IEEE Paper p1


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                                                                The following paper will be published in the proceedings of the 
                                                    2012 IEEE International Conference on Technologies for Homeland Security
                                                                      13-15 November 2012, Westin Hotel, Waltham MA
                                                                                                http://ieee-hst.org


                                                                  Re-supplying Water after an Earthquake

                                            Relay Pumping Control via a Digital Network for First Responders

                                            
                             Steve Shoap, Life Member IEEE
                                              IFFC LLC
                               Wakefield Massachusetts, USA
                                  steve.shoap@alum.mit.edu

Abstract - Earthquakes often break the water mains in affected localities. The broken mains remove an important source of water for firefighters and the public. Firefighters sometimes use a series of pumper trucks to move water long distances through hoses. In a system with manual control,
if an operator leaves the pump, the relay will probably fail. Because it is operationally challenging, relay pumping is not used as often as it might be. A solution can be found in a wire based Ethernet network controlling the pumps.
Such a system using the proposed network will work even if the operator leaves the site. This digitally controlled relay pumping system can be used to supply water to first responders, and civilians. It can be used as an infrastructure restoration strategy. It is also useful in delivering water to fight fires in water deficient areas.


INTRODUCTION

Relay pumping can supply water over long distances. It uses multiple pumps to overcome the friction losses in a long hose lay. It can supply water for fighting wildfires and also supply emergency water to populations after an earthquake or other disaster destroys water mains. It can even supply cooling water for atomic power plant operations when situations like the recent Fukushima Powerplant Disaster occur.

Existing relay pumping techniques requires continuous manual control of pressures and flows at each booster pump. An operator must be dedicated to each pump and must be able to communicate with all of the other operators on the relay to ensure that pump pressure and flow changes are coordinated.

In many situations, crews on a relay may be forced to remain at a location that might become dangerous. Terrain may inhibit radio communications. If only one crew leaves a pump, uncontrolled pressures can damage the pumps and hoses, and the relay may fail.

Adding a digital data network to a relay system changes this scenario dramatically. The data network runs on a wire pair embedded in the hose, and it enables a single operator to monitor and control all of the pumps. The number of personnel dedicated to operating the relay is significantly reduced.  Problems caused by radio communication failures are eliminated, and more personnel are available to actually
deal with the disaster situation. Safety is dramatically improved. In fact, if radio communication fails, the data network can provide an alternate first responder communication path between all pump vehicles.

 






                        Michael Laskaris-PE, Director of Engineering
                    Fire Suppression Division, Hale Products
                                 Conshohocken PA, USA
                                       mlengr@aol.com

Figure 1 shows a proposed relay pumping system where 4WD vehicles have a diesel pump and a large hose reel in their beds. The vehicles deploy the hose while driving from the water source to the final destination for the water.
 
Figure 1  Relay Pumping Example


DIGITAL NETWORK VS. RADIO NETWORKS

A digital, Ethernet-like network is similar to a group of pump operators on a common radio frequency. In a traditional relay pumping system, the pump operators use radios to coordinate pump settings. A digital network communicating over a wire pair in the hoses has advantages over a radio network.

Channel Access

In many radio networks, a firefighter waits until the radio channel is not being used and then does a Push to Talk (PTT), and starts talking. If another firefighter does a PTT at the same time, their transmissions will interfere with each other, and valuable time can be wasted.
In the proposed Digital Network, a pump circuit board waits until the wire pair is not being used, and then starts to send a digital message. If another circuit board sends a message at the same time, they both immediately stop sending. Each board waits a random amount of time, and if the wire pair is not being used, it tries to resend the message. If no other circuit board tries to use the wire pair, the message will be fully transmitted. This happens very quickly. In a 10 km relay pumping system with 1 km between pumps, the message delay from the beginning to the end of the system would be less than 1/10 second.

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