SMOKE DETECTIONIntroduction “Where there’s smoke, there’s fire” (McComb and Predko 2006, p. 632). I have chosen this topic because statistics show that the majority of fire deaths each year are cause not by burns but by smoke inhalation. It is the leading cause of death from fires as it contains numerous toxins that are generated during combustion. In 1997, according to Warren et. al. (2002, p. 44), there were over 70,000 house fires in the UK, resulting in approximately 550 deaths. In those cases where a smoke detector was present in the area of the fire, the death rate was approximately two deaths per 1000 fires while nine per 1000 where there was no alarm.
The overall rate of almost eight fatalities per 1000 fires reflects the distressing fact that in only 30 percent of cases was an alarm present in the area of the fire. Moreover, recent data for the UK shows that fires is the leading cause of child injury and death and are much more common in poor households. However, while providing smoke alarms may look like a good response, whether and how they are fitted, and whether they result in reduced injury and death, depends on characteristics of the alarms, individuals, families, houses, etc.
(Commonwealth Staff 2004, p. 97). In addition, there is an ongoing difficulty of educating the public concerning the true situation in a fire. Apparently, based on these statistics, the topic is interesting enough to attract the interest of policy makers and other stakeholders as it involves human lives that are being lost pointlessly. Smoke is an intricate fusion of heated air, suspended solid and liquid particles, gases, fumes, aerosols, and vapours.
Combustion products resulting from a fire are hard to predict and in reality, even the composition of smoke is somewhat unpredictable within the same fire environment. The association of smoke inhalation with burns give off a more severe systemic infirmity. Burn fatalities with smoke inhalation injury have higher morbidity and mortality than those with burns only. The occurrence of severe respiratory malfunction in burn victims with smoke inhalation injury is 61% against 12% in those with burns alone. In addition, burn ‘edema’ or the abnormal accumulation of fluid beneath the skin, is heightened and non-burned tissue has increased vascular permeability when correlated with smoke inhalation injuries (Goldfrank et.
al. p.1749). The outcomes of smoke inhalation are multifaceted since they can include numerous kinds of injuries, heat injury to the airways, exposure to toxic gases, and a chemical burn with deposition of carbonaceous particulates in the lower airways. The pulmonary response to smoke inhalation is similarly difficult and conditional on the length of the exposure, the composition of the material that burned, and the existence of any underlying lung disease (Morgan et.
al. 2001, p. 974). Smoke inhalation is avoidable if smoke can be detected in the soonest possible time. Smoke detection is thus very important not only to prevent the spread of fire but to the health and safety of residents and responding fire fighters. The primary purpose of fire-detection systems is to discover a fire when it is in its earliest phase and to respond by activating an alarm. Smoke detectors, the ionization or the photoelectric type are designed to react to the products of combustion.
The environment surrounding the point of origin of a fire contains particles of unburned fuel or carbon, toxic and non-toxic gases, and electrically charged atoms called ions. Thus, a smoke detector will act in response either to the visible products of combustion or smoke or to the invisible or chemical changes in the atmosphere (Redsicker and O’Connor 1996, p. 41).