Have you heard of fire sleeves? They are commonly used in airplanes. As shown in the adjacent photo, fire sleeves consist of a hollow, sleeve-like tube. For a better understanding of fire sleeves, including why airplanes have them, keep reading.
The Basics of Fire Sleeves
Fire sleeves are tubes made of fire-resistant materials. They are designed to protect wires, cables and hoses from fire damage. Some of the first fire sleeves emerged in the 1970s, during which they were used in military airplanes. In the years to follow, fire tubes made their way into the commercial and private aviation industries.
While available in different types, most fire sleeves aren’t made of a single material. Rather, they are made of multiple materials. They are constructed of a heavy-duty material, which is then surface-treated with one or more other materials The inner core of a fire sleeve may consist of fiberglass. Surface treatment materials, on the other hand, may consist of synthetic rubber or natural rubber.
Aside from their fire-resistant design, fire sleeves are flexible. They can flex and bend without breaking. The flexible properties of fire sleeves allow for easier installation. Aerospace manufacturers and technicians can run fire sleeves around corners and through tight spaces without fear of breaking them.
Why Airplanes Have Fire Sleeves
Fire sleeves offer protection against fire damage. Wires, cables and hoses can all fail when exposed to heat. The heat from a nearby fire can burn through wire and cable jackets, thus damaging the conductors. Fire sleeves are designed specifically to withstand heat.
Some of them are even classified as incombustible. Incombustible fire sleeves won’t burn or otherwise combust when exposed to a flame. They are rated to withstand temperatures of up to 500 degrees Celsius.
In addition to cables and wires, fire sleeves are used to protect hoses from damage. Airplanes, of course, feature many different hoses, including fuel and oil hoses. Fuel hoses carry jet fuel, whereas oil hoses carry lubricating oil. Some manufacturers encase fuel and oil hoses in fire sleeves. Fire sleeves will shield the fuel and oil hoses so that they are protected from fire damage.
Fire sleeves are exactly what they sound like: hollow sleeves that are designed to withstand heat. Airplanes use them to protect their cables, wires and hoses from fire damage. When placed inside of a fire sleeve, cables, wires and hoses can withstand more heat without succumbing to damage.