# Static Factors in Sitting Comfort: Seat Foam Properties, Temperature, and Contact Pressure
## 4 Conclusions  
In the absence of vibration, static comfort factors mainly influence passengers' perceived comfort. Static comfort is usually assessed using foam mechanical properties and interface pressure experiments. Additionally, the influence of temperature at the seat-passenger interface was also evaluated by employing an infrared thermographic assessment. This methodology revealed its suitability due to the high emissivity of fabric and leather covers. Map pressure allows for the analysis of the seat's influence on the user as a response to the applied body load distribution. In contrast, thermographic analysis permits measuring the opposite effect, i.e., what the passenger induces on the seat (increased temperature). In this way, these two methods can be considered complementary to the sitting comfort analysis. An analysis of the influence of users' anthropometric characteristics on interface pressure was performed. The results partially agree with those reported by [PERSON] et al. [35], as higher mean pressures and larger contact areas were obtained for heavier people. However, contrary to this author, higher peak pressures were also demonstrated for heavier  
Figure 13: Thermographic profiles of fabric cover seats, where (**a**) is comfort seat and (**b**) standard seat. individuals. Moreover, the pressure profile of the lighter subject and the heavier individual also show significant differences. While the former shows a longer pressure profile, the latter evidences a wider profile. The pressure in the ischial tuberosities area significantly influences the subjective results of discomfort. All pressure peaks were located in this area, which was rated as \"Slightly uncomfortable\" by all subjects. Thus, it is possible to conclude that the pressure profiles are directly related to discomfort levels. To assess the best foam and cover for railway seating applications, two foams with different densities and two covers made of different materials (leather and fabric) were analysed. The foams have the same properties as the current (lower density) and older (higher density) AP train seats. Older foams exhibited better pressure profiles (lower average and maximum pressures) and distributed the pressure more uniformly over the contact area. Combining these results with the assumption that lower pressure levels are associated with higher comfort levels, it is possible to conclude that the higher-density foams have a better static performance than the lower-density ones. This statement is also sustained by their mechanical characteristics, especially the high SAG factor and the low 25% ILD hardness. Both foams show similar results regarding hysteresis loss and energy-absorption capacity, so these are not considered differentiating factors. Moreover, by comparing comfort and standard seats, it was noticed that foam thickness does not influence pressure measurements, thus contradicting what has been reported by other authors. Finally, regarding the selection of a more appropriate cover, it was observed that the fabric cover promotes maximum, minimum, and average temperatures lower than the leather cover. Thus, this one is the most suitable for application in railway seats since lower interface temperatures promote higher comfort levels. Moreover, it should be highlighted that the experiments elapsed with real seat foams and not isolated foams as reported in most bibliographic research. Nevertheless, the reduced number of volunteers participating in the experiment represents its main limitation. Besides the need to expand the subject's sample size, it could be rather interesting to replicate the present study using children. This would allow us not only to determine the children's static comfort levels but also to determine a possible interface pressure pattern. Additionally, in the developed experiments, more properties could be assessed for the cover: breathability, moisture and water resistance, biodegradability, environmental impact, and even tear and pulling resistance.