Extinguishing water pumping over long distances
Extinguishing water pumping over long distances is necessary in the event of fires when larger amounts of water are required than are available in the area of operation. This is the case , for example, with forest fires or even major fires.
Basically, the extinguishing water supply works over long distances in the same way as with a shorter extinguishing water supply by the fire brigade . However, more pumps are required to transport the water through the longer hose line.
Terminology
When pumping extinguishing water over long distances, special terms are used depending on the country:
Jet pipe section
In Germany, the jet pipe route describes the route from the last fire pump in front of the point of use, the so-called fire site power pump (BKS), to the water delivery point, i.e. the jet pipes. In this area, the focus is no longer on conveying the water with as little pressure loss as possible, but on generating the pressure required to supply the nozzles.
Conveyor line
The conveyor line describes the area from the water extraction point to the fire place power pump. The pump that draws the water is called the OKS. All other pumps are called booster pumps (VKS). The conveyor line is divided into subsections; each subsection extends from one VKS to the next.
Friction loss
With flow rates
| Flow rate [l / min] | Pressure loss (p R ) per 100 m B-hose [bar] |
Pressure loss (p R ) per 100 m C-hose [bar] (42 mm) |
Pressure loss (p R ) per 100 m C-hose [bar] (52 mm) |
|---|---|---|---|
| 100 | - | 0.6 | 0.2 |
| 200 | 0.1 | 2.3 | 0.7 |
| 400 | 0.3 | 8.8 | 2.1 |
| 600 | 0.6 | ||
| 800 | 1 | 20th | 6.5 |
| 1000 | 1.4 | X | X |
| 1200 | 2 | X | X |
| 1600 | 4th | X | X |
With cross section
| Delivery distance E = 100 m delivery flow Q = 800 l / min | Cable in mm | Friction loss p R per 100 m |
|---|---|---|
| C42 | 42 | 20th |
| C52 | 52 | 6.5 |
| B. | 75 | 1 |
| pipe | 87 | 0.5 |
| pipe | 105 | 0.2 |
Requirements, planning, preparation and commissioning
There are various prerequisites and information that are required to set up a "water supply over long distances" - here using two examples during exercises at the Hessian State Fire Brigade School :
Exercise 1: closed series of switches with a single B line, 1.5 km, height difference approx. 30 m
Exercise 2: open series of 800 m single B line, then 600 m with double B line, total height difference about 60 m
- the water pumping requires planning time (in the example approx. 30 min)
- the required delivery rate must be known
- A (street) map should be available, and a topographic map should be available for differences in altitude
- Due to the time required for setup and commissioning (here in the two examples at least 1 hour), this “water source” is only available late
- sufficient staff (here at least tensile strength 1/3 / 18/ 22 )
- Material sufficient (tubing and pump, and often also by special vehicles such as hose reels , trolley logistics or LF 20 KatS provided)
Usually, a separate insert section is formed for this purpose at deployment sites.
construction
To determine the number and exact location of the pumps, various factors must be taken into account:
- Pump spacing : Assuming that a conventional centrifugal fire pump requires an inlet pressure of over 1.5 bar and an outlet pressure of around 8 bar in continuous operation, the result is a maximum delivery head per pump of around 65 m (10 m height difference corresponds to 1 bar Pressure difference).
- Pressure loss through hose length : The pressure loss in the hose lines must always be taken into account. A normally used B-hose has a pressure loss of approx. 1 bar at a flow rate of 800 l / min (the literature values vary between 1.0 and 1.3 bar) per 100 m length. A booster pump must therefore be used approximately every 600 m on a level stretch. If a double B line is laid with the same delivery rate, the pressure loss due to friction is reduced to around 0.3 bar for the same distance.
- Installation site : The installation site should be chosen so that the pump does not have to be carried too far in impassable terrain, but rather is placed on a forest road.
