Issue 2 Jul 05

INTERNATIONAL FIRE TRAINING CENTRE FIREFIGHTER INITIAL FIRE SERVICE EQUIPMENT (Hose, Branches, Hydrants) Throughout this note he means he/she and his means his/hers. Areas considered to be of prime importance are in bold type INTRODUCTION All equipment used in the Fire Service has been designed to operate effectively in the rigorous circumstances of an operational incident. The firefighter should recognise how to use and care for this equipment correctly so that whatever the piece of equipment is, it gives reliable and long lasting service. Now, more than ever before, we are using more complex equipment. The items discussed in this note are some of the most basic but perhaps most important, and without which the firefighter would be unable to operate. AIM The aim of this note is to introduce students to some basic items of Fire Service equipment, namely, Hose, Branches and Hydrants. OBJECTIVES After the lesson covering this subject and after careful study of this training note, you will be able to: •

State the various types of Fire Service Hose and detail its use.

•

Recognise what can cause damage to Hose

•

Explain the functions of a water spray branch

•

Describe a fire hydrant

CONTENTS Hose – General Information Types of Hose Required Performance of Hose Construction Care of Hose Branches Fire Hydrants Hydrant Marker Plates Summary

Issue 2 Jul 05

HOSE – GENERAL INFORMATION Hose is one of the basic pieces of equipment in the firefighters toolbox. It is used to channel water from its source to wherever it is required for firefighting purposes. Although it is a very basic piece of equipment, without it hundreds of thousands of pounds worth of fire appliance could be rendered ineffective. Hose of all types is designed to be durable and capable of withstanding some of the rigors placed upon it. It is however, vital that firefighters take care of hose so that it does not let them down when they need it most. TYPES OF HOSE There are three main types of hose in use in the Airport Fire Service; •

Lay-flat Delivery Hose (also referred to as soft suction)

•

Hose-Reel Hose

•

Suction Hose

REQUIRED PERFORMANCE OF HOSE Reliability in use Hose must be capable of safe operation at the pressures required without fear of bursting, breaking or leaking. When pressurised, they should pass round tight corners and bends without any kinking that will reduce or stop the water flow. Whilst all hose increases or decreases in length to some extent when pressurised, this length change must not be excessive (less than 5%) so as not to cause the hose to snake or twist when a sudden change of pressure occurs. Similarly, the increase in diameter with pressure must not be excessive (less than 10%) although the higher the change in diameter, the greater resistance to water hammer and the higher water flows. Pressure changes cause hose to twist to some extent but this amount of twist must tighten rather than slacken any screw-on couplings used. Handling and Storage To allow easy stowage in appliance lockers, hose needs to be as lightweight as possible, to be capable of easy, neat coiling into low diameter stable coils when wet or dry or in cold conditions. During storage, hose performance must not be impaired by mechanical damage, e.g., cracking on the lay-flat crease, by perishing (ozone attack) of the rubber or by moisture. Performance should not be unduly impaired by prolonged contact with liquids other than water, e.g. battery acid, petrol, where such accidental contact is made. Durability The durability and wearing capabilities of hose must be as high as possible and have a high resistance to abrasion. It must be able to withstand the inevitable rough usage it will get in service. It is also essential that the hose be easily repairable as hose will, no matter how well looked after, burst due to damage or other unforeseen circumstances. Friction loss Hose suffers a loss in pressure along its length reducing both the pressure and flow at the nozzle. This pressure loss is greatest for long lengths and small diameter hose. Hose is designed and constructed to minimise such losses.

Issue 2 Jul 05

Pressure and acceptance tests Hose must be capable of withstanding not only normal operating pressures but short-term pressure fluctuations and shock pressures possibly exceeding 10 bar. Manufacturers test short (1m) lengths to burst point, e.g. 35 bar, recording the short length burst pressure (SLBP). They also check that the full length delivered will withstand 22.5 bar (the ‘proof’ pressure) without burst, damage or leaking. CONSTRUCTION Lay-flat Delivery Hose In the past, delivery hose was constructed using mainly natural fibres like cotton or flax. These fibres were prone to rotting under damp storage conditions which could lead to the hose bursting in use. Modern hose is made from synthetic yarns, especially Polyester and Nylon, which not only eradicates the problem of rotting but also has extra strength. The use of modern rubber technology allows the use of thinner linings, therefore reducing weight and coil diameter. Although there are many sizes available, the Airport Fire Service normally use hoses of 25 or 30 metres in length and with a diameter of either 45mm or 70mm. The hoses are fitted with standard instantaneous couplings which allow inter-connectability of all sizes of hose, all equipment to be used with hose (i.e. branches) and all pressurised water supplies (i.e. pumps and hydrants) Hose-Reel Hose Hose-reel hose is a delivery hose of small diameter (normally 19mm) that is carried on a rotating drum. It must be flexible and not flatten when coiled. This allows the hose to be instantaneously brought into use with only the amount required needing to be payed off the drum. The hose is normally made in 18 metre lengths with three lengths joined end-to-end on the drum giving a working length of 54 metres. The hose is normally fitted with Hermaphrodite or MacDonald couplings which are designed to withstand the higher working pressures. Suction Hose Suction hose is designed to resist external pressure and is used exclusively between the water supply and the pump. Modern suction hose is made from heavy duty PVC with a high tensile carbon steel helix which gives the hose the necessary cross sectional rigidity to resist external pressure. Suction hoses used in the Airport Fire Service are normally 2.4 or 3 metres in length and have a diameter of 100mm. The couplings are threaded and require the use of suction wrenches to secure. CARE OF HOSE As previously stated, it is essential that firefighters handle hose with care, although it is designed to be durable, mishandling can lead to unnecessary damage that could lead to failure. Some general rules are: •

Do not drive vehicles over hose. Hose ramps should be used where it is necessary to deploy hose across road, etc.

