Shelter is one of the three basic needs, yet erection of buildings for shelter can be exponentially expensive. Building and construction is thus, in most cases a balancing act between quality and cost. The balance between quality and cost is then complicated by issues such as limitation of building space on the one hand, and extreme weather on the other. A good example of the complexity above is in high-rise residential buildings, commonly constructed in low-cost urban centers in the developed world. For a start, these buildings house a large number of people making safety a primary concern. Secondly, being low-cost housing makes limitation of construction costs, running costs and maintenance costs important bearing factors. Finally, most of the developed world, such as the USA and the EU is in extreme weather belts with extreme heat in summer but extreme cold in winter. A tripartite balance between safety, weather regulation and cost is a pertinent issue during the construction of such houses. The instant research paper addresses how the insulation in general and the toxicity of insulating materials acts as a bearing factor in the tripartite balance addressed above.
Background Information
Why Insulation Material is Important
The primary use of insulation material is weather control but there are secondary uses such as beauty and fire control. Among the principal uses of residential buildings is to regulate weather for the occupants. In the case of extreme weather conditions, weather control includes having an airtight living area, according to Al-Homoud (2005). If the area is not airtight, heat will slip through the cracks either into the building or outside the building depending on the weather. Insulation ensures that there is no exchange of air between the interior and exterior of the house, hence enabling better weather control. At the same time, the better weather control using insulation limits the need for mechanical weather regulation, for example using air conditioning systems (Al-Homoud, 2005). Lesser mechanical air conditioning reduces the initial cost of furnishing the residential house, helps protect the environment by limiting the carbon footprint and reduces the cost of running the house. Among the secondary use of insulation in some cases is an embellishment of the building, more so when used in the interior. Fire-resistant insulation also acts as a fire prevention or control mechanism.
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Criteria for Selecting Insulation Material
The selection of insulation material focuses on the tripartite balance of safety, weather regulation and cost, with the cost being the fundamental determinant in most cases. Modern advancement in technology has been able to develop insulation materials and methods that are both airtight and almost fully fireproofed (Al-Homoud, 2005). However, these advanced methods come at a steep cost, mostly beyond the purview of lower cost housing. Engineers thus find themselves having to come up with compromises. For example, in areas where only limited weather control is necessary, the compromise is on the efficacy of the material. Conversely, in areas where weather is extreme, the compromise is on safety. Engineers will use more flammable insulation materials that are better at weather control (Al-Homoud, 2005). Based on the totality of the above, whereas weather control and safety are important factors, the cost is always dominant.
Materials and Methodologies for Insulation of Buildings
A limited range of materials is available for use in building insulation but modern innovation in construction has widened the methodology of use for these materials. According to Stec & Hull (2011), insulation materials currently in use include advanced materials such as stone wool and glass wool. There are also relatively simpler ones such as polystyrene, phenolic, polyurethane, and polyisocyanurate. According to Nolan, (2019) other high-quality materials include vermiculite, perlite. Flammable insulation materials also include inorganic materials such as “ calcium silicate, mineral wool, diatomaceous earth or perlite, and mineral wool ” (Nolan, 2019, P. 293), that act as thermal insulators. The article, Al-Homoud (2005) addresses some of the methodologies used when applying the insulators above. Among the common methods is using insulators as thermal blankets that cover other materials. Another method is using fine insulation materials as filling by blowing it into the walls or spraying it on the surfaces. Mixing mineral insulators with concrete thus giving the concrete insulation properties. Another methodology, more so for polymer-based insulators, is to make rigid boards or solid blocks that cover walls and other surfaces. Finally, using reflecting materials on the surfaces can reduce heat absorption. (Al-Homoud, 2005).
Toxicity of Materials
Konecki & Gałaj (2017)
It is a statistical certainty that due to a variety of reasons, out of a number of residential houses, some will eventually catch fire. It is for this reason that safety is an important consideration when selecting the material and methodology of use in insulation. According to available research and commentary, during a fire incident, the conflagration may cause most of the structural damage but toxic fumes cause most of the fatalities. As reflected in the figure above, fumes from a fire, precede the fire to other parts of the building. The toxic fumes disable people who may not even be aware that there is a fire in the building as reflected in the figure below. Indeed, toxic fumes can choke residents tens of floors above actual fire itself.
