Firefighting equipment
Knowledge and information
March 2015
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Contents
Hose layers ........................................................................................................................................................ 3
High-volume pumping (HVP) units .................................................................................................................... 4
Foam-making equipment .................................................................................................................................. 5
Extinguishers...................................................................................................................................................... 7
Firefighting hose .............................................................................................................................................. 10
Branches .......................................................................................................................................................... 13
Monitors .......................................................................................................................................................... 14
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Hose layers
Many fire and rescue services have traditionally used hose laying vehicles to provide large-capacity hoses
delivered by vehicles over distances ranging up to 2km.
Hoses ranging from 70mm to 150mm diameter are stored in a number of ways. They are deployed using
vehicles at low speeds and retrieved using retrieval systems (mechanical or physical).
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High-volume pumping (HVP) units
An HVP unit consists of two demountable modules transported on standard New Dimension prime movers.
Each module consists of two further sub-units, a hose retrieval system and all associated ancillary
equipment. The sub-units carry either 1km of hose or the hydrosub.
A hook arm attached to the prime mover is used to dismount the modules for use. The sub-units are also
removable from the main module for placing as required at an incident.
Hose can be deployed using the 1km hose boxes at a maximum speed of 40km per hour.
HVP vehicle equipment
Hydrosub: The hydrosub is one of the four sub-units transported on the main modules; it weighs three
tonnes and is placed in position using the prime mover. It consists of the submersible pump unit, 60m
hydraulic hose-lines, 60m winch cable for pump deployment and recovery, control panel and the turbodiesel engine that drives both the hydraulic and electrical systems.
The submersible pump is a portable centrifugal pump with a high-flow impeller and flotation chamber,
which is deployed into the water supply. The submersible pump is capable of deployment up to 60m from
the Hydrosub. It is used either to supply water to a fireground or to pump out floodwater to a minimum
depth of 15cms. It is approximately the size and weight of a light portable pump but is fairly easy to
manoeuvre. It has a maximum pumping capacity of 7,000 litres per minute, but has the capability of
delivering large volumes of water at great distances using additional pumps as boosters in a relay system.
The hydrosub is also provided with scene lighting and flashing blue lights to allow it to be placed on roads if
required.
The hose recovery system: Each HVP module has a mechanical hose retrieval unit. Driving at a maximum
speed of 4km per hour, it assists two people located in the hose box to retrieve the hose, which is flaked
back into the hose box ready for redeployment.
Ancillary equipment: The HVP module carries a variety of ancillary equipment including hose adaptors,
five-way manifolds, Y-pieces, gate valves, non-return valves, water safety equipment, harnesses and
lanyards, hose ramps, change of direction equipment, edge protection, sack trolley and lighting, cones and
tape.
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Foam-making equipment
The following equipment is available in various sizes, ranging from those needing less than 50 litres per
minute to over 15,000 litres per minute of foam solution.
LX (low-expansion foam) handheld foam-making branches
These branches are intended to produce relatively low quantities of fully aspirated foam using either
concentrate through a foam pickup tube connected and inducted at the branch or a premixed solution
supplied either through a fire pump with an around-the-pump foam proportioner or an inline foam
generator.
Essentially, turbulence in the foam solution is created in the branch, which draws large quantities of air
through air inlet holes, producing the finished foam.
At the outlet, the branch is reduced in diameter to increase the exit velocity, thus helping the finished foam
to be thrown an effective distance. The design here is crucial – too narrow an outlet produces back
pressure which results in less air being drawn and a finished foam of very low expansion ratio and very
short drainage times. If the outlet is too large, the expansion is higher but the throw is reduced. Some
branches may also contain flow-straightening sections at the nozzle to reduce turbulence at the outlet of
the branch. These assist in forming a coherent ‘rope’ of finished foam with little fallout of foam along its
trajectory.
LX handheld hose reel foam unit
This consists of a portable handheld unit, similar to an extinguisher, which can contain up to 11 litres of
foam concentrate. An emergency fire vehicle hose reel is connected to an adaptor at the top of the unit
and water is supplied at between 2 and 10.5 bars.
A small proportion of the water is diverted to fill a completely deflated flexible bag in the container.
