt or snow.

When the arches remain pressurized, like a typical sprinkler system, a non-freezing fluid can be used (if required), the arch joints are made leakproof and the arches are not only kept cool in case of a fire but the added weight of the fluid in the arches adds to the mass inertia of the arches. In such cases, however, it would be best to add an air or steam bleed valve 21 (FIG. 1) and (FIG. 2) near the crown of the arch to make sure the arch is full of liquid. If only fluid filled arches are used, without a sprinkler system, a water circulating system can be used by installing a water outlet valve 22 (FIG. 1) on the opposite end of the arch from the supply end--along with a steam and air bleeding valve near the crown if desired.

Claims

I claim:

1. A fire protection system for an arch supported membrane structure comprised of a multiplicity of arches with curved bights mounted on a base or the ground; a flexible roof membrane operatively attached to said arches and tensioned between them to form a roof of compound curvature; at least one of said arches having a hollow cavity containing a cooling medium.

2. Same as claim 1, except that said arch with a hollow cavity has a relief valve connected to its hollow cavity to vent off air, vapor or/and liquid to keep the arch cool.

3. Same as claim 1, except that said hollow cavity in said arch serves as a conduit between a fire quenching liquid supply system and a fire quenching liquid distribution system.

4. Same as claim 3, except that said fire quenching liquid distribution system includes a liquid spray device.

5. Same as claim 4, except that said liquid spray device is automatically operated by a rise in temperature.

6. Same as claim 4, except that said fire quenching distribution system includes at least one branch conduit operatively attached to said hollow arch conduit.

7. Same as claim 3, except that said hollow arch conduit is operatively connected to a roof membrane wetting system.

8. Same as claim 7 except that said roof (spray nozzles are) wetting system is controlled by a pressure sensitive device.

9. Same as claim 3, except that said hollow arch serves as a dry conduit between a control valve that is operatively connected to a pressurized fire quenching supply system and said fire quenching distribution system.

10. Same as claim 9, except that said control valve is operated by a heat sensing device.

11. Same as claim 9, except that the hollow arch is segmented with the joints sufficiently tight to prevent excess leakage.