Definition of Hose:
HOSE is a flexible pipe used to convey water from the source to the scene of fire.
To achieve a better pressure resistance, hoses can be reinforced with fifers or steel cord. Commonly used reinforcement methods are braiding, sparling, knitting and wrapping of fabric plies. The reinforcement increases the pressure resistance but also the stiffness. To obtain flexibility, corrugations or bellows are used. Usually, circumferential or helical reinforcement rings are applied to maintain these corrugated or bellowed structures under internal pressure.
Types of Hose &Characteristics of Hose:
- This is connected to the discharge side of the pump.
- This is subjected to a pressure greater than the atmospheric pressure.
- These are available in the following type:
- Percolating/ Unlined / Canvas hose which are made of vegetable fibres.
- Non percolating hose made up plastic material forming both lining as well as the outer cover. These are no porous in nature.
Controlled percolating hose consisting of a jacket woven from vegetable fibres and having rubber/plastic lining.
Connected to the suction side of the pump. These are subjected to, either above or below the atmospheric pressure. These are of following types:
- Partially embedded.
- Smooth Bore fully embedded.
Hose Reel Hose:
These are made of reinforced rubber fitted with a swiveling joint bound over a reel squeeze nozzle is provided at one end.
Characteristics of Hose:
The main characteristics essential for a good fire fighting hose are:
- Hose must be sufficiently flexible too.
- Enable it to be handled with ease.
- The crease at the edges should be uniform and regular so that the hose does not bulge on one side after wobbling repeatedly.
- Enable it to be made up into a smooth and tight role.
- Hose must be a strong enough for it to be reliable during the ‘use.
- The material used in its construction must have high resistance to abrasion and should be able to withstand the rough usage,
- A tough plastic outer cover will provide additional protection to the jacket and prolong its life.
Resistance to rot:
Hoses made of natural fibers are prone to be affected by rotor fungi. These must be treated without ‘proofing agents such as zinc chloride, penta chlorophenyl laurate, 1. 5% by mass or penta chloro phenyl1- hydroxyl isopropyl, ether (Max 2% by mass).
Weft – Warp
It resist burst – Durability to resist wear and Tear
Flax – Flax
Nylon – Flax
Terylene – Flax
Nylon – Cotton
Terylene – Cotton
Terylene – Terylene
Causes, Nature of Damage and Remedial Measure (R):-
Nature of Damage
|(a) Abrasion||Improper laying & make up||Do not drag the hose on ground|
|(b) Mildew (Fungi)||Not drying after use Stored in damp state||Hose must be dried fully and stored in dry well. Ventilated rooms|
|(c) Shock||Throwing suddenly/abruptly stoppage of flow. Subjecting to high pressure suddenly without kink removal. Pressurizing without removing air||Handle, flow gently stop flow gradually Remove kinks before letting watering. Allow the water to come out at low pressure ensuring all air is removed before raising the pressure|
|(d) Ruber Acid||Improper drying||Dry the hose perfectly|
Care & Maintenance of Hose:
- Store in a cool dry and well ventilated place.
- Hoses should be cleaned’ & dried periodically.
- Rubber lined hoses should be cleaned b) ‘ passing water through them and dried on towers, periodically. These should not be exposed to hot dry air-or sun rays’ for long periods.
- Hoses should be stored in long folds in figure eight position.
- The folds should be changed periodically.
- Hoses contaminated with acids / alkali’s or oils should be cleaned and dried before storing.
- Hoses should be drained by under running and not be walking over them.
- Normally the cleaning is done with water alone.
- If the hose is contaminated with ‘grease/oil add a little soda in water and dean.
- If the hose is contaminated with thick grease acid /oil, use saw dust and fine sand to rub off the sticky substances.
In sheds constructed in such a way as to permit the entry of air as much as’ possible. But no rain should enter it. The hoses are hung from towers/or hooks at the roof of the shed with the help of pulleys.
- In chambers of brick construction. Provision is made to accommodate, 20 lengths of hoses. All the houses are coupled to manifold through which warm air is blown.
- An exhaust fan is fitted to the chamber so that constant air is circulated.
