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The Design and Construction of Fire Fighting Monitors Fixed and Mobile, Manual and Remote Control, Water and Foam A UTC Fire & Security Company

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Page 1: Angus Monitors

The Design and Constructionof Fire Fighting MonitorsFixed and Mobile, Manual and Remote Control, Water and Foam

A UTC Fire & Security Company

Page 2: Angus Monitors

Introduction Applications

2

Monitors spend most of their lives static andlifeless. But when a fire is detected they canoften be the only practical way of applyingfoam or water to the fire.

While simple in principle, monitors aresophisticated pieces of engineering made todeliver a specific performance after longperiods of inactivity. Like many engineeringchallenges the design of a monitor can takemany forms depending on the specifichazard it is intended to protect and themechanism and method of operation thedesigner uses to achieve the final layout.When designing a monitor the manufacturermust balance performance, operational lifeand ease of use against cost.

The installation of fixed monitors, or theprovision of mobile or portable monitors, isusually the outcome of a careful analysis ofthe fire risk and the realisation that withoutplanning in advance fighting any subsequentfire will present difficulties. It is essentialtherefore, that monitors are robust and willhave a long service life, even under adverseconditions.

Fixed monitors are found wherever there are substantialClass B fire risks while mobile or portable monitors areoften used to protect multiple risks by moving themonitors around the site.

Nearly all industrial fire hazards are candidates formonitor protection, but some of the more commonapplications are:

• Refineries

• Fuel distribution depots

• Chemical plants

• Warehouses

• Helicopter landing pads

• Aircraft hangars

• Loading jetties

• Process plants

• Industrial process areas

• Shipping

• Vehicle-mounted

Page 3: Angus Monitors

Fixed or mobile?

3

While many monitors are permanently fixed to pipeworkand designed to protect specific installations, it issometimes more convenient to mount monitors ontrailers that can be moved from hazard to hazard. Inaddition, smaller monitors can be designed to be movedby hand and placed on the ground to provide a rapidresponse in the event of a fire. However, mobilemonitors require a water supply, usually provided byhoses or portable pumps.

The jet reaction force for a portable monitor can varyfrom a few kg, for a small ground monitor, to over atonne for a larger trailer-mounted unit. Any portablemonitor must be secured so that it cannot move once thefull water flow and pressure is applied.

Small, hand-wheel portable monitors are specificallydesigned to be easy to manoeuvre and carried overrough terrain. To resist the jet reaction forces portableground monitors are provided with a method ofstabilising them on soft ground.

Larger monitors are usually mounted on trailers. Inaddition, the trailer is often fitted with outriggers toprovide stability. Water tanks on the trailer can be filledto provide additional weight for stability. Extra tanks canalso be specified to provide foam concentrate.

Trailer-mounted monitors provide a useful addition to the armoury of equipment a fire service can draw on should alarge fire occur. The mobile monitor can be used to protect locations inadequately covered by fixed monitors or providecooling to equipment adjacent to the fire.

Angus monitor with optional foam induction system anchored onsoft ground with bipod mechanism

Angus trailer-mounted monitors with self-inducing foam cannons

Page 4: Angus Monitors

Monitor Design

4

Design is always a compromise The layout of the pipes that make up a monitor mustserve several functions. They must contain the waterwhile allowing the jet to be moved in both thehorizontal and vertical planes; they must be strongenough to resist the pressure and reaction forcesgenerated by the water; and they must be robustenough to allow the mounting of additional items suchlevers, gearboxes, hydraulic actuators and nozzles. All ofthis must be achieved with a design that is cost effective,has an acceptable pressure loss, will resist corrosion andis not too heavy. Like many engineering designs a typicalmonitor is a compromise between cost, weight andperformance.

Pressure losses If too much water is forced around too many tight bendsat too high a speed there will be an unacceptablepressure loss between the monitor inlet flange and thenozzle. The result will be that the water or foam jet willnot travel as far as it could. Some designs use a verycompact layout forcing water to turn 90° bends andsplitting the water into two paths which meet again atthe outlet. While the dual path waterway layout iscompact its pressure losses can be unacceptable wherethe supply pressure is limited.

In addition, the turbulence created when the two waterstreams meet usually adversely affects the nozzleperformance and limits its range still further.

Waterways manufactured from cast bronze usually havetighter bends than those manufactured from steel sinceit is difficult to fabricate tight bends in steel tube. As aresult, stainless steel monitors generally have a lowerpressure loss than the equivalent cast bronze monitorwhile the dual waterway designs have the highestpressure losses of all.

Water takes on a spin when negotiating the bends in asingle or dual waterway pipe. By the time it hasnegotiated both the horizontal and vertical joint bendsthe spin generated can cause a reduction in throw. Thespinning water expands the jet stream creating greaterfriction as it passes through the air. To reduce the spincast bronze or iron waterway monitors often have vanesor blades cast into the tube to reduce the spin in thewater stream.

Bearings The normal practice is tosupport the two parts ofa monitor, where itmoves in the horizontalor vertical plane, using adouble ball race. A shaftseal is positionedbetween the ball racesand the waterway toretain the water underpressure. Plugs aremachined into the outercasing to allow the ballbearings to be insertedduring themanufacturing processand can be fitted withgrease nipples to allowlubrication duringmanufacture ormaintenance.

Monitor type Pressure loss at Typical nozzle1000 l/min throw

Single waterway 0.2 bar (3.0 psi) 38 mfabricated stainless steel

Single waterway 0.3 bar (4.5 psi) 37 mcast bronze

Dual path waterway 1.0 bar (15 psi) 33 mcast aluminium

NOZZLE

NO VEINS

TIGHT BENDS

VANES

SWEEPING BENDS

INCREASEDTURBULENCE

TURBULENCE

Sharp bends and merging flowscause turbulence

Flow straightners in pipe reduce water stream turbulence and rotation

Some designs include a second seal to prevent dirt anddust entering the bearing assembly. However, this cancause difficulties since the bearing chamber becomes asealed space with no room for expansion.