Inflation of the bag displaces the foam concentrate through a siphon tube, the concentrate entering the
main water stream, passing to an integral LX foam-making branch to give a jet of primary aspirated foam.
LX foam generators
As an alternative to a foam-making branch, a LX foam generator may be used. When inserted into a line of
hose, this induces appropriate amounts of foam concentrate and air into the water stream to generate
finished foam, which is then delivered through the hose to a water-type branch for application as finished
foam. The foam concentrate is induced using the same principle as that of an inline inductor, and the air is
drawn in through orifices adjacent to the water inlet.
LX foam monitors
Primary aspirating LX foam monitors are larger versions of foam-making branches, which cannot be
handheld. They may be free standing and portable, mounted on trailers or mounted on emergency fire
vehicles. They usually have multiple water connections, and may be self-inducing or used in conjunction
with other methods of foam concentrate induction. They can be found in fixed installations at oil tanker
jetties and refineries or as oscillating monitors in aircraft hangers. Similar monitors are fitted to airport
foam tenders, often with adjustable jaws which allow the option of a flat fan-shaped spray.
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MX (medium-expansion foam) handheld foam-making branches
With MX foam-making branches, an inline indictor is generally used to introduce the foam concentrate as a
premix. The branch then diffuses, aerates the stream of foam solution and projects it through a gauze mesh
to produce bubbles of a uniform size.
LX and MX handheld water branch snap-on attachments
Snap-on attachments are available for use with some hose reel and mainline water branches, which enable
primary aspirated LX and MX foam to be produced. Generally, the foam produced by these attachments is
not very well worked, making it less stable (it has much shorter drainage times) and less effective than that
produced by purpose-designed primary aspirating foam branches.
MX foam pourers
In addition to the MX handheld foam-making branches, some freestanding MX foam pourers are also
available. These are much larger than the handheld models, have higher flow requirements and hence
produce greater volumes of foam. However, as their name suggests, finished foam pours out of them
rather than being projected. They have been designed to stand on their integral legs for the unattended
delivery of MX foam into bunded areas such as those surrounding fuel storage tanks. They operate in a
similar way to the handheld MX foam branches described above.
HX (high-expansion) foam generators
High-expansion foam generators are designed to be used with particular foam concentrate only and usually
produce finished foams of expansion ratios of 200:1 to 1,200:1.
Air is blown through the generator by a fan, foam solution is sprayed into the airstream, and this is directed
onto the surface of a fine-net screen. The air blowing through the net wetted with foam solution produces
finished foam with a mass of bubbles of uniform size, which, like the MX foam pourers, is ‘poured’ rather
than ‘projected’.
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Extinguishers
While there may be a number of old types of fire extinguisher still in existence, which expel the
extinguishing medium by chemical reaction or by a self-contained hand pump, these have in the main been
superseded by types using an internal charge of pressurised gas. The latter is generally more efficient, less
damaging to materials and easier to refurbish.
According to standard BS EN 3, fire extinguishers in the UK, and throughout Europe, are red RAL 3000, with
a band or circle of a second colour covering between 5 and 10 per cent of the surface area of the
extinguisher indicating the contents. (Before 1997, the entire body of the fire extinguisher was colour
coded according to the type of extinguishing agent.)
BS EN 3 details portable fire extinguisher characteristics, performance requirements and test methods. The
BS EN 3 colour coding is:
Type
BS EN 3 colour coding
Water
Signal red
Foam
Red with a cream panel above the operating instructions
Dry powder
Red with a blue panel above the operating instructions
Carbon dioxide CO2
Red with a black panel above the operating instructions
Wet chemical
Red with a canary yellow panel above the operating instructions
Class D powder
Red with a blue panel above the operating instructions
Halon – 1211/BCF
No longer in general use
Water-type extinguishers
Water (gas cartridge) extinguisher
The water content of this plastic-lined steel cylinder is generally six or nine litres and the expellant gas,
usually CO₂, is contained in a cartridge fitted inside the body of the extinguisher. The removal of a safety
pin or plug and pressure applied on the operating lever of the extinguisher causes a pressure disc on the
cartridge to be pierced and at the same time opens a control valve. The release of gas exerts pressure on
the surface of the water, forcing it up through a discharge tube and out through a hose and nozzle
Water (stored pressure) extinguisher
This is of similar construction to the gas cartridge type and available in similar capacities, the difference
being that the whole container is pressurised. Air or nitrogen is pumped into it through a special adaptor in
the opening head. The extinguisher is operated by removing a safety pin or plug and squeezing an
operating lever. This opens the control valve and allows pressurised air to expel the water. Again, the
discharge can be controlled by the lever.
