THE FIRE HOSE

THE FIRE HOSE

The fire hose is a flexible duct used to carry water or medium-pressure foam/water mixtures in fire-fighting hydraulic devices. They are generally made of circular polyester fabric with an elastomeric rubber waterproofing layer and have standard fittings. 
Some countries use the other guillemin fittings instead they use the Storz fittings. In many buildings, such as schools, offices and businesses, there are wall hydrants. The operating pressure of a hose may vary between 8 and 20 bars (800 and 2000 kPa, 116 and 290 psi), while the explosion pressure can reach 40 bar (4,400 kpa, 580.151 psi). The fire hoses are also used to discharge the water sucked from the motor pumps or from the pump, during the floods or the emptying of invases. Usually after use the hoses are hung to dry, because the water that remains in a pipe for a long time can deteriorate the material and make it unreliable or unusable. Therefore in the typical fire station there are often high structures designed to accommodate the length of a pipe on which they are stretched for emptying and drying. 
Sometimes, fire hoses are used for the control of the crowd as for example in the events of the G8 in Genoa against the protesters. 
 

HISTORY
Until the mid-nineteenth century, most of the fires were fought by water transported to the place necessary by the use of buckets and it was not that in the late ' 60 that were introduced hoses to bring water ( By means of hand-operated or steam pumps), towards the fire. In 1673 in Amsterdam, Holland, the superintendent of the fire station Jan van der Heyden and his son Nicholaas built the first fire pipe using strips of leather sewn together like a boot leg, long 50 feet (15 m) and also with the pressure limitations, the hose attachment to the nozzle neck allowed tighter approaches and more accurate water delivery to the flames. 
Jan Van der Heyden was also credited with a primitive version of suction pipe with wire to keep it rigid. 
In the United States, the fire-escape pipe was introduced in Philadelphia in 1794, which, realized in canvas did not prove sufficiently resistant and subsequently was introduced a pipe similar to the Dutch one and made in sewn leather which however tended to burst Because of the pressure, so some members of the Philadelphia Humane hose Company invented a leather tube fixed with copper rivets and washers. Around the 1890 the first flexible hoses made of woven linen yarns appeared. The linen fibres offered the advantage of swelling in contact with the water and this clutched the texture, making the tube waterproof, keeping the water inside. 
These linen tubes were quickly replaced with rubber hoses in the municipal fire service because the linen was easily deteriorated after a few uses. 
The rubber hoses continued to be used on lines of internal pipes and supports for hoses up to the Sixties and today are still used for forestry applications. After the invention of the vulcanization process invented by Charles Goodyear, the next tube was a multilayer rubber-coated tube and fitted with an internal fabric reinforcement, but became uncomfortable and cumbersome, heavy and rigid (like the primordial tube in skin), but not subject to bursts or leaks and is also more resistant than the unironed linseed tube. 
Its construction and the type of winding was similar to some tubes still used today such as hoses for the supply of fuel used for the transport of airliners. 
 

MODERN USE
The modern fire fighting tubes are made of polyester circular fabric with a impermealazing underlay made of elastomeric rubber. These materials allow the storage of wet pipes without rotting and resist the damaging effects of exposure to sunlight and chemicals. Modern hoses are also lighter than older designs and this has helped reduce physical tension on firefighters. 
 

TYPES OF TUBES
There are different types of tubes created specially for the fire service. Those created to work under positive pressure are called preheating tubes and have 3 service diameters. Those created to work under negative pressure are called suction tubes. 
PREHEATING TUBES
The preheating tubes have 3 service diameters which are:

• 25 mm, Used to create pipelines for high pressure equipment and for extinguishing forest fires where a light tube is needed to maneuver on steep or rough terrain. The tube is in nominal diameters of 1.0 and 1.5 in (25 and 38 mm) and the standard length is 100 feet (30.48 m).
• 45 mm, Used to form on fire power ducts for small power spears and are also used for wall hydrants and the length of this hose can be 15, 20, 25, 30 m. 
• 70 mm, used to form pipes from the pump to fire and to power spears of great power, as well as are also used to bring water from a hydrant subsoil or supercharge to the pump. The length of this hose can be 15, 20, 25, 30 m.

The operating pressures of these hoses are around 25, 30 bars while the burst pressure and 40 bar. 
SUCTION TUBES
They are sometimes called "suction", these tubes are semi rigid with internal metallic reinforcements. They are used to suck water from unpressurized sources (such as ponds or rivers), by means of the vacuum effect. The nominal internal diameter ranges from 2.5 to 6.0 inches (from 64 to 152 mm), while the standard length is 10 feet (3.05 m). 

