Every hotel building, rooming house or apartment house, exceeding fifty-five feet and not over one hundred feet in height, unless already provided with a three-inch or larger standpipe on the outside, shall be provided with a vertical standpipe of not less than four inches in diameter. For every hotel, rooming house or apartment house building exceeding one hundred feet in height, unless already provided with a four-inch or larger standpipe, there shall be provided a vertical standpipe not less than six inches in diameter. Such standpipes shall be of wrought iron or steel and, together with fittings and connections, shall be of such strength as to safely withstand at least three hundred pounds of water pressure to the square inch when installed and ready for service. Such standpipes shall have one hose valve on the roof and a hose valve at each floor opening, with double Siamese automatic valves at the bottom, about one foot above the curb level and adjusted looking down at an angle of forty-five degrees. All valve openings shall be of brass protected by a substantial brass cap, and all fittings and threads shall be of the size and form to fit regulation fire department hose. Such standpipes shall, where possible, be attached to the fire escape with iron ladder, for use of firemen, running the full height of the building and over the roof, and all hose connections shall be toward the building. This section shall not apply in cities or villages not equipped with waterworks and firefighting equipment suitable for using vertical standpipe.