Large Fire Engines and Water Supply
In the January, 1948, issue of WATER WORKS ENGINEERING, the monthly journal of the water supply profession, appears an editorial by W. W. Brush, discussing large engines and their relation to water supply.
Because of the current interest in this subject in the fire service, and because the editorial discusses it in a thorough, forward-looking manner, the editorial is reproduced below in full. It offers food for thought.
“During the era of the steam fire engine, discharge capacities ranged from 500 gpm to 1,100 gpm, at 120 psi pump pressures. The latter unit was classed as a ‘double extra first size’ fire engine and was the largest commonly employed.
“With the advent of motor fire apparatus, employing rotary gear and piston pumps, pumping capacity ranged between 500 and 750 gpm at 120 psi. As motors of greater power were developed, and as improved designs of centrifugal pumps became available, the trend in fire engine capacities and pressures was definitely upward.
“Today, the 1,000 gpm 150 psi fire engine is becoming popular in cities, with the 1,500 gpm unit also growing in favor.
“The trend towards greater capacity in pumps remains unchecked. A 2,000 gpm pump unit at 150 psi, is now being built by one of the fire apparatus pump producers, and is available in fire engines produced by several of the leading builders. While this is the largest single fire apparatus pump now being made, the city of Los Angeles, Calif., has in service two big duplex fire engines, each equipped with two motors and two pumps, and each fire engine having a capacity of 3,000 gpm at 120 psi.
“The question may be asked as to why these bigger units are needed, or wanted, when the 750 and 1,000 gpm fire engines served so well in the past. Conditions in the fire service are changing just as they are in industry. The forty-hour week is gaining hold; and with the shorter work day, more men are needed. But cities with hard pressed budgets cannot afford to increase fire department personnel 33 1/3 per cent to 50 per cent to compensate for the shorter day, particularly as fire department salaries, too, have had to be raised.
“However, with the larger pumps. greater pumping capacity can be concentrated near the fire. This means shorter hose stretches from fewer hydrants, and, of course, fewer men to make the stretches. Fewer pump operators are needed; spare pump operators can work as hosemen. Better control of pump and nozzle pressures is possible when pumps are near the fire. Finally, it costs but very little more for a 2,000 gpm fire engine than it does for a 750 or 1,000 gpm unit. While the added capacity may not be used frequently, it is there when needed.
“This trend to larger fire engines is of direct concern to water works men. It is they on whom the responsibility for the successful use of the big fire engines must ultimately rest.
“Among the numerous questions for which answers are required to guide both the superintendents and fire chiefs where purchase of large pumpers is under consideration, are the following: What will be the maximum demand for fire extinguishment that should be provided in each area; how long will such demand continue; what changes must be made in the water system, including hydrants and connections, to meet such demand, and estimated cost of changes and time required to make them.
“For these reasons, water works superintendents and fire chiefs should get together for discussion before these pumpers of large capacity are purchased, for it is possible that some systems may not be able to adequately supply the water demand.”