•

Do not kink hoses around corners under pressure. Hose should be deployed as straight as possible.

•

Do not roll up when frozen. When the hose is frozen it can become brittle or can be damaged by sharp ice particles.

•

If the hose has been used with foam systems, always flush out thoroughly with clean water.

•

Always under-run the hose before rolling and re-stowing.

Issue 2 Jul 05

BRANCHES There are various types of branches in use in the Fire Service ranging from simple nozzles to complex foam making branches. The standard type in use in the Airport Fire Service is the hand-controlled branch. The purpose of a branch is to provide the velocity at the end of the hose to project the firefighting media to where it is required. The hand-controlled branch is a versatile piece of equipment that, when correctly used, offers the firefighter a range of operating options. There is a shut-off valve which gives the firefighter the ability to close down the branch in order to move position more safely, conserve water supplies and reduce water damage. The diffuser nozzle can be rotated in order to select a spray pattern that suits the operational circumstances. On a wide spray, the water can be used to provide the firefighter with protection from radiant heat. The spray pattern can be coned down from a wide spray to a jet which means the water will be projected a greater distance thus allowing the firefighter to move away from the fire. We rarely fight fires with a jet. We normally use a narrow cone-shaped spray pattern as this is the most efficient way of using water for firefighting.

FIRE HYDRANTS The purpose of a hydrant is to provide a link from below ground water mains to where the water is required above ground. There are various types of hydrant and means of identifying their location. The two main types of hydrant are: •

Screw down hydrants

•

Sluice valve hydrants

Screw Down Hydrants This is probably the commonest type, being found in one or other of its forms in most parts of the country. It is attached directly to the main, which is provided at the chosen point with a vertical branch having a flange to which that of the hydrant is bolted. A mushroom type valve closes on a seating in the base of the hydrant body just above the inlet flange. The valve has a facing of rubber or other suitable resilient material, while the seating is of gunmetal. The valve is attached to the lower end of a screwed stem and is lifted from its seating by the rotation of a hollow spindle into which the stem screws until it is clear of the waterway. Guides are provided to ensure accurate seating of the valve. A cover to the hydrant body carries the stuffing box and gland through which the spindle passes. The outlet is bolted to the upper end of a bend leading from the valve seating. The hydraulic efficiency of this type varies greatly with the design of valve and outlet bends.

SCREW DOWN HYDRANT

Issue 2 Jul 05

Sluice Valve Hydrant This type of hydrant is not placed above the main but alongside it on a short branch, the water flowing horizontally past the valve, and not vertically as in the screw down type. It consists of three main castings, the inlet piece which is connected to the pipe, the sluice valve itself, and the duckfoot bend leading to the outlet. The opening and closing of the waterway is affected by means of a gate or wedge, having gunmetal faces, which seats on corresponding faces in the body of the valve. Rotation of the spindle raises the wedge until it is clear of the waterway. The spindle passes through the valve cover by means of the usual gland and stuffing box. This hydrant is hydraulically very efficient, and when the valve is open, gives a full waterway with a negligible loss of pressure.

SLUICE VALVE HYDRANT

False Spindles The spindle of a hydrant is usually made of bronze or gunmetal, and in order to protect the squared top from wear caused by the loose-fitting hydrant key, a cap known as a false spindle, made of a harder metal such as cast iron or steel, is fitted over it and secured with a pin or screwed stud. Frost Valves When the valve of a hydrant is closed after use, a certain amount of water is trapped in the body of the hydrant between the valve and the outlet. This is a source of danger in a cold climate as it may freeze

Issue 2 Jul 05

and so prevent the valve being opened, or may crack the hydrant body. Where frost is likely to be experienced the hydrant should be fitted with means for draining off the water. The simplest way of doing this is by a hole drilled in a small gunmetal plug screwed into the body at its lowest point, as in many screwdown hydrants. The disadvantage of this method is that water is constantly discharging through the hole while the hydrant is in use, though the loss is comparatively small.

HYDRANT MARKER PLATES Hydrant Marker Plates are yellow with black characters or digits. Top Number:

The size of the main in millimetres

Bottom Number: The distance between the plate and the hydrant in metres Colour: Black on a yellow background

SUMMARY The Fire Service equipment detailed in this training note is the most frequently used. It is vital that the firefighter recognises its uses and its limitations. Careful handling and sound regular maintenance will ensure that the equipment gives years of reliable service. Misuse could lead to equipment failure when the firefighter is depending on it the most.