Tag: industrial lubricants

Fire-resistant lubricants are fluids that are used in applications and systems where the risk of ignition is high. Typically, these environments are near or contain: open flames, sparks, or hot metals. If an oil leak were to occur, the risk of injury, damage, and even death is magnified as sustained fires can occur. That is why fire-resistant lubricants have been developed and manufactured to protect personnel and equipment.

Why do I need a Fire-Resistant Lubricant?

Fire-resistant lubricants are most needed in environments need high-temperature surfaces and open flames. Regular fluids that have low flash points pose the greatest risks to fire and should be switched for fire-resistant lubricants that have higher flash points.

If using pressurized hydraulic lines, it is key to have a fluid with a high flash point as small leaks can aerosolize the lubricant easily. The lubricant spray is much more susceptible to fire. It takes much less heat to ignite and can spread to fluid reservoirs. The lubricant can ignite if it’s fire point and/or auto-ignition point is reached. The fire point is the temperature at which a fire is sustained and is typically several (50+) degrees higher than the flash point. Opting for fire-resistant fluids with higher flash points will reduce the risk of fire and damage.

Fire-Resistance Fluid Standards

The term “Fire Resistant” and “Fire Resistance” are often misinterpreted and sometimes overused. There is no single property or metric that conveys relative fire resistance. Metrics like flash point, fire point, and autoignition temperature are useful, but do not tell the whole story. Because of this, most fluids are vigorously tested and are classified as “fire resistant” if it can pass various tests and simulations.

The Factory Mutual Research Corporation (FM) developed key benchmarks for testing fire-resistance. FM tests every single commercially available “Fire Resistant” fluid to ensure it meets various benchmarks. FM 6930 is the standard for hydraulic fluids and is classified into 3 levels: 0, 1, and 2. This standard only measures a fluid’s flammability and does not consider other factors of the lubricant.

The Mine Safety & Health Administration (MSHA) has their own tests and standards for underground mines and applications. Their stringent testing produces more failures than FM. Both programs has strict auditing and inspection programs to ensure fire-resistant fluids meet performance standards.

Types of Fire-Resistant Lubricants

Oil-Water Emulsions

There are 2 types of oil-water emulsion fluids: oil-in-water and water-in-oil. Oil-in-water emulsions are formulated with oil droplets sustained in water. Approximately 95% of the fluid is made of water and the remaining 5% is composed of oil. These emulsions have excellent fire resistance and heat-transfer capabilities, but poor lubricity and poor corrosion protection.

Due to these poor lubricity characteristics, water-in-oil emulsions (also known as inverse emulsions) are better performing fluids. These are 40% water and 60% oil. It provides more balance of heat-transfer properties, lubricity, and corrosion protection. The fire-resistance primarily comes from the water, which turns into steam and reduces the oil’s combustibility.

Water Glycols

Water-in-oil emulsions have seen declining market share due to the rise of Water Glycol Fluids. Water Glycols contain 35-45% water and the remaining contents are some sort of glycol, such as ethylene glycol. These Water Glycols offer some benefits such as a lower freezing point and excellent fire resistance. Water Glycols do have drawbacks, but many of these can be mitigated by various additive packages. These fluids can be used in a variety of applications, but speed and strength ratings are reduced due to the limited performance of the fluid. Despite this, Water Glycols are one of the most popular fire resistance lubricants on the market today.

Phosphate Esters

Phosphate Esters provide the best fire resistance properties of any fluid. This is due to their natural molecular structure. They are non-corrosive, have excellent oxidative stability, great anti-wear characteristics, and are suitable for use up to 150 C. Despite this, they have been losing popularity due to stringent compatibility and maintenance concerns. They are still popular for aircraft and military applications. Additionally, they require special seals and coatings and require special care during disposal.

