# Uncontrolled and Controlled Destruction of Acetylene Pressure Cylinders
## 4 Discussion  
Based on the reference literature review and experimental measurements, the shooting through the acetylene cylinder shell as a prevention of physical destruction is effective. Measurements provided renewal of theoretical knowledge and practical experience. Shooting is very effective but represents a secondary risk. For this reason, it is necessary to have the procedure, operation and other requirements precisely specified. Penetration of cylinder shells is quick and more or less predictable. These facts can contribute to the effectiveness of fire intervention, safe time and also water, which would be normally used for cooling or water bath. As it was mentioned, in the Czech Republic Methodological List no. 33 [1] for fire with the presence of acetylene cylinders in fire condition is used. In this document, all essential knowledge and procedures for fire with acetylene cylinders is described. Shooting is mentioned in point no. 39 as an extreme solution in the case when it is not possible to stop cylinder destruction. It is necessary to consider that flammable gas will be ignited, and the resultant fire jet may reach up to ten meters. The cylinder can explode due to the inside pressure. Shooting can be performed only by specialists from the police department. The fact of lacking a description of procedures, conditions and specifications for shooting was the impetus for the study. Using this technique is necessary to prepare an extension in a certain way that follows Methodological List no. 33. This list is still primary, and after detection of an acetylene cylinder it is necessary to cool the cylinder shell. The time of the cylinder exposure to fire is not always clear, as well as the temperature and heat flux density and the amount of the gas inside. From the start, it is important to answer several questions. The method of shooting could be used only for acetylene pressure cylinders. According to evaluation of the conditions, this method could be used, and the acetylene pressure cylinder penetrated via shooting. It is necessary to consider potential risks in the case of unsuccessful shooting, used ammunition, the position of shooters and the accuracy. More shots ensure the faster gas release and have to be distributed along the entire length. The most advantageous is a combination of two shots at once into the lower part of the cylinder. This method can be used only for acetylene cylinders. For use with other gases, it is necessary to consider different working pressures, construction of cylinders, material, hardness, etc. Called shooters should have sufficient knowledge and training for this situation, as the shooter always decides on the position and other specifications. The shooter is responsible for the action itself. Emphasis should be placed on the communication among intervening forces. After successful shooting, the gas is released and initiated with the result of the fire jet. Immediately after releasing, outflow gas reaches a distance of about 10 m and then burns with approximate distance of fire of about 3 m. With decreasing amount of gas, the size of the flame decreases until it burns out. The releasing gas can accumulate if it is not initiated. Accumulation in a closed space can create explosive concentration. The next step in this problem can be addressed at the training: an option for the shooting of the other pressure cylinders, for example, an oxygen pressure cylinder or a combination of acetylene with oxygen pressure cylinder. For another experiment, other ignition sources can be used, such as a pool fire. With the increasing use of this method in the Czech Republic, knowledge and experience will be accrued. In connection with the current state of knowledge, it is necessary to count on ammunition that will be able to ignite releasing gas. What could be really interesting is the modeling of these situations and an option to predict the behavior of the acetylene cylinders. Modeling and computer animations are popular and can be helpful in the case of extraordinary events.