Firefighting nozzles and monitors

Published:  01 January, 2006

As was demonstrated at the UK Buncefield depot fire in December 2005,  firefighting monitor excels not only in its striking power but also in its ability to gain maximum ‘reach’ advantage during its application of water and foam.

As was demonstrated at the UK Buncefield depot fire in December 2005,  firefighting monitor excels not only in its striking power but also in its ability to gain maximum ‘reach’ advantage during its application of water and foam.
Accordingly, the tactical use of high-flow nozzles & monitors covers a broad range. Obviously the greatest need for high performance monitor systems exists in the industrial and petrochemical sectors and equipment is specifically designed to match the risk.
Petroleum and chemical  installations may be covered by systems ranging from fixed hydrant-mounted installations to jetty-side and mobile/afloat options. There is now an ever-increasing amount of support available from the manufacturers in terms of project and design  engineering.
Monitors & tank fires
The Williams Fire and Hazard Control organisation is an innovators in what it terms ‘Footprint Technology’ (US Patent) - which is a method for extinguishing flammable and  combustible liquid tank fires.
Using the more traditional ‘surround & drown’ techniques, the footprint technology concentrates on specific features of a tank fire, noting that the fire will actually be ‘breathing’ in an area known as the ‘sweet spot’ - this is where the fire takes in air (oxygen).
The fire pulsates adjacent to this ‘sweet spot’ - and so a combination of sweet spot, breathing and thermal drafts would normally drive foam back and away from the middle of the tank surface. Williams’ firefighters report that that this ‘sweet spot’ normally lies just off the centre of the tank and ‘footprint technology’ methods aim to place the foam predominantly toward this area. This takes into account not only a fire stream’s reach but also its maximum ‘run-time’ (as foam) along the surface of the flaming liquid (approximately 30 metres).
This approach involves the strategic placing of monitors around a tank fire so that effective ‘footprints’ of foam, adjusted for the height of the liquid in the tank, are placed onto an imaginary grid. This effect ensures the maximum coverage of the tank surface under the limitations of maximum foam runs.
What about high performance?
These monitors are categorised by their flow-rate capability,  which can range from anything as low as 55 lpm (15 gpm) to over 50,000 lpm (13,225 gpm).
A monitor’s range begins above 1,500 lpm (400 gpm) where the firestream is unmanageable or unsafe in hand-held terms. Top quality mid-range portable monitors popular with industry include the Task Force Tips Vector (Crossfire) 5,000 lpm which houses a unique safety valve (SafeTak) that automatically reduces flow to safe levels should the monitor lift while being flowed. This is a feature which prevents any likelihood of such equipment becoming a danger, enabling it to be left freestanding whilst operating on the fireground.
Other competitors to the Task Force Tips Vector would be the Akron Apollo, flowing at around 3,000 lpm (800gpm) and Elkhart’s Stinger which flows up to 3,800 lpm (1,000gpm).
Along with a wide range of connection options these monitors also come with 3” waterways and safety stops below 35°. The units can also be attached as Deck Guns or as remotely-controlled extensions from an appliance roof.
Going with the flow
The next group, fixed mid-range monitors, include the Elkhart Spitfire which flows up to 7,500 lpm (2,000 gpm) and the Akron StreamMaster with similar flows. Groupe Leader (France) has a range which can offer the higher flow 9,000 lpm (2,400 gpm) Projet version or the Task Force Tips waterway of the Petro-Jet (Protector) monitor flowing up to 4,700 lpm (1,200 gpm). All monitors work within a range of 50 - 75 metres horizontal throw capability.
At the extreme end of monitor technology are the flows achieved by monitors such as the Angus Mega-Colossus 40,000 lpm (10,500 gpm) high-capacity foam system - an exceptional aspirating foam cannon delivering stable amounts of foam 90-100 metres from the monitor. The smaller Colossus version throws its 15,000 lpm (4,000 gpm) of foam 85 metres ground-to-ground.
The Chubb Fire Slimjet range of foam/water monitors offers ‘mortar’ looking designs capable of flowing straight streams in excess of 43,000 lpm (11,400 gpm) of aspirated foam or 7,275 lpm (2000 gpm) of  water over 100 metres horizontally and 60  metres vertically. In the same league, the massive  17,000 lpm (4,500 gpm) Hyper-Projet from Task Force Tips can discharge its water-fog or jet stream up to 100 metres on the horizontal.
The highest flows are reserved for the Williams Fire & Hazard Control Trailer mounted monitor - Bigfoot - which at 53,000 lpm (14,000 gpm) will discharge its monumental ‘tower’ of water in excess of 135 metres horizontally and 35 metres vertically.
What about oscillating options?
Oscillating monitors may be either fixed, portable or trailer mounted. A wide range of oscillating type monitors is available which provide a powerful, sweeping waterstream for high-performance attack  and protection. The unique water-driven motor of Akron’s Ozzie sweeps back and forth in a smooth wave-like motion, discharging a capable 1,420 lpm (375 gpm) in an arc up to 30° either side of centre and 35-90° above horizontal. The Ozzie Master oscillating monitor uses an Apollo ground base and provides even greater flow capabilities.
The OT500W from Chubb Fire has speed control over the oscillation of up to 15 cycles per minute. The 2000 lpm (530 gpm) JCS 1901 available from Strebor operates at 6-cycles-per-minute and the Spectrum range from Firegard offers different models with flow-rates ranging from 380 - 1,890 lpm (100 - 500 gpm).