Like most engineering designs the layout of the bearingsis a compromise. The wider apart they are the lower theforces on each bearing race. However, widening thebearing spacing also increases the overall size of the unit.

To resist the loads steel balls are used. These are normallya high grade stainless steel such as SS316. When themonitor body is bronze the steel balls rest in tracksmachined into the casting. However, when the monitor isfabricated from stainless steel pipe and the bearingtracks are incorporated into the fabrication it is essentialto select a material for the steel balls that does not reactwith the steel of the bearing races or the balls may “pickup” causing the bearing to seize.

Page 5: Angus Monitors

5

Misalignment is more common in fabricated monitors.Unless great care is taken during the welding, and specialtechniques and jigs are used, the welded pipes can easilydistort.

A worm and wheel gearbox drive is generally used forcontrol in the vertical and horizontal planes for monitorswhere the flow is 3,000 l/min or more.

Ball Bearings Shaft Seal

Fitting Plugsfor BearingInsertion

Nozzle flow Total reaction Typical side force onat 7 bar force at tip monitor handle with

5° of misalignment in the horizontal plane

2,000 l/min 140 kg 6 kg

4,000 l/min 240 kg 11 kg

6,000 l/min 310 kg 14 kg

8,000 l/min 425 kg 19 kg

Gearbox actuation

Control of the vertical and horizontal movement using aworm and wheel gearbox is recommended for tworeasons. Firstly, it is easy for the operator to set themonitor in position. The handle loads are low andcontrol is precise. Secondly, a worm and wheel gearbox,if correctly designed, will resist any out of alignmentforces.

Provided the worm drive angle is less than 20° it ispossible for the worm to drive the wheel, but it isimpossible for the wheel to drive the worm due tofriction in the gearing. The mechanism is thereforeintrinsically safe and any out-of-balance forces in themonitor cannot move it off target.

Non-reversible worm drive makes it easy to steer and holds the monitorin position

Reaction forcesIt is important to arrange the layout of a monitor so thatthe thrust or reaction force caused by the water leavingthe nozzle or foam cannon is directed through the pivotpoint in both the horizontal and vertical planes.

If the monitor is distorted and the reaction force doesnot pass through the pivot there will be a sideways orvertical force on the monitor. If the out-of-line force isnot restrained the monitor will tip up or down or spin inthe horizontal plane. The consequences of this can beserious. If the monitor is spinning, often the only way tostop it may be to turn off the water at its base. If over 80kg of monitor body is spinning at 2 or 3 revolutions persecond it can be dangerous to climb underneath thespinning body to turn off the water! It could alsodamage or bend the pipework or other structures.

The forces exerted by the jet are considerable and even aminor misalignment can result in a large side load. If atthe same time there is a side wind acting on the monitorit is possible for the load on the handle to be too muchfor the operator to manage.

Out-of-balance forces cause the monitor to rotate or move outof alignment

Page 6: Angus Monitors

6

The materials most commonly used are steel in the formof fabricated tube or cast bronze, but aluminium andcast steel or iron are also available.

Fabricated steel

High quality steel monitors are normally fabricated fromgrade SS316 stainless steel tube, although some arefabricated from the lower grade SS304 to reduce cost butthese suffer corrosion problems in coastal areas andshould not be used with seawater. Steel monitors usuallyhave a larger footprint and are physically higher thancast units because of the limits imposed when bendingthe tube. It is impossible, when bending steel tube, toachieve the tight bend radius possible with a cast unit.However, the larger radius bends have the advantagethat the water pressure losses are lower with fabricatedstainless steel monitors when compared to cast bronze.

Typical performance comparison

However, when comparing stainless steel with bronzemonitors with similar flow rates bronze units aresubstantially heavier.

Typical performance comparison at similar flow rate

Low cost monitors or monitors intended for applicationswhere corrosion is not a problem can be fabricated frommild steel tube. The steel is sometimes galvanised toprovide some protection against corrosion, although apainted finish is often used to reduce cost.

Fabricated steel monitors present additional challengesduring manufacture. When the monitor is to be movedusing a gearbox, or a geared drive using hydraulic orelectric motors, it is necessary to join together thin walltube and robust cast or machined components of widelydiffering thicknesses. This can lead to distortion andstresses during the manufacturing process unless thefabricator is experienced or sophisticated jigs are used.

Where a monitor is made from mild or stainless steeltube it is important to ensure the ball bearings used inthe joints are compatible with the grade of steel used orthe bearing may fail under load.

Brass tube

Brass tube is the weakest of all fabrication materials usedfor monitors and it is limited in size because it is notstrong enough to resist the reaction forces from a largewater jet. In addition, it is impractical to operate themonitor using a gearbox because of the difficulties ofattaching the gearbox mechanism to the tube. As a resultit is only used for small, hand-operated units.

Cast bronze

While cast bronze monitors are heavier and generateslightly greater pressure losses for a given nominal pipediameter they are usually more compact and robust thanfabricated steel units. However, there is a wide range ofmaterials which are called “bronze” and it is important todetermine the specification of the material used whenjudging strength and corrosion resistance.

Nearly all cast bronze monitors use double race bearingsincorporating steel balls for the horizontal and verticaljoints. If the bearing is carefully designed to spread theload, and if the bronze is hard enough, it is usual to allowsteel balls to run in grooves machined directly into thebronze casting. This layout has the advantage of simplicityand will provide a long life if correctly maintained.

A standard published by FM Global calls for monitors tohave free movement in their bearings when subjected to apressure of 35 bar, having previously been subjected to astatic pressure of 58 bar. The end load on a bearing in a150mm (6”) monitor subjected to this pressure is over10,000 kg or 10 tonnes! To prevent the steel balls dentingthe bronze bearing face it is usually necessary toincorporate steel bearing surfaces inside the bronze castingsto withstand the test load. This can lead to extra cost andcorrosion problems in the long-term where the steel meetsthe bronze. In practice, monitors are rarely subjected topressures greater than 16 bar. As a result, manymanufacturers prefer to design to the UL standard or thenew European EU standard.