- Pump output : In addition, the delivery rate depends on the pump output of the weakest pump. The standard value for conventional portable pumps (PFPN 10-1000) is 1000 l / min. If only larger pumps, such as those usually installed in vehicles, are used, two-line pumps can also be used, i.e. the water is pumped via two parallel B-lines that are brought together via a claw on the inlet side of the pump. The most powerful pump of the entire conveying line should be used as a water extraction pump (OKS), as this has to provide the greatest performance.
- example
The following data are given:
- 8 bar pump outlet pressure
- Delivery rate through the hose 800 l / min
- Height difference upwards of 40 m
- Inlet pressure in the next pump approx. 2 bar
With one B-line you can get about 250 m and with two B-lines you get about 650 m.
variants
Closed switching series
The closed switching row is a term used by German fire departments. With this variant, several power syringes and a sufficient number of pressure hoses are required to cover the distance. In the closed switching series, the delivery line goes from power syringe to power syringe, i.e. H. a certain inlet pressure is required at each additional power syringe (approx. 1.5 to 2.0 bar). This variant is the most frequently used switching series as it is easier to implement than the open switching series.
Open series of circuits
In the case of the open switching series, the pumps do not feed each other, but each feed a storage container ( e.g. a collapsible tank ). Each power syringe sucks in from these containers when it is filled accordingly. The advantage over the closed switching series is that the extinguishing water supply can also be maintained for a certain time if a pump fails or has to be replaced.
Alternatives to pumping water using hose lines
Shuttle service
An alternative to this type of extinguishing water supply is the so-called shuttle traffic with tank fire engines . In this case, a larger tank fire engine or a larger expansion tank is available as a buffer in order to be continuously supplied with water from incoming tank fire engines . A number of fire trucks are constantly shuttling back and forth between the water extraction point and the buffer. These can be supplemented, particularly in rural areas, by tractors with slurry tanks . Especially in remote areas where only one-lane roads lead, this poses a challenge to the logistics team for the operations management team , in order to prevent the vehicles from meeting at bottlenecks and thus preventing commuting. Even if the effectiveness and practicality of commuting is often controversial among experts, as the effort and number of vehicles required with a sufficient water tank etc. a. depending on the distance is very high, it is often the only suitable option to bring extinguishing water to the appropriate place without having to give up the object to be extinguished. In addition, some fire trucks do not have all-wheel drive and many of the large vehicles that are well suited for commuting (in Germany, for example, the TLF 4000 and the like) have limited off-road capabilities in practice, even with all-wheel drive. Tractors, on the other hand, are suitable for off-road use, but (with the exception of modern, high-speed tractors) usually have a speed disadvantage on paved roads, so that vehicles of different speeds can hinder each other.
Efficient shuttle service (USA)
There are numerous volunteer fire departments in the USA who do not have hydrants in their area of responsibility. Nevertheless, some of them are able to provide an extinguishing water supply with the throughput of a Central European hydrant network. A tactic is pursued here, which European fire brigades use at best away from well-paved roads and paths: the shuttle traffic does not aim at the emergency site. Instead, foldable extinguishing water tanks with a capacity of 10,000 to 15,000 l are set up at the last point, which is easily accessible for water tankers (if possible in a loop drive without turning maneuvers). While an “attack pumper” goes to the actual site of the incident, another fire engine is positioned at the collapsible tanks and supplies the incident site via a hose line. So that a single pump is sufficient for longer supply distances, hose types with low friction loss are used that correspond to German A or F hoses. At least two other fire engines drive to redundant water intake points and get ready for tanker loading in the style of a pit stop. The shuttle traffic is carried out by water tankers with a capacity of 7,500 to 14,000 l, which are set up for gravity discharge of this amount of water within 50 - 90 s. The “Tanker Task Force” system is particularly successful. If a fire brigade goes out on a fire outside the hydrant system, they do not alert individual additional vehicles, but a group of water tankers made up of vehicles from surrounding communities. Since the water tankers are each manned by one person, the process only ties up few resources.