Foam extinguishers
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Most types of foam concentrate in common use can be found in portable extinguishers. These include
aqueous film-forming foam (AFFF), alcohol-resistant aqueous film-forming foams (AR-AFFF) and filmforming fluoroprotein (FFFP).
Chemical foam extinguishers
These have now largely been replaced by more modern types. The chemical reaction in the extinguisher
produces a foam containing CO₂ bubbles and the gas pressure itself causes the discharge.
Self-aspirating foam extinguishers
Here, a foam solution is stored in a container, usually of six or nine litre capacity, and either discharged by a
gas cartridge of CO₂ fitted in the body of the extinguisher or by compressed air or nitrogen, which has been
pumped into the container. In both cases, the solution is forced out through the delivery hose and
aspirated by the specially designed branch of the low-expansion type.
Non-aspirating aqueous film-forming foams AFFF extinguisher
This is usually a gas cartridge-operated type with a modified nozzle that sprays the AFFF onto the fire.
Powder extinguishers
Powder used to extinguish or control fires is composed essentially of very small particles of an appropriate
chemical or chemicals. This is treated with flow additives to give resistance to moisture absorption and
caking during storage and to give a free flow when discharged through hoses and nozzles. Different
chemicals are effective on different classes of fire, and powders are classified according to their potential
application.
Portable powder extinguishers are available in sizes ranging from 1kg to 12kg of powder content. The
methods of expelling the powder from the container are similar to those of water and foam extinguishers,
i.e. stored pressure or gas cartridge. The pressurised gas, when released, ‘fluidifies’ the powder and ejects
it through a discharge tube and nozzle.
Gaseous extinguishing media
Three groups of gaseous extinguishing media can be used in portable extinguishers:
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Carbon dioxide
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Halons, the use of which has been greatly restricted by the ratification of the Montreal Protocol
(Montreal Protocol on Substances that Deplete the Ozone Layer)
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More complex mixtures of non-halon gases
Carbon dioxide extinguishers
CO₂ extinguishers basically consist of a pressure cylinder, a control valve for releasing the gas and a
discharge horn for applying the gas onto the fire. The CO₂ is retained in a liquid condition in the cylinder,
which is usually filled to approximately two-thirds of its total capacity. A small amount of CO₂ evaporates
and fills the top third of the cylinder, and it is this gas which acts as the expellant. On actuation, the
discharging gas expands at a ratio of 450:1 and this mostly takes place in the discharge horn, which is used
to direct the gas onto the fire. The design of the horn is a very important feature; its main purpose is to
stop the entrainment of air with the CO₂ by reducing the velocity of the gas. Without this horn, the jet of
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CO₂ gas and air would act like a blowtorch and increase the intensity of the fire.
Halon extinguishers
Portable halon extinguishers commonly range from 0.7kg to 7kg and are invariably of stored pressure type.
They are normally pressurised to about 10 bars with dry nitrogen to ensure efficient discharge.
Most halon extinguishers have their discharge controlled by a lever but a few designs have a striker, which
may or may not give a controllable discharge. Several manufacturers incorporate some sort of pressure
indicator and/or method of showing whether the extinguisher has been used.
By their design, halon extinguishers, once used, need to be recharged either in workshops or by the
manufacturers or other specialists. Some smaller types feature a removable expendable body, with the
operating mechanism capable of removal and replacement on another cartridge. Others are completely
disposable.
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Firefighting hose
The main characteristics of good firefighting hose are:
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Flexibility: Hose must be sufficiently flexible to enable it to be handled easily and without knotting
when in use and for it to be made up into a smooth roll whether wet or dry
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Durability: The durability and wearing qualities must be as high as possible and the materials used,
particularly in the warp, must have high resistance to abrasion and be able to withstand the rough
usage which hose inevitably receives in service. A tough plastic outer cover gives additional
protection to the jacket and prolongs the life of the hose.