Flanges and material strength

While some monitors used in Europe are fitted with PN16European standard flanges, most monitors are suppliedwith US ANSI flanges. ANSI flanges come in two basic types,flat faced (FF) and raised face (RF). The full designation alsoindicates the maximum working pressure for the flange.For example a ANSI 4” 150 RF flange is a raised face flangeto fit a 4” (100mm) nominal diameter pipe and designed tobe operated at a maximum operating pressure of 150 psi(10 bar). Because a raised face flange, when tightened up,exerts a greater force on the gasket contact area than a flatfaced flange, raised face flanges can be used at greaterpressures than flat faced. However, if the material used forthe flange is not strong enough the flange will distortwhen bolted up. Therefore, when selecting a material for amonitor the style of flange and the working pressureneeded must be taken into account.

In general steel monitors use steel flanges. These can alwaysbe raised face since steel is strong enough not to distort atpressures used in fire fighting. However, leaded bronze orgunmetal, with its superior corrosion resistance, is relativelysoft and cannot always be used for a raised face flangewhich in turn can limit its pressure rating.

Construction

Material Nominal Flow at 7 bar Pressurepipe size inlet pressure loss

Cast bronze 80mm (3”) 4,000 l/min 3.5 bar

Stainless steel 80mm (3”) 6,000 l/min 0.9 bar

Material Nominal Flow at 7 bar Weightpipe size inlet pressure

Cast bronze 90mm (31/2”) 6,500 l/min 76 kg

Stainless steel 80mm (3”) 6,000 l/min 35 kg

Soft materials are unsuitable for raised face flanges

Flat Face Raised Face Raised Face (soft material)

Page 7: Angus Monitors

7

Material Symbols Tensile strengthGrey cast iron Fe + C + Si 275 MPaMild steel strip Fe + C 300 – 500 MPaStainless steel (SS316) Fe + Cr + Ni + Mo 480 – 600 MPaAluminium (casting grade – with Copper) Al + Cu 250 – 360 MPaCopper (annealed) Cu 210 MPaBrass (Copper with Zinc) Cu + Zn 285 – 400 MPaBronze (Copper with Tin) Cu + Sn 250 – 310 MPaLeaded Brass (Copper with Zinc and Lead) Cu + Zn + Pb 215 - 400 MPaGunmetal or Marine Brass Cu + Zn + Sn + Pb 200 – 250 MPaHigh performance Bronze (Nickel Aluminium Bronze) Cu + Al + Fe + Ni 300 – 750 MPa

One solution is to increase the thickness of a bronzeflange to give it sufficient strength to be machined as araised face flange and bolted up to the recommendedtorque.

MaterialsTo resist heat and have sufficient strength monitors aremade from different metals.

While the basic materials, namely iron, aluminium andcopper, can be used in their natural state it is morecommon to create alloys or variants of the basic metal toimprove their strength, corrosion resistance and theirability to be cast or formed.

Iron is cheap and easy to cast. However, it is heavy andcan be brittle if the carbon content is too high.Corrosion is a problem and it is normal practice toincrease the wall thickness of components to allow forcorrosion, which adds more weight.

Aluminium is light and easy to cast. However, itsstrength is low. Corrosion is a major problem andcomponents made from aluminium must be protected byanodising (a chemical process which puts a hard layer ofAluminium Oxide on the surface) or painting. Bothprocesses, if applied well, provide a hard coating whichseparates the water from the metal. However, once thesurface coating is scratched corrosion sets in quickly andcannot be reversed.

Copper does not have the strength necessary formonitors. It is also soft, which can lead to damage if themonitor is knocked. Copper is also too soft to work as aflange material. Corrosion resistance to salt water is poor.

Brass (Copper & Zinc) is popular for small, low cost,monitors but suffers from many of the same problems asCopper.

Bronze comes in many forms and is the most popularmaterial for manufacturing long lasting cast monitors.Simple Bronze is made from a mixture of Copper and Tin.However, while it is easy to cast and machine, it can beweaker and harder than Brass.

Nickel Aluminium Bronze is much stronger and anideal material. However, it is expensive to cast and costlyto machine. UK standards AB1-C and AB2-C forAluminium Bronze (AB2 contains extra Iron and 5%Nickel) have been superseded by European specificationsCC331G and CC332G. Nickel Aluminium Bronze isgenerally used for marine propellers, hubs and valves inpermanent contact with sea water and subject tocontinuous abrasion. These conditions do not generallyapply to monitors.

Gunmetal, with its added Lead, has excellent corrosionresistance but is not as strong as Aluminium Bronze. It is,however, easy to machine. In the UK two grades ofGunmetal are in common use, LG2 and LG4. Both thesedesignations are now renamed as CC491K and CC492K.

Bronze standards in common use

European standard BS EN 1982 is the new Europeanstandard for Copper alloy and Bronze specifications. Itreplaces the UK standard BS1400 and other nationalstandards such as UNI in Italy. US specifications forBronzes do not match European standards. However, formost of the European Bronzes in common use there is aclose match with the US ASTM standard bronzes.

