Pressure-flow relationships for distribution system connections

The suggested practice of using single point test data to construct a "stra ight line" (i.e., hydraulically scaled) water supply plot is investigated h erein. It is shown that this widely used practice may lead to large errors in determining the available pressure at a connection for a design flow con dition. It is further shown that using a second test point to construct a q uadratic water supply plot can produce far better accuracy. Inaccurate plot s of the available pressures can lead to erroneous fire flow predictions an d improperly designed fire protection sprinkler systems. This raises safety concerns in addition to poorly designed facilities.