Hand sanitizer has become a common product for maintaining hygiene. While highly convenient and effective for reducing germs, it is important to understand that hand sanitizer is indeed flammable.
Why Hand Sanitizer is Flammable
The primary reason hand sanitizer is flammable stems from its main active ingredients: alcohol. Most hand sanitizers contain either ethyl alcohol (ethanol) or isopropyl alcohol, typically in concentrations ranging from 60% to 95%. These high alcohol percentages classify the product as a Class I Flammable Liquid.
Flammability in liquids is characterized by a concept called “flash point.” The flash point is the lowest temperature at which a liquid produces enough ignitable vapor to form a combustible mixture with air, given an ignition source. For many hand sanitizers with around 70% alcohol, this flash point can be as low as 63 to 64 degrees Fahrenheit (about 17 to 18 degrees Celsius). This temperature is often below typical room temperature, meaning that flammable vapors can be present even in a cool environment.
It is important to differentiate the flash point from the ignition temperature. While the flash point indicates when ignitable vapors are produced, an external ignition source is still required to cause a fire. The actual ignition temperature for the alcohol in hand sanitizer is considerably higher, ranging from 680 to 700 degrees Fahrenheit. Therefore, while hand sanitizer can produce flammable vapors at room temperature, it will not spontaneously combust without an external flame or spark.
Reducing the Risk of Fire
Despite its flammability, the general use of hand sanitizer poses a low risk of fire when applied properly. The small amount typically used on hands evaporates quickly, minimizing any potential hazard. Once the sanitizer has completely dried on the hands, the risk of ignition is gone.
To mitigate any fire risk, always allow hand sanitizer to dry thoroughly on your hands before touching surfaces or engaging in activities near heat. This includes avoiding immediate contact with open flames, such as those from stoves, grills, lighters, or candles. It is also wise to avoid using hand sanitizer near sources of sparks or high heat, like electrical outlets or certain machinery. If hands are still wet with sanitizer, a static spark can even be an ignition source.
Proper storage is also important for safety. Hand sanitizer should be kept in a cool, dry place, away from direct sunlight and heat sources. This prevents the product from reaching temperatures that increase vapor production. Store containers securely to prevent spills and keep them out of children’s reach. For larger quantities, specific fire codes and guidelines apply, often requiring storage in specialized flammable liquid cabinets or areas with sprinkler systems.
Alcohol-Free Hand Sanitizers
For those concerned about the flammability of alcohol-based products, alcohol-free hand sanitizers offer an alternative. These products rely on active ingredients such as benzalkonium chloride (BKC) or other quaternary ammonium compounds (QACs) to eliminate germs. These compounds work by disrupting the cell membranes of bacteria and viruses, rendering them inactive.
Most alcohol-free hand sanitizers are non-flammable. This is because they do not contain the high concentrations of ethanol or isopropanol found in alcohol-based counterparts. The primary active germ-killing agents in alcohol-free sanitizers are not flammable.
Alcohol-free hand sanitizers can be effective in reducing microbes. They are often formulated to be gentler on the skin, incorporating moisturizing agents to prevent dryness. This makes them a suitable option for individuals with sensitive skin or those who prefer to avoid alcohol.