Alloy Type BS 1400 BS EN 1982 Copper Zinc Lead Tin Aluminium Iron Nickel Manganese(old) Cu Zn Pb Sn Al Fe Ni Mn

High Tensile Brass HTB3-C CC762S 63.0% 25.0% 5.0% 3.0% 4.0%

High Tensile Brass HTB1-C CC765S 61.0% 35.0% 1.0% 1.0% 2.0%

Copper Tin Nickel CT2-C CC484K 86.0% 12.0% 2.0%

Leaded Gunmetal LG1-C CC490K 84.0% 8.0% 5.0% 3.0%

Leaded Gunmetal LG2-C CC491K 85.0% 5.0% 5.0% 5.0%

Leaded Gunmetal LG4-C CC492K 88.0% 2.0% 3.0% 7.0%

Leaded Bronze LB4-C CC494K 86.0% 9.0% 5.0%

Leaded Bronze LB2-C CC495K 80.0% 10.0% 10.0%

Leaded Bronze LB1-C CC496K 78.0% 15.0% 7.0%

Leaded Bronze LB5-C CC497K 75.0% 20.0% 5.0%

Aluminium Bronze AB1-C CC331G 88.0% 10.0% 2.0%

Aluminium Bronze AB2-C CC333G 80.0% 10.0% 5.0%

Page 8: Angus Monitors

8

Country Designation Copper Zinc Lead Tin Aluminium Iron Nickel ManganeseCu Zn Pb Sn Al Fe Ni Mn

Leaded GunmetalEurope CC491K (formerly BS LG2) 85.0% 5.0% 5.0% 5.0%USA ASTM B30 C83 600 85.0% 5.0% 5.0% 5.0%Italy UNI 7013 83.0% 4.0% 6.0% 7.0%Aluminium BronzeUSA ASTM B30-C95 800/500 78.2% 9.4% 5.5% 5.5% 1.4%Europe CC333G (formerly BS AB2) 80.0% 10.0% 5.0% 5.0%

Note: the percentages of different materials shown in the table are all subject to tolerances. For example, the quantity of Zinc in the European standardleaded Gunmetal, CC491K, is shown as 5% but can be anywhere between 4% and 6%. This means that materials which are shown as having slightlydifferent compositions can be identical in practice when the tolerance bands are taken into account.

When specifying a material for monitor production it is necessary to trade off the excellent corrosion protection of theLead in Gunmetal against the extra cost and strength of Aluminium Bronze.

Materials

International standard Constituents Corrosion resistance ApplicationsGrade Cr Ni MoSS301 17% 7% * Springs, structural and wear partsSS302 18% 9% ** Kitchen sinks, water tubingSS304 18% 10% ** Food processing equipmentSS305 18% 12% ** Spun partsSS309 23% 14% ** Heat exchangersSS310 25% 20% ** Heated and electrical partsSS315 17% 10% 1.5% **** Sections and dying plantSS316 17% 12% 2.5% **** Monitors and process plantSS317 18% 13% 3.5% ***** Thick section process plantSS320 17% 12% 2.5% **** Thick section chemical plantSS321 18% 10% ** Heater elements and aircraft partsSS403 13% ** Turbine bladesSS409 12% ** Exhaust partsSS410 12% ** Gas turbine partsSS420 13% ** Kitchen knives430 17% *** Decorative houseware434 17% ** Car trim, wiper blades

* Low corrosion resistance ***** Extremely high corrosion resistance

International material standardsMost countries with an industrial base have standards formaterials which specify their composition andperformance. The most common standards in use are theUS ASTM standards and the European EN standards.However, many other countries have standards includingItaly, Germany, India and Japan.

Comparing materials from one standard to another isoften difficult. However, the US ASTM B62 (also knownas leaded red brass) is equivalent to EN 1982 CC491K (theold BS1400 alloy LG2) and the Indian specification IS:318– LTB2. In Europe SS316 stainless steel for sheet and rodis equivalent to the American ASTM A497.

Applications in chemically hazardous areasBronze is preferred by most users, particularly if themonitor is used for sea water or in coastal salt ladenatmospheres, but other materials have advantages whenother chemicals are present.

If Hydrogen Sulphide is present Bronze can blacken andcorrode. Hydrogen Sulphide can be a by product ofMethane and Propane production. For these applicationsstainless steel is the preferred material.

Salt (Sodium Chloride) and water (H2O) can combine,especially with heat from strong sunlight or processes, toform Hydrogen Chloride. Hydrogen Chloride is also usedin chemical plants for pH control and cleaning. HydrogenChloride attacks steel, including stainless steels such asSS316. Where Hydrogen Chloride is present Bronzemonitors are preferred.

Salt also attacks Aluminium or light alloy and whileAluminium is a good material for monitor production, asit is light and low cost its resistance to salt corrosion ispoor. Over a period of time salt will turn the metalsurface to a white powder if it is not protected and themonitor regularly flushed with clean water after use andkept out of salt laden atmospheres.

SteelMild or ???? steel is used in the form of tube for low costmonitors. Like Aluminium it must be protected againstcorrosion by painting or galvanising. Like Aluminium,once the coating has been damaged, corrosion spreadsquickly. While the material is low cost it presents technicaldifficulties when being welded as distortion can occurwhere there are rapid changes in section (typically wherethe thin wall section joins a bearing housing).

Stainless Steel, next to Bronze, is the most popularmaterial for fabrication of both small and large monitors.SS316 is generally considered the best grade of StainlessSteel for monitors since it combines excellent corrosionresistance with good welding and fabrication features.However, to save cost some manufacturers use SS304.

Page 9: Angus Monitors

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In many applications it is necessary to operate a monitorremotely. To do this motors are fitted to move themonitor body in the horizontal and vertical planes. Inaddition, if the monitor is fitted with an adjustablenozzle this will also need to be moved with a motor oractuator. Remote control monitors will often need tomeet the standards for operation in an area subject toexplosive gases such as ATEX in Europe or NEC in theUSA. Some applications require a master panel and slavepanel arrangement, while others require feed back toshow the operator where the monitor is pointing so thatit can be operated even when smoke obscures the view.

Hydraulic driveHydraulic motors have the advantage of low cost,simplicity and are usually explosion proof.

Advantages:

• No need to use limit switches on the motors. Whenthey reach the limit of travel they will simply circulatethe hydraulic fluid without damage

• Reliable, low cost and easy to maintain

• Option of a water driven hydraulic power pack meansthe system does not need an electrical supply

Disadvantages:

• General limited to 300 m maximum distance betweenthe monitor and control panel

• No facility for a secondary panel

• No facility for position indicators

Electric driveElectric motors must have a mechanism to stop thecurrent when they reach the limit of travel or they mayburn out. Modern positioning encoders and electroniccontrols are replacing the more traditional overloadprotection devices.

