QUESTIONS AND ANSWERS The following questions were among those asked at the extension courses of the New York Fire College, with answers by fire department engineers: Question: How many gallons of water will flow through a high pressure hydrant, when fully opened, with 150 pounds pressure on the high pressure main? Answer: Theoretically, without allowing any friction losses, the following amount would flow: One 3-inch outlet squared is 9 inches. Square root of 150 pounds pressure is 12.2. 9 109.8 30 barometric pressure. 3,294. gallons flow one outlet. 4 outlets. 13,176. In the Holyoke hydrant tests, the construction of barrel and outlets most nearly as used in the high pressure hydrants, has a coefficient of discharge of .71. While there would more than likely be a larger discharge comparatively from the high pressure hydrant, owing to the outlet being 3-inch and hydrant barrel being 10-inch, with correspondingly larger main valve,…
