Is Lubricating Oil Flammable? (Let’s Find Out!)

You probably already know the importance and uses of lubricating oil. It helps to reduce any friction that might occur between objects or surfaces. No doubt, lubricants enhance smoothness and minimize heating.

Most people are sometimes careful while using lubricant oil for fear of flaming up during its use. But is lubricating oil a fire hazard? In other words, is lubricating oil flammable?

Yes, lubricating oil is flammable, although they’re not volatile, so it would be hard to ignite or catch fire, except when they’re heated.

More details on that later.

What is Lubricating Oil?

First of all, the term “lubricating oil” connotes many different products made up of hundreds of base chemicals and additives. Lubricating oils can be mineral-based or synthetic. Although, this post is focusing on petroleum-based lubricating oils.

Lubricating oil consists of 80% to 90% of petroleum hydrocarbon distillates and 10% to 20% of additives, commonly used to lubricate different internal combustion engines.

Occupational and general populations are exposed to lubricating oil mainly through inhalation and dermal contact.

Acute exposure has been connected with irritation of the eyes, skin, and respiratory tract. Lubricating oil should be well labeled as possibly carcinogenic because some of the lubricating oils tested were carcinogenic.

Lubricating oil is extracted from heavy vacuum gas oil finishing (de-asphalting, hydro-treatment, solvent extraction, and dewaxing).

The finished base oils are mixed to produce various kinds of lubricating and hydraulic oils that achieve various physical- and performance-based properties.

Unused lubricating oil changes under the use conditions of heat and friction and, if appropriate, exposure to exhaust gases of internal combustion engines.

Used lubricating oil or used crankcase oil generally have higher concentrations of polynuclear aromatic hydrocarbons than unused oils.

This article is not specifically addressing the used oil but would be considered more toxic because of the increased presence of toxic constituents. Back to the question, is Lubricating Oil Flammable?

Is Lubricating Oil Flammable or Combustible?

Is Lubricating Oil Flammable

Well, as we earlier mentioned, lubricating oil can be flammable but is not combustible. It is not combustible because it is neither volatile nor capable of burning. It can only combust when it has a flashpoint that’s over 150 degrees Celsius.

In other words, for any substance like engine oil to produce enough flammable vapors that can ignite in the presence of an ignition source, it must be capable of accommodating temperatures that is above 150 degrees Celsius.

To buttress the above point, someone told a story about something that happened in November 2010, in which an Airbus A380 carrying about 469 passengers drove off from Singapore.

Four minutes on, No2 (left inboard) engine exploded, causing ripped holes in the wing, damaging hydraulic and electrical systems.

Meanwhile, the crew flew around for two hours examining systems before making an emergency landing.

The problem was caused by a broken lubricating oil pipe that sprayed oil near the burner, igniting the oil and creating a turbine runaway that damaged the engine. Therefore, lubricating oil can burn, but only when it is heated enough to evaporate.

What Kind of Oil is Flammable?

Aside from lubricating oil, there are kinds of oil that are also considered flammable but do not burn easily. Oils such as peanut oil, safflower oil, and soybean oil all possess a smoke point of 450 degrees Fahrenheit.

For that of grapeseed oil, it is 445°F, for canola oil, it is 435°F, 390°F for Sunflower, and 410°F for corn oil, olive oil, and sesame seed oil.

At What Temperature Will Lubricating Oil be Considered Flammable?

First of all, before we answer the above question, it is important to note that, for any substance to be considered highly flammable, it must have an ignition point (calculated as flashpoint) lower than 100 degrees Fahrenheit.

As far as lubricating oil is concerned, it hardly belongs to that category. In other words, it can only be flammable when it meets with an open flame or sparks.

The adopted lubricating oil is a strange mixture with multi-components, with a flashpoint temperature of 170 degrees Fahrenheit, which is above the flashpoint limit required for inflammation.

Its auto-ignition temperature is measured at atmospheric pressure of 365°C. Meanwhile, the lubricating oil works under high-pressure conditions up to 30 atmospheres and is then heated and cooled down continuously.

Also, explosive limits of lubricating oil are required at high pressures for fire safety.

How to Prevent Lubricating Oil from Inflammation

It is quite simple. Like other combustible and flammable materials, lubricating oil should be stored properly in flammable-safe cupboards or containers when you are not ready to use it.

Again, you must always adhere to the Safety Data Manual after buying new lubricating oil.

The Manual provides information about the flashpoint of the lubricating oil and other useful information concerning its toxicology, storage and handling, and physical and chemical properties.

This information will provide you with the good knowledge you seek to prevent fire hazards and other risk factors.

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