Advantages:

• Possible to have a master and slave panel arrangement

• Built in encoders will show monitor position if required

• Distance between the monitor and master panel is notlimited

Disadvantages:

• Can be expensive if explosion proof motors necessary

• Secondary panels in an explosion area need to becontained in explosion proof casings

Hydraulic/electric systemsFor some applications hydraulic/electric systems arepreferred. In these the monitor is moved using hydraulicmotors but the hydraulic power is provided by individualhydraulic power packs mounted at the base of themonitor. The power packs are generally explosion proof.

The advantages of this arrangement are that it combinesthe benefits of using hydraulic motors with the benefitsof electrical control panels, retaining the option of aslave panel and no distance limitations between themaster panel and the monitor.

Distance limitations

There is a limit to the distance it is practical to runhydraulic pipes. If the distance is too long there can beproblems with friction in the pipes. If the pipe size isincreased in diameter to reduce friction the costincreases, and there can be problems with air in thepipes. Both air and friction will cause the movement ofthe monitor to be sluggish or erratic.

Alternatively an electrical supply can be run almost anydistance. Generally a Zone 1 explosion rated multi coreelectrical cable is cheaper than the equivalent multi tubehydraulic pipe.

Remote Actuation

1500m

UP

LEFT

DOWN

RIGHT

POWER ONFAULTMAIN

MONITOR

NOZZLE

FULL FOG

CLOSEOPEN

VALVE

FULL FOG

NOZZLE

POWER ON

LEFT RIGHT

DOWN

TAG

FAULT

UP

MONITOR

1500m

UP

LEFT

DOWN

RIGHT

POWER ONFAULTMAIN

MONITOR

NOZZLE

FULL FOG

CLOSEOPEN

VALVE

FULL FOG

NOZZLE

POWER ON

LEFT RIGHT

DOWN

TAG

FAULT

UP

MONITOR

Optional secondary controlstation housed in explosionproof enclosure

Optional secondary controlstation housed in explosionproof enclosure

200m

Hydrauliccontrol panelwith electricdrivenhydraulicpower pack

Hydrauliccontrol panelwith waterdrivenhydraulicpower pack

Water

Hydraulic pipe Electric cable

Maximum practical distance 300 to 400 m 1,500 mbetween panel and monitor

Page 10: Angus Monitors

10

X

Explosion proof panelsIt is normal to mount themaster electrical panel ina safe area with thesecondary panel, nearthe monitor, containedin a explosion proofenclosure. Where thepanel is hydraulic it isnecessary, if it ispositioned in the riskarea, to ensure both thehydraulic power packand the panel areexplosion rated.

Where it is not considered good practice to have anelectrical supply to the monitor it is possible to use waterpressure to power a Pelton wheel driven hydraulic pump.In this way it is possible to install a remotely controlledmonitor which is totally independent of an electricalsupply and intrinsically safe for zone 1 areas.

Position indicatorsSome systems require the position of the monitor, itsdirection and elevation to be indicated on the mastercontrol panel. This can be useful when the area isobscured by smoke as they allow the operator to pointthe monitor at a specific target even though it cannot beseen.

Most electrically driven monitor designs can be fittedwith encoders on the horizontal and vertical movementswhich send a low voltage signal (intrinsically safe) backto the control panel where the position is shown on adial.

Manual overrideMany specifications require the ability to manuallyoperate the monitor in both the horizontal and verticalplanes in the event of a complete power failure.However, the addition of hand wheels also adds to thecost and complexity of the system.

Remote Actuation Nozzle and Cannon Design

FULL FOG

NOZZLE

POWER ON

LEFT RIGHT

DOWN

TAG

FAULT

UP

MONITOR

Two types of nozzle are generally fitted to monitors.Fog/Jet nozzles which can be adjusted to give either astraight jet or a wide spray water or non-aspirated foamfan, and foam cannons or nozzles specifically designed forthrowing aspirated foam by entraining a quantity of airinto the stream.

Fog/Jet Nozzles are generally manufactured from brass,bronze or aluminium. The simplest designs are adjusted byhand while hydraulic or electrical actuation is employedfor remote control monitors. The design is simple inprinciple and uses a plunger in the nozzle stream to forcethe water into a straight stream when the outer casing isextended, and into a wide jet when retracted. It is normalto use either water or foam solution in a Fog/Jet nozzle.However, the degree of air entrapment in a foam stream islimited to the small amount of air that is trapped in thestream once it leaves the nozzle, which limits the foamexpansion that can be achieved and reduces the stabilityof the foam once loaded.

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Foam cannons are usually not adjustable and will onlyprovide a straight jet. To generate expanded foam anorifice in the pipe entrance is used to generate a lowpressure area and draw air into the foam stream. Foamexpansion ratios of up to 8:1 are common.

Cannons are traditionally manufactured from stainlesssteel (SS316) for the expansion tube and bronze for thetube base. The design and shape of pipe end is criticalfor generating a coherent and tightly packed foamstream. If the foam stream diverges, not only does it pickup more air and expand, but its range will be less.

Self-inducing nozzles and cannonsFor some applications it is convenient to fit the nozzle orbranchpipe with an orifice and pick up tube which, whenthe water is flowing through the nozzle, will suck upfoam concentrate from a container. Foam pick-up tubesshould not be placed more than 4 to 6m from the nozzleor the efficiency of the inductor mechanism will beimpaired and the foam mix may be affected. The energyneeded to pick up the foam will have a small butnoticeable negative effect on the maximum throw.

