we are offering furnace oil, marine furnace oil introduction furnace oil furnace oil is a dark viscous residual product used as a fuel in different types of combustion equipment. it conforms to is:1593-1988 for fuel oils. presently mv-2 grade (kinematic viscosity range of 125 to 180 cst at 50ã�â°c) conforming to this specification is being marketed. broadly its applications can be classified as:.