As a supplement to the literature review around 50 case studies (app. ) of emergency responses were investigated in order to determine the materials and sheltering solutions that were implemented. Those are emergency cases that are relatively well documented and had an organised strategy of response. The case study investigation's aim was to withdraw the particular information concerning the dimensions, materials' choice and technical specifications of the shelters. During the investigation, it turned out that some materials are more likely to be used in an emergency response than others, regardless of the geolocation of the emergency. Among these, the plastic sheeting seems to be the most omnipresent material that is widespread dues to its low cost, versatility in use and durability.
Important facts that were discovered from the case studies:
- The first and responders to the emergency are always the affected people. Also, they are responsible for the major part of the construction works that take place. This leads to the notion that the sheltering solutions must low tech.
- Emergency shelters are often reused. Especially in the occurrence of disasters within the same country or region over a span of short time. This means that the shelters must be reusable.
- Above 90% of cases, the emergency shelters are designated for single-family use
- On average they have 17 sqm area
- Wooden frame+corrugated metal sheet structure is a common choice for a non-tensile rigid structure. This model might be used in the future as a comparison benchmark to assess the performance of newly suggested designs.
- The internal comfort issues are not properly addressed. In particular the thermal insulation layers exist rarely in the emergency shelters. Also by far no response was investigated that had a discussion about acoustical issues.
- Plastic sheeting is included in the majority(probably all) of emergency responses, however, its use is often limited to the imagination of the end user. Very few occasions are known where this material serves as a structural asset and performs sufficiently.
The last point is particularly interesting since the development for the possible new ways of the usage of plastic sheeting will bring new solutions to the industry without many spendings and might be retrofitted into existing camp structures as well.
Literature review conclusions
By analyzing the above-given research literature and investigations we can say that the studies of textile emergency shelters’ internal environment are very recent and progressively are entering into the realm of computer simulation and weather data-driven analysis. As we see in the examples of thermal assessment the computer models can be very well calibrated with the real shelters and give enough accurate results. However, the post-implementation data of comfort for such tents are limited and long-term evaluation of these objects are required to see whether the initial design anticipations do really match with the actual performance or not. On the other hand in recent years more and more tools are becoming available for researchers for comfort simulation. These tools continuously improve the accuracy and ease of use, thus giving an opportunity to the design developers not only to assess their concepts in terms of structural stability but also for internal comfort for practically any climatic zone. The weather data is increasingly accumulating in platforms such as ASHRAE and can serve for better decision making in the concept stage. As it is mentioned \citep{Obyn2014} it is better to solve these problems earlier rather than trying to solve it with the huge supply of wood and fuel. Evidently, the aspect of acoustical comfort, as opposed to the thermal comfort, was a matter of lesser concern so the knowledge and solutions here are much scarcer. Though the lack of acoustical comfort may not cause severe detriment to the occupants it may be a reason for a very poor life quality.
As we saw \cite{overview} the number of people that require sheltering is continuously increasing. The impact of this is truly global and requires immediate action. The solutions must become better and more sustainable. Ultra-lightweight structures potentially can contribute to transportability, easy deployment, thermo-acoustical comfort and many more performative benefits but until now the knowledge in this domain is very sparse. This research will be tailoring ultra-lightweight textile structure solutions to emergency sheltering problems to achieve a better outcome in facing the housing problem.
Specifically, by far we can’t see any research that tries to deal with the problems of thermal and acoustical comfort simultaneously. Developing an enclosure concept that takes into consideration both aspects may be beneficial.
On the other hand, until now the design processes were mainly human creativity driven and few optimization techniques may have been applied. By using nowadays available computation power we can evaluate hundreds of solutions in a row and determine the best possible properties in given constraints.
The research will aim to develop a solution of an emergency membrane shelter that will be optimized both in terms of thermal and acoustical comfort with a high degree of localization.
Research questions
The research will try to answer the following questions:
- What are the characteristics of the membrane structures used in emergency sheltering?
- Can these characteristics be enhanced? How?
- What are the potential composites/design solutions to be used?
The objective of this research is to deepen the knowledge in the field of temporary emergency tensile structures and brings solutions with better internal comfort while retaining their inherent features such as low cost, reversibility, low tech assembly. More specifically this research will focus on the potential use of plastic sheeting supplied for an emergency. The research will study:
- lightweight materials properties, related to heat transfer (conductivity, emissivity, optical and solar properties), acoustic transmission and absorption (sound insulation, sound absorption, reflection coefficients and scattering), mechanical behaviour (elasticity, resistance) and geometrical/chromatic issues (thicknesses, shapes, sizes, degrees of transparency);
- lightweight reversible structures, which can host effectively lightweight materials;
- modular structures design of different constructive typologies, which can result in energy-efficient and comfortable temporary constructions;
- Mounting and dismounting procedures, which have to assure performances and reusability.
Case Studies
Case study investigation is an ongoing process and the results will be continuously added to the research materials.
The upcoming studies to be analysed are more recent emergency reports that have more specific details. In particular the focus will be given to internal comfort issues.
If enough data will be collected a statistical analysis may be also performed to determine any trends in shelter design.