Konecki & Gałaj (2017)
By the time reports of fire are reach these individuals, their ability to escape or ease of rescue is already compromised. It is also possible that highly flammable insulation, more so those made of polymer-based materials can act as fire propellants while still releasing toxic fumes. Indeed, according to Konecki & Gałaj (2017), up to 80% of fatalities in residential fires result from toxins form polymer-based insulation.
From a broader perspective, the article Stec & Hull (2011) reports on a careful evaluation of the toxic output when different kinds of insulation materials are combusted. According to the article, the average fire’s fumes will contain carbon dioxide, carbon monoxide, and hydrogen cyanide among other gases. From the perspective of toxicity, carbon monoxide, hydrogen cyanide, Nitric Oxide, and ammonia are the most significant gases. The researchers thus investigated the different insulation materials currently in use for their carbon monoxide and hydrogen cyanide output upon combustion. It is also important to note that the most commonly used insulation is stable unless it catches fire. The researchers, therefore, also investigated the propensity for combustion for the materials they studied. Finally, the level of ventilation that the fire is exposed to is a major determinant of the toxicity of the fumes. In well-ventilated fired, fewer toxins will be released as compared with a poorly ventilated fire. Based on careful fire testing, the researchers came to the findings outlined in the chart below. Glass wool, reflected in the chart as GW is evidently the safest insulation option. Not only is glass wool most resistant to combustion but also having the least toxic output when combusted.
(Stec & Hull, 2011)
Stone wool, abbreviated as SW was found to be the second safest option, followed by Phenolic (PHF), and Expanded polystyrene (EPS) (Stec & Hull, 2011). All the above can be considered sage insulation options as far as toxicity is concerned. However, all the polymer-based options are extremely combustible and extremely toxic as and when they catch fire. The two tested polymer-based insulation materials were Polyurethane (PUR) and Polyisocyanurate (PIR). As reflected in the chart above, the two polymers are catastrophically toxic in a fire. Unfortunately, in most of the materials outlined above, the level of toxicity is inversely proportional to cost. The more toxic options are thus more in use than the less toxic ones due to cost implications.
Proposed Solutions
The solution to the toxic problem associated with insulation materials is to combine fire prevention and early alerts in the case of a fire incident. As indicated above, even with the best prevention mechanisms, it is statistically impossible to eliminate the possibility of a fire. For the sake of safety, it is important to have a comprehensive fire detection system in place. Among the fire detection mechanisms suggested by Nolan (2019) are human surveillance and mechanized smoke detector. Under human surveillance involves placing alarm system buttons around the building with instructions to press them upon the detection of a fire. Mechanized smoke detectors trigger similar alarms upon detection of any inordinate smoke. The other solution to insulator toxicity is fire prevention, which begins with a human component. Most fires result from human error or malignancy. Training can mitigate human error while proper security will prevent malignant people from causing fires. Finally, electing for less combustible and less toxic insulators would also mitigate damage caused by insulation toxins (Nolan, 2019).
It is evident from the totality of the above that the toxic output from insulators in the case of a fire is a substantive problem for the construction industry. On the one hand, insulators are necessary for essential weather controls in buildings. Further, effective insulators that are also safer in the case of a fire are quite costly, making cheaper options such as polymer-based insulators necessary. However, fumes from cheaper insulators cause as much as 80% of the fatalities in residential house fires. A quagmire thus ensures as the insulators meant to keep residents comfortable also places the lives of the same residents in dangers. It would be difficult to forgo all cheap insulation due to cost implications. Interim solutions for the problem thus include fire-prevention and early mitigation. The long-term solution can be continued research for the development of less toxic yet cheap insulators.
References
Al-Homoud, M. S. (2005). Performance characteristics and practical applications of common building thermal insulation materials. Building and environment , 40 (3), 353-366.
Stec, A. A., & Hull, T. R. (20 11). Assessment of the fire toxicity of building insulation materials. Energy and Buildings , 43 (2-3), 498-506.
Nolan, D. P. (2019). Handbook of fire and explosion protection engineering principles for oil, gas, chemical, and related facilities . Cambridge, MA: Gulf Professional Publishing is an imprint of Elsevier.
Konecki, M., & Gałaj, J. (2017). Flame transfer through the external walls insulation of the building during a fire. Procedia Engineering , 172 , 529-535.
