What are Fire-resistant Hydraulic Fluids
Fire resistant hydraulic fluids are special fluids that have been developed to replace petroleum-based fluids in applications where there is a potential ignition source. They are less hazardous and more fire-resistant than traditional hydraulic fluids, meaning they are difficult to ignite and do not propagate a flame.
Fire resistant hydraulic fluids can be classified into three main types: water-based fluids, synthetic fluids, and phosphate esters. Water-based fluids include water glycols and water-in-oil emulsions, which have excellent fire-resistant properties but require special hydraulic equipment and corrosion protection.
Synthetic fluids are water-free fluids that can cope with drastic temperature and pressure variations, but may have lower lubrication performance and higher cost. Phosphate esters are also water-free fluids that have good fire-resistant and lubrication properties, but are hygroscopic and corrosive to some metals. The selection of the appropriate fire resistant hydraulic fluid depends on various factors, such as the operating conditions, the environmental impact, the safety requirements, and the cost-benefit analysis.
When to use Fire resistant Hydraulic Fluids?
When lubricants are used under pressure, for example in hydraulic lines, there is a possibility of small leaks and lubricant being sprayed into the air. These leaks can happen due to component failure at joints, hoses and seals, especially if the systems have been recently serviced or have been in use for a long time.
If these leaks happen near an ignition source or high-temperature equipment, such as in steel mills or power plants, it could result in a disastrous fire.
Fire resistant Hydraulic Fluids are typically used in situations where there is a potential source of ignition, such as sparks, flames, hot surfaces, or electrical equipment. Some examples of applications that require fire-resistant hydraulic fluids are:
- Steel mills and metal processing plants, where molten metal or slag can come in contact with hydraulic hoses or pipes.
- Mining and tunneling equipment, where hydraulic systems are exposed to high temperatures and flammable gases or dust
- Aircraft and aerospace systems, where hydraulic fluids can leak or spray onto hot engines or exhaust systems
- Marine and offshore platforms, where hydraulic systems are subject to salt water corrosion and fire hazards from oil spills or leaks
- Power generation and transmission equipment, where hydraulic fluids can ignite due to electrical faults or overheating
Types of Fire-resistant Hydraulic Fluids
Understanding When to Use Fire-Resistant Hydraulic Fluids
There are three main types of fire-resistant hydraulic fluids: water-based, synthetic, and phosphate ester.
Water-based fluids are composed of water and a small amount of oil or glycol. They have excellent fire resistance, but low lubricity and corrosion protection. They are suitable for low-pressure systems that do not require high performance.
Synthetic fluids are composed of organic compounds that are chemically stable and resistant to ignition. They have good lubricity and corrosion protection, but high cost and environmental impact. They are suitable for high-pressure systems that require high performance.
Phosphate ester fluids are composed of phosphate esters and additives. They have good fire resistance, lubricity, and corrosion protection, but low compatibility with some seals and metals. They are suitable for medium-pressure systems that require moderate performance.
Characteristics of Fire-resistant Hydraulic Fluids
Fire-resistant hydraulic fluids have several characteristics that make them suitable for these applications, such as:
- Excellent lubricity: They provide adequate lubrication and protection for the hydraulic components, reducing friction and wear.
- Very high flash point: They have a high temperature at which they produce enough vapors to ignite. This reduces the chance of fire in case of a leak or spill.
- Stability of fluids in service: They resist oxidation and degradation over time, maintaining their performance and viscosity.