Throw Calculations

Water jet and self-inducing foam cannon mounted on a single monitorbody. Linked change over valves direct the water flow to the jet or thecannon

Distance travelled

The distance a jet of water or foam solution will travel is,in theory, simple to calculate. If the flow of waterthrough the monitor, typically in litres/minute, is knownand this is divided by the cross sectional area of thenozzle, the speed of the jet can be calculated. If it isassumed that there is no atmospheric drag then theoptimal angle for the jet is 45°. This is easier tounderstand by taking the two extremes. If the jet wereto be pointed straight up (90º) it would not travel anydistance horizontally and would fall back to groundwhere it started. If the jet were fired horizontally (0º) itwould hit the ground almost immediately and onceagain travel no distance. Half way between 90º and 0º,or 45º, gives the maximum distance that can, in theory,be travelled horizontally before gravity pulls the jetdown to the ground. For a monitor flow of 6,000 l/minwith an effective nozzle orifice diameter of 6 cm, the exitvelocity from the nozzle is 35 m/sec. If the nozzle is at anangle of 45º the vertical and horizontal components ofthe velocity are 25 m/sec. Gravity will slow the jet by 9.8m/sec for every second the jet is in the air. Therefore, thetime that will elapse before the vertical jet stream hitsthe ground is just under 5 seconds (2.5 seconds upwardsand 2.5 seconds downwards). During this time the jet willtravel horizontally for 5 seconds at 25 m/sec or atheoretical distance of 125 m before hitting the ground.However, in real-life air resistance and other dynamiceffects make the actual distance much shorter, typically80 m, or 50% to 60% of the theoretical distanceachievable.

Air resistance

The major influence on jet travel is air resistance. As thewater jet leaves the nozzle it breaks up into droplets,each one of which behaves as a small ball travellingthrough the air. The smaller the droplets, the wider thespread of the jet, the greater the air resistance and theshorter the throw. Not only is there resistance throughthe air but the jet is subject to wind, either from the sideor head on. Even a small air movement will make asignificant difference to the spread of the jet and thethrow of a nozzle.

Air resistance increases as a square of the water dropletspeed. Therefore, the jet slows at a greater rate when itfirst leaves the nozzle than when it is close to hitting theground at the end of its travel. Because of this effect theoptimum angle for achieving the maximum throw ordistance is not 45° but nearer 32°.

50% 60% 100%

theoretical throw

actual throw

CURVED LIP CAUSES JET SPREAD SHARP LIP MAINTAINS JET LINEARITY

Page 12: Angus Monitors

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Foam in the jet stream

Foam, especially aerated foam from an aspirating cannonincreases the area of the jet stream and therefore thetheoretical air resistance. However, in practice it can havethe opposite effect. Modern protein-based foam (FP orAR-FFFP), is cohesive and sticks to itself, increases thedroplet size. This has the effect of binding or coalescingthe foam stream into a “rope” helping the jet to punchthrough the air with reduced surface area and thereforereduced resistance. As a general rule a modern FP or AR-FFFP protein-based foam in the jet stream, provided it isnot expanded above 10:1, can increase the maximum jetthrow by around 5%.

However, synthetic based foam like AFFFS can have theopposite effect. The detergent bubbles slip and slide overone another and have no cohesive effect on the jet. Thisresults in a jet more likely to spread out, increasing windresistance. In addition, synthetic foam is often seenfalling short with wider levels of dropout between themonitor and the target, resulting in less foam reachingits destination. High performance ARAFFFS with theirpolymer additives help detergent foams behave morelike protein based products.

Distance or foam quality?

It is possible to design a foam cannon that will maximisethe distance the jet will travel. However, it is importantto ensure that the foam quality generated is goodenough to extinguish a fire. Unfortunately cannons thatgenerate foam with the best expansion ratios anddrainage times are not the same designs that will throwthe longest distances. It is essential when comparingcannons and monitors to ensure that distance claims arebacked up with foam quality tests. Distance alone isalmost always achieved at the expense of foam quality,in some cases to the point where the foam delivered willbe inadequate for effective fire fighting.

How far will the jet travel?

Unfortunately there are so many conflicting effects thatcome into play that it is difficult to predict with anydegree of accuracy how far a given combination ofmonitor, nozzle and foam will throw or what height thejet will clear. Not only are there the effects of nozzledesign but wind, foam type, self-inducing pressure lossesand the general condition of the equipment will allaffect the distance travelled. Figures given in data sheetsmust of necessity be taken as an approximate guide tothe best that can be achieved under ideal circumstances.

Allowances need to be made for prevailing conditionsduring use that can reduce the distance travelledthrough no fault of the monitor, nozzle, inductionsystem or foam concentrate being used.

Throw Calculations Water, Foam & Powder

Fluorprotein-Based Foam

Synthetic-Based Foam

WaterWhere the primary function of a monitor is cooling, dustcontrol or water jetting the only considerations arewhether the water is potable, brackish or seawater. If saltis present then a bronze or SS316 stainless steel monitoris required. Mild steel and light alloy will be quicklyattacked by salt, severely reducing the working life ofthe product, leading to high maintenance and unreliableoperation.

Where cooling is the objective it is important to ensurethat the correct quantity of water can reach the hazardafter taking into account obstructions.

Depending on the application either a fog/jet nozzle or asimple water cannon for maximum throw is adequate forwater alone.

FoamThe majority of monitors are used to place foam on to afire or fire hazard. The monitor design, its throw and jetheight are critical to ensure the foam can reach its targetwhile still maintaining adequate quality in terms ofdrainage time and expansion ratio.

Modern FP, ARFFFP or ARFFF foams are preferred sincethey enhance the throw of the jet and minimise dropoutand wastage. They also minimise fuel pick up fromforceful plunging and provide superior burnbackresistance with longer post-fire security.

Most monitors are designed to produce their optimumperformance using only one manufacturer’s foam. Wherethe monitor producer does not manufacture foam then itcan be difficult to determine performance in the field.

PowderThe use of fire fighting powders is particularly usefulwhere pressurised gas and liquid leaks may occur.Because of the nature of these hazards it is essential tochoose the correct powder. For powder applicationsspecialist assistance is recommended from themanufacturer at an early stage in the specification of themonitor and powder cannon but Monex is the discerningchoice by many leading class B, C, E fire professionals.

