[CHAPTER XV.]
QUESTIONS ASKED ENGINEERS WHEN APPLYING FOR A LICENSE.[7]
Q. If you were called on to take charge of a plant, what would be your first duty?
A. To ascertain the exact condition of the boiler and all its attachments (safety valve, steam gauge, pump, injector), and engine.
Q. How often would you blow off and clean your boilers if you had ordinary water to use?
A. Once a month.
Q. What steam pressure will be allowed on a boiler 50 inches diameter ⅜ inch thick, 60,000 T. S. 1-6 of tensile strength factor of safety?
A. One-sixth of tensile strength of plate multiplied by thickness of plate, divided by one-half of the diameter of boiler, gives safe working pressure.
Q. How much heating surface is allowed per horse power by builders of boilers?
A. Twelve to fifteen feet for tubular and flue boilers.
Q. How do you estimate the strength of a boiler?