For some years now the 1 3/4-inch handline has been working its way into the fire service as a replacement for the ever-faithful 1 1/2inch line. The 1 3/4-inch has some advantages over the 1 1/2-inch line, among them larger gpm flows, less friction loss, and less pump discharge pressure needed.
Most fire science students and pump operators eventually become familiar with the given formula used in determining engine discharge pressure for a given hose layout: EP = NP + FL + BP Where: EP = engine pressure (pump discharge)
The School of Public Safety Administration of the William Paterson College of New Jersey teamed up with the North Jersey Volunteer Firemen’s Association recently to assist in the development and testing of a revolutionary fire stream propellant and wetting agent.
—New York F. D. photo. Tests of “slippery water” by the New York Fire Department indicate that friction losses need not continue to limit flows through 1 1/2-inch hose to the extent that they now do. Slippery water is made either by educting an additive into a hose line or by putting the additive into a booster tank.
One of our pet ideas is that fireground hydraulics need not be complicated. As a matter of fact, if a pump operator is going to provide proper pressures as rapidly as they are required on the fireground, he had better stick to a simple but reasonably accurate brand of hydraulics that he can handle without pencil and paper.
DURING the past year, Lieutenant Commander Henry S. Morton carried out a project at the hydraulic laboratories of the University of Washington, on friction loss determinations in hard suction hose of 4 1/2-inch, 5-inch and 6inch diameters for varying flows. These data will very effectively supplement those secured in a series of experiments by John R. Freeman, which were conducted in 1889 on the flow of water through fire hose, of which the values of friction factors, at velocities ranging between ten and thirty feet per second, were obtained.
THE matter of the most advantageous size of fire hose for exterior work in large fires is one which engages the attention of every fire chief. The necessity for the adoption of a standard for the large size of hose to be used by the fire defiartment is advocated in the following paper: From the earliest days before Christ when clay pipes were used for conveying water, keen students of the laws of nature observed that there was a loss in pressure when water flowed through pipes and the longer the pipe the greater the drop in pressure.