H.W. Johns-Manville Co.
There are several of these unusual covers on the south side of the Cathedral of St. John Divine Close in Morningside Heights Manhattan. The H.W. Johns-Mansville Company was founded in 1901 and officially dropped the "H.W." in 1926. This time-window fits with the building of the Cathedral and the adjacent buildings at the start of the 20th century.
The simple design is text heavy, with two clear messages, what the cover is covering and who made it. Johns-Manville included insulated and fire-proof pipes in their varied product lines.
The spacious layout of the cathedral grounds required a private contractor for the electric lines. Power was supplied on Amsterdam Ave by either the New York Edison Co (DC) or their rival United Electric Light and Power Co. (AC).
The clutch of covers at St. Johns are the only ones of their type I have seen in New York.