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.

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.

 

Senior Design Project Definition

1. Project Title: Design and Prototyping of a Bi-Directional Flow Control Valve

2. Submitting Organization and Company: Fire Research Group, Air Force Research
Laboratory, Tyndall AFB, FL

3. Liaison Engineer Information:
Name: Kris Cozart
Title: Engineer
Address: 104 Research Road, Building 9708; Tyndall AFB, FL 32404
Phone: (850) 283-9787
FAX: (850) 283-9797
e-mail: kris.cozart.ctr@tyndall.af.mil

4. Project Background: Current fire codes (NFPA 13) are only designed to protect
against small fires. A bigger problem exists in that breaking even one pipe can make
an entire system fail. Designing a fault tolerant system would require that the
sprinkler manifold be supplied by at least two pumps. In addition, bi-directional flow
control valves can be utilized throughout the system to isolate broken sections of pipe
and retain water flow and pressure to the rest of the intact system.
The use of an Excess Flow Control Valve or Flow Fuse is common in industry. Flow
Fuses should be installed in Pneumatic and hydraulic systems for the prevention of
loss of life, injury, or flight hardware damage due to expulsion of high pressure
gaseous or liquid media. Their main function is to stop the full flow of fluid contents
automatically should a line rupture and reset automatically when repairs are made.
When a line breaks the increased velocity of flow creates a pressure drop across the
valve which overcomes the preset maximum flow setting of the valve and the valve
closes. After the excess flow control valve is triggered it will remain closed until the
flow line is repaired and the pressure is balanced automatically across the valve.

5. Most Important Project Objectives: Design and fabricate a prototype bi-directional
flow control valve. Model each valve configuration using CFD, to determine
pressure drop and actuation flow. The valve will close when threshold water flow is
exceeded in either direction. The valve will also incorporate a small leakage flow
when closed to facilitate re-activation when the sprinkler system is repaired. No
external water leakage shall be allowed. Common tools such as pipe wrenches or
crescent wrenches should be all that are required to install the Flow Control Valve
onto standard NPT pipe.

6. Design/Result Expectations: A single Bi-Di Flow Control Valve housing shall be
designed and fabricated that shall accept different internal components (springs and
poppets) to allow for the setup of 5 different threshold flow rates. A test fixture shall
be assembled with a pump, flow meter, and appropriate valving to test / demonstrate
the flow properties of the Flow Control Valve.

7. Prototype Expectations: A good size for the first prototype should be setup with 1.5”
Female NPT connections; to accept 1.5” NPT pipe. Initial threshold flow values
should be 60, 70, 80, 90, and 100gpm.

8. Estimated Costs of Hardware, or Items Provided by Sponsor. Brass material - $200.
Stainless Steel material - $200. Stainless springs - $100. UHMW - $50. Pump -
$1500. Flow meter - $500. Valves - $500. Piping - $200.

9. New Technology Requirements: The functional nature of the way these valves work
is nothing new. The bi-directional nature of this valve is new.

10. Special Information: A lot of valuable design information can be obtained by
researching existing Excess Flow Control Valves, Flow Fuses, and Excess Flow Check
Valves.