Background: Fire insurance premiums in the USA depend on the class in which the local fire department is classified, on a scale from 9 to 1. "Class 8" for citizens outside the hydrant area is only achieved if the fire department in a two-hour test 950 l / min can deliver without interruption from the 6th minute after the arrival of the first vehicle. For an even better evaluation, the flow rate must be increased after a further 10 minutes and then maintained at this level up to the two-hour mark. Because citizens can easily finance better equipment for the fire service with part of the saved insurance premiums, there is a considerable incentive for US fire services in rural areas to be able to provide a water volume of 2000 or 3000 l / min for commuting.
Records for pumping water over long distances
On June 12, 1999, the youth fire brigades in the Upper Palatinate districts of Neumarkt , Regensburg , Schwandorf and Amberg-Sulzbach set the Guinness world record, the longest water-bearing fire hose in the world . The hose line was almost 46 km long and ran from Hohenfels to the LGS site in Amberg . 115 portable pumps were used to pump the approx. 200,000 liters of water from the trout stream .
The fire brigades in the Salzkammergut are also claiming a record. In 2004 they overcame a difference in altitude of 794 m with 78 pumps over 25 km and thus pumped water from the Attersee to the Traunsee . They needed more than 1,200 B-hoses for this.
Similarly, in 2013, the Lower Austrian fire brigades laid a hose line over a distance of 25.4 km from Mautern to St. Pölten , through which Danube water was pumped to St. Pölten.
See also
literature
- Franz A. Schneider: Die Rote Hefte, volume 7 - Extinguishing water delivery . 14th edition. Kohlhammer, Stuttgart 1994, ISBN 3-17-013208-3 , p. 46-63 .
- Holger de Vries, Andreas Weich, Wolfgang Freinik, Arvid Graeger, Ulrich Cimolino: Application practice : water pumping over long distances: tactics and technology . 2004, ISBN 3 609 68664 2 .
Individual evidence
- ↑ a b c water supply long distance, fire brigade school of the city of Cologne
- ↑ a b c d e f Training of the volunteer fire brigades - machinist for fire trucks, Neckar-Verlag 2002, pages 32–35
- ↑ a b Fire brigade specialist knowledge: Engineers for fire engines - Basics ", ecomed Verlag, 1st edition 2009
- ^ The fire brigade textbook, BrandSchutz - Deutsche Feuerwehrzeitung, Verlag W. Kohlhammer, 1st edition 2012
- ^ Lothar Schott, Manfred Ritter: Fire Brigade Basic Course FwDV 2 . 20th edition. Wenzel-Verlag, Marburg 2018, ISBN 978-3-88293-220-1 .
- ↑ A good example is the Rattlesnake Fire Protection District ( Memento from May 12, 2014 in the Internet Archive ), even if it has a hydrant over 170 km².
- ↑ Using this video of a barn fire , the usual setup can be clearly understood.
- ↑ The gravity discharge of water tankers is clearly shown in this video by a "Tanker Task Force" from Hunterdon County in New Jersey.
- ^ Insurance Services Office, Inc .: Water-Supply Evaluations ( Memento September 15, 2011 in the Internet Archive )
- ↑ On the website of the consulting company "GotBigWater" there is a description of an exercise (PDF; 8.1 MB), which can be used to understand the process of such a test.
- ↑ Freiwillige Feuerwehr Schlicht / Vilseck ( page no longer available , search in web archives ) accessed: January 18, 2010
- ↑ World record with FF Haselbach in the Braunauer Stadtnachrichten p. 19 of December 2004, accessed on September 28, 2017
- ↑ Line 13 on the website of the Lower Austrian Fire Brigade Association of September 14, 2013, accessed on September 15, 2013
Web links
- Free extinguishing water supply calculation programs
- Automatic calculation of the extinguishing water delivery with a map view
- Water pumping over long hose lines , State Fire Brigade School Würzburg, 10/2009