RAW MATERIALS
In the past, cotton was the most common natural fibre used in fire hoses but the most modern tubes use synthetic fibres such as polyester or nylon filaments. The synthetic fibres offer an additional strength and a better resistance to abrasion. The fiber strands can be dyed in various colors or can be left in the original color. 
Coatings and seals include synthetic rubbers that provide varying degrees of resistance to deteriorating agents such as temperature, ozone, ultraviolet (UV) radiation, mold or abrasions, and different coatings for applications Specific. 
The suction hose consists of several layers of rubber and woven fabric, encapsulating an internal propeller of steel wire. A very flexible suction pipe uses a thin covering of polyvinyl chloride and also the internal propeller is made of polyvinyl chloride plastic. 
 

PRODUCTION PROCESS
The hose is manufactured in a plant specialised in the supply of flexible pipe products to municipal, industrial and forestry fire-fighting departments. Here is a typical sequence of operations used to manufacture a double-coated rubber tube: 
PREPARATION OF THE YARN

• There are two different yarn fibers that are woven together to form a flexible hose jacket. Yarns running along the hose are called warp and are made of polyester yarn or nylon yarn that form the inner and outer surfaces of the jacket providing the necessary resistance to abrasion of the pipe. Yarns wrapped in a tight spiral around the circumference of the tube are called filler yarns and are made of polyester yarn. They are trapped between the cross warp wires and provide the resistance needed to withstand the internal pressure of the water. Yarn in polyester wire yarns are specially prepared by a specific manufacturer and are shipped to the hose plant. 
• The filament's continuous polyester fibers are collected in a bundle of 7-15 fibers and are wrapped on a frame to form the filler yarns. The wire, once combed and twisted, is then wrapped on a filling coil.

JACKET TEXTILE 

1. The warp threads are staged on a slit, which feeds them along the bottom through a circular frame. Two filling coils with the filler wire are put into place in the frame. 
2. When the frame starts machining, the fill coils wrap the filler wire in a circle through the warp wires and as soon as the coils pass, the frame crosses each pair of adjacent warp yarns to trap the filler wire. Between them. This weaving process continues at a high speed because the lower end of the jacket is slowly dragged through the frame and the coils continue to wrap the filling yarns around the circumference of the jacket in a spiral Narrow. The braided jacket is finally wrapped on a reel. 
3. The inner and outer jackets are woven separately. The inner jacket is woven to a slightly smaller diameter so that it fits inside the outer jacket and depending on the demand, several thousand feet of jacket can be woven at the same time. After an inspection, the two jackets are placed in stock. 
4. If the outer jacket is to be coated, it is picked up through a filling tank filled with the coating material and then passed through an oven where the coating is dried and cured. 

LINING EXTRUSION
Soft, sticky and hardened rubber blocks are fed into an extruder. The extruder heats the tire and presses it through an opening between a solid inner and outer circular piece to form a tubular covering. The rubber coating is then heated in an oven where it is subjected to a chemical reaction called vulcanization. This makes the rubber strong and flexible as the liner passes through a machine called a "rubber grille" that forms a thin sheet of hardened rubber and wraps it around the outside of the liner.
FORMATION OF THE FLEXIBLE TUBE
The jackets and the upholstery are cut to the desired length, then the inner jacket is inserted in the outer jacket, followed by the lining. The end of the assembled tube is fastened to a vise and pressurized steam is injected into the hose while the tube is stretched. This pushes the lining of the liner against the inner jacket and causes the vulcanization of the thin sheet of hardened rubber and forms the tying of the lining with the inner jacket. 
Metal end fittings or couplings are attached to the hose and the outer portion of each coupling is slid onto the outer jacket with a ring that is inserted into the rubber liner. A tool called "expansion spindle" is positioned inside the tube and expands the inner ring to tighten the jackets and their lining between the inner ring and the outer portion of the joint forming a durable seal all the way around the tube. 
TESTING PRESSURE OF THE FLEXIBLE TUBE
The established rules of the National Fire Protection Association require that every lenght of a new double tube must be subjected to pressure at 600 psi (41,4 bar; 4.140 kPa) but the majority part of the manufacturers are tested at 800 psi (55.2 bar; 5,520 kPa). After the delivery, the tube is tested annually at 400 psi (27,6 bar, 2,760 kPa) by the fire service. While the tube is under pressure, it is checked in order to see if there are leaks or to determinate that the joints are firmly attached. Aftere the verification the tube is drained, dried, laminated and shipped to the customer. 
QUALITY CONTROL
Beyond the final pressure test, every pipe is subjected to various inspections and tests in every step of the production. Some of these inspections and checks included visual inspections, tests of resistance to ozone, accelerated aging tests, adhesion tests of the bond between the coating and the inner jacket, determination of the amount of torsion under pressure, dimensional checks and many others.

