Fog nozzle

Nozzles (abbreviation: HSR) are fittings of the fire extinguishing agent to constituents (water or water - foam mixtures) that are used in addition to the special lances, multi-purpose jet tubes and foam nozzles. These are water delivery.

HSR find now becoming more widespread. For hollow jet tubes, the water is passed through an annular die so that a hollow jet of water is formed, but which can be filled with droplet by certain techniques such as a fixed or rotary ring gear, which allows a better water distribution, and thus a more effective exhaust gas cooling. A jet from such Ringstrahldüse is more stable ( less rainout ) than a conventional jet ( " jet rod " ) and reached a higher throw. It can thus also infinitely spray cone of partially to over 120 degrees are reached. Mostly, nor be regulated the flow of the HSR, the water discharge must not to be interrupted. Thus, the foregoing nozzle operator to perform a water-saving and dynamic fighting attack.

In the fire service very different hollow spray models are used and it has been for years a lively discussion going on, what type of hollow spray probably be best suited for use by firefighters.

Differences in features

The Nozzles can be equipped with a rotating or a fixed gear. With a lance with rotating ring gear of the beam is cut by the rotating ring gear in fine water mist, which leads to a better extinguishing success. However, this can lead to a " prime" the flame in the water cone, which is used to for the emergency services, but in some situations also quite desired, for example for capturing and directing a gas flame. Depending on the design of the ring gear of the spray cone may be filled with water drops empty, partially or completely. Nozzles that produce a filled cone will be more useful in general.

In automatic tubes of the flow of the jet is controlled within specified limits by means of a built-in spring pack which opens when the pressure increases further, thus increasing the flow rate while the pressure is kept constant. This not hang the spray pattern and the casting distance on the flow rate. However, it must (approx. 6 bar) present at a sufficiently high pressure jet ever. However, these pipes are suitable only for a very limited inside attack, since they provide no longer sufficient amount of water for self-protection of the squad at low pressure conditions ( see test LFKS RLP).

The maximum flow varies widely with different jet models. Are usual Nozzles ends (with C - coupling ) with a flow rate of 130 l / min to 300 l / min, but there are also models available, the flow rate at 20 l / min starts or above 1000 l / min. For pipes that are used in interior attack, a maximum flow rate of 130-150 l is sufficient, provided that no flash -over prevention should be carried out with these nozzles. For an effective flash -over prevention beamlines with a water supply of at least 230 l / min are required, otherwise not sufficient given the amount of water for flue gas cooling. For this reason, can be performed with a pressure hose S no internal drive to flash -over prevention, since the pressure hose S only has a water supply of about 130 l / min. On top of the enormous pressure loss within the pressure tube p

Advantages and disadvantages compared to multipurpose beamlines

• The continuous adjustment of spray cone and flow rate allows a fast and flexible adaptation to the conditions of a fire. Thus, serious water damage can be prevented.
• The spray can cover a larger area ( by partial to over 120 degrees opening angle). This allows on one hand an improved cooling and extinguishing effect ( especially in the flue gas cooling in the interior attack to prevent flash -overs ), on the other hand, an increased safety for the attack team (HSR have an effective " man protection " standard multipurpose beamlines without special water curtain not ).
• The spray consists of smaller droplets ( ~ 0.3 mm ) than in classic multi-purpose beamlines, thereby the surface of the drops increases in total and thus the cooling effect. The opposite high and very high pressure beamlines ( droplets around 0.1 mm) even larger droplets of the HSR are currently (2004/ 2005) viewed as an ideal compromise between cooling effect and penetration depth and are considered ideal for flash -over fighting.

However, the improved jet properties have to be learned by special brigade training. Since many different Nozzles are used, this training must always be oriented to the local amenities. Useful Nozzles are to purchase tend to be much more expensive than multi-purpose beamlines ( about twice to 10 times as expensive, depending on the model and manufacturer from ~ € 200 / piece 2005), but considerably cheaper than high or very high pressure extinguishing systems ( cost usually several thousand euros and in the application are often very limited ).

Nozzles can at roughly contaminated water (algae, dirt from open water, dissolved incrustations of risers ) easily clog under circumstances that HSR should therefore have a flushing forever.

Procurement Policies

In the procurement of HSR, the intended use should be carefully considered.

The DIN EN 15182, with its four parts replaced in early 2007 DIN 14365 multipurpose nozzles and the DIN 14367 Nozzles. In Part 3, the recommendation is taken not to use the pipes under Part 3 (eg multi-purpose beamlines ) at the inside attack. In part 1, no electrical testing is included. Instead, the recommendation was to maintain a distance of at least 1 m ( up to 1000 V ) in a spray of at least 30 °.

In Austria there is the policy GA21 "purchase of hollow jet tubes " of the Austrian Federal Fire Brigade Association.

Swell

• De Vries, Dr. Holger: Fight fire with water and foam, ecomed Landsberg, 2000
• De Vries, Dr. Holger: Studies on the optimization of the control of solid fires with water and foam in the mobile use of the fire department, www.bod.de ( doctoral thesis on the subject )
• DIN 15182