Angus Colossus large-capacity aspirating foam monitor

Page 13: Angus Monitors

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Explosion Proof Rating

Many monitors are sited in areas where flammableliquids or gases are processed, stored or transported.While there is little risk of explosion when the liquidsand gases are contained, it must be assumed that there isa risk of explosion if there is a breakdown, an emergencyrelease or sudden ignition. To allow for this,specifications normally call for monitor and monitorcontrol systems to be manufactured to internationalexplosion proof standards such as ATEX (ATmosphèresEXplosibles) or NEC (National Electrical Code) in the USA.

Most fire fighting equipment will be sited in:

“A place in which an explosive atmosphere is likely tooccur in normal operation occasionally.” These areclassed as Zone 1 or Class 1 areas.

ATEX DirectiveFor gases (and vapours given off by flammable liquids)this represents a Zone 1 area. (Zone 0 is the continualpresence of flammable gas, Zone 2 is where flammablegas is not likely to occur).

Equipment for use in these areas is classified into Groupsand Categories.

Zone 1 requires monitors and control equipment to beGroup II approved. (Group I is reserved for miningequipment).

Equipment is given a Category depending on the Zone inwhich it is intended to operate. A Zone 1 environmentrequires equipment classified as Category 2G, where Gstands for gas. (There are separate categories for dusthazards - D).

The type of protection applied is defined by the CENELEC(Comité Européen de Normalisation Electrotechnique)code. Ratings are defined by a letter preceded by EEx. Anexplosive or flame proof enclosure for a control panelintended for a Zone 1 area would be classed as EEx d. Inaddition, the maximum surface temperature theequipment can generate is also added to ensure itcannot form the source of ignition for any gases present.The code “T4” indicates a maximum temperature of135°C which caters for most fire fighting requirements inindustrial areas.

Therefore, for a monitor used to protect a Zone 1 area,for example a hydrocarbon loading jetty, the ATEXapproval should read: CE Ex II 2 II EEx d T4.

Note: The ATEX classification system only applies toequipment containing electrical components orapparatus which could cause a spark or become hot andcan cause ignition and a subsequent explosion.Equipment which is only mechanical and cannot cause aspark or produce sufficient heat to ignite gas cannot beATEX approved.

USA – Hazardous area classificationsUnder the US NEC system areas are firstly given a “Class” location for specific applications. Class 1 coversflammable gases, vapours or liquids. (Class 2 is dust and 3 fibres). Classes are further subdivided into “Divisions”.

Division 2 is defined as “Where ignitable concentrationsof flammable gases, vapours or liquids are not likely toexist under normal operating conditions”. (Division 1 isfor flammable gases present some or all of the timeduring normal operating conditions).

There is a further classification for the type of gas orvapour that may be present and their ignitiontemperatures. Most industrial systems fall under GroupsC and D.

A typical monitor installed under the US classificationsystem may be required to operate in a Class 1, Division 1, area in which gases in Groups C and D may bepresent.

Comparison of ATEX and NECThe ATEX system was made mandatory in Europe in July2003 and reflects a more up to date method of working. It also takes into account a wider range of parametersthan the US system. As a result, ATEX is a morecomprehensive system and is therefore the preferredsystem for most international fire fighting specifications.

Comparison of ATEX and NEC zone classifications:

ATEX

Zone 0

Where ignitable concentrations of flammable gases,vapours or liquids are present continuously or for longperiods of time under normal operating conditions

Zone 1

Where ignitable concentrations of flammable gases,vapours or liquids are likely to exist under normaloperating conditions

Zone 2

Where ignitable concentrations of flammable gases,vapours or liquids are not likely to exist under normaloperating conditions

NEC (USA)

Division 1

Where ignitable concentrations of flammable gases,vapours or liquids can exist all of the time or some of the time under normal operating conditions

Division 2

Where ignitable concentrations of flammable gases,vapours or liquids are not likely to exist under normaloperating conditions

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Titan Range

Angus Fire has beenmanufacturing fixed andportable monitors for over 40years. The range includes lightalloy, stainless steel andbronze models ranging innominal flow from 1000 to40,000 l/min. The trailermounted fixed range ofmonitors is supplemented by awide range of fog/jet nozzlesand foam cannons. Self-inducing nozzles and cannonsare also available.

Angus Fire, the manufacturerof the unique Monnex®

powder, manufacturespecialist powder nozzles forselected models.

AR-AFFF is increasinglypopular by those committedto synthetic detergent basedproducts on the basis ofexceptional Last Fire testperformance.

Hydraulic, electrical andhydro/electric remote controloptions are available on allmonitors together with a widerange of single and multi waycontrol panels. Remotecontrol panels for use in areaswhere explosive regulationsapply are also available.

Angus Fire is the worldsleading manufacturer of firefighting foam concentrates.Angus Fire monitors aredesigned to optimise theperformance of Angus Firefoams, maximising throw andflow without reducing foamquality. Modern FP or AR-FFFPprotein-based foams, such asAngus Fire Tankmaster, arepreferred since they enhancethe throw of the jet andminimise dropout andwastage. They also minimisefuel pick up from forcefulplunging and provide superiorburnback resistance withlonger post fire security.

