Citation

Hanel SE, Dartman T, Shishoo R. Int. J. Ind. Ergonomics 1997; 20(2): 163-172.

Copyright

(Copyright © 1997, Elsevier Publishing)

DOI

unavailable

PMID

unavailable

Abstract

The hardness of a seat or a bed, more commonly expressed as its softness, is an important factor in reducing or preventing the pain or discomfort. A user-relevant rating system for this factor is very important. At IFP a new test method including a modular set of indentation devices has been developed, which provides more information about the mechanical and thermal comfort properties of the seat, bed or upholstery system well correlating to the subjective assessment of total comfort. The indentors are equipped with pressure or heat-flow sensors along the surface to determine the magnitude and distribution of the contact pressure at the indentor/support interface or the heat flow into the upholstery.Comparison of 5 different beds and 6 mattresses has been carried out using the IFP method for mechanical testing and a draft CEN-standard proposing firmness rating. The results show that the CEN rating tends to group together most combinations even if they show a distinct difference in hardness when tested according to the IFP method.IFP's heated device has been used to test heated car seats, giving significant results concerning the placement of the heating element but also of the various layers in the seat. Experimental work has started with a third set of indentor for testing the moisture transport properties in different layers of upholstery at various degrees of compression. It has been shown that below a certain degree of compression, heat or moisture is mainly transported in the surface layer.