Fast acting, pneumatically and centrally controlled, fire extinguisher /firex/ system is effective in freezing climates. The easy-to-operate system provides a fail-dry function which is activated by an electrical power failure

Branum, J. C.

English

NASA Technical Reports Server

December 1967	 Brief 67-10622 
NASA TECH BRIEF 
NASA Tech Briefs are issued to summarize specific innovations derived from the U.S. space program, 
to encourage their commercial application. Copies are available to the public at 15 cents each 
from the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
Fire Extinguisher Control System Provides Reliable Cold Weather Operation 
4-way Fail-Wet 
Fail-Dry Handvalve
To Other 
Firex Systems To Other 
Firex 
Systems 
-*•• To Other I 3-Way 3/4	 3/4" Prese 150 psi	 Firex Pneu. Valve N.C. Control GN2	 I	 -- Systems 
Firex	 I Valve 
Control	 I 
Manif.	 L
N.C.C/4" Control Valve 
Com	 (Fail- Dry)
Firex Header	 I Shutoff Valve 
The problem: 
To develop a 'fast-acting fire extinguisher system, 
effective in freezing climates and capable of operation 
after electrical power loss. Previous systems are de-
pendent upon controls which might be frozen at sub-
freezing temperatures. Pneumatic fire extinguisher 
(firex) controls appear to be a logical solution to the 
cold climate problems, but they are extremely slow 
when controlled by one "fail-wet" valve. The addition 
of multiple "fail-wet" valves to speed the response 
increases the time necessary to put the system in "fail-
wet" operation.
The solution:	 - 
A fast acting, pneumatically and centrally con-
trolled, fire extinguisher (firex) system has been de-
signed for geographical areas subject to freezing. The 
easy-to-operate system provides a "fail-dry" function 
which is activated by an electrical power failure. In-
stead of the multiple "fail-wet" valves previously sug-
gested, one hand-operated, four-way "fail-wet" valve 
is used.	 - 
How it's done: 
The firex system consists basically of one 4-way 
"fail-wet" valve, one 3-way pneumatic valve, an ordi-
nary firex solenoid control valve, 150 psi gaseous 
conunueU overieai 
This document was prepared under the sponsorship of the National 	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States 	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States 	 will be free from privately owned rights. 
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nitrogen manifolds, and a solenoid preset valve for 
each shutoff valve on the firex headers. 
The system is normally in the electrically operated 
"fail-dry" mode. Gaseous nitrogen flows through the 
pneumatic valve and through the normally open con-
trol valve to the shutoff valve on the firex header. 
The gas pressure holds the shutoff vahe in the closed 
position, preventing fluid flow. To turn on the fire 
extinguisher, the control valve is electrically activated, 
automatically, or by a hand switch. This closes the 
normally open side of the valve, shutting off the gas 
flow, and opens the normally closed side, venting the 
closing pressure of the shutoff valve. Thus the shutoff 
valve is open, allowing the firex fluid to flow. 
When the "fail-wet" mode is required, the preset 
valve is activated, but not the control valve. The 4-way 
valve is opened, allowing the gaseous nitrogen to pass 
through the pneumatic valve where it is rerouted 
through the preset valve. The preset valve is acti-
vated by an electrical failure, as the valve is opened 
and vent is closed electrically. 
Thus, if the electrical power fails, the open side 
of the preset valve closes, stopping the nitrogen gas
flow to the shutoff valve. The vent side opens, venting 
the closing pressure of the shutoff .valve, and allow-
ing the fire extinguisher fluid to flow. 
Notes: 
1. This may be of interest to manufacturers and users 
of fire protection systems, and gas and pipeline 
control systems. 
2. Inquiries concerning this invention may be directed 
to:
Technology Utilization Officer 
Marshall Space Flight Center 
Huntsville, Alabama 35812 
Reference: 867-10622 
Patent status: 
Inquiries about obtaining rights for the commercial 
use of this invention may be made to NASA, Code 
GP, Washington, D.C. 20546.
Source: J. C. Branum
of North American Aviation, Inc. 
under contract to
Marshall Space Flight Center

(MFS-13031) 
Brief 67-10622	 .	 Category 05


Fire Extinguisher Control System Provides Reliable Cold Weather Operation

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