- After use the hose “should be inspected carefully to detect any, damage and to repair the same for future use. Every damage such as pin holes should be marked and the defective hoses should be rolled with male coupling inside for the sake of identification.
- Generally the following repairs are carried out.
- Hose coverings & Bandages:
- Leather gaiters and canvas bandages are applied where the hose appears to be weakened.
- Darning: Pin holes are generally repaired by darning some strands of flex. A patch should be placed on the same.
- Patching” Leaks in the hose are satisfactorily repaired by patching.
Hose fittings ,Grouping and Coupling:
Hose fittings: –
- Fittings of Hose are the equipment’s used in fighting major fires which cannot be controlled with the help of portable fire extinguishers.
- Hose fittings are used to connect hose to the source of water supply, to another hose and to connect the required type of nozzles / branches.
Broadly hose fittings are grouped as follows:
- Hose Ramps
- Collecting Heads and Suction Hose Fittings
These are Meta fittings used for joining two lengths of hose together or a hose to an apparatus vice versa. These are fitted to either end of the hose lengths used for suction or delivery purposes. All couplings are always a pair of two pieces. One is called the “male” and the other a le Instantaneous couplings are now standard in India for delivery hose and pump outlets whereas “threaded couplings are used on suction hose and pump in lets. Instantaneous couplings a provided with the spring loaded lugs with the help of which the hoses can be snapped on and of in an instant. These are provided with the swiveling action for running the coils.
Components of Coupling:
- Serrated Tail.
- Serrated Tail.
- Two hollow lugs.
- Spring loaded plunger with cam shaped tooth.
- Stop nut.
- Metal Disc.
Suction Hose Couplings:
- Serrated Tail.
- Externally threaded end.
- Two fixed lugs.
- Serrated Tail.
- Nut (threaded inside with four legs).
Branches, Nozzles &Branch Holder:
Branch pipe or branch, as it is called generally, is tapering metal fitting used at the delivery ends of a hose. The water-way is slowly narrowed down causing the water on the outside to move more quickly and maintain the same speed as the inner core. It consists of brass pipe or copper pipe, the length of which varies according to its type of manufacture. It has male instantaneous coupling at the base to receive the hose. The other end tapered to a smaller diameter is threaded externally for fixing the nozzle. A washer is also used to make the connection water tight.
Therefore the purpose of the branch is to increase the velocity of water and may be define as “a metal fittings’ between hose and the nozzle that converts pressure energy into velocity energy to provide the nozzle a solid let of water for fire: fighting”.
Types of Branches:
- Uncontrolled (Jet Type).
- Controlled (Jet, Spray, Fog etc. With control).
- Special Types
A typical branch for dealing with fires involving coal heaps, hay stacks etc. It consists of 63 ng dia 10 feet long steel pipes with a pointed head having a’ number of Ve” holes on it the het end has a thread on which may be screwed either collar containing a standard hose Coupling or another10 feet (3 mm) section of piping to extend.
Hand Controlled Branch:
Also known as “London Branch”, has devices either to. Shut off, alter to spray, or to get jet or deliver jet and spray simultaneously. Each function capable of independent control. This branch as the following metal parts.
Main Body Semi Circular handle
Hexagonal base Jet valve
Flange Rotating collar
By turning the rotating collar anti clockwise direction the spray can be varied from a cone of 300 to a flat sheet of 1800 but the size of the jet is not adjustable and depends on the size of nozzle 16 mm or 19 mm. It can be maximum 22 mm because the 1D of the branch would not permit.
This branch can give sprayer jet of variable size which can be shutoff as may be required the spray could be varied from an intense mist over an angle of 180′ to a common shut up.
Its parts are:
Man body, Adjustable rotating leave, must room’s have deflector.
Special Types of Branches:
Revolving head Branch:
This is a gun metal fitting having 63 mm male instantaneous coupling at the lower end and a revolving roundhead supported on ball bearing on both sides with cylindrical cap and nut on top. The revolving round head having the appearance of a dome is pursued with9 holes of 6. 35 mm diameter. Each Hole has gone through a conical shape of revolving plane, there in the centre of the upper half pointing upwards at 600 to the vertical.
