A single-effect evaporator with a heat transfer area of 70 m² concentrates a salt solution using steam. The salt solution feed rate and temperature are 10000 kg h⁻¹ and 40 °C, respectively. The saturated steam feed rate and temperature are 7500 kg h⁻¹ and 150 °C, respectively. The boiling temperature of the solution in the evaporator is 80 °C. The average specific heat of the solution is 0.8 kcal kg⁻¹ K⁻¹. The latent heat of vaporization is 500 kcal kg⁻¹. If the steam-economy is 0.8, the overall heat transfer coefficient is ________ kcal h⁻¹ m⁻² K⁻¹ (rounded off to the nearest integer).