A fire water network can be defined as a set of links interconnected through nodes. In a water distribution network system, the pipes are connected to form a complex loop configuration which is created by using nodes and pipe links. Pipes are links that convey water from one point in the network to another. The node is a junction where two or more pipes combine or a point where water consumption is allocated and defined as demand. Function of these elements (links and nodes) is to lead water from the network source, which is a water reservoir, to the extremes points of the network, called hydrants.
The NFPA, OISD and TAC standards requires that the hydraulic design of the pipe distribution network meet the required flow and pressure for a hydrant or a sprinkler system. The network analysis is done during the design stages of the system and before envisaging any alteration/ modifications of the pipe network. There are many accident case histories wherein the fire could not be put under control due to lack of the fire water supply because of failure of pipelines in the network. In addition, factors like pipeline corrosion and ageing of the water pipelines add to the cause of pressure loss and hence it is necessary to have robust and efficient fire water network.
Objectives
The need for the fire water network analysis is to determine the water flow in each line and pressure in each node as per the standards.
General procedures of the network analysis
The distributing network is either designed new or recommend an improvement or rehabilitation to the existing network system. In this case, the network systems are already designed and the system is to be analyse at different operating conditions ( i.e. at different demands ) in order to determine the capability of the networks to deliver the required pressures and flows.
The general procedures of analysing any pipe networks are:
- The layout of the pipe network should be determined.
- The characteristics of all the network components should be determined from the source to the area to be protected
- The two basic hydraulic equations are applied: Continuity Equation and Energy Equation
The Need for Software for Hydraulic Analysis Network:
In a simple hydraulic system consisting of one pipe or combination of pipes in which flow directions are all known unambiguously. In more complex systems, pipes might be in combined interconnected loops in ways that makes it difficult to determine even the direction of flow in any given pipe.
In such a system, where the pipe network is complex, the solution is quite complicated because it involves simultaneous consideration of continuity equation, energy conservation and head-loss function. Also, the unknown parameters are more and manual calculations becomes cumbersome, the sheer number of equations that needed to be satisfied to determine the complete flow condition is daunting. The conditions in such a system are usually solved with specialized computer program designed specifically to meet the purpose which makes the comparison of various scenarios are easy.
Results
The result shows how simulation of steady state FW Network could be used in finding a method of bringing the pressure surge down to an acceptable level.
