Milk flowing through a stainless steel inner tube (40 mm inner diameter) of a double tube-type heater is heated from 10\(^\circ\)C to 85\(^\circ\)C by steam condensing at 120\(^\circ\)C. Total heat transferred is 146200 kcal h\(^{-1}\), and overall heat transfer coefficient is 750 kcal h\(^{-1}\) m\(^{-2}\) \(^\circ\)C\(^{-1}\). The total length of the heating tube in m (rounded to one decimal place) is \(\underline{\hspace{1cm}}\).