Needs Assessment

Automatic fire suppression systems are designed and installed in accordance with National Fire Protection Association (NFPA) 13.  Fire suppression systems are a key element in building construction to protect life and property against small fires.  When designed properly, a fire suppression system is one of the best first lines of defense to control a fire before the fire department can arrive at a building.  However, if damage occurs to the piping or the main riser or pumps, either through malicious acts or wear and tear, this renders the fire suppression system inoperable placing the building, its contents, and the people in the building in greater danger.  This project involves designing a bi-direction flow control valve that will close off part of the suppression system if there is an increase in pressure above the normal levels within the pipe and providing two riser systems to supply water.  This will allow the suppression system to continue to operate and control the fire. 

Project Scope

Problem Statement

Once the piping in a fire suppression system or the riser has been disabled or broken in any part of the system, the entire system is rendered inoperable.  The purpose of a fire suppression system is to control the fire until the fire department arrives.  This gives occupants a greater chance of survival by allowing them additional time to escape from a building.  Currently, there are no bi-directional flow control valves on the market.  The ones that do exist only control the flow in one direction.

Justification/Background

One of the lessons learned from the terrorist attack on the Pentagon on September 11, 2001, is that a fire suppression system can be taken out of operation with a single malicious act.  At present time, there is no flow control valve available on the market to prevent this from happening.  The design of a bi-directional flow control valve will be designed for the client, the Air Force Research Laboratory (AFRL) at Tyndall Air Force Base (AFB).  This product will be able to be used in all types of occupancies where a fire suppression system is installed.  In particular, this product will help provide enhanced security for our nations high priority buildings by ensuring the fire suppression system in these building will not be able to be disabled maliciously.  In addition to using the bi-directional flow control valve, the fire suppression system will also be designed to use a two riser system to supply water.

Objective

Design and fabricate a bi-directional flow control valve that will close automatically, by sensing a pressure drop, if either side of the piping is broken.  The valve will sense a pressure drop when threshold water flow is exceeded in either direction.  The valve will not leak, but will incorporate a small leakage flow when closed in order for the valve to restart once the piping is repaired.  This leakage flow will be contained within the valve.  Common tools will be able to be used to install valve onto standard National Pipe Thread (NPT) piping.  A bi-directional valve system would be able to isolate a broken pipe.  This will stop the problem of water continuing to flow after a break, and more importantly, allow the system to still operate after a pipe is broken.  The valve should accept a 1.5 inch NPT pipe and allow initial threshold flow values of 60, 70, 80, 90, and 100 gallons per minute.

Methodology

The project begins with researching valves and related material to get as much background information on the subject as possible.  Once sufficient information is gathered, the group will begin designing a bi-directional flow control valve.  This part of the process will take approximately 30 to 40% of the group’s time.  Computational Fluid Dynamic (CFD) software will be used to analyze and model the valve operation before fabrication begins to determine pressure drop and flow actuation.  Once the valve has been developed, analyzed, and modeled, fabrication will begin, keeping in mind all design specifications.  Once the valve has been fabricated, it will be tested ensure it meets all the criteria set forth by the client.

Expected Results

The overall expectation of this project is to design and prototype a bi-directional flow control valve housing.  The prototype will be able to allow for multiple internal components (springs and poppets) which will accept five different flow rates.  Using test piping with a pump, flow meter, and appropriate valves, the flow properties and the functionality of the set up will be demonstrated and tested.  Our results and trials will be fully displayed and explained verbally as well as visually.  Included in the final deliverable among other things will be test results, costs, trial and final designs.

Constraints

            AFRL at Tyndall AFB has provided extensive information on the desired functionality of the end product, along with the pledge to support this project financially or in any other way necessary.  Pumps, flow meters, pipes, valves, and any other materials may be purchased directly or through AFRL with the understanding that these items will be returned at the completion of the project.  Locating the necessary test equipment such as the pump, dynamic flow meter, and valves are constraints on testing the equipment if they are not provided.  These are the higher dollar items which would increase the current budget needs.