On seagoing vessels, mushroom ventilator cowls are used in head form in ventilation systems as non-closable or as closable with the shapes A and B on deck for ventilation. In Table 1, dimensions and masses of shape A and shape B with nominal widths of 1 000 mm to 1 800 mm were determined. The standard describes the design, such as welding, surface treatment, hoisting eyes, etcetera. The locking system (angle drive) with hand crank is common, although other locking systems are also permitted. The material to be used for manufacture shall be a weldable steel with a minimum tensile strength of Rm = 360 N/mm2. In addition, the standard contains requirements for the design of the closure and the inspection openings. For the closure there is an obligation of acceptance by a classification society. This standard has been prepared by the DIN Standards Committee Shipbuilding and Marine Technology (NSMT), Working Committee NA 132-02-03 AA "Lüftungs-, Klima- und Kältetechnik" ("Heating, ventilation and air-conditioning").