Fuel Oil
Asia-Pacific Economic Cooperation (APEC)

European Commission - Eurostat
This covers all residual (heavy) fuel oils (including those obtained by blending). Kinematic viscosity is above 10 cSt at 80oC. The flash point is always above 50oC and density is always more than 0.90 kg/l.

International Energy Agency (IEA)
This covers all residual (heavy) fuel oils (including those obtained by blending). Kinematic viscosity is above 10 cSt at 80oC. The flash point is always above 50oC and density is always more than 0.90 kg/l.

International Energy Forum Secretariat (IEFS)
Heavy fuel oil is a blended product based on the residues from various refinery, distillation and cracking processes. It is a viscous liquid with a characteristic odour and it requires heating for storage and combustion.

Heavy fuel oil is used in medium to large industrial plants, marine applications and power stations in combustion equipment such as boilers, furnaces and diesel engines.

Heavy fuel oil is a general term and other names commonly used to describe this range of products include: residual fuel oil, bunker fuel, bunker C, fuel oil No. 6, industrial fuel oil, marine fuel oil and black oil. Moreover, terms such as heavy fuel oil, medium fuel oil and light fuel oil are used to describe products for industrial applications to give a general indication of the viscosity and density of the product.

Two main categories of fuel oil can be distinguished according to their sulphur content:
?? Low sulphur fuel oil: sulphur content is lower than 1%
?? High sulphur fuel oil: sulphur content is 1% or higher.

Latin American Energy Organization (OLADE)
Fuel Oil may consist of a single derivative or group a large variety of heavy fuels by viscosity.

United Nations Economic Commission for Europe (UNECE)
This covers all residual (heavy) fuel oils (including those obtained by blending). Kinematic viscosity is above 10 cSt at 80oC. The flash point is always above 50oC and density is always more than 0.90 kg/l.

UNSD Energy Statistics Section
Residual fuel oil is a heavy oil that makes up the distillation residue. It comprises all fuels (including those obtained by blending) with a kinematic viscosity above 27.5 cSt at 38oC. Its flash point is always above 50oC and its specific gravity is higher than 0.90.

It is commonly used by ships and industrial large-scale heating installations as a fuel in furnaces or boilers.