Monitors & appliances
Varying styles of monitors can be fixed to fire appliances and pumpers. There are roof-mounted manually-operated or remote-controlled deck guns, telescopic extending monitors and bumper-mounted turrets for wildland operations.
The Akron Deckmaster is an electric remote-control monitor with an automated elevating  capability to 600mm above the base of the flange, flowing 4,800 lpm (1,250 gpm) at 90° above and 45° below the horizontal for ‘blitz’ style attacks on rapidly escalating fires. A natural  competitor may be found in the Groupe Leader hydraulic remote control range of Projects: Hyper-Projects and hydraulic telescoping Top-Gun masts (to 56cm elevations) where flows range from 500 - 20,00 lpm (130-5,300 gpm) are available. PAUL GRIMWOOD
Nozzles for firefighting
If you haven’t got your firestream design right, you cannot expect to extinguish a fire, writes Richard Ellis. After mastering issues such as friction loss, hydraulics, pump & hose operations, attention must be paid to the nozzle or discharge appliance. Let us consider different applications and the technology available.
Is your discharge correct?
Consider the example of a 1 1/4” solid tip handline nozzle which is 2 1/2” at the connection point to the hose and tapers to the 1 1/4” discharge opening at the end of the nozzle. The water stream is forced into a smaller and smaller passageway as it flows from the hose into the nozzle. The effect is to discharge a high velocity stream with a solid column of water, with a decent range of stream reach.
Fog stream nozzles also starts out with a tapered design with the inbound cross- section of the nozzle’s interior being larger than the cross-section within the nozzle. The difference is that in a fogstream nozzle a dispersion plate/device is installed in the water pathway within the nozzle barrel.
Water is forced through to to hit the plate, which then breaks the solid column of water into droplets. The droplets flow around the  outside edge of the plate and continue through the nozzle to the discharge orifice. The result is a stream of droplets being  discharged from the nozzle rather than a solid column of water. 
Taking the adjustable approach
Most fog stream nozzles have the ability to be adjustable in the width and the form of their discharge stream. With an adjustable fog stream nozzle patterns can be set from a very wide (+100°) angle to a straight stream, where the discharge stream is approximately the diameter of the attack hose.
While a straight stream form is still a fog stream, while it appears to be straight, like a solid stream, the discharge is still made up of droplets of water rather than a solid column of water.
Fire teams often ask - which type or design of nozzle should we use (especially for interior attacks), fog or solid tip? In truth, both designs have their pluses and minuses. Ideally, the local authorities can assess their potential firefighting situations and equip appropriately. On a daily basis you may carry one design of nozzle pre-connected to the attack hose, yet, you have several of the alternative design nozzles on the fire engine/ pump.
According to the type and volume of fire, you may switch the nozzles prior to or during the suppression efforts. Knowledge of which nozzles perform the best under different fire situations is the critical key.
A solid tip nozzle streams allows for deep penetration into the fire and flame zone immediately above the fuel with minimal steam conversion occurring as the stream penetrates the superheated air above the fuel area. The lack of steam conversion taking place allows for more water to actually strike the target area, thereby increasing the cooling effect on the burning fuel itself. The reach and penetration benefits can be very helpful when trying to cool a fuel source directly.
Nozzle advice
On a large fire, solid tips are dramatically more effective in penetrating large thermal columns and impacting the fuel itself. The use of Master streams (streams flowing over 400 GPM ) usually requires solid tips to penetrate the superheated environment above the fuel sources.
Fog Stream nozzles provide a very fast absorption of heat in an atmosphere. The droplets in the stream allow for more surface area of the water discharge to be exposed to heat simultaneously. This additional surface area causes the heat to be absorbed much quicker and the conversion of water into steam takes place in seconds.
If you have to cool down superheated air currents and reduce the chance for a flashover, fog streams work very well. By placing a fog stream in the straight stream position, one can provide a concentrated stream of water droplets onto the fuel source as well.
In the past 15 years we have increased the flow rates through the traditional hand attack hose lines, by increasing the diameter of the smaller hose lines (formerly 1’/2”) to 1 3/4” or 2”. This slight increase in diameter has allowed us to double the flow rates.
Choices for initial attack lines
The typical flow rates for a 1 3/4” attack hose line is 200 GPM, with the standard 2 ‘/2” attack line flowing between 250 GPM and 300 GPM. With most brigades being limited on personnel, the 1 3/4” hose, which can be handled by two firefighters, has become the common choice for an initial attack line. As interior crews begin their attacks with 200 GPM per hose line, one could justify in many cases that the total volume of the stream being delivered through the fog steam is adequate to cool fuels.
Most interior fires can be suppressed by using a 1 3/4” attack line with the appropriate fog nozzle. Using two 1 3/4” attack lines side by side gives a considerable knock down effect in interior structural attack operations. The ability to quickly adjust a nozzle to the wider fog pattern can also provide some personal protection for the attack crew in the event of a flash over or a flare up of fuel materials.
A wide fog pattern can absorb fast moving heat and prevent the firefighters from taking as much of a thermal hit as they would have with out the cooling effect. As applied to Masterstream operations the fog nozzle has a place for cooling exposures (the droplets have less impact and tend to damage property less than a solid stream), dispersing vapour clouds of toxic materials, knocking down fire brands and can, in some cases, be used to suppress the fire and flow foam.
Some firefighters prefer to keep hand attack lines fitted with large volume (200 GPM or more) fog nozzles with solid tips available if needed. The high volume flows accompanied by an aggressive ventilation effort to remove the excess heat and steam produced by the attack have given very good results.
Master streams can be kept with with solid tip nozzles attached, as they are the main suppression punch required in the majority of large fire attack exterior operations. It is very important to keep in mind though that when using either solid or fog stream nozzles, the pump operator must be accurately supplying the nozzle with the correct pressure to meet the required flow for the nozzle to operate correctly and for the Incident Commander’s suppression strategy to work.

  • Operation Florian

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