Steel worker mixing melted steel

Shell Fire-Resistant Hydraulic Fluid S1 DU

Worker in protective clothing at work in a steel foundry


Effectively reducing the risk of fire-hazards

Keep your systems running smoothly and safely while reducing the environmental impact of your operations.

Hydraulic systems operating in industrial and marine settings – along with mobile set-ups – often need specific protection that goes beyond preventing component wear and equipment breakdown.

To run efficiently in conditions that can range from moderate to severe, they also need lubrication that improves safety through increased fire resistance and enhances the protection of local ecosystems.

Shell Fire-Resistant Hydraulic Fluid S1 DU is based on natural esters and fire-resistant hydraulic fluid that provides this enhanced protection, alongside excellent anti-wear properties.

Performance Advantages

Worker at a furnace pouring melted metal

Deliver peak performance

Hydraulic and fluid transmission systems in exposed environments are subject to wide variations in temperature. The naturally high-viscosity index of Shell Fire-Resistant Hydraulic Fluid S1 DU helps to deliver responsive performance from cold start to full-load heavy-duty operations. Its high viscosity index and shear stability provide consistent viscosity where wide variance in ambient conditions is common.

  • The low temperature performance properties enable responsive performance from cold stat to full load heavily duty operations.
  • A high viscosity index in combination with robust shear stability provides durability at higher operating temperatures.
  • In addition to protecting the machine over a wide temperature operating range, shear-stable, high viscosity index fluids enable increased hydraulic efficiency.

Environmental Advantages

Old mine in coastal setting

Protect your equipment and the environment

When operating in environmentally sensitive settings, you need to know that your hydraulic fluids are not only able to protect your equipment but also help you to mitigate any impact on local ecosystems.

Shell Fire-Resistant Hydraulic Fluid S1 DU is engineered to work in a wide range of settings and has been designed to help you meet your environmental responsibilities.

  • Designed to be readily biodegradable1 and feature low toxicity, Shell Fire-Resistant Hydraulic Fluid S1 DU can be used in applications across environmentally sensitive areas.
  • Shell Fire-Resistant Hydraulic Fluid S1 DU is a USDA-Certified Biobased Product in the USDA BioPreferred programme.
  • Shell Fire-Resistant Hydraulic Fluid S1 DU has a high flash point, fire point and autoignition temperature for reduced risk of fire. As an FM Approved Fire-Resistant industrial fluid, Shell Fire-Resistant Hydraulic Fluid S1 is suitable for high-pressure systems where fire hazards are a concern.

Service Life Advantages

Liquid metal furnace using water

Lower operating costs and reducing downtime

Shell Fire-Resistant Hydraulic Fluid S1 DU provides anti-wear and film strength properties necessary for hydraulic systems under moderate to severe conditions.

  • Shell Fire-Resistant Hydraulic Fluid S1 DU has lower wear compared with the Eaton Vickers V104C pump test limit (ASTM D 7043) and provides better wear protection than industry standards and mainstream mineral oil hydraulic fluids.
  • Excellent anti-wear protection demonstrated in vane pump tests (ASTM D7043) can help achieve lower maintenance costs and less downtime.

Improving Air release - Air in the oil can lead to undesirable consequences such as reduced efficiency and responsiveness and increased likelihood of erosion, cavitation or other harmful system issues that can cause unplanned downtime and increased maintenance costs.

  • Shell Fire-Resistant Hydraulic Fluid S1 DU exceeds equipment manufacturers’ air release limits.

Designing fire-resistant hydraulic fluids with reduce wear protection and improved air release helps to extend the life of components and service life of your equipment. It improves the efficiency of your hydraulic systems and keeps them running for longer.

Test method ISO 46 ISO 68
ISO viscosity grade 46 68
ISO fluid type ISO 6743-4 HEES/HFDU HEES/HFDU 
Kinematic viscosity at 20°C, cSt ISO 3104 1,522 2.640
Kinematic viscosity at 40°C, cSt ISO 3104  47.2 67.7
Kinematic viscosity at 100°C, cSt ISO 3104  9.41 12.3
Viscosity index ISO 2909 188 183
Density at Kinematic viscosity at 15°C, kg/m³ ISO 12185 921 924
Fire point, °C ASTM D92  372 371
Flash point (Cleveland open cup), °C ISO 2592  320 320
Autoignition temperature, °C ASTM E650 400 -
Pour point, °C ISO 3016  -42 -39
Biodegradability (28d), %  OECD 301B 76 68

Download the product sheet

Find out more about how Shell Fire-Resistant Hydraulic Fluid S1 DU can protect your hydraulic systems in extreme conditions to drive productive operations.

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Delivering value across the industrial space

Download our white paper to find out more about how fire-resistant hydraulic fluids can bring value to your operations – driving performance, extending service life and helping you to meet your environmental responsibilities.

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1 Shell Fire Resistant S1 DU, S2 DU and S3 DU are biodegradable by greater than 60% after 28 days in the OECD 301B Carbon dioxide evolution test.