Urea, (NH2)2CO, is a common chemical commodity used in a wide range of products. For NOx reduction urea is normally delivered as a ready mixed solution with 40% of urea and 60% of de-ionised water, and specific weight about 1112 kg/m3 at 20°C. Steel tanks should be internally coated with epoxy or similar material and pipes and fittings should be made of stainless steel or plastic (Urea is corrosive on Copper and its alloys). The consumption of urea solution is generally within 5-8% (wt) of the fuel consumption depending on the desired NOx reduction versus the base line emission.