It is also essential that the hose is easily repairable by simple means. However good a hose may be initially,
bursts do occur through damage and other reasons.
Change in length and diameter
Any increase in the length or diameter of hose when under pressure indicates that the materials are
stretching. Unlimited stretch would tend to weaken and burst the hose. Moreover, lengthwise stretch or
extension causes hose to ‘snake’ when under pressure.
Frictional loss
The internal surface should be as smooth as possible to reduce to a minimum loss of pressure through
friction.
Weight
The weight of hose is important, not only from the point of view of handling at fires and drills but also for
stowing on emergency fire vehicles.
Hose pressure and acceptance tests
Hose has to stand high internal pressures. During firefighting these pressures may be as high as 10.5 bars
and shock pressures may be even higher. Hose must be designed to give an adequate margin over pressure
likely to be encountered and it is usually constructed to withstand at least twice the pressure to which it is
likely to be subjected in service. Manufacturers sometimes indicate the average burst pressure of their
various hoses. This is referred to as the ‘short length burst pressure’ and may be as high as around 40 bars
depending on the type and quality of the hose.
Storage of hose
Many different methods have been developed for storing hose, which may be listed as:
•
The roll (or coil)
•
Dutch roll (or roll on the bight)
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Flaking
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Figure of eight
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The Cleveland coil
Deterioration of hose
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Mildew: Synthetic materials are not affected by mildew but fungus may grow on them if damp and dirt is
present. Although mildew has no deleterious effects on synthetic yarn, proper care should nevertheless be
exercised.
Shock: It is not generally realised that shock is a frequent cause of hose failure. Hose should always be
treated with care and rolls of hose should never be thrown roughly to the ground even though they may be
dry and in good condition. Shock may also arise when water is allowed to flow too rapidly into a line of
hose which is badly kinked; the sudden straightening out of hose under pressure and the ensuing rush of
water which flows only to be checked by the next kink set up a series of pressure waves which may lead to
a burst at a weak point. Similarly, a burst may also occur if a hand-controlled branch is shut off suddenly, or
a line is charged too rapidly after a temporary shutdown.
Acids, oils, grease and petrol: Some types of fire hose are liable to damage by contact with acid, oil, grease,
petrol, etc., and hose should be stored well away from these substances. Care should also be taken when
working at oil installations and industrial undertakings to ensure that, as far as possible, hose has minimal
contact with oils and the like. For example, petrol may cause the rubber lining to separate from the fabric.
Hard suction hose
Suction hose or hard suction hose is the name applied to hose designed to resist external pressure. It is
used exclusively between the water supply and the pump. As it will withstand internal or external pressure,
it can be used when working a pump either from pressure-fed mains or from open water supplies. It is an
essential part of the equipment of every pumping emergency fire vehicle. The diameter of the hose must
be such as to enable the pump it is used with to operate at maximum capacity according to the rated
output of the pump.
Although the lengths and diameters of suction hose vary with the emergency fire vehicle on which it is
carried, the construction is substantially the same in every case. The principal feature is that it should
possess sufficient strength to withstand without collapsing the pressure of the external air when a vacuum
has been created inside. It should also be strong enough to resist the maximum hydrant pressure normally
encountered, and at the same time possess the maximum of lightness and flexibility compatible with this
strength.
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Care of firefighting hose
Fire and rescue services should follow the following guidelines on the care of firefighting hose:
Hose should be stored in a cool, dry, well-ventilated place
Hose unused for long periods should not remain on emergency fire vehicles but should be removed
and placed on racks or towers
•
Rubber-lined hose should have water passed through it from time to time to keep the lining in good
condition, after which it should be thoroughly drained and dried in towers or by hanging in a warm
room
•
If hose becomes frozen it should on no account be bent as it will be liable to crack
•
Great care should be taken of rubber-lined hose, especially when cooling down after large fires, as
it may have been stretched over debris. As bricks and stone retain heat for a long time, the outer
covering is liable to scorch, weakening it and shortening its life.