Polyol Esters

Polyol ester fluids have gained popularity due to its fire resistance properties, excellent lubricity, and good viscosity stability across different temperatures. These contain additive packages to impart good performance and high thermal properties. These are much more compatible and versatile than phosphate esters. This has led to their rising popularity and market share in recent years.

Maintenance and Other Considerations

When switching to fire-resistant fluids, compatibility must be considered before restarting the equipment. By carefully draining the machine, this decreases the likelihood of any incompatibility issues.

High-water content fluids require a lot more maintenance and care to ensure they perform properly. Water provides a great medium for bacteria and biocide treatments are recommended to prevent bacteria growth. As temperatures rise, water evaporates and needs to be replaced to ensure the fluids cooling properties are not compromised. pH levels should be monitored along with corrosiveness and wear protection. It is important to follow proper storage practices to maximize efficacy and shelf life.

Like any other oils, fire-resistant fluids degrade in heat and reduce oxidative stability. It is important to note rotating pressure vessel oxidation test (RPVOT) values to ensure your fluid has enough oxidative stability.

Conclusion

Fire-resistant fluids are great options for equipment and environments that are susceptible to fires. If you have high-pressure machines, it is imperative to consider fire-resistant fluids to prevent potential sprays that can ignite. Twin Specialties offers both water glycols and polyol esters to meet your needs. Contact Twin Specialties for product information.

Viscosity

Not all cold starts are equal. There are varying temperatures and the lubricant you need will depend on the ambient temperature. If temperatures are below -20 C/- 4 F, it is recommended to use base oils that can flow in low temperatures. For engine oils, using an SAE 0W or SAW 5W grade lubricant is recommended. When the temperature drops below -30 C/- 22 F, operators should use a SAE 0W or SAE 5W lubricant, but whose base oil is a synthetic base stock and/or a base oil that is considered “multi-grade” or “multi-viscosity.”

Many of these multi-viscosity and multi-grade lubricants are designed for extreme weather conditions including cold start conditions. These lubricants maintain their viscosity better than conventional lubricants. Generally, multi-viscosity lubricants exhibit viscosity characteristics found in 2 different ISO viscosity grades (i.e. ISO 32-46) and multi-grade lubricants exhibit viscosity characteristics found in 3 different ISO viscosity grades (i.e. ISO 32-46-68).

Viscosity Index

When the temperature drops, the lubricant becomes more viscous, thus making it more difficult to circulate and flow through the engine or machine. Having a lubricant with a high viscosity index, defined as a viscosity index greater than 130, ensures that your lubricant better maintains its viscosity in extreme temperatures. Lubricants with high viscosity indices have either a highly refined or synthetic base stock or include viscosity index improver additives.

Monograde lubricants will have viscosity indices in the 95-105 range and will not perform as well as in cold start conditions. Many operators will use different monograde lubricants depending on the ambient temperature. This may cause issues with change outs and cold temperature properties.

Pour Point

As mentioned earlier, not all cold starts are created equal. In colder temperatures, a lubricant’s pour point could be the difference between success and failure. Pour point is defined as when a lubricant no longer flows and congeals. When operating in temperatures below -30 C/-22 F, it is imperative to use a lubricant with a pour point lower than -50 C/-58 F. Similar to viscosity index, lubricants with highly refined or synthetic base stocks have lower pour points. Some lubricants are manufactured with pour point depressants that prevent wax formation and the congealing of the lubricant.

Oil Integrity and Storage

While you can meticulously select the perfect lubricant based on your OEM requirements, ambient climate, and budget, it could be costly if you do not maintain it properly. Just like any oil, it is important to regularly check the oil for cleanliness and contamination. Taking regular samples is key to ensure your lubricant and machine is in good health. When storing lubricants. It is helpful to store the lubricant indoors or in a warmer environment so that it flows easily during start-up. Proper storage will also protect against contamination. If contaminated, the additives such as VI improvers or pour point depressants may not be as effective and could hurt lubricant performance.

What are Fire Resistant Lubricants?