Castrol Biobar

Environmentally Responsible Hydraulic Fluids.


  • Hydraulic systems and hydrostatic transmissions incorporating gear pumps, vane pumps, radial piston or axial piston pumps and motors where there is a perceived risk of egress into the environment in the event of spillage or leakage


Castrol BioBar hydraulic fluids combine excellent protection, extended drain performance and versatility in Offshore operations to provide the following key benefits:
  • Superior oxidative and thermal stability extends product life, therefore minimising product consumption and waste
  • Good resistance to “judder” under high load / slow speed operating conditions on deck equipment
  • Compatible with all common seal materials (KBR, Viton, Nitrile) allowing simple replacement of mineral oil in hydraulic systems
  • Good filterability. Assured hydraulic pump wear protection: exceeds the requirements of the Eaton-Vickers 35VQ25 pump test
  • Reduced environmental impact when compared to conventional lubricants - demonstrable benefits in the following key environmental performance criteria:
   - Superior biodegradation
   - Significantly reduced bioaccumulation* and toxicity
   - Enhanced renewability

     *Using OSPAR criteria for assessing bioaccumulation potential


Castrol BioBar contains selected additives ensuring good oxidation stability, good anti-corrosion and anti-wear properties and low aquatic toxicity. The combination of base oils used in Castrol BioBar endows it with a very high viscosity index and an extremely low pour point as well as giving excellent compatibility with elastomeric seal materials. The careful choice of the saturated synthetic ester enables the product to operate up to +120°C system temperature.

The product level biodegradability of Castrol BioBar was measured in an extended OECD 306 (seawater) biodegradation test with a result greater than 60%, making it 100% more biodegradable than conventional mineral oils. This ensures its biodegradation should it enter the marine environment. The toxicity of Castrol BioBar was measured on 6 marine species and was found to be up to 100 times less toxic than conventional mineral oils. It also has >50% less potential for bioaccumulation and >30% of Castrol BioBar is derived from renewable resources.

Castrol BioBar is miscible with conventional mineral oil based hydraulic fluids. When changing from mineral oil based products to Castrol BioBar, the system should be drained to ensure that the mineral oil content of the refilled system is less than 5%. This is necessary to ensure that the maximum environmental benefit can be achieved.