NYCDOT Ferries Division (Staten Island Ferry) requires that the Aqueous Urea Solution (AUS) / Diesel Exhaust Fluid (DEF) which is provided be a blended solution of 32.5% high purity urea and 67.5% deionized water and offer freeze/crystallization protection down to 11.3° F (-11.5° C). In order to meet the requirements laid forth by the Marine Diesel Engine Manufacturers (Electro Motive Diesel, Caterpillar, etc.), the AUS/DEF solution to be used shall be SCR Grade AUS32, or Aqueous Urea Solution of 32.5% concentration with quality properties per ISO 22241-1. By definition, this solution shall be homogeneous, allowing partial or total freezing and thawing without changing the concentration. Please note that fertilizer grade, agriculture grade, or technical grade urea may contain elements that will clog the injector nozzle and are not acceptable for this application per the Marine Engine SCR Manufacturers AUS/DEF requirements. The supplied Marine Engine AUS/DEF shall always have the properties and approvals in accordance with the following organization’s current recommendations and current references AUS/DEF: • Electro Motive Diesel (EMD): EMD Series 710 E 23B SCR System • Quality Properties per ISO 22241-1