•
Hose should never be bent or kept at an acute angle, especially under pressure, since this causes a
severe strain on the fibres. This is a frequent source of breakage, particularly if the edge under
strain is rubbed sharply or knocked against a hard surface.
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•
Hose laid across roads should always be ‘ramped’ to prevent damage by passing vehicles
•
Hose known to have been contaminated with acids or alkalis should be thoroughly washed
immediately with clean water
•
Hose should be drained by under-running. When under-running it is essential to see that kinks do
not form at the bends, which may lead to the formation of pockets of water or pockets of vacuum
and thus prevent the complete removal of the water.
•
Personnel must not be allowed to walk on hose to flatten it out or rid it of water before rolling. This
may not only drive any flints or grit which may be present into the fabric but also imposes a heavy
strain on the fibres on either fold, which considerably weakens the hose. In practice, it is found that
bursts almost invariably appear at the two opposite points on the hose where it has been flattened.
•
With lined hose, avoidance of such treatment is of even greater importance because not only are
the fibres of the jacket weakened but the lining itself becomes fretted and particles of dirt lodge in
these frets causing a rapid deterioration of the rubber. The correct method of clearing water by
under-running is to raise the hose shoulder-high while avoiding kinks, which will trap the water
•
When making up hose on the roll, the female coupling should not be doubled down onto the hose
too tightly and the first coil should be somewhat loose. This will minimise the possibility of the
coupling edge cutting into the hose and, in the case of lined hose, the lining becoming separated
from the jacket due to strain. In this connection, it is advisable to examine couplings periodically
and remove ‘burrs’ which might cause damage.
•
Care should be taken when hose is stowed on emergency fire vehicles to avoid the possibility of
hose chaffing against the locker sides due to vibration
•
Emergency fire vehicle locker doors should be opened at frequent intervals to allow air to circulate
and condition the hose
Branches
Branches without control facilities
The standard type of branch and nozzle has been used for many years in fire and rescue services. However,
with technological advancement, the majority of fire and rescue services now use various configurations of
modern types of hand-controlled branches. It is worth noting that there may still be areas in the sector
where this type of equipment remains in use.
Branches with control facilities
There are many different patterns of hand-controlled branch in use by fire and rescue services, all designed
to enable branch operators to control or change in one way or another the formation of the water stream
by the operation of levers, triggers or various forms of attachment. With most hand-controlled branches,
the pattern of the water stream can be changed from a jet to a diffused spray or vice versa, or to stop the
flow altogether.
Hose reel branches
Fire and rescue services use many different types of hose reel branch, which have the dual-purpose
function of providing either a straight jet or a spray that can be adjusted by the operator to give a dense
mist of fine intensity or coarse spray. With some models, both jet and spray can be used.
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Monitors
While many monitors are permanently fixed to pipework and designed to protect specific installations, it is
sometimes more convenient to mount monitors on trailers that can be moved from hazard to hazard.
Smaller monitors can be moved by hand and placed on the ground to provide a rapid response in the event
of a fire. However, mobile monitors require a water supply, usually provided by hoses or portable pumps.
The jet reaction force of a portable monitor can vary from a few kilogrammes for a small ground monitor to
over a tonne for a larger trailer-mounted unit. Any portable monitor should be secured so that it cannot
move once the full water flow and pressure is applied.
Small hand wheel portable monitors are specifically designed to be easy to manoeuvre and carried over
rough terrain. To resist the jet reaction forces, portable ground monitors are provided with a method of
stabilising them on soft ground.
Larger monitors are usually mounted on trailers. The trailer is also often fitted with outriggers to provide
stability. Water tanks on the trailer can be filled to provide additional weight for stability. Extra tanks can
also be specified to provide foam concentrate.
In many applications, it is necessary to operate a monitor remotely. To do this, motors are fitted to move
the monitor body in the horizontal and vertical planes. If the monitor is fitted with an adjustable nozzle, this
will also need to be moved with a motor or actuator. Some applications require a master control panel and
slave control panel arrangement, while others require feedback to show the operator where the monitor is
pointing so that it can be operated even when smoke obscures the view.
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