New Orleans Tests Pumping Procedures on Lengthy Mississippi River Bridge
New Orleans F. D. photos by Ted Picone
THE GREATER NEW ORLEANS BRIDGE stretching across the Mississippi River from New Orleans to Algiers, La., opened to traffic on April 15. It is 3,019 feet in length and its 1,575-foot central span is said to be exceeded only by the Firth of Forth Bridge in Scotland and the Quebec Bridge in Canada.
The new bridge is not equipped with standpipes for fire protection purposes, a factor which poses both hydraulic and apparatus problems to the New Orleans Fire Department. On April 13, Superintendent of Fire Howard L. Dey, with Assistant Superintendent Edward J. O’Brien and First Deputy Chief Gerald Sumners, conducted a pumping drill on the bridge to familiarize personnel with methods of obtaining water for extinguishing purposes.
Participating were training division and maintenance division officers; chief officers of the Second District; Engines 1, 2, 5, 6, 33; Ladder 2; Hose Tender 1; Rescue Unit 1 and Salvage 1.
The first test was a relay employing 3-inch hose. Using hose rollers, Hose Tender 1 lowered 200 feet of 3-inch hose from the bridge deck to Engine 5 located next to a hydrant on the ground near the base of the first bridge pier. The vertical distance at this point is 160 feet. Salvage 1 had secured ¾-inch ropes at the second and third couplings of this hose, using rolling hitches, in order to support it and relieve possible excessive stress on the couplings. These were anchored to the towing hooks of the apparatus.
Engine 5 stretched two lengths of 2½inch hose to a Siamese attached to the 3-inch line. On the bridge, this hose was attached to the intake of Engine 6, and 500 feet of 3-inch hose was then stretched to Engine 2. Two nozzle lines, each 200 feet of 2 ½-inch hose, were attached to Engine 2. One line was equipped with a l-inch tip and the other with a 1⅛-inch tip.
Engine 5 supplied the relay with water at 150 psi. In turn, Engine 6 pumped at 100 psi and Engine 2 supplied the nozzles at 80 psi pump pressure. Pitot readings showed 48 psi at the 1 1/8-inch tip and 50 psi at the 1-inch nozzle indicating a total flow of approximately 468 gpm.
Engine 6 proceeded to the hydrant used in the previous test and pumped at 230 psi into 1,000 feet of 2 1/2-inch hose of which approximately 730 feet was stretched on the bridge floor. The remainder spanned the 160-foot elevation between the ground and the bridge. A nozzle with a 1-inch tip was attached to the line and the pressure was measured at 50 psi; discharge was 209 gpm.
The fire tug “Deluge” tied up alongside the central river pier, New Orleans side, and one 3-inch line was lowered. Again ¾-inch ropes were used to support the hose and couplings and were secured to the tow hooks of Rescue 1, located above the tug. This line was connected to Engine 33 and two 2 1/2-inch nozzle lines, each 200 feet in length, were stretched to the bridge rail. Again 1-inch and 1 Vs -inch tips were employed.
The tug pumped at 175 psi and Engine 33 pumped at 80 psi. Nozzle pressures were 58 psi for the 1-inch tip and 50 psi at the 1 1/8-inch tip. Total discharge was approximately 490 gpm.
A third 2 ½-inch line was then stretched from Engine 33, and together with the original two, was connected to the deluge set mounted on Rescue 1. The tug supplied the relay at 175 psi and Engine 33 pumped at 100 psi. A nozzle pressure of 64 psi was recorded with an approximate discharge of 533 gpm.
In the final test the “Deluge” supplied the 1½-inch tip on Rescue 1 at 200 psi. Nozzle pressure was 40 psi and the discharge approximately 422 gpm.
From the tests, the fire department personnel found that it is possible to obtain fair amounts of water on the bridge by use of the various methods. The back pressure encountered, due to the extreme heights, is a factor which must be taken into account by pump operators. By calculation it is 69.44 psi on the New’ Orleans side and 73.78 psi on the Algiers side of the bridge.