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Fire Hose
A fire hose or water line is basically a length of flexible piping that’s designed to deliver pressurized liquid over a significant distance. There are many different types of fire hose and they differ based on their construction materials and design, where they are located, and what size they are intended to handle. Regardless of type, these devices are built to withstand extreme temperatures, pressure and volume flows.
Fire hoses are generally categorized according to several factors including the type of material used for construction, the number of sections in the hose, the gauge (thickness) of the tubing and/or fittings, whether an inner tube is present, and the diameter or internal cross-sectional area of the pipe. Pipe diameters range from about 1⁄8 inch (0.32 cm) to 1 foot (30.48 cm) and may be single-walled or multi-walled. In addition to being able to withstand pressures from a fire hose, pipes are often selected for specific uses due to size and strength requirements. Pipes are also manufactured in many different lengths, ranging from less than 10 feet (3 meters) to more than 100 feet (30.48 m).
The three most commonly seen types of fire hoses are:
• Rubber or vinyl hoses. These are flexible and relatively inexpensive. Vinyl hoses are widely used throughout North America and are suitable for most applications. They resist damage well at high temperatures. Rubber hoses are stronger, heavier and more expensive. They are ideal for situations where a hose is subjected to heavy use and is likely to break.
• Metallic or stainless steel hoses. Stainless steel is resistant to corrosion and rusting, making them particularly useful for environments where hoses are exposed to saltwater, chemicals or industrial fumes.
• Plastic hoses. Polyethylene plastic hoses, or PE, offer excellent resistance to heat and chemical damage. However, PE hoses are slightly brittle and have good surface abrasion characteristics. As a result, they tend to wear out sooner than metallic or rubber hoses. Despite these limitations, PE hoses remain popular in certain applications.
There are two basic types of connections between ends of fire hoses: couplings and elbows. A coupling connects two ends of a hose together while an elbow joins two perpendicular sections of a hose. Couplings are either male or female, depending on whether they fit inside of each other. Male couplings are usually threaded and female couplings are flared. To connect a pair of fire hoses, a male fitting is inserted into the end of one hose and then turned clockwise, causing the female coupling to engage with the male fitting. Once connected, the two hoses are joined and run together. Elbows work similarly, except that they join two parallel sections of a hose instead of two perpendicular ones. Connections are installed using special tools called elbows, which are similar to the ones firefighters use.
Once a connection is made, it should be tested regularly to ensure that it remains firm and secure. If a connection starts separating, it should be replaced immediately. This is especially true if the device is exposed to extreme heat or is in a potentially explosive environment.
Fire hoses come in a wide variety of colors, designs and sizes. A few examples of colors include red, green, yellow, blue, orange, purple and black. Many models come in various gauges, meaning that their wall thicknesses vary. Gauge refers to the thickness of a section of a fire hose, measured in millimeters. Most fire hoses fall into the following categories:
• Very thin hoses – These hoses are 0.25 mm thick or less. They are often used for short distances, such as around a house or apartment, or for temporary purposes only.
• Intermediate thickness hoses – Hoses in this category are often 1–1.50mm thick.
• Thick hoses – Commonly referred to as “Buckets,” these hoses are 2.00mm thick or greater. The thicker they are the longer they last and the larger the volume they hold.
Hose manufacturers make sure that fire hoses meet certain standards before they release them onto the market. These standards are set forth by NFPA, American Society of Heating, Refrigeration, and Air Conditioning Engineers (ASHRAE), and ASTM International. ASHRAE has developed a set of standards known as ANSI/ASHRAE Standard 188 for the sizing and testing of fire protection equipment. NFPA offers its own standard, NFPA 502, which sets minimum performance criteria for safety valves and hydrants. NFPA also offers a number of standards for sprinkler systems.
Regardless of type, fire hoses are designed to withstand extreme conditions. For example, some hoses are rated to operate up to 300 degrees Farenheit, or roughly 150 degrees Celsius. Because of this, fire hoses must be kept away from direct sunlight and extremely hot surfaces, and they must be protected from mechanical damage as well. Hoses are also required to retain their integrity when exposed to cold temperatures. Hoses that are not properly maintained will lose their resilience or become weak and fail. For this reason, fire hoses are stored in a cool location and are often wrapped in blankets or placed in bags to keep them from drying out.
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