RECURRENT CHECKING, DURATION AND GUARANTEE
RECURRENT CHECKING
All the fire-fighting piping must be checked periodically and subjected to the following checks:

• Every six months must be completely unrolled and subjected to a normal pressure of the system operation;
• The ligatures must be verified which must not present leaks or leakage;
• They must be visually verified and, if they have lesions or cracks, must be checked at the maximum working pressure indicated by the regulations or technical tables and, where appropriate, they must be replaced; 
• In any case every five years they must be subjected to the maximum working pressure; 
• After use, even if the indicated period of time has not elapsed, the hoses must be drained in order to avoid stagnation of liquid inside and if they are dirty with grease, oil etc., after having been cleaned with a cloth with lukewarm water, without use detergents which may injure the hose, they must be checked at normal mains pressure to check for any damage to the waterproofing coating.

All the above operations must be noted in the appropriate register and reported, if existing, on the periodic verification card applied to the tubing. 
DURATION
The hoses don't have a fixed deadline but theu bust be replaced every time that the periodic verifications foreseen by the rules give negative result.
GUARANTEE
The manufacturer guarantees the hoses for two years from the date of production (stamped on the hose); Beyond that date no replacement is made under warranty. Replacement under warranty is only possible for hoses that have been properly stored and serviced (e.g.: do not leave in particularly critical environments like in the sun, must be dried after each test/use before rewinding).

FITTINGS AND DIAMETERS
Pipe fittings are often made of brass, although hardened aluminium connections are specified. Threaded couplings are used in Italy, the United States and Canada. Each of these countries uses a different type of fitting. Many other countries have standardized quick hooks, which do not have a male and female end, but are linked in both ways. There is no international standard: in Central Europe, the Storz connector is used by a number of countries. Belgium and France use the Guillemin Connector. Spain, Sweden and Norway each have their own rapid coupling. The countries of the former area of the Soviet Union use the pair of GOST. Baarle-Nassau and Baarle-Hertog, two municipalities on the Belgian-Dutch border, share a common one with the International fire Service. The fire trucks were equipped with adapters to enable them to work with the Storz and Guillemin connectors. 
In the United States, a growing number of services use Storz fittings for large power pipe or other fast-acting joints. 
 

UNI REGULATIONS
The fire hoses UNI 45 - 70 produced fom april 1989, with the entry into force of the UNI 9487 rule, they must report permanently and indelibly:

• Reference of the standard 
• Name of the constructor 
• Nominal diameter 
• Length 
• Year of construction 

The fire hoses with a range of internal diameters from 25 mm to 52 mm produced from December 2007 with the entry into force of the norm UNI EN 14540, at least twice (on the piping), must report in a legible and indelible way: 

• Manufacturer's name and/or mark 
• Number and date of European standard 
• The inner diameter 
• The maximum operating pressure in MPa or bar 
• Quarter and year of manufacture 
• Test temperature if less than-20°c 
• The approval number and the certifying body or its reference, where applicable 

HOSE COLLECTION
There are 3 different ways to collect an hose; each of these have a specific purpose:
SPIRAL 
Spiral or even called by launching, and the normal collection hose that is found in the hydrants or on tankers, is also the most used if not the only way of harvesting in Italy. This hose is stretched by grasping the fittings and throwing it down. This type is convenient when you have to lay a line outside of a house. 
"Z" RECOLLECTION
This system is much more practical than teh Spiral collection hose when you have to reach the floor of a building involved in the fire, because as you climb the stairs, it is "laid" without creating folds that would obstruct the passage of the water. Once arrived to the floor affected by the fire, it is connected to a "O"-collection hose. 
"O" COLLECTION
This system is laid on the floor affected by the fire by placing the hose in a circle shape so that it remains stationary and without creating bottlenecks and is very versatile in confined spaces beacause the tubing can be laid vertically without creating any problem.
The "O" and "Z" systems are collection systems which are used mostly in United States.
 

WHEN WE DON'T HAVE TO USE A FIRE HOSE
In the following situations the use ofa flexible hose may pose a danger: 
With a gas burner. A portable fire extinguishing agent is suitable for this purpose. 
Under tension devices. Spray-Mist extinguishers and CO2 extinguishers are suitable. 
With magnesium burns. An extinguisher D is the appropriate extinguishing agent for this purpose. 
Frying fire. An F extinguisher is suitable for this purpose. You can also use a CO2 extinguisher. 
In some other types of fires, for which a D extinguisher is more suitable.