A fire hose (or firehose) is a high-pressure hose that carries water or other fire retardant (such as foam) to a fire to extinguish it. Outdoors, it attaches either to a fire engine, fire hydrant, or a portable fire pump. [1] Indoors, it can permanently attach to a building’s standpipe or plumbing system.
The usual working pressure of a firehose can vary between 8 and 20 bar (800 and 2,000 kPa; 116 and 290 psi) while per the NFPA 1961 Fire Hose Standard, its bursting pressure is in excess of 110 bar. (11,000kPa; 1600psi)[2] Hose is one of the basic, essential pieces of fire-fighting equipment. It is necessary to convey water either from an open water supply, or pressurized water supply. Hoses are divided into two categories, based on their use: suction hose, and delivery hose.
After use, a fire hose is usually hung to dry, because standing water that remains in a hose for a long time can deteriorate the material and render it unreliable or unusable. Therefore, the typical fire station often has a high structure to accommodate the length of a hose for such preventive maintenance, known as a hose tower.
On occasion, fire hoses are used for crowd control (see also water cannon), including by Bull Connor in the Birmingham campaign against protesters during the Civil Rights Movement in
Until the mid-19th century, most fires were fought by water transported to the scene in buckets. Original hand pumpers discharged their water through a small pipe or monitor attached to the top of the pump tub.[3] It was not until the late 1860s that hoses became widely available to convey water more easily from the hand pumps, and later steam pumpers, to the fire.[4]
In Amsterdam in the Dutch Republic, the Superintendent of the Fire Brigade, Jan van der Heyden, and his son Nicholaas took firefighting to its next step with the fashioning of the first fire hose in 1673.[5] These 50-foot (15 m) lengths of leather were sewn together like a boot leg.[6] Even with the limitations of pressure, the attachment of the hose to the gooseneck nozzle allowed closer approaches and more accurate water application. Van der Heyden was also credited with an early version of a suction hose using wire to keep it rigid.[7] In the United States, the fire hose was introduced in Philadelphia in 1794. This canvas hose proved insufficiently durable, and sewn leather hose was then used. The sewn leather hose tended to burst, so a hose fabricated of leather fastened together with copper rivets and washers was invented by members of Philadelphia’s Humane Hose Company.[8]
Around 1890, unlined fire hoses made of circular woven linen yarns began to replace leather hoses. They were certainly much lighter. As the hose fibers, made of flax, became wet, they swelled up and tightened the weave, causing the hose to become watertight. Unlined hoses, because of their lack of durability, were rapidly replaced with rubber hoses in municipal fire service use. They continued to be used on interior hose lines and hose rack until the 1960s to 1980s. In January 1981, the Occupational Safety and Health Administration revised their standards such that unlined hoses were to no longer be installed for interior hose lines.[9]
Following the invention of the vulcanization process as a means of curing raw soft rubber into a harder, more useful product, the fire service slowly made the transition from bulky and unreliable leather hose to the unlined linen hose, then to a multi-layer, rubber lined and coated hose with interior fabric reinforcement. This rubber hose was as bulky, heavy, and stiff as a leather hose, but was not prone to leaking. It also proved more durable than unlined linen hose. Its wrapped construction resembled some hoses used today by industry, for example, fuel delivery hoses used to service airliners
Modern fire hoses use a variety of natural and synthetic fabrics and elastomers in their construction. These materials allow the hoses to be stored wet without rotting and to resist the damaging effects of exposure to sunlight and chemicals. Modern hoses are lighter weight than older designs, which has reduced the physical strain on firefighters.[10] Various devices are becoming more prevalent to remove air from the interior of fire hose, commonly referred to as fire hose vacuums. This makes hoses smaller and somewhat rigid, allowing more hose to be packed into the same compartment on a fire-fighting apparatus.[11]
Suction Hose
Suction hose is laid down on the suction side of pump (inlet) where the water passing through it is at a pressure either below or above that of the atmosphere. It is designed to resist internal and external pressure. It should have sufficient strength to withstand the pressure of external air when a vacuum has formed inside. It should also be strong enough to resist hydrant pressure. Usually an appliance has to carry about 10 m of suction hose in either 3 m or 2.5 m length. The diameter of the hose depends on the capacity of the pump, and three standard sizes such as 75mm, 100mm, and 140mm are generally used.
