Ventilation and Impact of Explosion Fires on People - Coursework Example

Author’s name Instructors’ name Course Date Introduction Ventilation is one of the most important aspects in preventing the impact of fire. In a fire rescue situation, the mass of air that is entering a compartment be it a single compartment or a building, should equal the mass of air and smoke that is exiting the same building or compartment. According to Purkiss (2006), it means that a part from in extremely short term, if smoke is exiting the house, air will be entering. In actual sense, the mass in the inflow must always equal that of the outflow mass. It is advisable that when one is doing ventilation, especially for large structures, he should refrain from the use of interior stairs for access. According to Garcia et al (2006), it is important to use vertical shafts if present. Further, Purkiss (2006) suggests that the primary opening section should be where the smoke is showing. At the same time, after the roof has been ventilated, the next step should be to the floor. If it is not possible, it is good to open windows using an aerial ladder or platform for one’s safety. Impact of Explosions on People In any given fire scenario where people are involved, there is an obvious expected injuries if proper measures are not taken into consideration. In most of the fire incidences, there are different types of fire injuries that should be expected. One of these is the Barotrauma. This is a discomfort or injury that is felt where there is a change of pressure in between the outside atmosphere and an air filled body cavity. A good example of this type of feeling happens is in a passenger’s ear as an aeroplane is landing or taking off. At the same time, Barotrauma is often felt in ears of a scuba diver as one is descending in water. It should be noted that the same takes place during fire incident. This is usually when one is engulfed in a smoke of fire which creates an imbalance between an outside and inside pressure. The human body has a given atmospheric pressure on land. Since A high percentage of the human body consists of both solid and liquid, then it is believed to have ability of withstanding any changes of both water and air pressure that takes place in the outside. Despite this, some parts of the body such as ears, lungs or sinuses are most filled with air and therefore they are forced to contract or expand if there are such changes of pressure in the outside. This is very crucial especially when it happens suddenly. In most cases, a drastic atmospheric pressure can rapture or damage some body’s delicate tissues. The above explanation relates directly to Boyle’s which indicate that the gas’ volume is inversely proportional to the absolute pressure, provided the temperature remains the same. This premise also explains why people get barotrauma in fire incidents. Purkiss (2006) observes that in a scenario where one is caught in a fire, say in a house or when mining, the temperature is increased leading to the reduced volume of gas thus affecting one’s delicate body parts such as ears or lungs. Boyle’s law also explains why a bottle water, which is half full, pops when one opens it soon after taking off in an aeroplane and also why an empty bottle will crush soon after landing. As noted above barotrauma is mostly found in both air travellers and divers, but despite this fact, those people on a ventilator are at a high risk of having the same condition. This is the case if the machine pumps to mush of air into their lungs. At the same time, people who are standing an explosive blast or discharging a gun are also at risk of being affected by pressure wave. Barotrauma is usually felt by an individual; as a simple ear popping or deadly or deadly rupture of the lungs, for those who are flying and scuba diving respectively. Some of the symptoms of Barotrauma include discomfort or pain in the ears, face, sinuses, teeth, lungs or intestines. Further, one may feel his ears being stuffy or full. Other experiences include nausea, dizziness or headache. There are some precautions that can ease or prevent barotrauma. If an individual is experiencing pain, then he can try to equalize pressure for the inside and outside cavity. According to Purkiss (2006), this can include yawning, chewing or swallowing something for those who might be flying. Babies are advised to drink or nurse from a bottle during takeoff when landing. Scubas are advised to do Valsalva manoeuvre in order to clear air pockets in their masks or ears. Divers can also ascend slowly so that they can allow their lungs to slowly equalize. Application of Blast Wave Scaling Laws in determining the effect of explosions According to Williamson (2010), for many year scientists including engineers have struggled to come up with studies showing how waves and vibration affect people and buildings or property after explosions. Most of these studies have been applied in protection of lives and structures against fires and explosions. However more still need to be done on this front. One of the most basic concerns I show to asses the impact of blasts on surfaces. The process of assessing the impact of blasts is based on scaled distance together with an analytical approach. If an nm explosion s occurs inside a building, there is always development of a complex blast pressure –time loading. The ‘quasi-static’ load or gas pressure’, as detonation pressure also plays part in loading. Williamson (2010) argues that in assessing the impact of an explosion on people, property or environment, Blast Wave Scaling Laws are usually applied. In actual sense, parameter of blasts depends on the energy of detonation as well as the distance from an explosion. A normalized universal description of blast effects could be given through scaling distance relative to (E/Po) 1/3 and pressure relative to Po. Where, E= energy release (kJ) Po= ambient pressure (typically 100 kN/m2). However, it is a common procedure to express charge weight W or the basic explosive input as mass equivalent of TNT. The results are expressed as a function of the dimensional distance parameter: Z = R/W1/3 Where, Z= scaled distance (results) R= actual effective distance from the explosion The weight (W) is expressed in terms of kilograms, which is used to determine the impact of detonation energy on surfaces. Effect of Fire on People There are several effects of fire on human beings. It is thus vital to measure the impact of fire in human skin or body. Yung (2008) notes that penetration depth refers to the process of assessing how deep light or an electromagnetic radiation can enter or penetrate into a material. It is considered as the depth through while the intensity of radiation inside a material covers up to about 37% of the original value or simply beneath the surface. Figure 2: An illustration of the penetration depth of x-rays in water-a function of photon energy. Source: Bowen TE and Bellamy RF, eds, Emergency War Surgery. Washington, DC. According to Yung (2008), in a room-fire environment, the skin of an individual, together with body tissues act as function of wavelength. The nature of body tissues can change, for instance based on the contents such as blood, water, bones that interfere with the time it takes for the effect of fire to be felt in a human body. Thus, the nature of body tissues of an individual determines the time it will take for the impact of fire in such environment. Conclusion The risk of injury occurrence in any given fire incidences can be managed or reduced if proper and effective ventilation processes are followed. At the same time, fire rescue mission should be carried out by trained and qualified personnel who understand how to control the mass flow and thus reduce injuries or destruction of property or environment. The application of scaled score in explosions is an effective way of determining the impact of fire on people or property. It gives the extent to which the damage has occurred. Further, if for one reason or the other one experiences barotrauma, the above measures are helpful but more need to be known on what to do in different scenarios. Bibliography Acock, A. C. (2008). A gentle introduction to Stata. College Station, Tex, StataCorp LP. Fitzgerald, R. W. (2004). Building fire performance analysis. Chichester, England, J. Wiley. Garcia, K., Kauffmann, R., & Schelble, R. (2006). Positive pressure attack for ventilation & firefighting. Tulsa, Okla, Penwell. Purkiss, J. A. (2006). Fire Safety Engineering Design of Structures. Burlington, Elsevier Williamson, E. B. (2010). Blast-resistant highway bridges: design and detailing guidelines. Washington, D.C., Transportation Research Board. Yung, D. T. L. (2008). Principles of fire risk assessment in buildings. Chichester, U.K., Wiley. Read More