Portable / mobile

Hand lever withfriction locks

Hand wheel*with worm andwheel gearbox

*Chain drive optional

Automatic oscillating gearbox

Hydraulic drive(EExd rated)

Hydraulic drivewith electro/hydro powerpacks(EExd rated)

Electric drive(EExd rated)

1,800 - 3,900 l/min 4,000 - 5,900 l/min 6,000 - 7,900 l/min 8,000 - 9,000 l/min 15,000 - 30,000 l/min 50,000+ l/minMax throw 80m Max throw 90m Max throw 95m Max throw 100m Max throw 115m Max throw 130m

NO VEINS

TIGHT BENDS

V

INCREASEDTURBULENCE

TURBULENCE

Double row stainlesssteel bearings

Computer aided bendsreduce flow losses

Jig welded stainless steel minimises offset forces

PMA 18 1,800 l/min

PMS 27-372,700 - 3,700 l/min

GMS 303,000 l/min

GMA 303,000 l/min

MSS 065

LMB/A 303,000 l/min

LMS 303,000 l/min

REMA 303,000 l/min

RHMA 303,000 l/min

RHEMA 303,000 l/min

GMS 454,500 l/min

GMB 505,000 l/min

LMB 404,000 l/min

LMS 454,500 l/min

OMB 404,000 l/min

OMB 363,600 l/min

RHMB 505,000 l/min

RHEMB 505,000 l/min

REHMB 505,000 l/min

RHMS 606,000 l/min

RHEMS 606,000 l/min

REMS 606,000 l/min

LMS 606,000 l/min

GMS 606,000 l/min

A Light alloy body L Hand lever and locks

B Bronze body M Monitor

C Continuous rotation O Oscillating movement

CG Chain drive Gearbox P Portable

E Electrical motors R Remote control

G Worm and wheel gearbox S Stainless steel 316 body

H Hydraulic motors

PMB 656,500 l/min

PMB 404,000 l/min

Titan

Page 15: Angus Monitors

15

- 7,900 l/min 8,000 - 9,000 l/min 15,000 - 30,000 l/min 50,000+ l/minthrow 95m Max throw 100m Max throw 115m Max throw 130m

Stainless Steel 316Alloy Bronze

Angus Fire, Thame Park Road, Thame, Oxon, OX9 3RT, UKTelephone +44 (0)1844 265000 Fax +44 (0)1844 265156

E-mail [email protected] Web www.angusfire.co.uk

Nominal flows and throws shown at 7 bar inlet pressurewith foam and no wind conditions

NOZZLE

N VANES

SWEEPING BENDS

Wide range of fog jet nozzles and foam cannons

r aided bends ow losses

Electro-hydraulic, water-hydraulic and electrical panels

FULL FOG

NOZZLE

POWER ON

LEFT RIGHT

DOWN

TAG

FAULT

UP

MONITOR

Panels for hazardous areas

© Angus Fire. Angus Fire reserves the right to modify any specification without prior notice

RHMB 656,500 l/min

REMB 656,500 l/min

RHEMB/C 656,500 l/min

LMB 656,500 l/min

OMB 656,500 l/min

GMB 656,500 l/min

LMS 808,000 l/min

GMS 808,000 l/min

REMS 808,000 l/min

RHMS 808,000 l/min

RHEMS 808,000 l/min

RHEMB/C 858,500 l/min

REMB 858,500 l/min

LMB 858,500 l/min

GMB 858,500 l/min

RHMB 858,500 l/min

OMB 858,500 l/min

RHMS 20020,000 l/min

GMS 20020,000 l/min

REMS 20020,000 l/min

RHEMS 20020,000 l/min

REMS 30030,000 l/min

LEO + HYD 80

RHMS 30030,000 l/min

GMS 30030,000 l/min

RHEMS 30030,000 l/min

RHMS 50050,000 l/min

RHEMS 50050,000 l/min

PMS 100 - 30010,000 - 30,000 l/min

PMS 808,000 l/min

n Monitor Range

Page 16: Angus Monitors

A UTC Fire & Security Company

THAME PARK ROAD, THAME, OXFORDSHIRE, OX9 3RT, ENGLAND

Tel: +44 (0)1844 265000 Fax: +44 (0)1844 265156

e-mail: [email protected] Web site: www.angusfire.co.uk

REF: 6445/1-01/07 © Angus Fire Printed in England

Angus Fire reserves the right to modify any specification without prior notice.

Technical datasheets containing further information are available on request from your local Angus Fire representative orfrom our website www.angusfire.co.uk

Approvals

In common with most fire fighting equipment,monitors can be approved by third party nationaland international accreditation bodies. While somebodies verify the manufacturers’ specifications,others test the equipment to their own, clearlydefined standards.

The two most common test standards for fixed fireprotection equipment are FM Global and UL(Underwriters Laboratories Inc) based in the USA.Others in common use are Lloyd’s Register/MCA(Lloyd’s Register plus UK Maritime and CoastguardAgency), Bureau Veritas (France), ABS (AmericanBureau of Shipping), DNV (Det Norsk Veritas –Norway) and RINA (Registro Italiano Navale). Thelatter are approvals based on codes for theprotection of ships but are also often accepted forland-based systems.

It is expected in the future that fire fightingequipment that generates foam will need to betested by an independent third party test house forcompliance with the EEC Construction EquipmentDirective. The test standards and scope of thissection of the Directive are in the process of beingformulated.

FM standard

FM Global specifies that monitorsshould to be tested for movement ofthe monitor after high and lowtemperature and salt spray tests. Inaddition the standard calls for a 58 barstatic pressure test (monitors are notnormally exposed to pressures greaterthan 16 bar in operation) and a 35 bardynamic test.

FM Global also require the “K” factor of the monitorto be logged at various flows and the straight waterjet throw distance (using an FM standard jet) to bemeasured at a variety of inlet pressures. This is usefulfor water jets but has little relevance for foamapplications.

UL standard

Underwriters Laboratories Inc. followsa similar system to FM with oneimportant addition. For UL Listing thequality of the foam generated by themonitor is measured under various conditions and must conform to set criteria.

Where monitors are installed for spraying foam thequality of the foam generated is paramount andoften critical to the successful control and extinctionof a fire. In this respect UL Listing is generally morecomprehensive and relevant to the practicalapplication than other monitor standards.

Lloyd’s Register, Bureau Veritas, ABS and RINA

Unlike FM Global and UL theseapprovals are, in the main, verifications that themanufacturers’ specifications areaccurate and that the equipmentperforms as stated in their specificationand will meet the minimum marineequipment performance criteria.