Fire hose
A fire hose is a high-pressure hose that carries water or other fire retardant to a fire to extinguish it. Outdoors, it attaches either to a fire engine, fire hydrant, or a portable fire pump. Indoors, it can permanently attach to a building's standpipe or plumbing system.
The usual working pressure of a firehose can vary between while per the NFPA 1961 Fire Hose Standard, its bursting pressure is in excess of.
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 occasions, fire hoses have been used for crowd control, including by Bull Connor in the Birmingham campaign against protesters during the Civil Rights Movement in 1963.
History
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. 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.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. These lengths of leather were sewn together like a boot leg. 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. 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.
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.
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 usage
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. 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.Suction Hose
Suction hose is laid down on the suction side of pump 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 suction hose
Fully embedded 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, 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.| Name | Definition |
| Attack | Attack hose is a fabric-covered, flexible hose used to bring water from the fire pumper to the nozzle. This hose ranges in nominal inside diameter from and is designed to operate at pressures up to about. The standard length is. |
| Supply and relay hoses | Supply and relay hoses are large-diameter, fabric-covered, flexible hoses used to bring water from a distant hydrant to the fire pumper, or to relay water from one pumper to another over a long distance. These hoses range in nominal inside diameter from. They are designed to operate at pressures up to about for the smaller diameters and up to for the larger diameters. The standard length is. |
| Forestry hose | Forestry hose is a fabric-covered, flexible hose used to fight fires in grass, brush, and trees where a lightweight hose is needed to maneuver it over steep or rough terrain. Forestry hose comes in nominal inside diameters and is designed to operate at pressures up to about. The standard length is. |
| Booster hose | Booster hose is a rubber-covered, thick-walled, flexible hose used to fight small fires. It retains its round cross-section when it is not under pressure and is usually carried on a reel on the fire pumper, rather than being stored flat. Booster hose comes in nominal inside diameters and is designed to operate at pressures up to. The standard length is. |
| Suction hose | Suction hose, sometimes called hard-suction hose, is usually a rubber-covered, semi-rigid hose with internal, metal reinforcements. It is used to suck water out of unpressurized sources such as ponds, rivers, or swimming pools for home wildfire protection purposes. Hard-suction hose comprises multiple layers of rubber and woven fabric encapsulating an internal helix of steel wire. Some very flexible hard-suction hoses use a thin, polyvinyl chloride cover with a polyvinyl chloride plastic helix. Suction hose ranges in nominal inside diameter from. The standard length is. |
Another suction hose, called a soft-suction hose, is actually a short length of fabric-covered, flexible discharge hose used to connect the fire pumper suction inlet with a pressurized hydrant. It is not a true suction hose, since it cannot withstand negative pressure.
Raw materials
In the past, cotton was the most common fiber used in fire hoses, but most modern hoses use synthetic fiber like polyester or nylon filament. The synthetic fibers provide additional strength and better resistance to abrasion. The fiber yarns may be dyed various colors, or may be left natural.Coatings and liners use synthetic rubbers, which provide varying degrees of resistance to chemicals, temperature, ozone, ultraviolet radiation, mold, mildew, and abrasion. Different coatings and liners are chosen for specific applications.