Studying thermal characteristics of seating materials by recording temperature from 3 positions at the seat-subject interface.

Aim of the study - To determine whether 3 fixed positions of seat-subject interface temperature measurement offer more information than a single point of measurement. Materials and methods Temperature data was simultaneously acquired (sampling frequency 1Hz/sensor) from each of three sensor positions (right and left mid-thigh and coccyx), from the subject-seat interface. The data was acquired whilst subjects (6 males, 5 females: 21-40 yrs: BMI 19.3-26.4) sat for 20min on each of three types of seat material (foam, gel mould and solid wood). Data collection was performed at the same time of day for each subject: ambient temperature between 21.1 and 21.2°C, ambient relative humidity 50.9%. Results Analysis of data from the sensors, post mathematical smoothing, for each subject (n=11; ANOVA, followed by post-hoc t-tests) revealed each of the measurement positions to have a significantly different recorded temperature (pandlt;0.01). However, profile of temperature change at the same measurement position using the same seating material during the 20min sitting period, was highly correlated (randgt;0.99) between subjects, a consistent finding across all 11 subjects regardless of seat material selected. Conclusion Use of 3 positions of measurement (3 sensors) appears necessary when performing detailed studies of temperature change at the seat-subject interface. The high level of comparability of results between subjects supports potential of this method to resolve quantitative components of qualitative measurements, e.g., thermal comfort