Spatial Distribution of Thermal Environment Parameters and its Impact on Passengers’ Comfort in 14 Boeing 737 Aircraft Cabins

Abstract

Passengers’ comfort in air craft cabin is related to many factors. Besides the level of thermal environment parameters, its spatial distribution in aircraft cabin and the place where passengers sit should also matters. In this investigation, a total of 14 Boeing 737 aircrafts including 7 airlines were measured. Each airline had two aircrafts, starting from Qingdao and returning right away after landing. Large-scale subjective questionnaire investigation regarding passengers’ comfort was conducted on each flight. As a result, 979 questionnaires were collected. Thermal environment parameters’ measurement contained air temperature and relative humidity, wall temperature, radiant temperature, air velocity, noise, illumination, and absolute pressure. The questionnaires collected basic information of passengers (age, height, weight, and clothes level) and their evaluation of the environment (thermal comfort, perceived air quality, and symptoms). The main purpose of this study is to investigate the spatial distribution of thermal environment parameters and find its relationship with passengers’ comfort. Thus, different parts in aircraft cabin including both horizontal (front, middle, and back) and vertical (head, knee, and feet) were measured. The passengers’ evaluation was also divided according to the place they sat (front, middle and back, window, middle and aisle). The results showed that the uniformity of air pressure and noise in aircraft cabin was quite good. Air velocity was under 0.2 m/s which was imperceptible for passengers. Air temperature was between 24 and 29 °C in all flight, and the deviation in each flight was below 3 °C. The average relative humidity was from 20 to 30 %, and the lowest was between 5 and 20 %. The difference between air temperature and black globe temperature was less than 1.4 °C. Spatial distribution of air temperature, black globe temperature, and relative humidity was relatively small (<3 °C, <10 %) on different cross-sections, while on the same cross-section, difference was smaller (<1 °C, <2 %). For vertical direction, temperature at the head was higher than the feet but within 2 °C. Wall temperature changed greatly during the flight especially the floor, usually 1–7 °C lower when taking off. Floor temperature near the window seat was generally lower than middle and aisle seat. Passenger was satisfied with cabin environment. Overall evaluation of environment showed no difference among passengers at front, middle, and back. However, passengers at window seat and middle seat showed more comfortable than those at aisle seat.