Partially Embedded suction hose
Partially Embedded suction hose is usually made of a tough rubber lining embedded fully as a spiral, with tempered, galvanized steel wire. This embedding is arranged so that it provides a full waterway and a relatively smooth internal surface. The wall of the hose is prepared from several layers of canvas and rubber lining so that turns of each one lie midway between turns of the other. The complete wall is consolidated by vulcanizing.
Fully embedded (smooth bore) suction hose
Fully embedded (smooth bore) suction hose has a thick, internal rubber lining embedded fully with a spiral of wire. Suction hose should be constructed to withstand a pressure of 10.5 bar.
Delivery Hose
Delivery hose is laid down from the delivery side of the pump (outlet), and the water passing through it is always at a pressure greater than that of the atmosphere. Delivery hose is divided into two categories: percolating hose, and non-percolating hose.
Percolating hose Percolating hose is used mainly to fight forest fires. The seepage of water through the hose protects the hose against damage by glowing embers falling onto it or the hose being laid on hot ground.
Non-percolating hose In fire services, non-percolating hoses are generally used for delivering water. Non-percolating hose consists of a reinforced jacket made from polyester or nylon yarns. This type of hose has an inner lining of vulcanized rubber fixed to the jacket by an adhesive. The use of non-percolating hose is recommended in certain applications, as friction losses will be much less than that of percolating hoses.
Lined hose are divided into 3 types:
Type 1: Lined hose without external jacket treatment: Such hose absorbs liquid into reinforcement jacket and requires drying after use.
Type 2: Coated lined hose: This has a thin, elastic outer coating that reduces liquid absorption into the jacket and may slightly improve abrasion resistance.
Type 3: Covered lined hose: Covered lined hose has a thicker elastic cover that prevents liquid absorption but also adds substantial improvements to abrasion and heat resistance.
Types
There are several types of hose designed specifically for the fire service. Those designed to operate under positive pressure are called discharge hoses; they include: attack hose, supply hose, relay hose, forestry hose, and booster hose. Those designed to operate under negative pressure are called suction hoses.
Hose connections are often made from brass, though hardened aluminum connections are also specified.[15] In countries which use quick-action couplers for attack hoses, forged aluminum has been used for decades because the weight penalty of brass for Storz couplers is higher than for threaded connections.
Threaded hose couplings are used in the United States and Canada. Each of these countries uses a different kind of threading. Many other countries have standardized on quick-action couplings, which do not have a male and female end, but connect either way. Again, there is no international standard: In Central Europe, the Storz connector is used by several countries. Belgium and France use the Guillemin connector. Spain, Sweden and Norway each have their own quick coupling. Countries of the former Soviet Union area use the Gost coupling. Baarle-Nassau and Baarle-Hertog, two municipalities on the Belgian-Dutch border, share a common international fire department. The fire trucks have been equipped with adapters to allow them to work with both Storz and Guillemin connectors.[18]
In the United States, a growing number of departments use Storz couplers for large-diameter supply hose, or other quick-action couplings. Because the usage is not standardized, mutual aid apparatus might have a compartment on their trucks dedicated to a multitude of hose adapters.
The different styles of hose couplings have influenced foreground tactics. Apparatus in the United States features “reconnects”: Hose for a certain task is put into an open compartment, and each attack hose is connected to the pump. Time-consuming multiple connections or problems with male and female ends are avoided by such tactics. In countries where Store (or similar) connectors have been used for attack hoses for generations, firefighters drop a manifold at the border of the danger zone, which is connected to the apparatus by a single supply line. As a result, the tiny item “hose coupler” has also influenced the looks and design of fire apparatus.