The nozzle is a small metal fitting made of gun metal or brass or bronze having a taper shape generally. But it can be made to several shapes depending on the nature of purpose it is many factored for. These have female thread (internal thread). For attachment to the branch. As a precaution against damage the delivery orifice is counter sunk in the nozzle to a depth of 3 mm. the base of the nozzle is hexagonally shaped to permit the use of spanner.
Standard nozzles to fit any branch with 63 mm or 70 mm hose are made of machined gun metal and vary in length from 4 to 4%”. The bores of the nozzle vary in diameter from 4. 6 mm to 44 mm. larger bores are used in Deluge sets or Monitors etc. Besides there are 2ozzies used for Hose Reel Hose, Portable Extinguishers. Also there are nozzles made suitable tor providing fine mist or combination of spray etc.
This branch cart be adjusted to ‘give a water stream for straight jet, a fine or coarse spray and complete shut off. The fine spray is in the form of mister fog, thus the name. A floating rotary valve connected with the handle facilitates the control operations. To prevent the entry of any foreign material wiremen ship provided in a cylindrical rub in between the rotary valve and the male Instantaneous coupling so that the holes’ of the spray nozzle or spray head, are not blocked the spray head is detachable and held in position by the spring loaded interlocking arrangement. With this type of hand controlled branch.
The spray head or spray nozzle can be extended with extension piece or low pressure applicator can be connected to fight small oil fires or discharge the fog directly to the burning surface. The size of the jet is normally 16 mm.
These are mounted on vehicles or fitted on Fire Hydrants which can handle large amounts of water. Single person can operate them.
Collecting Head and Suction of Fitting:
It consists of a metal casting of aluminium or gun metal fitting with two, three, four or six inlets for Delivery Hose and a. single Female Suction Coupling for attaching to the suction inlet of a pump. The water pressure forces the valve off its seating preventing the escape of water, Collecting Head and Suction of Fitting getting fast stuck to its seating. The valve lift must not be less than 16 mm.
This consists of a metal suction strainer fitted with an extension tube in the casting between the strainer proper and the coupling, In this extension, a flap – type reflux valve is fitted in such manner that, water. Rising up into’ the suction forces it open. If the pump is stopped the flow ceases immediately in the suction, the flap valve falls back on its seating, thus preventing the Foot Value: water from escaping and keeping the suction fully changed. This avoids re-priming of the pump when it is to be started again.
Deep Lift Suction Fitting:
It consists of a light alloy body incorporating an inlet strainer plate and housing a two stage ejector unit. The inlet connection is 63 mm instantaneous male and outlet depends on the application. When used for Fire Services it usually has102 mm diameter outlet, two eyes provided for attaching the lower ropes.
It takes delivery of high pressure water from the normal fire pump and transfers the energy to, large volume of water at lower head. Lifts upto80 feet are possible with this fitting.
Cast in gunmetal, brass or bronze, these are used to unite two lines of hose into one. These are also available in designs suitable for uniting two or more suctions to a common inlet these are ‘Y’ shapes. Each of two legs is fitted with a male coupling and a Female coupling is attached to the third leg.
Cast in gunmetal, brass or bronze, these are used to divide one line into two. These are also ‘V shaped. Each of the two legs has a Female coupling and the third leg has a male coupling.
These are metal casting suitable for: Joining couplings of the same type i. e., male to male or female to female. Hydrant plugs. Connecting delivery hose to hard suction.
To facility at a crossing of vehicles over the charged livery hoses, the ramps are place Dover them. The ramps are so constructed as to have an angle of inclination on both sides. Ramps can be made to accommodate one or more hoses. These are made with wood or steel.
Miscellaneous Hose Fittings:
Elbow for Nozzle:
This is a metal attachment fixed between the branch and the nozzle to deliver jets at right angles. These are useful in fighting smoky fires in basements.
Metal cover which is attached to the delivery outlet or a suction inlet when not in, use.
Maintenance of Hose Fittings:
- Inspect and clean the fittings periodically.
- All moving parts shall be oiled to ensure free operation.
- Check washers for wear and tear.
- Replace couplings which are reshaped and do not match properly.