Furnace Oil


Furnace oil is one of the cheapest fuels available for industrial use. It is a by-product of oil refineries. When processing CRUD oil, FO (furnace oil) is one of the products along with other petroleum fuels like HSD, gasoline, etc.

Usually, it has a calorific value of 10,000 cal/g. The furnaces are mainly used for heating or preheating large quantities of metal which are the main uses of FO. This can be stored in both vertical and horizontal tanks, above ground or even underground in some cases. The size and capacity of these tanks are pre-determined by CCOE in India, the regulator of the fuel storages.

For direct combustion, FO is viscous and not suitable for complete combustion. It is preheated to 55 degrees Celsius and higher, depending on the application. Flow increases with temperature and also improves combustion. A water-based scrubber is used in the furnace exhaust, which prevents a significant amount of subsequent carbon and improves emissions.

The whole FO yard, according to IS standard, the preheating in the storage tanks as well as the pipes and pumps etc., the pumping station, the level controller, the control panel and the entire distribution pipeline are set up. Design according to application requirements, storage requirements. capacity, logistics, space availability and government standards.

The uses of heating oil are:

  • As fuel for power generation in the DG
  • As fuel for boilers / furnaces / air preheaters / any other heating equipment
  • Fuel
  • Fuel/raw material in fertilizer plant


Typical Furnace Oil Specifications (Indian standards IS:1593–1982)

Requirement For
Method of Test
Grade LV
Grade MVI
Grade MV2
Grade HV
Ref to [P : ] of
IS : 1448*
(1)Acidity, inorganicNilP : 2
(2)Ash, percent by mass, Max0.1P : 4
(Method A)
(3)Gross, calorific valueNot limited, but to be reported
(See Note 1)
P : 6
(for reference) and
P : (for routine)
(4)Relative density at 15/15°CNot limited, but to be reported
(See Note 2)
(5)Flash point, [Pensky martens (closed)], Min66°CP : 21
(6)Kinematic viscosity in centistokes at 50°C, Max80125180370P : 25
(7)Sediment, percent by mass, Max0.25P : 30
(8)Sulphur, total, percent by mass, Max
(See Note 3) : 33
(for reference)
and P : 35
(for routine)
(9)Water content, percent by volume, Max1.0P : 40

NOTE 1: Normally the gross calorific value is of the order of 10,000 cal/g.

NOTE 2: Fuel oil for marine uses in diesel engines shall not exceed a limit of 0.99.

NOTE 3: Recognizing the necessity for low-sulphur fuel oils in some specialized uses; a lower limit may be specified by mutual agreement between the purchaser and the supplier.

Effective 01.04.10 FO/LDO supplies to rail fed customers is through BTPN (8 wheeler) rakes only since railways has withdrawn conventional (4 wheeler) rakes from circulation.