N.Y. Comp. Codes R. & Regs. tit. 12, § 14-1.12 – Blowoff tanks.

(a) Boilers operating at pressures in excess of 100 psi and boilers not having a safe place of discharge shall be provided with blowoff tanks. The blowoff tanks shall be constructed in accordance with the provisions of the ASME Code, section VIII, division 1.
(b) The outlet from the blowoff tank shall be twice the area of the boiler blowoff pipe and made to extend internally within six inches from the bottom of the tank.
(c) A vent pipe, at least twice the diameter to the inlet, shall lead to the outside atmosphere.
(d) Vents shall be as direct as possible to the outside atmosphere and discharge at a point not less than seven feet above the adjacent walkway or areas without a valve or other possible obstruction such as a water pocket.
(e) For convenience in cleaning the tank, a manhole or an access opening shall be provided in the upper head or shell of same.
(f) All pipe connections between tank and blowoff valves on the boiler shall be made as direct as possible. The piping and fittings shall be in accordance with the ASME Code.